ADDITIONAL CHEMICAL EXAMINATIONS. 603 
Alumina, wikeapiar in sith 
Oxide of iro 1:2 
Magnesia, te fe 0:73 
Manganese, 4 9 
otash 7 
Soda, : 1-1 
Water, 
This mineral does not agree exactly in composition with any mineral of which I have seen an analysis. 
It comes nearest in its composition to a variety of Phillipsite from Iceland, analyzed by Damour, except 
that magnesia replaces the lime in Phillipsite, and this mineral would therefore be a magnesian Har- 
motome. 
It differs, too, in its degree of hardness, from the Phillipsite, or lime Harmotome. 
e magnesian Harmotome from Minnesota decrepitates before the blow-pipe, and fuses to a nearly 
colourless blebby glass, with a faint tinge of yellow 
The analysis of this mineral gives a slight excess, hich ought probably to be deducted from the alumina, 
which being bulky was very difficult to wash clean. 
It exists in the cells of the amygdaloids of Kettle River, in its nascent state, and could be spread 
with a knife, just like the saponite mentioned by Alger, who states that some of the miners of Brucks- 
veden tried to eat it as a substitute for butter. 
ANALYSES OF OTHER MINERALS FROM THE NORTH SHORE OF LAKE SUPERIOR. 
An analysis of a radiated mineral, of a wavy lustre and silky fibrous structure, in the cells of the 
amygdaloid No. 371 of Dr. Norwood’s collection, from the northwest shore of Lake Superior, probably 
a variety of mesole, gave the following results :— 
Water, H = 12 
Silica, Si = 43 
Alumina, Al = 25 
Lime, Ca ae'g 
Magnesia (with a trace of | Mn), Mg = 10 
Oxide of iron and matter insoluble in potash, Fe = 2 
Alkalies, . ‘ . , ; . 5 4 
99 
The analyses of different varieties give considerable variation in the amount of lime and magnesia, as 
if they replaced one another in the mineral in question. 
The following is an analysis of a light-red, foliated mineral, having a pearly lustre encrusting argil- 
laceous iron ore, collected by Dr. Norwood, on the northwest shore of Lake Superior : 
Water, H = 14-000 
i Si = 55-200 
Insoluble silicates of alumina, lime, and alkalies, 7734, . , = = 10-400 
Ca — 5:184 
Alk— 6:°556 
Oxide of iron, z ‘ a trace. 
Alumina, dissolved by HCl, . : ; ; . Al = 7-040 
Alkalies, with a trace of Mn, 1-600 
Loss, 00-02 
100-000 
The silica in this mineral agrees best with stilbite, but the water is more nearly that existing in Heu- 
landite; the lime is nearly 2 per cent. less than in stilbite, and the alkali 4 to 6 per cent. in excess, but 
