S/K WILLIAAf S/EAtENS, F.R.S. 325 



1>\ different methods ; and it is satisfactory to find that their final 

 values diller only in the fourth decimal, the figures being, accord- 

 ing to 



, Earth Quadrant 



Lord Rayleigh . . 1 Ohm = 0-98651 



Second 



Messrs. Glazebrook, &c. = 0-98G271 



Professor E. Wiedemann, of Leipzig, has lately called attention 

 to the importance of having the Ohm determined in the most 

 accurate manner possible, and enumerates four distinct methods, 

 all of which should unquestionably be tried with a view of 

 obtaining concordant results, because upon its accuracy will 

 depend the whole future system of measurement of energy of 

 whatever form. 



The word Energy was first used by Young in a scientific sense, 

 and represents a conception of recent date, being the outcome of 

 the labours of Carnot, Mayer, Joule, Grove, Clausius, Clerk- 

 Maxwell, Thomson, Stokes, Helmholtz, Macquorn Ilankine, and 

 other labourers, who have accomplished for the science regarding 

 the forces in Nature what we owe to Lavoisier, Dalton, Berzelius, 

 Liebig, and others, as regards Chemistry. In this short word 

 Energy we find all the efforcs in nature, including electricity, 

 heat, light, chemical action, and dynamics, equally represented, 

 forming, to use Dr. Tyndall's apt expression, so many " modes of 

 motion." It will readily be conceived that when we have esta- 

 blished a fixed numerical relation between these different modes of 

 motion, we know beforehand what is the utmost result we can 

 possibly attain in converting one form of energy into another, 

 and to what extent our apparatus for effecting the conversion falls 

 short of realising it. The difference between ultimate theoretical 

 effect and that actually obtained is commonly called loss, but, 

 considering that energy is indestructible, represents really secondary 

 effect which we obtain without desiring it. Thus friction in the 

 working parts of a machine represents a loss of mechanical effect, 

 but is a gain of heat, and in like manner the loss sustained in 

 transferring electrical energy from one point to another is 

 accounted for by heat generated in the conductor. It sometimes 

 suits our purpose to augment the transformation of electrical into 



