ra 
J. Lawrence Smith on Emery. 63 
* 
The method of analysis, was to break the mineral in small 
fragments, to place it in a’small platinum crucible, which was in- 
troduced into an earthen crucible and surrounded by pulverized 
quartz: in one word, I pursued the same method as that for esti- 
mating the water in emery. For the other ingredients, a new 
portion was taken, pulverized finely, and attacked either by 
concentrated sulphuric acid or melted with carbonate of soda, 
and afterwards dissolved in hydrochloric acid with the addition 
of a little nitric acid evaporated to dryness, and treated with di- 
lute hydrochloric acid. The liquid separated from the silica is 
treated with an excess of caustic soda, and the filtered liquid is 
neutralized by hydrochloric acid and the alumina precipitated by 
carbonate of ammonia. 
The contents of the filter which are essentially peroxyd of iron, 
are placed in a capsule, dissolved by hydrochloric acid, heate 
and precipitated by ammonia and thrown on a filter. From the 
filtered solution the lime and magnesia are separated in the ordi- 
nary way. The peroxyd of iron remaining on the filter after be- 
ing well washed and dried, is weighed and decomposed 1n a cur- 
rent of hydrogen gas. ‘To the oxyd thus reduced, nitric acid di- 
luted with thirty times its weight of water is added, and digested 
at 100° to 120° C. for about an hour, stirring frequently, when if 
the iron has been thoroughly reduced it will be taken up by the 
acid, and a little alumina left which ‘is weighed and added to the 
first portion. Ordinarily I never have found more than from 
one to two per cent. of alumina with the oxyd of iron. Care 
must be taken to decompose the iron completely, as otherwise 
the iron will not be entirely taken up by the acid. ‘The min- 
eral thus analyzed afforded as follows :— 
Magne- | Titanic | Manga- Potash 
sia. 
acid. nese. |& soda 
Silica. 
Alu- |ar iron. Water Lime. 
Sen ae RED Sea mina, jof iron Sa. 
Decomposed by not es-\not es-not es-jnot es- 
sulphuric acid,| 24-10! 39°8 | 27-55| 65 |timat'd|timat’d|timat’ditimat’d) 0°30 
ecomposed 
carb. soda, .. .|23-94| 39°52 | 28:05) 7-08| 0:45 | 0°80 | érace.| 052 —— 
Decomposed 
es-| 
|_ carb, soda, ...|23-20| 40:21 | 27-25 697] 0°83! 0°95 | trace, |timat'd —— 
These analyses correspond to the following composition. 
Atoms. At. weight. Prec 
Silica, 2 1133-40 23-87 
Alumina, 3 1925-88 40-57 
Protoxyd of iron, 3 1350-00. 28-44 
_ Water, 3 337-50 7:12 
The most probable formula is 
ee Ai Sithe® Sisk 
