534 



Prof. H. F. Weber's Researches on 



Date. 



*. 



T. 





Nov. 1 



01244 



o 



in 





Nov. 2 



Dec. 6 



01 245 

 0-1262 



1-0 

 1-3 f 



Mean, £=0-1252 for T=l°20. 



Dec. 7 



0-1257 



1-4 J 





Nov. 3 



02427 



18-81 





Nov. 4 



Dec. 8 



0-2443 

 2413 



18-9 

 18-5 f 



Mean, £=02421 for T=18°-55. 



Dec. 10 



0-2400 



180 J 





Nov. 7 



0-4128 



44-4^ 





Nov. 8 



Dec. 11 



0-4163 

 0-4101 



45-2 1 

 44-1 f 



Mean, £=04146 for T = 44°70. 



Dec. 12 



04194 



45-1 J 





From these results it follows that the quantity of diffusion, 

 k, within the temperature-interval 0° to 45°, increases in an 

 approximately linear manner with the temperature ; the rela- 

 tion 



&=01187 [1 + 00557*] 



corresponds very well w T ith the observations. For the 

 temperature 9°*5 we obtain from this relation the value 

 & = 0'1815 ; the series of experiments made at the same 

 temperature according to the first method of experiment gave 

 0-1849. 



Influence of the Degree of Concentration upon Diffusion- 

 quantity k. — Fields elementary law of hydrodiffusion includes 

 the hypothesis that the diffusion-quantity k is independent of 

 the degree of concentration. 



A closer analysis of the experimental procedure made use 

 of by us makes it evident that both methods of experiment 

 are adapted to enable us to give a trustworthy decision for or 

 against that hypothesis only in case the course of diffusion be 

 studied in a series of solutions with as different initial concen- 

 trations as possible. If (as is to be expected, supposing that 

 this dependence at all exists) the dependence of the quantity 

 k upon the degree of concentration is but very slight, it can 

 hardly be recognized in one and the same series of observa- 

 tions, even with the nicest reading, on account of the differences 

 of concentration therein being too slight. In order to test 

 the hypothesis in question, I repeatedly ascertained the quan- 

 tity of diffusion for two solutions with the very different initial 

 concentrations z = 0'2 14 and ^ = 0*318, at the temperature of 

 the apartment, by the second method of experiment. The 

 values found are contained in the two following Tables. 



