Lives of Boulton and Watt by Samuel Smiles: Chapter 15
CHAPTER XV. WATT AGAIN VISITS CORNWALL - INVENTION OF THE ROTARY MOTION - THE PATENT RIGHT AGAIN ASSAILED.
Watt’s presence being much wanted in Cornwall, he again proceeded thither, accompanied by his wife and family, and arrived at Cosgarne towards the end of June, 1781. He found that many things had gone wrong for want of the master's eye, and it was some time before he succeeded in putting affairs in order. The men had been neglecting their work, "going a-drinking." Cartwright had "contracted a fever in his working arm, and been swallowing ale for a cure" until he heard Watt had come, when the fever left him. Mrs. Watt also found occasion to complain of sundry little grievances, and favoured Boulton with a long catalogue of them. Gregory and Jessy had caught cold on the journey, and workmen were hammering about the house making repairs. There was, however, one gleam of brightness in her letter: "James’s spirits were surprisingly mended since his arrival."
Watt was a most voluminous correspondent. He wrote Boulton several times a week great folio sheets, written close, in small hand. The letters must have occupied much of his time to write, and of Boulton's to read. The latter, seeing his partner's tendency to indulge in "worrit" about petty troubles, advised him in a kindly spirit not to vex himself so much about such matters, but to call philosophy to his aid. Why should he not occupy some of his spare time in writing out a history of all his steam-engine contrivances, to be dedicated to Joseph Banks, and published in the "Transactions of the Royal Society? " But Watt Was extremely averse to writing anything for publication, and the suggestion was not acted on. Then, knowing Watt's greatest pleasure to be in inventing, Boulton in a subsequent letter advised him to take up afresh, and complete a plan which they had often discussed, of producing rotary motion, by which the engine might he applied to work mills and drive machinery.
Watt had from the first regarded the employment of the steam-engine in producing continuous rotary motion as one of its most useful applications, and with this object he invented his original wheel-engine. No steps were taken to introduce the invention to practical use; but it occurred to Watt that the same object might be better effected by employing the ordinary engine for the purpose, with certain modifications.  The subject had partially occupied his attention during his first visit to Cornwall; for we find him writing Boulton from Chacewater, in 1779, "As to the circular motion, I will apply it as soon as I can, but foresee that I shall be very busy shortly, and much out of doors." On his subsequent return to Birmingham, after frequent conferences with his partner on the subject, he proceeded to prepare a model, in which he made use of a crank connected with the working beam of the engine to produce the rotary motion. There was no originality in the employment of the crank, which was an expedient that Watt had long before made use of.  The crank was, indeed, one of the most common of mechanical appliances. It was in daily use in every spinning-wheel, in every grindstone turned by hand, in every turner's and knife-grinder's foot-lathe, and in every potter's wheel. It was one of the commonest, as it must have been one of the oldest, of mechanical expedients. "The true inventor of the crank rotative motion," said Watt, "was the man who first contrived the common foot-lathe: applying it to the engine was like taking a knife to cut cheese which had been made to cut bread."
Though Watt had become very reserved, especially to strangers, about his inventions, he could not altogether keep from the knowledge of his workmen the contrivances on which his thoughts were occupied. He was under the necessity of employing them to make patterns after his drawings, from which any ingenious man might readily apprehend what he was aiming at. The Soho workmen were naturally curious about the new inventions and adaptations which Watt was constantly producing, and these usually formed the subject of conversation at their by-hours. While the model of the crank engine was under construction at Soho in the summer of 1780, a number of the workmen met one Saturday evening, according to custom, to drink together at the "Waggon and Horses," a little old-fashioned low-roofed, roadside public-house, still standing in the village of Handsworth. The men were seated round the little kitchen-parlour, talking about their work, and boasting, as men will do over their beer, of the new and wonderful things which they were carrying forward in the shops. Dick Cartwright, the pattern maker, was one of the loudest of the party. He was occupied upon a model for the purpose of producing rotary motion, which he declared would prove one of the best thing's Mr. Watt had ever brought out. The other men were curious to know all about it and to illustrate the action of the machine, Cartwright proceeded to make a rude sketch of the crank upon the wooden table with a bit of chalk. A person who sat in the kitchen corner in the assumed garb of a workman, drank in greedily all that the men had been saying; for there were many eavesdroppers constantly hanging about Soho, some for the purpose of picking up surreptitious information, and others to decoy away skilled workmen who were in the secrets of the manufacture. Watt himself had never thought of taking out a patent for the crank, not believing it to be patentable; but the stranger aforesaid had no such hesitation, and it is said he posted straight to London and anticipated Watt by securing a protection for the contrivance. 
Watt was exceedingly wroth when he discovered the trick which had been played him, and he suspected that Matthew Washborough was at the bottom of it. Washborough was a Bristol mechanic, who carried on several branches of mechanical trade, amongst others that of clock-making on a large scale. Watt had employed Washborough to make nozzles for several of the Cornish engines, but was not satisfied with his work for we find him writing to his partner, "If Washborough makes no better engines than he does eduction-pipes, he will soon be blown: the Wheal Union pipe is the worst job you ever saw, being worse than Forbes's, which was very bad; I scarce know what to do with it." It would appear from this that Washborough had begun to make engines, thereby turning to account the knowledge he had acquired in Cornwall. One of the first he made was for the purpose of driving the lathes of his own manufactory at Bristol; and it affords a clear proof of Washborough's ingenuity that in this engine he employed both the fly-wheel and the crank. He has been styled the inventor of the fly-wheel, but he was no more its inventor than he was of the crank; the Irish Professor Fitzgerald having proposed to employ it as part of a Papin's engine as early as the year 1757. Washborough shortly after erected an engine after the same plan for a manufacturer on Snow Hill, Birmingham; and then it was that Watt learned that he had been "bolted out" as he termed it, from making use of the crank.
At first he was puzzled what to do to overcome the difficulty, but his prolific mind was rarely at a loss, and before many months were over he had contrived several other methods for effecting rotary motion. "I dare not, however," he wrote to Boulton, "make my new scheme, lest we be betrayed again; I believe we had best take the patent first." At the same time Watt was persuaded that no contrivance could surpass the crank  for directness, simplicity, and efficiency. He was therefore desirous, if possible, of making use of it in his rotative engine, as originally proposed and he wrote to Boulton, then at Redruth, "I think you ought to call upon Washborough as you return, and let him know that we will dispute his having an exclusive right to those cranks."  Boulton called upon Washborough accordingly, and gave him notice to this effect. But Watt hesitated to use the crank after all. Although the contrivance was by no means new, its application to the steam-engine was new; and, notwithstanding the unfair way in which Pickard had anticipated him, Watt did not like to set the example of assailing a patent, however disputable, as it might furnish a handle to those who were at the time seeking to attack his own. The proposal was made to him that he should allow the Washborough Company to use his steam-engine in exchange for their allowing him to use the crank; but this he positively refused to agree to, as be felt confident in yet being able to produce a circular motion without employing the crank at all.
