moving the parts of the engine itself; and the third is that of heat by transfer, without transformation, by conduction and radiation to surrounding bodies.  In modern engines, the latter is but three or five per cent., in the best cases; the second waste constitutes perhaps ten per cent.; while the first of these losses amounts very usually to seventy per cent., of which last one-third or one-fourth is of the kind discovered by Watt, the rest being the thermodynamic waste incident to all known methods of operation of heat engines, and apparently unavoidable.  In our very best and largest engines, the waste found by Watt to constitute three fourths of all heat supplied has been brought down to ten per cent., a fact which well exemplifies the advances made since his time of apprenticeship by himself and his successors of this nineteenth century.  The steam engine of to-day, in its most successful operation, gives us twenty-five times as much power from a pound of coal as did the engine that the great inventor sought to improve:  this is the magnificent fruit of that one discovery of James Watt, and of application of the simple principle which he so concisely and clearly stated.

The method adopted by Watt to secure a remedy, so far as practicable, of this defect of the older machine was as simple and as perfect as was the principle which it embodied.  He first removed from the cylinder the prime source of its wastes; providing a separate condenser, and thus avoiding the repeated chilling of its surfaces by the cold water used in condensing the steam at exhaust, and also permitting its strokes to be made with far greater frequency, thus giving less time for cooling by the influence of the remaining vapors after condensation.  He next went still further, and provided the cylinder with a closed top, keeping out the air, and a “jacket” of hot boiler steam to keep it as hot as the steam which entered it.  These were the two great improvements which converted the first real steam engine into an economical form of heat engine and essentially finished the work so grandly begun by Newcomen and Calley.  These changes gave us the modern steam engine; and these are Watt’s first and greatest, but by no means only, contributions to the production of the modern world with all its comforts, its luxuries and its opportunities for material, intellectual and moral advancement of individual and of race.  His work was to this extent complete in 1765.

But Watt did not stop here.  There still remained for him the no less important and the, in some senses, still more imposing, work of finding employment for the new servant of mankind and of setting it at its work of giving the human arm a thousand times greater strength, to the mind of man uncounted opportunities to promote the advancement of knowledge, of civilization, of every good of the race.  His was still the task of adapting the new machine to all the purposes of modern industry.  It had been hitherto confined