The Great Events by Famous Historians [Volumes 1-14]

No doubt will remain on the immense importance of this economical observation, when I shall have stated that the Glasgow model at each oscillation expended a volume of steam several times larger than that of the cylinder. The expense of steam, or, what comes to the same thing, the expense of fuel, or, if we like it better, the pecuniary cost of keeping on the working of the machine, would be several times less if the successive heatings and coolings, the inconveniences of which have just been described, could be avoided.

This apparently insolvable problem was solved by Watt in the most simple manner. It sufficed for him to add to the former arrangement of the engine a vessel totally distinct from the cylinder, and communicating with it only by a small tube furnished with a tap. This vessel, now known as "the condenser," is Watt's principal invention.

Still another invention by Watt deserves a word, the advantages of which will become evident to everybody. When the piston descends in Newcomen's engine, it is by the weight of the atmosphere. The atmosphere is cold; hence it must cool the sides of the metal cylinder, which is open at the top, in proportion as it expands itself over the entire surface. This cooling is not compensated during the whole ascension of the piston, without the expense of a certain quantity of steam. But there is no loss of this sort in the engines modified by Watt. The atmospheric action is totally eliminated by the following means:

The top of the cylinder is closed by a metal cover, only pierced in the centre by a hole furnished with greased tow stuffed in hard, but through which the rod of the piston has free motion, though without allowing free passage either to air or steam. The piston thus divides the capacity of the cylinder into two distinct and well-closed areas. When it has to descend, the steam from the caldron reaches freely the upper area through a tube conveniently placed, and pushes it from top to bottom as the atmosphere did in Newcomen's engine. There is no obstacle to this motion, because, while it is going on, only the base of the cylinder is in communication with the condenser, wherein all the steam from that lower area resumes its fluid state. As soon as the piston has quite reached the bottom, the mere turning of a tap suffices to bring the two areas of the cylinder, situated above and below the piston, into communication with each other, so that both shall be filled with steam at the same degree of elasticity; and the piston being thus equally acted upon, upward and downward, ascends again to the top of the cylinder, as in Newcomen's atmospheric engine, merely by the action of a slight counterpoise.

Pursuing his researches on the means of economizing steam, Watt also reduced the result of the refrigeration of the external surface of the cylinder containing the piston, almost to nothing. With this view he enclosed the metal cylinder in a wooden case of larger diameter, filling the intermediate annular space with steam.

Now the engine was complete. The improvements effected by Watt are evident; there can be no doubt of their immense utility. As a means of drainage, then, you would expect to see them substituted for Newcomen's comparatively ruinous engines. Undeceive yourselves: the author of a discovery has always to contend against those whose interest may be injured, the obstinate partisans of everything old, and finally the envious. And these three classes united, I regret to acknowledge it, form the great majority of the public. In my calculation I even deduct those who are doubly influenced to avoid a paradoxical result. This compact mass of opponents can only be disunited and dissipated by time; yet time is insufficient; it must be attacked with spirit and unceasingly; our means of attack must be varied, imitating the chemist in this respect—he learning from experience that the entire solution of certain amalgams requires the successive application of several acids. Force of character and perseverance of will, which in the long run disintegrate the best woven intrigues, are not always found conjoined with creative genius. In case of need, Watt would be a convincing proof of this. His capital invention—his happy idea on the possibility of condensing steam in a vessel separate from the cylinder in which the mechanical action goes on—was in 1765.

Two years elapsed without his scarcely making an effort to apply it on a large scale. His friends at last put him in communication with Dr. Roebuck, founder of the large works at Carron, still celebrated at the present day. The engineer and the man of projects enter into partnership; Watt cedes two-thirds of his patent to him. An engine is constructed on the new principles; it confirms all the expectations of theory; its success is complete. But in the interim Dr. Roebuck's affairs receive various checks. Watt's invention would undoubtedly have restored them; it would have sufficed to borrow money; but our associate felt more inclined to give up his discovery and change his business. In 1767, while Smeaton was carrying on some triangulations and levellings between the two rivers of the Forth and the Clyde, forerunners of the gigantic works of which that part of Scotland was to be the theatre, we find Watt occupied with similar operations along a rival line crossing the Lomond passage. Later he draws the plan of a canal that was to bring coals from Monkland to Glasgow, and superintends the execution of it. Several projects of a similar nature, and, among others, that of a navigable canal across the isthmus of Crinan, which Rennie afterward finished; some deep studies on certain improvements in the ports of Ayr, Glasgow, and Greenock; the construction of the Hamilton and Rutherglen bridges; surveys of the ground through which the celebrated Caledonian Canal was to pass, occupied our associate up to the end of 1773. Without wishing at all to diminish the merit of these enterprises, I may be permitted to say that their interest and importance were chiefly local, and to assert that neither their conception, direction, nor execution required a man called James Watt.