Thus matters stood until the beginning of the year 1781, when Washborough, having entered into an arrangement with the Commissioners of the Navy to erect an engine for grinding flour at the Deptford Victualling Yard,  a formal application was made to Boulton and Watt to apply their engine for the purpose. Watt protested that he could not bring himself to submit to such an indignity. If the Commissioners thought proper to employ him to erect the necessary engine, rotative motion, and machinery, be would exert every faculty which God had given him in doing so, but he "would never consent to hold the candle to Washborough."
"Had I esteemed him," he wrote to Boulton, "a man of ingenuity and the real inventor of the thing in question, I should not have made any objection; but, when I know that the contrivance is my own, and has been stolen from me by the most infamous means, and, to add to the provocation, a patent been surreptitiously obtained for it, I think it would be descending below the character of a man to be found in any way aiding or assisting him in his pretended invention. . . . I think, therefore, that you should propose to the Honourable Board to undertake the direction of the whole; and, provided you can agree with them about the customary premium for the savings by our engine, you should do the whirligig part [the rotative motion] for love. If this proposal should not be accepted, I beg of you to decline having any concern with it, and leave the field clear to Washborough. We may perhaps gain more by so doing than we can lose, as I assure you I have a very mean opinion of the mechanical abilities of our opponents. They have committed many gross errors in such of their works as I have had occasion to know about, and we may, get honour by rectifying their mistakes. Perhaps this may seem to you to savour of vanity. If it does, excuse it on account of the very provoking circumstances which have extorted the confession. If these engineers had let us alone, I should not have meddled with them; but, as it is, I think we should be wanting in common prudence if we suffered a marriage between our machine and theirs, and if we did not do all we could to strip them of their borrowed feathers, which I hope there is justice enough left in England to enable us to do." 
Boulton acted on his partner's advice, and declined the proposed connexion. The Navy Board were placed in a dilemma by this decision. They then referred the matter to Mr. Smeaton, and requested him to report to them as to the most suitable plan of a flour-mill, and the steam-engine best calculated to drive it. To the great surprise of Watt as well as Washborough, Smeaton reported that both their engines were alike unsuited for such a purpose. "I apprehend," he said, "that no motion communicated from the reciprocating lever of a fire-engine can ever produce a perfect circular motion, like the regular efflux of water in turning a water-wheel!" This report relieved the Commissioners. They abandoned their scheme, and the order for Washborough's engine was at once countermanded. 
So soon as Watt had got fairly settled at Cosgarne, in the summer of 1781, he proceeded to work out the plan of a rotary-working engine. Boulton was making experiments with the same object at Soho, communicating to him the results from day to day. He was stimulated to prosecute the inquiry by the applications which he received from many quarters for steam-engines suitable for driving mills. He therefore urged Watt to complete the invention, and to prepare the drawings and specification, declaring his readiness at any time to provide the money requisite for taking out a patent. "The people in London, Manchester, and Birmingham," said he, "are steam-mill mad. I don't mean to hurry you, but I think that in the course of a month or two we should determine to take out a patent for certain methods of producing rotative motion from the vibrating or reciprocating motion of the fire-engine, — remembering that we have four months in which to describe the particulars of the invention." 
Watt proceeded to put his ideas in a definite shape as fast as his bad health and low spirits would allow. Every now and then a fit of despair came upon him about his liability to the bankers, and so long as it lasted he was unmanned, and could do nothing. At the very time that Boulton was writing the letter last quoted, Watt was thus bewailing his unhappy lot:—
"When I executed the mortgage," said he, "my sensations were such as were not to be envied by any man who goes to death in a just cause; nor has time lessened the acuteness of my feelings. . . I thought I was resigning in one hour the fruits of the labour of my whole life, - and that if any accident befell you or me, I should have left a wife and children destitute of the means of subsistence, by throwing away the only jewel Fortune had presented me with. .. . These transactions have been such a burden upon my mind that I have become in a manner indifferent to all other things, and can take pleasure in nothing until my mind is relieved from them; and perhaps, from so long a disuse of entertaining pleasing ideas, never may be capable of receiving them any more." 
Boulton made haste to console his partner, and promised to take immediate steps to relieve his mind of the anxiety that weighed so heavy upon it and he was as good as his word. At the same time he told Watt that he must not suppose he was the only man in the world who had cares and troubles to endure. Boulton himself had, perhaps, more than his share, but he tried to bear them as lightly as he could. With his heavy business engagements to meet, his large concerns to keep going, he was not a man much to be envied yet he continued to receive his visitors as usual at Soho, and to put on a cheerful countenance. "I am obliged," he wrote, "to smile, to laugh, to be good-humoured, sometimes to be merry, and even go to the play! Oh, that I were at the Land's End!" Such was his playful way of reminding Watt of the necessity of cheerfulness to enable one to get through work pleasantly.  But Watt's temperament was wholly different. His philosophy never rose to the height of taking things easy. He could not cast his cares behind him, nor lose sight of them; but carried them about with him by day, and took them to bed with him at night; thus making life a sort of prolonged vexation — a daily and nightly misery.
But a new and still more alarming source of anxiety occurred to disturb the mind of poor Watt, and occasion him many more sleepless nights. The movement to abolish the patent by repeal of the Act of Parliament having broken down, attempts were now made in many quarters to evade it by ingenious imitations, in which the principle of Watt's engine was adopted in variously disguised forms. But to do this successfully would have required an inventive faculty almost as potent as that of Watt himself; and he had drawn the specification of his patent too carefully to be easily broken through by the clumsy imitators who made the attempt. It was, however, only natural that the success of the new engine should draw the attention of ingenious mechanics to the same subject. Watt had drawn a great prize, and why should not they? though they little knew the burden of sorrow which his prize had brought upon him. They only knew of the large annual dues — probably exaggerated by the tongue of rumour — which were being paid to the patentees for the use of their engines; and they not unnaturally sought to share in the good fortune. There might possibly be other mechanical methods by which the same objects were to be accomplished, without borrowing from Watt; at all events it was worth trying. Hence the number of mechanical schemers who made their appearance almost simultaneously in all parts of the country, and the number of new methods of various kinds contrived by them for the production of motive power.
