41 2 
Geology . 
5ly. Of the water. This is very important. All dirt, 
makes the colour dull All the earthy salts sadden the 
colour. If it contain non, it will give the violet tinge. 
It is indispensible to ascertain what iron it contains, and 
by evaporation of a quart of it, how much and what earthy 
salts it holds in solution. 
Hence, the making of the tin mordant for scarlet cloth, 
as well as the necessary examination of all the other in- 
gredients requires chemical knowledge to proceed with 
any degree of certainty. By and by it will be worth while 
for some chemist in this country to make the composi- 
tion as an article for sale. 
Common salt is not so good a vehicle of the tin as sal- 
ammoniac. 
Filings of tin are given as a medicine in cases of worms : 
but I do not know of any further use of this metal. The 
smoking liquor of Libavius is not of importance as yet 
in a manufacturing point of view. .* i 
GEOLOGY. 
Outline of Geology , by the Editor . 
Before I enter on the relative ages of metallic sub- 
stances, it may not be amiss to give a brief sketch of the 
formation of the earth, according to the best acknowledg- 
ed facts we possess, and the most probable opinions 
hitherto advanced. In doing this, I shall not scruple to 
blend my own views of the subject, with the remarks 
which I shall be induced to adopt from other writers, 
chiefly Werner, as exhibited by Jamieson ; confining my- 
self however, as well as I can, to fair deductions from 
known phenomena. 
