The greatest invention of all, the condenser, is fully covered by the first patent of 1769. The best engine up to this time was the Newcomen, exclusively used for pumping water. As we have seen, it was an atmospheric engine, in no sense a steam engine. Steam was only used to force the heavy piston upward, no other work being done by it. All the pumping was done on the downward stroke. The condensation of the spent steam below the piston created a vacuum, which only facilitated the fall of the piston. This caused the cylinder to be cooled between each stroke and led to the wastage of about four-fifths of all the steam used. It was to save this that the condenser was invented, in obedience to Watt's law, as stated in his patent, that "the cylinder should be kept always as hot as the steam that entered it"; but it must be kept clearly in mind that Watt's "modified machines," under his first patent, only used steam to do work upon the upward stroke, where Newcomen used it only to force up the piston. The double-acting engine—doing work up and down—came later, and was protected in the second patent of 1780.

Watt knew better than any that although his model had been successful and was far beyond the Newcomen engine, it was obvious that it could be improved in many respects—not the least of his reasons for confidence in its final and more complete triumph.

To these possible improvements, he devoted himself for years. The records once again remind us that it was not one invention, but many, that his task involved. Smiles gives the following epitome of some of those pressing at this stage:

Various trials of pipe-condensers, plate-condensers and drum-condensers, steam-jackets to prevent waste of heat, many trials of new methods to tighten the piston band, condenser pumps, oil pumps, gauge pumps, exhausting cylinders, loading-valves, double cylinders, beams and cranks—all these contrivances and others had to be thought out and tested elaborately amidst many failures and disappointments.

There were many others.

All unaided, this supreme toiler thus slowly and painfully evolved the steam engine after long years of constant labor and anxiety, bringing to the task a union of qualities and of powers of head and hand which no other man of his time—may we not venture to say of all time—was ever known to possess or ever exhibited.

When a noble lord confessed to him admiration for his noble achievements, Watt replied, "The public only look at my success and not at the intermediate failures and uncouth constructions which have served me as so many steps to climb to the top of the ladder."

Quite true, but also quite right. The public have no time to linger over a man's mistakes. What concerns is his triumphs. We "rise upon our dead selves (failures) to higher things," and mistakes, recognised as such in after days, make for victory. The man who never makes mistakes never makes anything. The only point the wise man guards is not to make the same mistake twice; the first time never counts with the successful man. He both forgives and forgets that. One difference between the wise man and the foolish one!

It has been truly said that Watt seemed to have divined all the possibilities of steam. We have a notable instance of this in a letter of this period (March, 1769) to his friend, Professor Small, in which he anticipated Trevithick's use of high-pressure steam in the locomotive. Watt said:

I intend in many cases to employ the expansive force of steam to press on the piston, or whatever is used instead of one, in the same manner as the weight of the atmosphere is now employed in common fire engines. In some cases I intend to use both the condenser and this force of steam, so that the powers of these engines will as much exceed those pressed only by the air, as the expansive power of the steam is greater than the weight of the atmosphere. In other cases, when plenty of cold water cannot be had, I intend to work the engines by the force of steam only, and to discharge it into the air by proper outlets after it has done its office.

