220 G. J. Brush on native hydrates of Iron. 
method by first reducing with hydrogen, and subsequently vola- 
tilizing the iron by heating in a current of dry hydrochloric acid 
gas. The analytical results were all obtained by Mr. Rodman. 
Composition : 
ds 2. Mean. 
Ferric oxyd, - - - 91°45 91°29 91°36 
Manganicoxyd, -_ - 0°67 0°55 61 
Alumina, - ae PR ee ed baa “15 
ee 0:22 0-24 23 
Phosphoric acid, sulphuric acid 
and cobaltic oxyd, } one’ wee — 
Insoluble in acid, en See ARS rire 1°83 
Water, - - - - 5°20 5°21 5°20 
100°12 99°98 
Other determinations of water on different specimens gave 5'02 
and 5: 
Five grams of the mineral yielded only minute traces of sul- 
phuric acid, and three grams showed but an unweighable trace 
of phosphoric acid. A very perceptible trace of cobalt was 
Fe 94:00 Mn 0°63 FH 5°35 = 99-98 
Oxygen, 28-20 019 4°75 
Sh diskeeper cia sd 
28-39 
giving the oxygen ratio 6:1 or Bett. 
. Nee Lae y ai 
this article, gave 5:34 
cial attention to 
eee hee 
per cent, and Prof. Roepper calls espe 
w 3 
eee College collection, a fine specimen of the red hydrate 
Of ee specimens from Salisbury in Connecticut. A mineral 
of like composition has also been found by Bergemann* at the 
Louisa Mine near Horhz usen in Prussia. From these numerous 
* Ratanelshiers: Benth, 6. v0: 
3.4. : oee 
vou 
