314 a new solution of a Case in Spherical Trigonometry/, 



Were we possessed of complete tables of versed sines ; the 

 expressions 



r + 2 ver S + ver (5 ^ C) -♦- ver (5 4- C) ) 

 4 ver y = 1^2 ver<r+ suv (<r — C) + suv («r + C) J "~ ^ ' 



{+ 2 ver D + suv (D — y) + suv (D + y) 1 

 + 2 vef S + ver (S — y) + ver (S + y) f "" '^ ' 



would be much more convenient, as then all the quantities 

 would be additive. 



Edward Sang. 



32 St Akdbew Square, 

 16^ June 1832. 



Remarks on Electrical Decompositions. By William M. 

 HiGGiNs, P. G. S. and J. W. Draper. Communicated by 

 the Authors. 



JVIetallic reduction by the galvanic battery is always con* 

 ducted in one of the three following ways : Either the substance 

 to be decomposed is presented in solution with water, as in the 

 case of sulphate of copper and nitrate of silver ; or it is only 

 moistened with water, as when hydrate of potassa is acted up- 

 on ; or it is presented in a liquid form by heat, as in Davy's ex- 

 periments with the carbonate of lithia. 



The galvanic battery has generally no effect on solids, so that 

 metallic salts must be presented in the form of solutions, for ef- 

 fectual decomposition. 



All the simple bodies are either very good or very bad con- 

 ductors ; and the greater the number of substances in a com- 

 pound, the more easily is it decomposed. 



At temperatures between 40° and 120° F., compound sub- 

 stances, not containing oxygen as one of their elements, are non- 

 conductors of galvanic electricity. 



When metallic salts in solution, with an excess of water, are 

 presented to the galvanic battery for decomposition, no hydro- 

 gen gas is given off at the negative pole, if the power of the 

 battery be proportionate to the strength of the solution, provided 

 the revived metal can exist in water. If it cannot exist in wa- 

 ter, then, as soon as an equivalent is revived, decomposition of 



