34 Drs. A. Matthiessen and C. Vogt on the Influence of 



materially from 5*64 " [should be 6*05]*, " the value given in col.^ 

 B reduced to the same standard, when we consider that the con- 

 ducting power of solid silver, according to Dr. Matthiessen, is 

 not less than 58*05 " [should be 65-9f], "and according to Dr. 

 Siemens 64*78." An important question here is, How is it that 

 the values deduced for the conducting power of silver from its 

 amalgams differ so greatly ? 



Let us compare the observations made by Dr. Siemens and 

 our own. As the values obtained for zinc differ also, we will 

 include these in Table III., taking as unit the gold-silver alloy 

 (hard drawn) = 100 at 0°. 



Table III. 



Siemens. 



Matthiessen and Vogt. 



Siemens. 



Matthiessen and Vogt. 



Silver per 



cent, in the 



amalgam. 



DeducedJ 



conducting 



power of 



silver. 



Silver per 



cent, in the 



f.malgam. 



Deduced 



conducting 



power of 



silver. 



Zinc per 



cent, in the 



amalgam. 



Deduced 



conducting 



power of 



zinc. 



Zinc per 



cent, in the 



amalgam. 



Deduced 



conducting 



power of 



zinc. 



0044 



0-21 



0-53 



96 



101-5 

 85-1 



005 

 010 

 020 

 050 



69-5 

 68-2 

 64-2 

 55-9 



076 



0-825 



1-520 



138 

 122 

 122 



0-5 

 10 

 20 



94-4 

 937 

 83-5 



The differences between the two series of values can hardly be 

 due to any errors in observation, but are most probably due to 

 the method employed in making the amalgam and filling the 

 tube with it. And this brings us to the next point in Mr. Sa- 

 bine's paper ; for on this subject he says (page 460) that it is 

 doubtful whether in our experiments filtration of a poorer amal- 

 gam into the thermometer-tubes did not take place, and in this 

 manner the values obtained for the richer amalgams appear lower 

 than they really are. He also stated that it would have been 

 better to have analysed the amalgams after each test. 



The best answer we can give to these remarks is, to state in a 

 few words the manner in which we made and tested the amal- 

 gams. All the amalgams were made in the tube in which they 

 were tested ; for we found that when we made the amalgams 



* Owing to Mr. Sabine having made a slight error in calculating the 

 values for the conducting power of silver, he has given as the mean value 

 61 '46 instead of 660. 



f Mr. Sabine has here compared the conducting power of hard-drawn 

 silver at 13° with annealed at 0°. He ought, however, to have taken the 

 value given for annealed silver, viz. 66'6, at 0° (Phil. Mag. Feb. 1861), or, 

 more correctly, that given in a later paper, 65*9 (Pogg. Ann. vol. cxv. p. 363), 

 this number being the mean of several experiments. 



% Deduced from the observed conducting power of the amalgams, assu- 

 ming that the hypothesis we started with be correct. 



