424 Dr. Genth’s Contributions to Mineralogy. 
Mr. Chas. A. Kurlbaum, Jr. has examined the green mineral, 
which was apparently quite pure and obtained the following 
result : - 
Silicie acid, - - 0-72 p.c. 
Phosphoric acid,  =—- 3261 “ contains oxygen 18:28 
Protoxyd of iron, of i “5 * 0°84 
esquioxyd of iron, - 5374 “ . 4 16:10 
Waiter, - - 10°49...“ * ie 9°32 
100°95 
From the oxygen ratio of POs: FeO: FezOs: HO, we find 
that the atomic ratio is 8°65: 0°84: 5°87 : 9°83, which is 
ual to 13 .c* S-210-«2. 88,3, of 
nearly gives the formula: 
(8FeO, POs +8HO)+6(8Fe20s, 2PO5+4H0). 
It appears that the mineral analyzed contained some vivianite 
mixed with it, and that the formula of the pure dufrenite would 
4HO 
€2VU3, 5 . ' 
The calculated percentage corresponding with this formula is: 
Phosphoric acid, - - . - - 84:10 
Sesquioxyd of iron, - - is . 5 Les 
Water, : : : : ‘ 859 
100 00 
It is remarkable that the amount of sesquioxyd of iron, caleu- 
lating all the iron as sesquioxyd, would be 57°51 p.c. It is not 
improbable that this dutrenite is in the state of alteration into 
vivianite. 
13. Hitchcockite (Shepard). 
Hitchcockite, according to Prof. C. U. Shepard’s statement (Re- 
port on the Canton Mine), is a “white earthy shell, sometimes n0 
thicker than a mere varnish,—a hydrated phosphate of alumina with 
oxyd of zinc,” and is enumerated by him amongst the “ores of 
zinc.” 
On my late visit to the Canton.Mine I procured a considerable. 
number of specimens of this interesting new mineral, and 
following are the results of my examinations. er 
‘With a good magnifier only it can be observed that this min- 
eral has a erystalline structure. It usually occurs in botryoidal 
concretions or small mamillary incrustations. Color white, yel- 
lowish, bluish and reddish-white; powder white. Lustre sub- 
resinous, subvitreous and dull. ‘Translucent. ns 
Tt has an argillaceous odor when breathed upon. Brittle; 
fracture uneven. H.=4°5. Sp. Gr. (at 20° Cels.) about + 
both in boilin nd chlorhydric 
tter. The following are the results of my analyses: 