Watt was very soon informed of the schemes which were on foot in his immediate neighbourhood - much too soon for his peace of mind. He at once wrote to his partner: "Some Camborne gentlemen (supposed to be Bonze and Trevithick) have invented a new engine which they say beats ours two-thirds, and one of the partners has gone to London to procure a patent for it. A. Mr. Vice says he has also invented a new engine, and that they have stolen his and compounded it with ours; he intends to take out a caveat against them."  Though Bonze was an excellent engineer, and elicited the admiration of Watt himself, it turned out that he had no concern with the new invention. Its projectors proved to be the Hornblowers, also engineers of considerable local repute. Watt had befriended the family, and employed them in erecting his engines, by which means they became perfectly familiar with their construction and mode of action. Jonathan Hornblower had a large family of sons, of whom Jabez, Jesse, Jethro, and Jonathan were engineers, like their father. Jabez, one of the cleverest, had spent some time in Holland, from whence he had returned with some grand scheme in his head for carrying out an extensive system of drainage in that country. Like his father and the other sons, he was employed in erecting Watt's engines,  which had the effect of directing his attention to the invention of a new power which should supersede that of his employer.
It was for some time doubtful what was the precise character of the new engine. Indeed the Hornblowers themselves long remained undecided about its actual form, being still in the throes of invention. They knew that they must copy discreetly, so as not to lay themselves too open to attack; and though they urged the superiority of their engine so strongly as to induce several of the mining companies to believe in them, and even to withhold orders from Boulton and Watt, they refrained as yet from publishing their invention. Watt wrote to his partner that he understood the Hornblowers' engine was on some new principle, and the only novelty he could think of was a caloric air-engine. He therefore asked Boulton to make all the inquiries he could as to the respective bulks and prices per 1,000 feet of all possible kinds of air in their most expanded states. "I am much vexed," he continued, "by this affair. Jabez does not want abilities: the rest are fools. If they have really found a prize, it will ruin us. . . .Bankruptcy might ensue to both. But I don't fear getting my bread independent of engines, though much easier with them."  Watt was, however, in error as to the nature of the Hornblowers' engine, which he discovered three days later, when he wrote Boulton,—
"The matter is this: Ever since the ungrateful, idle, insolent Hornblowers knew anything about our engines, they have laboured to evade our Act, and for that purpose have long been possessed of a copy of our specification. They made an attempt at Wheal Maid two years ago, by connecting two cylinders together and injecting into one of them, which did not succeed, although they had gathered together numbers of their friends in order to make a great exhibition. Since that, Jonathan the coppersmith, who, like Alexander of the like trade, hath done me much evil, has laboured close at some more successful evasion, which he says he has now completed and taken a patent for, concerning which I hear as follows from public reports, propagated by Jethro's confidants — 1st. That Jonathan Hornblower is the inventor and patentee; that Winwood, Jones and Company, of Bristol, are his partners and supporters with money (that Winwood was lately in this country on a sleeveless errand is certain); that they have made their model work to 14 lbs. on the inch, and expect it will work to 18 lbs. 2ndly. That they press the piston down by steam, and maintain they have a right to do so, because, say they, it can be proved that such was done before my patent. I suppose by this they allude to Gainsborough's bauble, which, by-the-by, was after the patent. If they do not mean this I am at a loss, as I now declare that I do not know of any one having done it before the patent except myself. However, it behoves us to inquire into this, and if the exhibition was not a public one it avails not. 3rdly. That they pretend to condense the steam in the cylinder; but I have heard that they do it in a separate vessel within the cylinder, or close to it. 4thly. That they do not use an air or water pump, from which I conjecture that they let the hot water down the shaft by a pipe more than 30 feet long, as you know I proposed but had several objections to. You will remember, and I dare say Joseph and Peploe also do, that we made the 18-inch Soho cylinder work by blowing the hot water out of the eduction-pipe and used no air-pump, but found a waste of steam by so doing. There is also some confused report about a wheel being employed on their engine, which makes one suspect that M. Washborough may be the Bristol man concerned with them." 
Two days later Watt wrote, — "My principal hope is that almighty Nature will prove Lord Chancellor, and put a negative on their scheme. Amen, so be it! I abhor lawsuits, and reckon a cause half lost that is litigated."
On the 23rd of July he returned to the subject:—
"The Horners," said he, "continue bragging of what they are to do, and I hear the country in general takes part with them, as even the aversion they have to the Homers does not equal the pleasure they would feel at our undoing. . . . . The Horners say they can make a common engine equal to ours, but that their new engine is one-third better. We must now attend too making use of all the elastic power of the steam, which, unless I am much deceived, will save one-half over our best engines, and at any rate it may easily be applied to work the condenser, which will save about one-eighth. I will not conceal from you that I am rendered very unhappy by one thing and another, but fight with it all I can."
In the mean time Boulton continued to urge Watt, to complete the specification and drawings of his rotary engine, informing him of the success of the model which he had now completed at Soho:—
"Though you studied a thousand years," said he, "I do not think you could make one ten. per cent. better than a small model with two cones which Joseph has executed after my drawings. It has little friction, goes sweeter than anything of the kind you have yet touched, and has not the least shake. It is so perfect that I don't consider it worth while even to think of any other for horizontal motions. I am therefore positively decided in my mind as to the necessity of taking out a patent and including in it all the principles and constructions you please; for if it be not secured soon we may lose it." 
In the same letter; Boulton communicated to Watt the rumours that had reached him from Scotland of more inventions of engines that were to beat Watt's out of the field. "The cry is still, they come!" said he. "Hatley from Scotland is going with Lord Dunmore to Virginny; says that he and somebody else in Scotland have invented an engine that is three times better than yours."
Boulton recommended that a search should be made at the Patent-Office, to ascertain what was going on in new engine patents. Watt entirely approved of this, and urged that the search should be made at once. "I do not think we are safe a day to an end," he wrote, "in this enterprising age. One's thoughts seem to be stolen before one speaks them. It looks as if Nature had taken an aversion to monopolies, and put the same thing into several people's heads at once to prevent them; and I begin to fear that she has given over inspiring me, as it is with the utmost difficulty that I cam hatch anything new."
Notwithstanding this confession on the part of Watt, his inventive faculties were really never at any period of his life more vigorous than now; for he was rapidly maturing his rotative engine, with its various ingenious methods for securing circular motion and working out the details of the double-cylinder expansion engine, with its many admirable contrivances hereafter to be described. Boulton continued to receive applications at Soho, from various quarters, for engines capable of working flour-mills and other machinery, and Watt himself was urged by like inquiries from manufacturers in Cornwall. "Mr. Edwards," he wrote Boulton, "waits impatiently the success of our rotative machine. He wants a power able to lift a hammer of 700 lbs., 2 feet high, 120 times per minute. In relation to the circular engine, an experiment should be made on a large scale, and to work a hammer. I want your ideas on that head."  A fortnight later, Watt had matured his own ideas, and made the necessary declaration of his invention before a magistrate, preliminary to making the usual application for a patent. 
