312 



F. R. Fraprie — Chromates of Caesium. 



The growth of crystals under pressure was undertaken with 

 the idea of ascertaining whether any change in habit or crys- 

 tallographic constants could be produced by mechanical stress- 

 during the crystal growth. The results thus far obtained are not 



ready for publication, and it is proposed to continue this work 

 in the near future in the Chemical Laboratory of Harvard 

 University. 



Caesium Chromate /3, Cs 2 Cr 4 . 



On one occasion some of the crystal powder taken from the 

 bomb, composed of extremely minute particles, showed under 

 the microscope, besides a few dark red bichromate crystals and 

 large numbers of the ill-formed long pale hexagonal needles, 

 two or three well-formed crystals of a very much deeper yel- 

 low color and bounded by definite planes and angles. The 

 whole mass of crystals which had been separated from the 

 mother-liquor and dried, was searched in the hope of finding 

 some crystals of this character large enough to measure, but in 

 vain. The mother-liquor had been set aside, and the next day, 

 when it was sought for the purpose of making another experi- 

 ment, it was unexpectedly found to contain several large, deep 

 yellow, apparently orthorhombic crystals. Although they had 

 partly redissolved, a measurement showed that they were 

 orthorhombic, isomorphous with and composed of the same 

 forms as are found on potassium chromate, caesium sulphate, 

 and the other members of this group. No further crystals of 



