314 WRITINGS OF JOSEPH HENRY. [1853 



improvement of machines beginning anew instead of build- 

 ing on what has been done before him. 



Every complex machine consists of parts which may be 

 classified as follows : 



1st. The receivers of the power — such as the buckets and 

 other parts of the water-wheel, the vane of the windmill. 



2d. The transmitters and modifiers of the motion, viz., 

 wheels, pinions, levers, pistons, screws, &c. 



3d. The supporters — such as the frames, the friction- 

 rollers, &c. 



4th. Regulators to render the motion uniform. 



5th. Operators or parts applied immediately to the matter 

 on which the work is to be done. 



The preparation and publication of charts of the element- 

 ary parts of machines and their combinations would do im- 

 portant service to the practical mechanic, and is an object 

 among many others worthy of the attention of this Institute. 



The most important source of mechanical power among 

 those we have mentioned, and which promises almost to 

 supersede all others, is that of burning coal. This material — 

 like a watch wound up, is matter in a state of power, or in 

 a state of unstable equilibrium, ready to rush into combina- 

 tion with the oxygen of the atmosphere as soon as the in- 

 itial action is given, and to evolve power in the form of heat 

 until the whole is consumed. It has been proved that on 

 an average /owr ounces of coal is sufiicient to draw — on a rail- 

 way, one ton a mile. It has also been found by experiment 

 that a man working on a tread-mill continuously for eight 

 hours will elevate one and a half million of pounds one foot 

 high. Now, good Cornish engines will perform the same 

 work by the expenditure of the power of a pound and a half 

 of coal. It follows from these data that about five tons of 

 coal would evolve as much power during its combustion as 

 would be equal to the continued labor of an able-bodied man 

 for twenty years, at the rate of eight hours per day; or in 

 other words, to the average power of a man during the active 

 period of his life. Providence has therefore stored away in 

 the form of coal, for the use of man, an incalculable amount 



