214 



HYDRATES IN AQUEOUS SOLUTION. 



confirmed in detail all the statements made above and derived from the 

 photographs. Each one of the sixteen solutions absorbed the red and 

 orange completely. The more refrangible end of this band moved so gradu- 

 ally to shorter wave-lengths, that it was only possible to see a very slight 

 shift when the spectra of two consecutive members of the set of solutions 

 were viewed simultaneously; but it was not possible to assign a number to 

 the magnitude of the displacement. The best that could be done was to 

 observe the extreme members of the series at the same time, and to obtain 

 the average shift of the visible end of the band by dividing by 15. 



The penumbra of the band in question appeared to have the same intensity 

 at 0.640/z, for the most dilute solution, as at 0.628/'. for the most concen- 

 trated. Therefore, the mean observed displacement was 8 A. U. When 

 the last-named solution was compared with distilled water, it was observed 

 that the spectrum transmitted by the water had about the same intensity 

 at 0.760/ as the penumbra for the solution had at 0.628/<. Also the solu- 

 tion did not transmit any color as completely as the water; i. e., the former 

 possessed appreciable general absorption between the regions of complete 

 extinction of light. 



The freezing-point lowerings for the solution containing the chlorides of 

 copper and of calcium are given in the following table: 



TABLE 109. 



* Interpolated from the results of Jones and Bassett. Amer. Chem. Journ. , 33, 546 (1905) . 



As the temperature of the green and yellow-green solutions decreased, 

 the color became bluer. The solution of concentration 3.247 was very 

 viscous and jelly-like near its freezing-point. 