Watt was exceedingly busy about this time in superintending the erection of new engines. No fewer than twelve were in progress in different parts of the county. As he travelled about from one mine to another on horseback, and spent a good deal of his time in the open air, his mind was diverted from preying upon itself according to his ordinary habit, and his health and spirits improved accordingly. Boulton was equally busy at Soho, where he was erecting a powerful engine for blowing the furnaces at Walker's ironworks at Rotherham, and another for Wilkinson's forges at Bradley, in which he proposed to employ a double cylinder, with a double crank  and a pair of fly-wheels. At intervals he went into Yorkshire, Lancashire, and Shropshire, to look after various other engines in progress; writing Watt cheerful letters as to the improving prospects of the firm. He found the steam-engine everywhere gaining in public estimation. "The more it is known," he wrote, "the more it will be in demand. As to the scheme of the Hornblowers, they shall sooner press me down into the earth than they shall press down a piston with steam." And again, "Give yourself no uneasiness about the Homers' engine. Our title to the invention is as clear as can be and it is as well secured as an Act of Parliament can make it-
"Doubt that the sun is fire,
Doubt all the powers of sight,
Doubt truth to be a lyer,
But never doubt our right."
Watt's first surmise, that the Hornblowers intended to work their engine by heated air or gas, had set Boulton upon a series of inquiries and experiments on the subject, in which he was assisted by Dr. Priestley, who had shortly before settled in Birmingham, and was a willing co-operator in all investigations of this nature. Their object was to ascertain whether it was practicable to produce mechanical power by the absorption and condensation of gas on the one hand, and by its disengagement and expansion on the other.
What you propose," Watt wrote, "is exceeding probable, and akin to what I have long contemplated — the use of mixed air and steam, which have a wonderful expansion and contraction. Nevertheless, I fear that there is in all such cases a proportional assumption of latent heat; but be it tried though it be beginning a new series of vexations and expense. . . . I suspect that a forcible compression would hinder the gas from separating from the water, and on the contrary any tolerable degree of vacuum would hinder the water from attracting it; but perhaps part of both may be used. . . . My greatest hope is in the expansive engine with double or single cylinder, which I consider as proved by many facts, and shall send you my ideas of the execution of it very soon. At the same time I am clear to take the air patent, which, as I have worded the petition, may include some other improvements on the steam-engine. . . .I hope my last letters have relieved you, as the knowledge of the Horners' being a steam-engine working on our principle relieved me. I have some trust in the judges, though I have little in the law; and I think impartial people will regard us as injured persons, and not suffer the thief of our horse to escape because he has painted him of another colour." 
Watt's fears for his patent were about this time excited anew by the great Arkwright trial, in which Arkwright was nonsuited, and compelled to forego the rights derived from his improvements and combinations of spinning-machinery. The principal ground on which the patent was set aside was that the specification was unintelligible. On this, Watt observed,—
"Though I do not love Arkwright, I don't like the precedent of setting aside patents through default of specification. I fear for our own. The specification is not perfect according to the rules lately laid down by the judges. Nevertheless, it cannot be said that we have hid our candle under a bushel. We have taught all men to erect our engines, and are likely to suffer for our pains. . . . I begin to have little faith in patents; for, according to the enterprising genius of the present age, no man can have a profitable patent but it will be pecked at, and no man can write a specification of a fire-engine that cannot be evaded, if the words and not the true intent and meaning be attended to. As kissing goes by favour, and as, in dubious cases, men are actuated by their prejudices, so, where a blue is very like a green they may decide either way." 
Watt continued to be alarmed by the rumours of the forthcoming Hornblowers' engine. "I have heard," he wrote, "that a female confidant of Jonathan's has seen the engine, and says that they evaporate half a hogshead Of water with one ounce of coals! . . . . . that in a few days they are to publish in print what their invention is, illustrated with a copper-plate. Then we shall see and admire, if God pleaseth; I hope we shall not believe and tremble." Later he wrote, - "Our cause is good, and yet it has a bad aspect. We are called monopolists, and exactors of money from the people for nothing. Would to God the money and price of the time the engine has cost us were in our pockets again, and the devil might then have the draining of their mines in place of me. Yet all are not alike. Some are just, and I believe do not grudge us, and some are friendly. All this is to no purpose. The law must decide whether we have property in this affair or not, and we must submit to what we cannot help." 
At length Watt learnt the precise nature of the Hornblowers' invention. "It is no less," he wrote Boulton, "than our double-cylinder engine, worked upon our principle of expansion." This was an old idea of Watt's, which he had pursued while labouring upon his model at Kinneil. "It is fourteen years," he said, "since I thought of the double-cylinder engine, and I think that I mentioned it to Mr. Smeaton, when I explained the expansion engine to him in your parlour, some years ago. Wm. Murdock and Mr. Henderson can testify to my having mentioned it to them; but this of the Homers seems to be a different thing, being hung on the same beam."  As early as May, 1769, he had communicated to Dr. Small a clear and explicit description of his method of working steam expansively and he adopted the principle in the Soho engine, in 1778, as well as in the Shadwell engine erected in the same year. He was, however, prevented carrying it out extensively in practice by the inexpertness of the workmen. "Though the effect of the steam," he explained to a correspondent, "is thereby increased 50 per cent. (by theory 100 per cent.), it cannot be done without rendering the machine more complicated than we wish; and simplicity is a most essential point in mechanics. There are other contrivances known to us which would increase the effect in an inferior degree, say from one-fourth to one-sixth, but they are all attended with peculiar inconveniences which forbid their use until the illiterate and obstinate people who are intrusted with the care of the engines become more intelligent and better acquainted with the machine." 
Though suffering much from his usual headaches which frequently disabled him from thinking, Watt finished the drawings of the rotary engine in a week, and forwarded them to Boulton at Soho. "I believe" he said in a later letter "a well regulated expansive-engine is the ‘ne plus ultra’ of our art". But he intimated that a new trouble had come upon him in the shape of another inventor of a steam-engine in which all the distinctive principles of his own invention were embodied. "If he be engine mad," said Watt, "and if it agreeable to you, he shall have my share of them, provided he will come to my price. I wish to retire, and eat my cake in peace, but will not go without the cake. All mankind seem to have resolved to rob us. Right or wrong, they will pluck the meal from our mouths."  Boulton, on his next journey to London, called upon the alleged inventor, a Mr. Ewer, and declared to Watt that the invention, so far as it was new, -was not worth a farthing, and that all that was good in it was borrowed from their engine. Though the white marks on your cow or your horse," said be, "may be changed to black, the cow and horse are not the less your property." He therefore counselled Watt to relieve himself of all anxiety on this account. Watt replied, "Ewer seems to have a genius more capable of inventing than of prudently examining the merits of his invention. Poets lose half the praise they would otherwise get did they but tell us what they discreetly blot. We must publish a book of blots."
