130 O. D. Allen—Hatchetiolite and Samarskite. 
per cent. Iron was — assumed to exist as protoxide 
and uranium as U A calculation of the relative number 
of atoms from No..: 1 wae the following : 
Atomic weights. T : 
182 a "13 ; 
95 Cb 252 t “ 
50 Ti 020 
U 240 UO, 054 
Fe "030 
Mg “004 } 268 
Ca "158 
Na, 022 
H,O0 255 
Ss 
n 002 
Disregarding the small amount of tin or tungsten and deduct- 
ing Ti with R sufficient to form with it normal titanate, there 
remain R 248 R 386 H,O -255, whence R: R: H, O= 228-4; @ 
a ratio closely approximating to that required by R, R, 2H,O or 
R, R, O, +2RR, O,+4H,0, in which R represents one atom 
of a bivalent basic radical or two of sodium and R, Ta, or Ob. 
The investigations of Rammelsberg* lead to the sudihsiobie that 
three columbates 5 (in which Cb may be replaced by Ta) occur 
in minerals, viz: RCb, Ae R, Cb,0., and R Cb, O,, correspond- 
ing to phosphates and “arsenates ; which, singly or combined 
with iat) other, with or without titanates., zirconates, thorates, 
éte., vabininace mineral species. Hatchettolite appears to be 
rst two with a small quantity of normal titan- 
ate.t It it perhaps questionable whether there is any signifi- 
cance in the fact that the amount of water present bears 
simple ratio to the other constituents. 
Some pew from one side of the specimen uae Bip ie 
material for analysis was selected had the specific gra 
4°60 to 4°70 per cent and were rejected. They lost ne ‘Daition 
4°97 per cent. Hatchettolite may have resulted from alteration 
of a mineral having essentially the same chemical constitution, 
as well as crystalline form, as pyrochlore, an alteration consist- 
ing of hydration and removal of alkaline fluorides, 
Il. Samarskite. 
marskite from Mitchell Co., mite to the analysis of 
the writans has the following compositio 
* Jour. Chem. Soc., vol. xxv, p. 1 
Ph mara (Jour. Chem. Soc., vol. Xxv, p. 203) supposes that these three 
compounds may isomorphous, and that they exist in the isometric crystalline 
on Ba 
Dd Beats Sons Bitie ot Mincealogy, p. 340, March, 1877. 
