268 Voltaic Energy of Electrolytes. [Jan. 17, 



IJ. "Relative Amounts of Voltaic Energy of Electrolytes." 

 By GK GORE, F.R.S. Received November 24, 1888. 



( Abstract.) 



In this research the author has determined by means of the 

 :< voltaic balance " the relative amounts of voltaic energy of upwards 

 of 100 aqueous solutions of elementary substances, acids, salts, bases, 

 organic substances, &c., exerted by them upon a simple voltaic couple 

 at ordinary atmospheric temperature. 



The method of measuring the amount of energy of a substance 

 was as follows : Take two small glass cups containing known volumes 

 of distilled water. Form two voltaic cells of them by means of strips 

 or stout wires of unamalgamated zinc cut from the same piece, and 

 two small sheets of platinum, also cut from the same piece. Connect 

 them together in series to a sufficiently sensitive galvanometer (say, 

 ore of from 100 to 1000 ohms resistance), so that the currents from 

 the two cells oppose each other, and produce no visible deflection of 

 the needles. This arrangement constitutes a " voltaic balance," and 

 is extremely sensitive to change of chemical composition of the liquid 

 in one of the vessels. Make an aqueous solution of known strength 

 of the substance, and add it in sufficiently small quantities at a time 

 to the water in one of the cups until the needle of the galvanometer 

 visibly commences to move, and note the proportion of the substance 

 and of water then contained in that vessel. 



As the amount of energy required to move the needle is the same 

 in all cases, the different numbers thus obtained with different sub- 

 stances represent the relative amounts of voltaic energy of those 

 substances. And as each substance or mixture of substances gives 

 a different number, it is possible by this method to detect substances, 

 to ascertain the degrees of strength or concentration of liquids, to 

 ascertain whether a substance contains a soluble impurity, &c. The 

 method also is in many cases an extremely sensitive one. 



The names or formula of the substances, together with their 

 amounts of energy, are arranged in the form of a table as a volta- 

 tension series of electrolytes, commencing with chlorine, which gives 

 a plus number of +1,282,000,000, and ending with caustic potash, 

 which gives a minus one of 270,985, and a certain mixture of salts 

 which gives -959,817. 



