44 



Dr. G. Gore on a Method of Measuring 

 Table XVIII. — Positive metal, Zinc. 



Strength of Solution 1 equivalent weight in grains in 31,000 

 grains of water. 



Ingredients. E.M.F. 



Mixture. 



E.M.F. 



Calculated 

 E.M.F. 



Change of 

 E.M.F. 



Per 



cent. 



H o Cr0 4 . 

 K^S0 4 . 



1-4988 

 1-2843 



H 2 Cr0 4 4-K 2 S0 4 . -14416 



1-3711 



Gain -0705 = 5-14 



Conclusions from Results of Section D. 



1st. A sufficient number and variety of instances of what 

 are generally considered to be mere mechanical mixtures are 

 here given to show that such cases are attended some by a 

 loss and others by a gain of energy. 2nd. The gains were 

 more frequent than the losses in the proportion of 23 to 2, 

 and were of greater magnitude. Whilst with cadmium 

 in Table XII. of Section B, where the energy of chemical 

 union was much larger, the number of cases of loss was 14 

 and gain 6, in this section the numbers were 2 and 22 

 respectively ; and whilst in the cadmium table of the former 

 section, the largest loss was 15*64 per cent., in this one it was 

 only 1*6 per cent. ; in this section there was no case of large 

 loss because there was none of strong chemical union. And 

 3rd. In this series, as in Sections A and B, the order of 

 magnitude of the results appears to agree with that of the 

 magnitudes of the atomic weights of the metallic bases. 



Section E. — Acids + Acids. 



Table XIX. — Positive metal. Zinc. 



Strength of Solution 1 equivalent weight in grains in 31,000 

 grains of water. 



Ingredients. 



E.M.F. 



Mixture. 



E.M.F. 



Calculated 

 E.M.F. 



Change of 

 E.M.F. 



Per 

 cent. 



HCl. 



H o S0 4 . 



HN0 3 . 



Citric acid. 

 Formic „ 



H 2 Cr0 4 . 

 Oxalic acid. 



1-41014 



1-41300 



1-3844 



1-37296 



1-21566 



1-4988 

 1-3701 



H 2 S0 4 +2HC1. 141014 



„ +2HNO r 1-3924 

 Citric acid+3HCl. 1-3924 

 2 „ „ +3H„S0 4 . 1-3924 

 Formic,, +HC1. 1-31576 

 2 „ „ +H,S0 4 . 1-3129 

 3H.,CrO A 4-2 Citric acid.1-4845 

 Oxalic acid +H S0 4 . L3844 



1-4117 

 13969 

 1-3864 

 1-3903 

 1-3015 

 1-3174 

 1-4333 

 1-3924 



Loss -0015 



„ -0045 



Gain -0060 



„ -0021 



„ -0142 



Loss -0045 



Gain -0512 



Loss -008 



•106 

 •322 

 •43 

 •15 



1-09 

 •34 



3-57 

 •57 