In these days patents could be very easily blocked, as Watt experienced with his improved crank motion. He proceeded therefore in great secrecy to erect the first large engine under his patent, after he had successfully made a very small one for trial. An outhouse near one of Dr. Roebuck's pits was selected as away from prying eyes. The parts for the new engine were partly supplied from Watt's own works in Glasgow and partly from the Carron works. Here the old trouble, lack of competent mechanics, was again met with. On his return from necessary absences, the men were usually found in face of the unexpected and wondering what to do next. As the engine neared completion, Watt's anxiety "for his approaching doom," he writes, kept him from sleep, his fears being equal to his hopes. He was especially sensitive and discouraged by unforeseen expenditure, while his sanguine partner, Roebuck, on the contrary, continued hopeful and energetic, and often rallied his pessimistic partner on his propensity to look upon the dark side. He was one of those who adhered to the axiom, "Never bid the devil good-morning till you meet him." Smiles believes that it is probable that without Roebuck's support Watt could never have gone on, but that may well be doubted. His anxieties probably found a needed vent in their expression, and left the indomitable do-or-die spirit in all its power. Watt's brain, working at high pressure, needed a safety valve. Mrs. Roebuck, wife-like, very properly entertained the usual opinion of devoted wives, that her husband was really the essential man upon whom the work devolved, and, that without him nothing could have been accomplished. Smiles probably founded his remark upon her words to Robison: "Jamie (Watt) is a queer lad, and, without the Doctor (her husband), his invention would have been lost. He won't let it perish." The writer knows of a business organisation in which fond wives of the partners were all full of dear Mrs. Roebuck's opinion. At one time, according to them, the sole responsibility rested upon three of four of these marvellous husbands, and never did any of the confiding consorts ever have reason to feel that their friend did not share to the fullest extent the highly praiseworthy opinion formed of his partners by their loving wives. The rising smile was charitably suppressed. In extreme cases a suggested excursion to Europe at the company's expense, to relieve Chester from the cruel strain, and enable him to receive the benefit of a wife's care and ever needful advice, was remarkably effective, the wife's fears that Chester's absence would prove ruinous to the business being overcome at last, though with difficulty.

Due allowance must be made for Mrs. Roebuck's view of the situation. There can be no doubt whatever, that Mr. Roebuck's influence, hopefulness and courage were of inestimable value at this period to the over-wrought and anxious inventor. Watt was not made of malleable stuff, and, besides, he was tied to his mission. He was bound to obey his genius.

The monster new engine, upon which so much depended, was ready for trial at last in September, 1769. About six months had been spent in its construction. Its success was indifferent. Watt had declared it to be a "clumsy job." The new pipe-condenser did not work well, the cylinder was almost useless, having been badly cast, and the old difficulty in keeping the piston-packing tight remained. Many things were tried for packing—cork, oiled rags, old hats (felt probably), paper, horse dung, etc., etc. Still the steam escaped, even after a thorough overhauling. The second experiment also failed. So great is the gap between the small toy model and the practical work-performing giant, a rock upon which many sanguine theoretical inventors have been wrecked! Had Watt been one of that class, he could never have succeeded. Here we have another proof of the soundness of the contention that Watt, the mechanic, was almost as important as Watt the inventor.

Watt remained as certain as ever of the soundness of his inventions. Nothing could shake his belief that he had discovered the true scientific mode of utilising steam. His failures lay in the impossibility of finding mechanics capable of accurate workmanship. There were none such at Carron, nor did he then know of any elsewhere.

Watt's letter to his friend, Dr. Small, at this juncture, is interesting. He writes:

You cannot conceive how mortified I am with this disappointment. It is a damned thing for a man to have his all hanging by a single string. If I had wherewithal to pay the loss, I don't think I should so much fear a failure; but I cannot bear the thought of other people becoming losers by my schemes; and I have the happy disposition of always painting the worst.

Watt's timidity and fear of money matters generally have been already noted. He had the Scotch peasant's horror of debt—anything but that. This probably arises from the fact that the trifling sums owing by the poor to their poor neighbors who have kindly helped them in distress are actually needed by these generous friends for comfortable existence. The loss is serious, and this cuts deeply into grateful hearts. The millionaire's downfall, with large sums owing to banks, rich money-lenders, and wealthy manufacturers, really amounts to little. No one actually suffers, since imprisonment for debt no longer exists; hence "debt" means little to the great operator, who neither suffers want himself by failure nor entails it upon others.

To Watt, pressing pecuniary cares were never absent, and debt added to these made him the most afflicted of men. Besides this, he says, he had been cheated and was "unlucky enough to know." Wise man! ignorance in such cases is indeed bliss. We should almost be content to be cheated as long as we do not find it out.

