208 J.D. Whitney on Algeriie and Apatite. 
very little acted on by chlorohydrie acid, even when digested 
with it fora long time. The acid however took up a small por 
tion of lime which was intimately disseminated through the min- 
eral in the form of a carbonate. After the ignition it was no- 
ticed that portions of the ignited mineral remained nearly unal- 
- tered in appearance, while the larger part acquired a brick-red 
color, and on examination with the microscope was seen to coll 
tain silvery white scales, apparently of mica. 
As only a small quantity could be used for analysis, the results 
can be relied on only as approximately correct. ‘They are as 
follows : . 
Silica, - - - - - - 52:09 
Alumina, and a little Pe, —- - - 18-63 
Phosphate of lime, - - - . 8-22 
Carbonate of lime, -  - - - 4-41 
ater, - - - - - - 6:68 
Loss, potash and soda? wichita - 9:97 
100-00 
The difficulty of reconciling this analysis with either of those 
cited above, on the hypothesis of the algerite being a mineral of 
a fized composition, will be apparent. Several specimens were 
examined and all were found to contain phosphate of lime. — 
_ Scapolite is, of all others, a mineral which seems most liable 
to metamorphosis. Numerous examples of this will be found in 
Bischof’s “ Lehrbuch der chemischen und physikalischen Geolo- 
gie” (ii, 403, 1433, &c.). It is proved by the analysis of a mica 
in the form of scapolite (from Arendal) that all the lime of this 
mineral may be removed and a part replaced by potash. It is 
proved by numerous analyses that a portion of the lime may 
main in combination with carbonic acid. It is also demonstrated 
that the lime may be exchanged for magnesia so as to give ris 
o a magnésian mica; also that the entire mass may be ¢0P 
verted into steatite, or a hydrous silicate of magnesia. My analy- 
sis shows in addition to these facts, that in the process of mela 
morphosis a part of the lime may enter into combination with 
phosphoric acid. i is iuteresting to notice, in this connection, 
the analyses by Messrs. Brewer and Garrett of a substance V 
similar in composition to the Algerite, and also evidently 0 a 
tered scapolite, which are published in Dana’s Mineralogy, uh 
edition, p. 680. 
So much is evident, that the Algerite is not a homogeneous 
mineral and cannot claim to rank as a distinct species; and vat 
highly probable that it adds one to the already numerous list 
the products of the transformation of the scapolite family- Fur 
ther analyses of specimerts from this locality, if such can be ob- 
tained, will throw more light on this interesting subject. 
