30 Br. G. Gore on a Method of Measuring 



and only measures the influence and changes of a portion of 

 the molecular motion of the substances present, viz. that por- 

 tion which neutralizes some of the molecular motion of that 

 metal and converts it into electric current. In a research on 

 " Relation of Yolta Electromotive Force to Latent Heat, 

 Specific Gravity, &c. of Electrolytes" (Phil. Mag., August 

 1891, p. 157), I have shown that in various cases of dilution 

 or mixture of such liquids, a gain of mean amount of electro- 

 motive force of the two liquids occurs simultaneously with a 

 loss of latent heat during the act of mixing, the kind of energy 

 therefore measured by this method is not identical with that of 

 heat ; and as we do not know definitely of what " chemical 

 affinity" really consists, we cannot say that what is measured 

 is identical with chemical energy. Whilst the thermochemical 

 method only measures the proportion of energy which causes 

 thermal change, the present one only measures that which 

 produces electric change ; and it is probable that the kind of 

 energy measured differs somewhat with each different kind of 

 positive metal. That we are unable clearly to define either of 

 the fundamental kinds of energy, and that the modifications 

 of them are very numerous, is generally admitted. 



A number of suitable pairs of acids and bases, acids and 

 carbonates, acids and salts, &c. were examined with different 

 positive metals according to this method, and the percentage 

 amounts of loss or gain of molecular energy ascertained. All 

 the measurements of electromotive force are given in volts. 

 The means emplo} r ed of obviating undue influence of polari- 

 zation have already been described (Phil. Mag., Dec. 1890, 

 p. 484), and were sufficiently effectual in nearly all cases. 



It would have saved much labour, and have yielded more 

 simple and apparently more important results, if the measure- 

 ments had been limited to those obtained with a single positive 

 metal. But whilst taking great care to obtain substantially 

 reliable results, I have avoided making only a small number 

 or a very limited variety of experiments, because it imparts a 

 false degree of apparent consistency and importance to the 

 results, and leads to the common and erroneous conclusion 

 that the phenomena of nature are more simple than they 

 really are, and consequently the conclusions drawn have to be 

 sooner or later corrected. In an extensive subject like the 

 present one, a considerable number and sufficient variety of 

 facts is necessary in order to arrive at truthful conclusions. 



The substances employed were in nearly every case of a 

 high degree of purity. Distilled water was used in making 

 all the solutions. The caesium carbonate was obtained from 

 Dr. H. Trommsdorff, of Erfurt, and both it and the carbonate 