Meanwhile Watt went on inventing, even while he was complaining of his inability to invent, and of the uselessness of inventing. Invention had grown into a habit with him, which he could not restrain. In the very letter in which he wrote "It is of no use inventing — everybody is seizing upon our schemes," he communicated to Boulton that he had contrived a machine, then erecting at Dalcoath, for the purpose of stopping the engine when at full speed, when any accident happened to the rods or outside chains, — first taking away the power, and then holding the bob fast whenever it might be at the turn.  A few days later he communicated that he had contrived a new way of opening the regulators. He was also finishing his plan of the new equalising beam, and the double expansion engine, which he requested might be proceeded with at once. "I have shown the equalising beam," said he, "to no person whatever. Please push it on. It is our ‘dernier ressort’, and may perhaps be all that villany will leave us, and that not long."  Boulton wrote back, bidding his partner to be of good heart. "If our spirits don't fail us," said he, "I think our engine won't."
At the same time Watt was inventing his new jointed top-working gear, which he reported answered exceedingly well with the Dalcoath engine and, in pursuance of an idea thrown out by Boulton, he perfected the model of a horizontal-axled elliptical with one pulley, which he described as performing ‘a merveille’, being free from all untoward frictions. He was also busy inventing a new method of an equalising beam, by causing the gudgeon to change its place; and another by means of a roller acting upon a curve in the nature of the working gear. Besides his experiments in mechanics, he was prosecuting investigations as to the properties of nutgalls in combination with various chemical substances, for the purpose of obtaining the best kind of ink for use with his copying machines; and at another time we find him contriving various iron cements for joints, confessing that he had "lost all faith in putty;" the result of which was his discovery of the well-known metallic cement.
In the correspondence between the partners on these various topics, we seem to see the ideas out of which so many inventions grew, in their various stages of birth, growth and development. They concealed nothing from each other, but wrote with the most perfect unreserve. Each improved on the other's ideas, — Watt upon Boulton's, and Boulton upon Watt's both experimenting on the same subject at the same time, and communicating the results in the most elaborate detail. The phrase often occurs in their letters: "I write thus fully that you may see exactly what is passing in my mind." The letters were sometimes of extraordinary length, one of Boulton's (dated 25th September, 1781) extending to eight pages folio, closely written, containing upwards of 4,000 words. Scarcely a day passed without their spending several hours in writing to each other. Boulton also kept up a correspondence with Mrs. Watt, in addition to his elaborate letters to her husband. The lady entered into various matters of personal interest, describing her occupations and domestic pursuits, and communicating the state of her husband's health, which was a matter of no less interest to Boulton than to herself.
As the autumn set in with its fogs and rains, Watt's headaches returned with increased severity, and be repeatedly complained to Boulton of being "stupid and ill, and scarcely able to think." "I tremble," said he, "at the thought of making a complete set of drawings. I wish you could find me out a draughtsman of abilities as I cannot stand it much longer."  Watt's temper was also affected by the state of his health; and he confessed that he felt himself not at all cut out for the work he had to do, so far as related to business: "I am not philosopher enough," he said, "to despise the ills of life and when I suffer myself to get into a passion, I observe it hurts me more than it does anybody else. I never was cut out for business, and wish nothing so much as not to he obliged to do any; which perhaps will never fall to my lot; therefore I must drag on a miserable existence the best way can." 
Watt was very busy at this time in preparing the specification and drawings of the circular motion, which he said he found an extremely difficult job owing to the distracted state of his head. The letters patent for the invention had been secured on the 25th October, 1781, and he had four months allowed him in which to prepare and lodge the full description. He laboured at his work late and early, his mind being for months is in the throes of invention. In the beginning of November we find him writing to Boulton, sending him the "first three yards of the specification," written out on folio sheets joined together. Watt's letters to his partner at this time contain numerous rough sketches of his proposed methods for securing circular motion without using the crank, from which he conceived himself to be in a measure precluded by Pickard's patent. He devised no fewer than five distinct methods by which this object might be accomplished, by means of wheels of various sorts rotating round an axis. The method eventually preferred was the one invented by Wm. Murdock, and commonly known as the sun and planet motion.  "It has the singular property," said Watt, "of going twice round for each stroke of the engine, and may be made to go oftener round if required without additional machinery.
Rough sketches of these various methods were forwarded to Soho in order that the requisite careful drawings of them might be prepared in time to be lodged with the specification but when they reached Watt in Cornwall, he declared them to be so clumsily executed that be could not for very shame send them in; and though greatly pressed by mining business, and suffering from "backache, headache, and lowness of spirits," he set to work to copy them with his own hands. He worked up his spare time so diligently, that in ten days he had the plans finished and returned to Boulton, whom he wrote saying that he had improved the construction of several of the machines, and "got one copy of the specification drawing finished in an elegant manner upon vellum, being the neatest drawing he had ever made."  The necessary measures being then taken to perfect the patent, it was duly enrolled on the 23rd February, 1782.
During the time that Watt was busy completing the above specification and drawings, his mind was full of other projects, one of which was the perfecting of his new expansive engine.  It is curious to find him, in his letters to Boulton, anticipating the plan of superheating the steam before entering the cylinders, which has since been carried into effect with so much success.
By the middle of March he had sufficiently matured his ideas of a reciprocating expansive engine to enable him to take out letters patent, and the invention was enrolled on the 4th of July in the same year. It included the double engine and double-acting engine (steam pressing the piston upwards as well as downwards), the employment of steam on the expansive principle, various methods of equalising the power of the engine, the toothed rack and sector for guiding the piston-rod, and a rotative engine or steam-wheel. While perfecting these beautiful adaptations, Watt was often plunged in the depths of distress through many causes, by sickness, headaches, and low spirits; by the pecuniary difficulties of the firm; by the repeated attempts of the Cornish miners to lower their dues; and by threatened invasions of his patent from all quarters. Another of his worries was the unsteadiness of his workmen. His letters to Boulton were full of complaints on this score. Excepting Wm. Murdock, who was in constant demand, there was scarcely one of them on whom he could place reliance. "We have very little credit, indeed," said he, "in our Soho workmen. James Taylor has taken to dram-drinking at a most violent rate, — is obstinate, self-willed, and dissatisfied." And again, "Cartwright's engine has been a continued scene of botching and blunders. J. Smith and the rest are ignorant, and all of them must be looked at daily, or worse follows. Had I had any one man of common prudence and experience, who would have attended from morning till night, these things might have been avoided, and my life would have been more comfortable. As things are, it is much otherwise."  "Three months later, matters had not mended. J. Smith is pronounced "a very slow hand," and "J. Taylor is sometimes three days together at the alehouse, except when he judged I should be going my rounds. . . . . Dick Cartwright also continues too much devoted to beer. . . . . I have read all our men lectures upon industry and good hours, though I fear it will not be to much purpose; idleness is ingrained in their constitution."  Boulton wrote to him to "send home the most rascally of the Sohoites;" but this was impracticable, as better men to replace them were not at that time to be had. Things were quite as bad at Soho itself; for early in 1782 we find Boulton writing thus: "The forging-shop wants a total reformation; Peploe and others constantly drunk; spoke mildly to them at first, then threatened, and am now looking out for good hands, which are very scarce." 
