_ D.M. Balch on Orthite from Swampscot, Mass. 349 
orthite of this locality appears always to occur massive, at 
specimens that I have founds} i f crystal faces, 
sAtaSi i any Signs ol! crysta: 
Sp. gr. at 18° C. 3-69—3'71. Lustre, resinous and in some 
ases nearly vitreous. Color, jet black, and streak gray, Heated 
n thin splinters before the blowpipe, fuses slowly to a black blis- 
glass; dissolves readily in borax and gives a globule, red 
when hot, but yellow after cooling; with soda gives a slight man- 
gahese reaction ; in its natural state is very easily decomposed 
hydric acid, but after ignition is not affected by it in the least. 
Asmall portion being reduced to powder, dried at 110° C., 
and then ignited, lost 1:49 per cent of combined water. 
_ The preliminary analysis was performed on -445 grms.; from 
it I ascertained the composition of the mineral, but was unable 
to determine accurately the amount of those substances present 
ia small quantity. My method of analysis was that given by 
Wohler,* in which cerium, yttria, &c., are separated from iron 
and alumina by moist carbonate of baryta. The following re- 
sults were obtained : 
Silica, - - - : -— 82°62 
Alumina, z i i - a 
Ferric-oxyd, t wing 
Ceric-oxyd, de. = - : - - 24-14 
Lime, - - - 805 
gn ee ; 
. The ceric oxyd, &c., weighing about a decigramme, ‘was exam- 
ied for yttria, and abundant traces of it found; also inconsider- 
The succeeding analyses undertaken paren, to ascertain 
ucted as follows: A 
aid being added during th ration to peroxydize the iron) 
and Ses oF ae a Les ficats from the 
Magnesia being held in solution by the chlorid of ammonium 
formed by the excess of chlorhydric acid wigngs in the liquid ; 
this precipitate, which I will designate by @, was completely 
ashed by washings, 
from the lime magnesia was precipitated by phosphate of sod 
*0rn t] precipi MB gine! a, 
48 I did not mena 40 determine ss 
2% tracess that it was disregarded. _ ; 
Tn order to separate the ceric-oxyd and yttria from sesquioxyd 
* Practische Uebungen in der chemischen Analyse, Gottingen, 1853, 8, 112. 
