General Science. 4*01 
afterwards brought to this country, has been, repeated several 
times, and the Dutch pound Troy loeiglit wa^ found equal to - 
492,1677^ grammes. Now, supposing that one gram English 
Troy is equal to 0,0647508 grammes, we have . 
Log 492,16772-^.69^1181 
Log 0,0647508 = 8.8112458 
8,8808678 Number is 7600,95 
5 0 
2 B' 
Therefore, I conclude, that the Dutch Troy weight, as actually 
in use in this country, is 7600,95 English Troy grains, which 
leaves a difference of 79 grains in the pound with Mr Ander- 
son’s statement. The standard of the Dutch Troy weight, 
which was in use in 1558, in the reign of Charles V., is still 
preserved, and it may be shewn that this standard underwent 
no alteration since that time. This old standard is somewhat 
lighter than that which is used now, the difference being abdut 
288 milli-grammes in the pound of Dutch Troy weight.” — 
Letter front Professor Moll of Utrecht. 
57. Detonations in Mount Brasier. — M. Dubois Ayme exa- 
mined, in 1818, the structure of the mountain (situated be- 
tween Senes and Lardgne in the Alps) which is known to 
emit flame, and to produce detonations, which are most fre- 
quent when the wind is in one direction. He found that there„ 
were beds of pyritous-chalk, marly schists, radiated sulphuret of 
iron, and bituminous substances, &c. in tlie strata of limestone 
that formed its sides, and he supposes that the flames and deto- 
nations are produced by the accidental inflammation of hydro- 
gen liberated by the action of water on the above substances. 
58. Method of rendering Cloth mcombustihle.—M.. Gay Lns- 
sac has found, that the most effectual solutions for rendering 
cloths incombustible, are solutions of muriate, sidphate, phos~ 
phate and borate of ammonia, with borax, and also some mix- 
tures of these salts. M. Merat Guillot of Auxerres has 
shewn, that the acidulous phosphate of lime possesses the same 
property. When linen, muslin, wood, or paper, are dipped in 
a solution of that salt, of the specific gravity of from 1.26 to 
1.30, they become completely incombustible. They may be char^ 
red by an intense heat, but they will not burn. 