William Murdock was by far the ablest and most efficient of the Soho men, and won golden opinions in all quarters so much so, that he was in constant request. We find him described as "flying from mine to mine," putting the engines to rights. If anything went wrong, Murdock was immediately sent for. He was active, quick-sighted, shrewd, indefatigable, and an excellent workman. His wages, down to 1780, were only 20s. a week, and, thinking himself worth more, he asked for an advance to two guineas. Boulton, instead of refusing, adroitly managed to obtain a present of ten guineas from the owners of the United Mines, to which he added other ten, in acknowledgment of the admirable manner in which he had erected their new engine; Mr. Beauchamp, the Chairman of the Company, having publicly declared that "he regarded William as the most obliging and industrious workman he had ever known." Though Murdock's wages were not then raised, and though Bonze, the Cornish engineer — a man of means as well as of skill and experience — invited him to join in an engineering partnership, William remained loyal to the Boulton and Watt firm, and in due time he had his reward.
Murdock's popularity with the Cornishmen increased so much that Watt seems to have grown somewhat jealous of him, for when William was to be had they preferred him to Watt himself.  At Wheal Virgin, the adventurers insisted upon having him all to themselves but this was not practicable, as there were other engines in progress requiring constant attention, — Wheal Crenver, which Watt described as "in the enemy's country, Pool hardly completed yet, and Dalcoath in its childhood."
"I cannot now leave Wheal Virgin a single day," wrote Watt, "without running the risk of some vile blunder, particularly as the boilers are now setting. Wm. Murdock was at Wheal Virgin one day this week, and that day was taken, up with Mr. Wedgwood,  so that it was partly lost. Yesterday he was taken away by Crenver people and is not returned. I fear I cannot get much of his help, and I assure you I need it much, for there cannot be a greater plague than to have five engines making by ignorant men and no helpmate to look after them. I have been tolerably well these few days, but cannot get up my spirits, from having too much to think upon."
Combined with the troubles arising out of the perversities, blunderings, and bad conduct of his workmen, Watt had also to struggle against torment of mind and body, aggravated by bad news from home. Boulton was in the crisis of his troubles with his partner Fothergill, from which he was desperately struggling to shake himself free. 
Watt was made additionally miserable by the state of the bankers' account, which was still overdrawn to a very large amount. The bankers were urgent for repayment, but neither of the partners saw where the money was to come from. Watt again thought of giving up altogether, and selling his share of the business as the only means of relief which presented itself.
"I am almost moved," he wrote, "if Lowe, Vere, and Williams will free me from any demands on my future industry, to give up my present property altogether, and trust to Providence for my support. I cannot live as I am with any degree of comfort. The want of the superfluities of life is a trifle compared with continual anxiety. I do not see how you can pay L. V. W. £1,000 per quarter; I am sure it cannot be from the engine business, unless we can reduce the amount of our general expenses to and live, upon air ourselves. . . . Though you and I should entirely lose this business and all its profits, you will get quit of a burdensome debt and as both of us lived before it had a being, so we may do afterwards. Therefore consider what can be done, and do it without reluctance, or with as little as you can; and depend upon it that I am sincerely your friend, and shall push you to nothing that I do not think to be for your advantage." 
Two days later, while still in a heavily desponding humour, he wrote thus:—
"If matters were to come to the worst, many methods may be fallen upon whereby we may preserve some consequence in the world. A hundred hours of melancholy will not pay one farthing of debt. Summon up your fortitute and try to turn your attention to business, and to correct the abuses at Soho. . . . All the idlers should be told that in case they persevere in want of attention, then dismission must ensue. . . . The Soho part of the business has been somehow a perpetual drain to us, and if it cannot be put on a better footing, must be cut off altogether by giving out the work to be done by others." 
To add to their troubles, a fire broke out in the house of Boulton and Watt's London agent for the sale of their copying machines, and the building, with its contents, was burnt to the ground, thereby causing a loss to the firm of above a thousand pounds. The mining trade was also wretchedly bad in Cornwall, several of the more important mines being unproductive, while ore was selling at low prices. The adventurers were accordingly urging Watt to abate the agreed dues for the use of their engines, and in several cases threatened to close the mines unless he did so. The United Mines asked to be reduced £50 a month. Watt having refused to make the abatement, the mine was ordered to be stopped, on which he consented to give up the dues altogether for a period of six months. "There seemed," he wrote to Boulton, "to be no other course, if we would maintain our right, and at the same time do justice to the poor people, who must otherwise absolutely starve, and are already riotously disposed through the stopping of Wheal Virgin."  "In short," said he, "almost the whole county is against us, and look upon us as oppressors and tyrants, from whose power they believe the horned imps of Satan are to relieve them." Watt was indeed thoroughly sick of Cornwall, and longed to get back to Birmingham. He confessed he did not see how, under the present state of things, be could be of any more use there. The weather was very tempestuous, and he felt the fatigue of travelling from mine to mine too much for him to endure. On the 4th of April he wrote,— "I returned from the coast to Cosgarne last night with an aching head, after a peregrination of two days in very stormy weather." "Upon the whole," he wrote to Boulton, "I look upon our present Cornish prospects as very bad, and would not have you build too much upon them nor upon the engine business, without some material change. I shall think it prudent to look out for some other way of livelihood, as I expect that this will be swallowed up in merely paying its burdens."  Watt, accordingly, finding that he could do no more good in Cornwall, left it about the middle of April, and returned with an aching head and heavy heart to Birmingham.
- Lives of Boulton and Watt by Samuel Smiles
- Lives of Boulton and Watt by Samuel Smiles: Chapter 14
- Lives of Boulton and Watt by Samuel Smiles: Chapter 16
- In June, 1780, we find Boulton describing to Colonel Watson the progress of the Soho business, as follows:- "Since I had the honour of seeing you in England we have erected upwards of 40 of our new steam-engines, and have (from so much experience) obviated every difficulty, and made it a most practicable and perfect machine. The steam wheel we have not meddled with since you were at Soho, as we have been employed upon large beam-engines; besides, we have applied the beam engine to rotative motions so successfully that the wheel engine seems almost unnecessary."
- Watt had made use of the crank at a very early period. Thus we find him writing to Dr. Small on the 20th September 1769,— "As to the condenser, I laid aside the spiral wheels because of the noise and thumping, and substituted a crank: in other respects it performed well enough."
