40 HEROES OF INVENTION AND DISCO VERY. 



that end, and combined with, and aided by, its other equally 

 valuable property which had alone been called into action in the 

 more recent machines. 



These were the great improvements which Watt introduced 

 in what may be called the principle of the steam-engine, or, in 

 other words, in the manner of using and applying the steam. 

 They constitute, therefore, the grounds of his claim to be 

 regarded as the true author of the conquest that has at last 

 been obtained by man over this powerful element But original 

 and comprehensive as were the views out of which these 

 fundamental inventions arose, the exquisite and inexhaustible 

 ingenuity which the engine, as finally perfected by him, displays 

 in every part of its subordinate mechanism, is calculated to 

 strike us, perhaps, with scarcely less admiration. It forms, 

 undoubtedly, the best exemplification that has ever been 

 afforded of the number and diversity of services which a piece 

 of machinery may be made to render to itself by means solely 

 of the various application of its first moving power, when that 

 has once been called into action. Of these contrivances, how- 

 ever, we can only notice one or two, by way of specimen. 

 Perhaps the most singular is that called the governor. This 

 consists of an upright spindle, which is kept constantly turning, 

 by being connected with a certain part of the machinery, and 

 from which two balls are suspended in opposite directions by 

 rods, attached by joints, somewhat in the manner of the legs of 

 a pair of tongs. As long as the motion of the engine is uniform, 

 that of the spindle is so likewise, and the balls continue steadily 

 revolving at the same distance from each other. But as soon 

 as any alteration in the action of the piston takes place, the balls, 

 if it has become more rapid, fly farther apart under the influence 

 of the increased centrifugal force which actuates them — or 



