250 Wells and Boltwood—Double Salts of Cesium Chloride 
drying with paper and over sulphuric acid, gave the following 
results upon analysis: 
Calculated for 
A. B. C. D. 2CsCl. CrCl 5. H.O. 
Cesium _.- 50°31 49°72 49°64 SIGE: 51°79 
Chromium _ 10°44 10°53 10°68 10°70 TOS 
Chlorine... 34°65 84°77. “S437 coe 34°56 
Waterss so) 411 5°12 Le agh bideds 3°50 
99°51 100°14 100°00 
The salt 2CsCl.CrCl,.4H,O is deposited from cold con- 
centrated solutions in the form of green, apparently monoclinic 
crystals. It is somewhat deliquescent, very soluble in water 
and loses no water in the desiccator over sulphuric acid. At 
110° it readily loses three molecules of water and is converted 
into the violet salt. Three crops analyzed were prepared as 
follows: Crop A, by evaporating a solution of 50g. cesium 
chloride and 25 g. of chromic chloride; Crop B, by dissolving 
the violet salt in water and evaporating over sulphuric acid ; 
Crop C, by cooling a concentrated solution of 50g. of each 
chloride with the aid of ice and saturating it with hydrochloric 
acid. The results were as follows: 
Calculated for 
A. B. C. 2CsCl . CrCl; . 4H.0. 
Crass tee 46°40 46°13 46°73 46°86 
Chromium ._.- 9°80 9°53 10°79 9°19 
Chlorine .-_-_. -- 31°30 olor gis 3127 
Waters tee ee a mh ine 12°68 
A determination was also made of the water lost at 110°: 
Calculated for 
' Found. 3H.O in 2CsCl. Crcls c 4H,0. 
Water.) 5225 ee 9:90 MQ" bal 
The variation in color of the two salts that have just been 
described is interesting in connection with the violet and green 
modifications of chromic salts in general, which have furnished 
the ground for much investigation and discussion. In the case 
under consideration the transformation from one color to the 
other is accomplished by the addition or subtraction of water. 
It seems highly probable, however, that the change in water is 
accompanied by a fundamental change in the molecular struc- 
ture, because the violet salt, containing the smaller amount of 
water, is very much more slowly soluble in water than the 
green salt, forming like the latter a green solution. We have 
found that the whole of the chlorine, in the cold green solu- 
tions of these ceesium salts, is not precipitated as silver chloride, 
