THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



JANUARY 1853. 



I. On the (Economical Production of Mechanical Effect from 

 Chemical Forces. B?/ 3.V. Joule, F.R.S. 6fc.* 



lERHAPS the most important applications of dynamical 

 theory are those which refer to the production of motive 

 power from chemical and other actions. To point out the rules 

 for constructing an engine which shall approach perfection as 

 nearly as possible, and to determine the quantity of work which 

 ought to be evolved by a perfect engine of any given class, are 

 objects of the greatest consequence in the present state of society, 

 and which have in fact been to a great extent already accom- 

 plished by the labours of those who have taken a correct view of 

 the nature of heat. I intend on the present occasion to submit 

 to the Society some of the laws which have been recently arrived 

 at by Professor Thomson and myself, and to offer some hints as 

 to the means of carrying out into practice the deductions of 

 theory. 



Engines which derive their power from the operation of che- 

 mical forces may be divided into three classes. The first class 

 comprises those exquisite machines in which chemical forces 

 operate by the mysterious intervention of life, whether in the 

 animal or vegetable creation. The second class includes machines 

 in which the chemical forces act through the intervention of 

 electrical currents, as in the ordinary revolving electro-magnetic 

 apparatus. The third comprises those engines in which the 

 chemical forces act through the intervention of the heat they 



* From the Memoirs of the Literary and Philosophical Society of 

 Manchester, 1852, vol. x. Communicated by the Author. 



Phil. Mag, S. 4. Vol. 5. No. 29. Jan. 1853. B 



