Experiments on Bichlorure of ISulphur, 6^c. 71 



2a ^^ 

 Dividing (11) by — .e we obtain 



\ I ax -ax\ 



This is the complete form of the function sought, since it con- 

 tains the two arbitrary constants c and c' ; substituting this func- 

 tion in ( 1 ) it becomes 



1 / a{x+z) -a{x-z) a(x-z) -a{x+z)\ 



|^i^(^e -cc'^- .e —cc'^.e +c^&* . e j = 



1 / a(x+z) -a(x+z) a(z-z) -a(x-z)>. 



2^\e -cc'^ . e +e -cc'^ . e \ (13). 



If we equate the co-efficients of the like terms of (13), we 

 shall find that c= —Aa^, ^'—'9' ' substituting these values of 



ax -ax 



c and & in (12) we find cpx=e +e (14). 

 It now remains to find the value of a. 



n 



When a;=p = 90^, the two forces oppose each other, and then 

 (px=Q] substituting these values in (14) we get 



It Tt 



= e'^ +e '^ (15). 

 Equation (15) gives a = \/ — 1 ; therefore (14) finally becomes 



cpx = e + e =2 cos. x (16) ; this value of cpx=. 



2 cos. X agrees with Poisson's value ?'a;=2cos. ax, since he shows 

 that it is necessary to take a~\. Moreover it is evident that no 

 other value of qx can be found which will satisfy the conditions 

 of the question, since equation (12) is in its most general form. 



Art. VII. — Experiments on Bichlorure of Sulphur and certain 

 carhures of hydrogen, made in the laboratory of Jefferson Col- 

 lege {Loxdsiana) ; by Prof. F. Chevet. 



A CURRENT of bicarbure of hydrogen being brought to bear on 

 some bichlorure of sulphur, under the influence of the solar rays, 

 the gas was absorbed in considerable quantities with a great 

 throwing otf of heat. The hquid, at first of a very deep pome- 



