COBALT CHLORIDE IN METHYL ALCOHOL. 245 



berecl that the other solution was not quite tenth-normal, cobalt chloride 

 being only slightly soluble in methyl alcohol. 



Eye observations of typical solutions of the set gave the following results : 

 The depth of cell used was 3 cm. The mother-solution had a clear purple 

 color, with a decided reddish tinge when viewed by diffuse daylight trans- 

 mitted through the cell. Transmission began about 0.766/< and extended 

 to the beginning of the absorption band in the green. Weak partial absorp- 

 tion appeared in the red at 0.704/. The brightest region of transmission was 

 in the immediate neighborhood of 0.625/t, i. e., in the yellow. No narrow 

 absorption bands in the red, orange, or yellow, such as were observed for 

 aqueous solutions of cobalt chloride, were visible. The band in the green 

 was narrow, but intense, its maximum being near 0.540,".. It was much more 

 abrupt on the less than on the more refrangible side. For one definite 

 exposure a photographic film does not necessarily show the position of the 

 maximum of intensity of an asymmetric absorption band, so that it is not 

 surprising to find 0.525/t for the center of the photographic band, and 0.540/< 

 for the maximum of absorption with the prism spectroscope. To see if 

 there were any other absorption bands the cell was filled to the brim of the 

 larger glass tube, and the rest of the system was not put in place. In this 

 manner a column of solution 4.5 cm. long was obtained. The several faint 

 maxima and minima of transmission could be seen in the red. If the solu- 

 tion could have been made more concentrated, or, better, if the cell had 

 been deeper, it is extremely probable that all the bands observed in aqueous 

 solutions could have been seen with the alcoholic solution in question. As 

 the spectra of the solutions which contained greater and greater amounts of 

 water were brought into the field of view, it was observed that the various 

 regions of absorption grew weaker and weaker, and that the entire spectra 

 remained qualitatively similar to the spectrum of the mother-solution. Of 

 course the regions of weak absorption around 0.704/t soon disappeared. The 

 maximum of intensity of the absorption band in the green had the wave- 

 length 0.525/ for the solution which contained the greatest percentage of 

 water, 12.00. Consequently, the maximum of this band was displaced about 

 150 A. U. towards the blue, when the amount of water in the solution was 

 changed from 0.00% to 12.00.% 



COBALT CHLORIDE IN ETHYL ALCOHOL. [See plates 24 and 25 (a).] 



The concentration of the mother-solution of cobalt chloride in ethyl alco- 

 hol was 0.0967. The percentages of water in the solution were 20.00, 10.00, 

 8.00, 7.50, 7.00, 6.00, 5.50, 5.00, 4.00, 3.00, 2.00, and 0.00. The successive 

 differences in per cent were 10.00, 2.00, 0.50, 0.50, 1.00, 0.50, 0.50, 1.00, 1.00, 

 1.00, 2.00. As the quantity of water decreased, the colors of the solutions 

 changed from pink, through various shades of violet, to deep blue. The 

 photographic strips corresponding to the solutions which contained the 



