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POPULAR SCIENCE REVIEW. 
II. Applied Chemistry. — We have alluded above to the almost 
universal distribution of arsenic. A remarkable instance of the presence of 
this element, in comparatively large quantities, in a drinking water, lias 
recently been published. In the village of Bou-Chater (anciently Utica), 
there is a warm spring, which contains alkaline arseniates to the enormous 
extent of four grains to the gallon. The temperature of the spring is 
40° C. It is clear, and has no unpleasant taste; the villagers drink it 
after letting it cool. The water flows from a basin about two yards in 
diameter. It is confined by stones, and there an old tortoise lias taken up 
his abode, where he has lived from time immemorial, and is looked upon 
by the inhabitants as the genius of the place. The overflowings of the 
basin form a stream which, in the absence of a definite bed, spreads on 
all sides, forming a marsh of considerable extent, covered with rushes, 
Indian grass, and other plants peculiar to this kind of earth. The 
inhabitants make use of the stream for washing their linen and sheep’s 
wool, and along the course of it their flocks of all kinds drink habitually. 
It is supposed that this spring is the same as that mentioned by Csesar in 
his “ Commentaries ” as having such a terrible effect on the army 
of the Curio. M. Guyon, the chemist, who furnishes the analysis 
of the water, thinks that the spring was formerly more charged with 
arsenic than it is at present. It would be interesting for physiologists to 
study the influence which this water exercises on men and cattle, in 
reference to the recently raised questions on the economic action of 
arsenious acid. 
The manufacture of saltpetre is being carried on to some considerable 
extent in America, and native chemical talent is being strained to the 
utmost to produce it in quantities sufficient to render the Government 
independent of foreign supplies. It is now being made in the States of 
Tennessee, Alabama, Kentucky, and Arkansas, from nitrous deposits 
collected in caves. The crude material of which it is made is a greasy, 
tough, yellow clay, having a saline taste. The caves in which it is found 
are very irregular ; the best deposits being found in narrow crevices and 
dry localities amongst the rocks, where there are strong currents of air. 
It requires considerable experience to select the crude material. There is 
one establishment near Batesville, Arkansas, in which 1,000 lbs. of saltpetre 
are produced daily. It is not generally known that, during the previous 
war with England, saltpetre was manufactured in considerable quantities 
at the Mammoth Cave in Kentucky. 
A curious calculation, of especial interest to makers, has been made by 
a continental chemist. It is considered, by the most reliable authorities, 
that the tobacco crop of the whole world amounts to 250 millions of kilo- 
grammes per annum ; taking the plant to contain an average of five per 
cent, nicotine, that would give 12^ millions of kilogrammes of this poison 
produced annually. The specific gravity of nicotine being a trifle greater 
than that of water, this quantity would fill 100,000 barrels, and would 
give 293 grains to every man, woman, and child on the globe. As a few 
drops will produce death, it is probably much within the mark*to say, 
that the nicotine from one year’s crop of tobacco would destroy every 
