140 Prof. J. P. Cooke and Mr. F. A. Gooch on two 



V. 





(1) (2) (3) 

 Loss at 100° C. . . 10-28 9-66 



(4) 

 10-17 



„ about 300° C.\ Q ko f4-24\ 

 „ red heat . . J V °° \5-43J " 



9-36 



19*86 19-33 



19/53 



VI. 





(1) (2) (3a) 

 Loss at about 300° C.l -. n *» f470 4-46 

 „ red heat . .J iU4fc '\6-01 6-20 



(36) (4) 



10-47 10-71 10-66 10-45 10-42 



The mean of (1), (2), {M), and (4) of Table VI. is 10-51. 



It would appear from analyses (3) that the amounts of water 

 lost at 100° (j.j and over sulphuric acid during a period of three 

 months, are very nearly identical. Assuming that 10'51 (the 

 mean of the four determinations above) represents the percentage 

 of water in the mineral dried at 100°, the following scheme con- 

 tains the published analyses of JefFerisite reduced to this basis. 

 Analyses (1), (2), and (3) are those of Professor Brush, Dr. 

 Koenig, and Mr. Thomas M. Chatard respectively : — 



Si. "h. Fe. Fe. Mg. Ca, K. H. Total. 



100-84 



(1) 

 f 



38-47 

 2-56 



18-24 10-92 V31 20-38 -56 

 1-06 -34 -04 102 -02 



•45 



•01 



1051 

 V17 



Ratio <( 

 | 





^ ' V V 



1-40 1-09 









256 



: 2-49 : 





1-17 



(2) 



r 



i 



37*25 

 2-48 



19-87 8-17 236 21-51 — 

 1-16 -31 -06 1-07 



— 



10-51 

 1-17 



Ratio < 



2-48 



1-47 1-13 



. ^ ; 



: 2-60 : 





1-17 



- 



38-04 

 256 



18-39 8-84 2-33 21*34 — 

 1-07 -33 -06 1-07 



— 



10-51 

 1-17 



Ratio d 





1-40 1-13 







99-67 



99-45 



I 2-56 : 2-53 : 1*17 



Table VII. gives the percentages of water found in air-dried 

 specimens of the green variety of Hallite ; and Table VIII. gives 

 the percentages of water found in the same specimens dried at 

 100°. In analysis (4) the mineral was dried for three months 



