On a new Electro-nmgnetic Engine. 489 



Let Q'=66-4 and Q=79-5, then 



Appendix III. 



In order to calculate how the loss of electricity distributes 

 itself over the several times of observation, a few indications 

 which have reference to the calculation of the Table a" will suffice. 



The loss V is the difference between the primitive charge and 

 that which we know to have been withdrawn. According to the 

 Table a, the primitive charge was 0'474,2 ; at the first discharge 

 0*2951 was withdrawn; then, according to Table «', the collected 

 residues amounted to 0-1307, to which we may add 0-0075, 

 equal to the last residue, as the quantity which probably still 

 remained in the jar but could not be collected. Then is 



V = 0-4742 -(0-295 1+0- 1382) = 0-0409. 



The superficial area F enclosed by the curve of disposable 

 charge is 



= i[(0-4742 + 0-4133)l84- (0-4133 + 0-3896)(50-18) + ....] 

 =228-086. 



The area enclosed by the curve of collected residues is 

 0=/ +/"+/" + &«.... 



=1 [0-0443 . 65 + 0-0166. (153-65) + ] 



=30-767. 



Hence the constant for the loss of electricity is 

 V 0-0409 



a = 



E + <^ 258-863 

 Everything else is immediately given 

 Marburg, Oct. 1853. 



= 0-000158. 



LXXVI. On a neiv Eledro-Maynetic Engine invented by M. Marie 

 Davy. Bij M. Becquerel*. 



ATTEMPTS have been made for the last twenty years, to 

 construct machines in which the magnetic property im- 

 parted to soft iron by the electric current, should be employed 

 as a motive power; but the electromotive machines hitherto 

 brought forward have been far from presenting any cecouomical 

 advantages over steam-engines. 



* From the Cotnptes Rendus, for May 16, 1864, p. 853. 



