OP ARTS AND SCIENCES. 



497 



with larger machines. Activities ranging from 1.31 horse-power to 

 .004 horse-power have been obtained with efficiencies varying from 

 84.5% to 10.1%. Professors Ayrton and Perry in their paper on 

 " Electro-Motors and their Government," (Journal of Society of Tele- 

 graph Engineers, 1883,) state that motors may be constructed to de- 

 liver one horse-power per one hundred pounds of dead weight. Table 

 III. shows the horse-power per pound weight of the various motors 

 tested and in no case does it rise as high as .01 of a horse-power. 

 Their own motor, as will be seen by referring to the table, gives but 

 .0045 of a horse-power per pound of dead weight. In the most efficient 

 machine tested, the horse-power delivered per 100 lb. dead weight of 

 machine falls a little short of .8 of a horse-power. I think that for 

 moderately small motors about 300 lb. per horse-power would be a 

 closer figure, although with larger motors this would of course be 

 considerably reduced. 



TABLE III. 



Name of Motor. 



Griscora 



Ayrton and Perrj' .... 

 Gramme " a petite lumiere " 

 Magneto Gramme .... 



Thompson 



Deprez 



Monarch 



Cleveland 



Model Edison 



Diehl 1 



Diehl2 



Hilll 



Hill 2 



Weight in 

 Pounds. 



2.80 



39.00 



172.00 



70.00 



6.30 



9.60 



6.10 



18.50 



15.25 



9.50 



20.00 



7.00 



16.00 



Maximum Ilorse- 

 Power delirered. 



.0202 

 .1738 

 1.3160 

 .1512 

 .0138 

 .0138 

 .0041 

 .1290 

 .0544 

 .0209 

 .0309 

 .0120 

 .0374 



Ilorse-Power per 

 Pound Weight 



.0072 

 .0045 

 .0077 

 .0022 

 .0022 

 .0015 

 .0007 

 .0032 

 .0030 

 .0022 

 .0015 

 .0017 

 .0023 



Rogers Laboratory or Physics, March, 1887. 



VOL. XXII. (n. S. XIV.) 



32 