- The invention was patented by James Pickard, a Birmingham button-maker, on the 23rd August, 1780 (No. 1263). Matthew Washborough of Bristol arranged with Pickard for employing it in the engine invented by him for securing circular motion. Washborough's own patent has no reference to the crank, though he is usually named as the inventor of it.
- At a later date we find him writing to his partner thus:— "I cannot agree with Mr. Palmer's notion about the crank engine, as, though a crank is not new, yet that application of it is new and never was practised except by us. It is by no means our interest to demolish the crank patent, because then all our own machines of that kind will be of no use, and I am convinced that the crank can be made their superior."— Watt to Boulton, 15th October, 1781.
- Watt to Boulton, 19th November, 1780.
- Boulton and Watt were by this time employing their engine for a like purpose, as appears from a letter of Boulton to S. Wyatt, dated 28th February, 1781, in which he says,— "We are now applying our engines to all kinds of mills, such as corn mills, rolling iron and copper, winding coals out of the pit, and every other purpose to which the wind or water mill is applicable. In such applications, one hundred weight of coals will produce as much mechanical power as is equal to the work of ten men for ten hours, and these mills may be made very much more powerful than any water-mills in England." To Mr. Henderson he wrote at the same date:— "I make, no scruple to say but that I could readily build a more powerful and in every respect better copper-rolling mill by steam than any water-mill now in England. As soon as the Cornish engines are at work, I intend to turn millwright and make our steam-mills universally known."
- Watt to Boulton, 21st April, 1781. On the following day (the 22nd April) Watt wrote another long letter to Boulton on the same subject. His mind could not be at rest, and he thus unburdened himself of his indignation:— "If you find yourself so circumstanced, as you say you are, that you dare not refuse to erect the proposed engine for the Navy Board, then let them pay M. Washborough and have done with him, and let the engine be erected under our direction or Mr. Smeaton's. With the latter I will go hand in hand; nay I will do more — I will submit to him in all mechanical matters; but I will by no means submit to go on with thieves and puppies, whose knowledge and integrity I contemn. Though I am not so saucy as many of my countrymen, I have enough of innate pride to prevent me from doing a mean action because a servile prudence may dictate it. If a king were to think Matt Washborough a better engineer than me, I should scorn to undeceive him. I should leave that to Matthew. The connexion would be stronger as the evidence would be undeniable. So much for heroics! . . . . I will never meanly sue a thief to give me my own again, unless I have nothing left behind. As it now stands, I have enough left to make their patent tremble, and shall leave no mechanical stone unturned to aggrieve them. I will do more. I will publish my inventions, by which means they will be entirely precluded, because they must be fools indeed that will pay them for what they can have for nothing. I am very ill with a headache, therefore can write no more than passion dictates."
- Washborough was much mortified by the decision of the Navy Board, and alleged that he had been badly used by them. The anxieties occasioned by his failure, and the pecuniary losses he had sustained, preyed heavily upon his mind, and he was seized by a fever which carried him off in October, 1781, when only in his 28th year. He was unquestionably a young man of much ingenuity and merit, and had he lived would have achieved high eminence and distinction as an engineer.
- Boulton to Watt, 21st June, 1781.
- Watt to Boulton, 21st June, 1781.
- While Boulton spoke good humouredly to his partner in Cornwall with the object of cheering him up, he privately unbosomed himself to his friend Matthews in London. When requesting him to call at once on the bankers and get the account reduced to an advance of £12,000, and thus obtain Mr. Watt's release, he complained of the distress which the communications of the latter had caused him. He thought his conduct ungenerous, taking all the circumstances into account, and considering that the firm were within a year of being tolerably easy in money matters. "When I reflect," he wrote, "on his situation in 1772 and my own at that time, and compare them with his and mine now, I think I owe him little. . . I some time ago gave him a security of all my two-thirds, after paying off L. V. and W. [the bankers], from which you may judge how little reason he has to complain. He talks of his duty to his wife and children; by the same rule I ought not to neglect mine. His wife's fortune joined to his own did not amount to sixpence: my wife brought me in money and land £28,000. I advanced him all he wanted without a security, but in return he is not content with an ample security for advancing nothing at all but what he derived from his connexion with me."— Boulton to Matthews, 28th June, 1781. Boulton MSS.
- Watt to Boulton, 24th June, 1781
- Watt befriended Jabez like the other members of his family, as appears from the following passage in a letter to Boulton (6th September, 1778):— "Capt. Paul has turned Jabez adrift, having for some time taken umbrage at him because he would do his work well and therefore expensively. Jabez has a bad wife, is poor and unhappy. He is very clever, a good engineer, and industrious, though he seems not to have the faculty of conciliating people's affections. I fear he will go to Holland, and as he can hurt us [there being no patent for the engine secured there] I must try to get him bread here." Later, Boulton wrote Watt from Redruth (18th November, 1780),— "Old Hornblower has disobliged Mr. Daniel. I have my fears they will not employ him; but when our own business is sealed to-morrow, I will make a push in his favour. That family hath not been successful in conciliating the affections of the people in this neighbourhood."
- Watt to Boulton, 16th July, 1781.
- Watt to Boulton, 19th July, 1781. Boulton MSS.
- Boulton to Watt, 28th June, 1781. On the 3rd July following he writes, - "The great rotative engine is finished, and I expected the union between it and the little engine would have been performed this evening, but it can't be till to-morrow. Robert set the elliptic out so true that it had no shake and required no alteration. It does so much better than the little model made by Joseph that I am now ashamed to send the little one. The great model makes a delightful horizontal foot-lathe. I gave it a few strokes with my foot, and it made 30 revolutions after I withdrew it, and that, in a quiet and peaceable manner, which shows how steady and frictionless it is."
- Watt to Boulton, 5th July, 1781.
- Yesterday I went to Penryn and swore that I had invented ‘certain new methods of applying the vibrating or reciprocating motion of steam or fire engines to produce a continued rotation or circular motion round an axis or centre, and thereby to give motion to the wheels of mills or other machines,' which affidavit and petition I transmit to Mr. Hadley by this post with directions to get it passed with all due expedition." Watt to Boulton, 26th July, 1781.
- Watt suggested caution as to making use of the cranks. "In relation to Wilkinson's forges, I wish you would execute them without the double crank. We shall soon have a bad enough lawsuit on our hands without it." - Watt to Boulton, 19th July, 1781.
- Watt to Boulton, 28th July, 1781. A few days later Boulton wrote Watt that Dr. Priestley had proceeded with the experiments, and that he had come to the conclusion that "there is nothing to he feared from any of the tribe of gases, which cannot be produced nearly so cheap as steam; and as to steam you know its limits better than any Man."
