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200 Brush and Penfield—Scovillite and Rhabdophane. 
Art. XXIV.—On the identity of Scovillite with Rhabdophane ; 
by Geo. J. BrusH and Samuget L. PENFIELD. ~ 
Last spring we described a hydrous phosphate of the cerium 
and yttrium earths from Salisbury, Conn., as a new mineral, 
giving it the name Scovillite.* Our attention has recently 
been called to the close resemblance of this mineral with rhab- 
ophane, a mineral from Cornwall in England, originally de- 
scribed by W. G. Lettsom,t as essentially a phosphate of didy- 
mium and other cerium earths and supposed to be analogous 
to monazite in composition. A further investigation of rhab- 
relative amount of the constituent isomorphous earn he 
must conclude that the American mineral (scovillite) is esse 
ated with a carbonate of the composition R,(CO,), 3H,0. 
Assuming this to be true we have present in the analysis We 
have given 14-11 per cent of this carbonate with 85°72 per cent 
of R,(PO,), 2H,0. If we may calculate the theoretical compo 
sition of this phosphate, assuming the relation of the be 
_ to the cerium earths to be 1:4, we have P,O, 28°40, (Y,Er).8 
11°12, (La, Di),O, 53-28 H,O 7-:20=100. This is in close sive 
* This Journal, III, xxv, 459, June, 1883. b va 
+ Comptes Rendus, April 22, 1878. Communicated to the Academy PY ®” — 
de Boisbaudran. > ae 
Bulletin de la Société Minéralogique, iii, 61. ir 
Journal of Chemical Society, May, 1882, p. 210. 