It was at such a crisis as this that another cloud, and a dark one, came. The sanguine, enterprising, kindly Roebuck was in financial straits. His pits had been much troubled by water, which no existing machinery could pump out. He had hoped that the new engine would prove successful and sufficiently powerful in time to avert the drowning of the pits, but this hope had failed. His embarrassments were so pressing that he was unable to pay the cost of the engine patent, according to agreement, and Watt had to borrow the money for this from that never-failing friend, Professor Black. Long may his memory be gratefully remembered. Watt had the delightful qualities which attracted friends, and those of the highest and best character, but among them all, though more than one might have been willing, none were both able and willing to sustain him in days of trouble except the famous discoverer of latent heat. When we think of Watt, we picture him holding Black by the one hand and Small by the other, repeating to them

The patent was secured—so much to the good—but Watt had already spent too much time upon profitless work, at least more time than he could afford. His duty to provide for the frugal wants of his family became imperative. "I had," he said, "a wife and children, and I saw myself growing gray without having any settled way of providing for them." He turned again to surveying and prospered, for few such men as Watt were to be found in those days, or in any day. With a record of Watt's work as surveyor, engineer, councillor, etc., our readers need not be troubled in detail. It should, however, be recorded that the chief canal schemes in Scotland in this, the day of canals for internal commerce, preceding the day of railroads that was to come, were entrusted to Watt, who continued to act as engineer for the Monkland Canal. While Watt was acting as engineer for this (1770-72), Dr. Small wrote him that he and Boulton had been talking of moving canal boats by the steam engine on the high-pressure principle. In his reply, September 30, 1770, Watt asks, "Have you ever considered a spiral oar for that purpose, or are you for two wheels?" To make his meaning quite plain, he gives a rough sketch of the screw propeller, with four turns as used to-day.

Thus the idea of the screw propeller to be worked by his own improved engine was propounded by Watt one hundred and thirty-five years ago.

This is a remarkable letter, and a still more remarkable sketch, and adds another to the many true forecasts of future development made by this teeming brain.

Watt also made a survey of the Clyde, and reported upon its proposed deepening. His suggestions remained unacted upon for several years, when the work was begun, and is not ended even in our day, of making a trout and salmon stream into one of the busiest, navigable highways of the world. This year further improvements have been decided upon, so that the monsters of our day, with 16,000-horse-power turbine engines, may be built near Glasgow. Watt also made surveys for a canal between Perth and Coupar Angus, for the well-known Crinan Canal and other projects in the Western Highlands, as also for the great Caledonian and the Forth and Clyde Canals.

The Perth Canal was forty miles long through a rough country, and took forty-three days, for which Watt's fee, including expenses, was $400. Labor, even of the highest kind, was cheap in those times. We note his getting thirty-seven dollars for plans of a bridge over the Clyde. Watt prepared plans for docks and piers at Port Glasgow and for a new harbor at Ayr. His last and most important engineering work in Scotland was the survey of the Caledonian Canal, made in the autumn of 1773, through a district then without roads. "An incessant rain kept me," he writes, "for three days as wet as water could make me. I could scarcely preserve my journal book."

Suffice it to note that he saved enough money to be able to write, "Supposing the engine to stand good for itself, I am able to pay all my debts and some little thing more, so that I hope in time to be on a par with the world."

We are now to make one of the saddest announcements saving dishonor that it falls to man to make. Watt's wife died in childbed in his absence. He was called home from surveying the Caledonian Canal. Upon arrival, he stands paralysed for a time at the door, unable to summon strength to enter the ruined home. At last the door opens and closes and we close our eyes upon the scene—no words here that would not be an offence. The rest is silence.

Watt tried to play the man, but he would have been less than man if the ruin of his home had not made him a changed man. The recovery of mental equipoise proved for a time quite beyond his power. He could do all that man could do, "who could do more is none." The light of his life had gone out.