- Watt to Boulton, 30th July, 1781. Later he wrote,— "I am tired of making improvements which by some quirk or wresting of the law may be taken from us, as I think has been done in the case of Arkwright, who has been condemned merely because he did not specify quite clearly. This was injustice, because it is plain that he has given this trade a being — has brought his invention into use and made it of great public utility. Wherefore he deserved all the money he has got. In my opinion his patent should not have been invalidated without it had clearly appeared that he did not invent the things in question. I fear we shall be served with the same sauce for the good of the public! and in that case I shall certainly do what he threatens. This you may be assured of, that we are as much envied here as he is at Manchester, and all the bells in Cornwall would be rung at our overthrow."— Watt to Boulton, 13th August, 1781.
- Watt to Boulton, 13th November, 1791.
- Watt to Boulton, 19th November, 1791.
- Watt to Samuel Ever, jun., 9th Jul, 1781. Boulton MSS.
- Watt to Boulton, 30th August, 1781.
- Watt to Boulton, 30th August, 1781. In a subsequent letter he explained the invention as follows:— "The method I propose to stop an engine when the pump rods break is by means of an air bellows or forcing pump of a good large diameter fixed in the shaft and having a solid piston in it which is wrought constantly by the engine and quite easily while it goes at its ordinary speed, because there is a large valve open in its bottom or rather top, which suffers the air to pass and repass easily; but whenever the engine attempts to move quick, that valve shuts and all exit from the air is cut off, and it becomes a feather-bed to save the blow of the engine. This is exemplified by turning the valve-hole of a common bellows upwards and stopping the nozzle, then working the bellows first slowly and then quickly. I think this contrivance will be of great use and may prevent damage, especially those bangs which occur in setting on an engine."— Watt to Boulton, 27th September, 1751.
- Boulton to Watt, 10th September, 1781. Boulton immediately proceeded with the erection of the new engine as secretly as possible. "The principles of the expansion engine," said he to Watt, "you had invented before Dr. Small died, as Mr. Keir can testify as well as others. However, it is highly proper to execute every kind of beam that can be devised for the purpose of equalising the power. I have removed the little portions into the wooden house next the smith's shop, and have blinded the window and barred the door. There is a convenient well that can be filled from the back brook, and the engine may be applied to the raising of water, which is the best sort of load to calculate from."
- Watt to Boulton, 20th September, 1781.
- Watt to Boulton, 18th October, 1781.
- Watt in a letter to Boulton, dated the 3rd July, 1782, speaks of it as an old plan of his own "revived and executed by William Murdock:" but we were informed by the late Mr. Josiah Parkes, that at an interview which he had with Mr. Watt at Heathfield, at which Murdock was present, Murdock spoke of the Sun and Planet motion as his invention, which Watt did not contradict. Boulton also attributed the invention to Murdock, as appears from his letter to Henderson, dated 22nd January, 1782; in which he says,- "Mr. Watt's packet is not ready. I am to wait till his drawings [of the rotatory motion] are completed, which he is executing himself. There was some informality in those sent from Soho. Besides, he has another rotative scheme to add, which I could have told him of long ago, when first invented by William Murdock, but I did not think it a matter of much consequence."
- Watt to Boulton, 26th Jan., 1782.
- "I have some time ago thought," wrote Watt, "of a new expansive engine — a reciprocating engine with a heavy circular fly moved by a pinion from the end of the beam, so as to make three turns per down-stroke and as many contrariwise per return; so that in the first half of the stroke it may acquire a momentum which will carry it through the last half; and if a weight equal to half the load be put upon the inner end of the beam, and the engine be made to lift it during the return, by making a vacuum above the piston and using a rack instead of a chain, a cylinder of the present size may work to the same depth by half the steam; and I believe the engine will work very sweetly."- Watt to Boulton, 16th January, 1782.
- Watt to Boulton, 20th September, 1781.
- Watt to Boulton, 20th December, 1781.
- Boulton to Watt, 26th March, 1782. The following was Boulton's method of dealing with a refractory and drunken workman:— "I told you in my former letters how Jim Taylor had gone on, — that I had talked to him in a friendly way but all to no purpose. He came last Monday evening to the smith's shop, drank more ale, was sent for, and he became abusive to the men, saying we had nobody could work well but himself, and that we could not do without him. The next morning I went into the shop predetermined to part with him. I stopped the noise of bellows and hammers, and appealed to the jury of the shop for the justice of my determination, and made the best use I could of the example. I sent Taylor off with deserved contempt, and to convince him that we really could do without him. However we are very much behind hand in nozzles."— Boulton to Watt, 19th April, 1782.
- To-day day was account day at Wheal Virgin, when there was nothing remarkable, only that Mr. Phillips insisted upon William Murdock being wholly at Wheal Virgin, which I told him could not possibly be complied with, unless I went to Crenver in his place, as I had nobody else to send thither nevertheless, that William should be here as much as possible. This did not satisfy him, and I know not what to do, as Crenver will be ready to work in three weeks and must not be delayed. . . .I think my personal attendance should satisfy Wheal Virgin adventurers, but as they seem to have more confidence in William, I will for peace's sake yield to their will, being satisfied that William will do the business well."— Watt to Boulton, 15th November, 1781.
- One of the pleasantest events that occurred to Watt in the course of his stay in Cornwall, was the visit of Wedgwood, who had come to inspect some of the mines in which, on Boulton's recommendation, he had taken an interest, and at the same time to search for clays for use in his earthenware and porcelain manufacture at Etruria. "Mr. Wedgwood," he wrote Boulton, "has been in this country some days hunting clays and soap rocks, cobalts, &c. I have had two visits of him at the expense of a day and a half. Nevertheless I don't grudge that, as I am glad to see a Christian. He has just left me."— Watt to Boulton, 18th October, 1781.
- Fothergill died insolvent in 1782. Notwithstanding what he had suffered by the connexion, Boulton acted with great generosity towards Fothergill's family, providing for his widow and orphan children. "Whatever the conduct of any part of that family towards me may have been," said he, "their present distresses turn every passion into tender pity. I waited upon Mrs. Fothergill this morning, and administered all the consolation that words could give, but I must do more, or their distresses will be great indeed. I never wished for life and health so fervently as at present; for I consider it my duty to act as a father to that family to the best of my power, and the addition of a widow and seven children is no small one." Boulton was as good as his promises; and he not only helped the Fothergill family through their difficulties, but he undertook to pay an annual sum (though under no obligation to do so) to a Mrs. Swellingrebel — a widowed lady from whom Fothergill had obtained money which he lost; and who, but for Boulton's generous help, must have been left destitute.
- Watt to Boulton, 16th March, 1782.
- Watt to Boulton, 18th March, 1782.
- Watt to Boulton, 27th March, 1782.
- Watt to Boulton, 30th March, 1782.