LARSEN AND WHERRY: LEVERRIERITE FROM COLORADO 211 



temperature than this, and again may be given off only at a much 

 higher temperature. 



In the case of the mineral here described the temperature of 

 100° possesses no significance whatever, as is clearly shown by 

 Table 1, in which the loss at different temperatures is recorded. 

 The coarsely powdered mineral was heated to each tempetature 

 in a covered platinum capsule for 2 hours. 



TABLE 1 

 Loss of Water from Leverrierite from Colorado 



In interpreting the results it must be borne in mind that the 

 amount of water lost at a given temperature depends on the 

 fineness of grinding, the length of heating, the humidity of the 

 atmosphere in which the heating is done, etc., so that too great 

 significance should not be attached to such data. It is worth 

 noting, however, that over one-third of the total water is given 

 off below 50°, and nearly two-thirds below 110°. Nearly all 

 the water is lost below 350°. By way of contrast it may be 

 mentioned that a sample of halloysite recently studied by us 4 

 retained 12.9 per cent of H 2 at 400°. 



4 Larsen, E. S., and Wherry, E. T. Halloysite from Colorado. Journ. Wash. 

 Acad. Sci., 7: 178. 1917. 



