220 



HYDRATES IN AQUEOUS SOLUTION. 



The next solution of the series (of concentration 1.017) absorbed the red 

 a little more than the solution of concentration 0.763. The stronger solu- 

 tion exerted marked general absorption on all the light transmitted, and it 

 absorbed completely all the blue and green as far as the beginning of the 

 yellow-green. If the extreme limits of the regions of transmission for the 

 more concentrated solution be given roughly by 0.630/< and 0.50S/<, then 

 the corresponding wave-lengths for the less concentrated solution would be, 

 respectively, 0.636/-t and 0.468/*. 



The solution which contained the greatest amount of calcium bromide (of 

 concentration 3.804) was completely opaque to all visible light in layers of 

 0.93 cm. deep. A layer 0.12 cm. thick transmitted weakly a narrow band of 

 red extending from about 0.716/* to 0.653j. Red alone was transmitted by 

 a layer of this solution only at 0.06 cm. in thickness. When placed in the 

 wedge-shaped cell, the solution showed very distinctly the two bands given 

 by plates 16 (a) and 16 (6), i. e., the one in the blue-green and the other in 

 the violet and ultra-violet. The absorption of the solution in question was 

 so very intense that when a little of it was poured on a plane parallel piece 

 of quartz, and allowed to drain off with the quartz placed vertically in front 

 of the slit of the spectroscope, the band in the blue-green could be seen 

 distinctly. The results of the freezing-point determinations for the solutions 

 which contained copper chloride and calcium bromide are given in table 111. 

 The dark-green solutions became much lighter in color when they were 

 cooled down in the neighborhood of their freezing-points. 



The electrical conductivities of the solutions in question were not deter- 

 mined. 



TABLE 111. 



* Interpolated from theresultsof Jones and Bassett. Amer.Chem. Journ., 33,550 (1905). 



