86 
MISCELLANY. 
he has found that the combination is effcted by the fermentation of organic 
substances universally distributed over the surface of the soil, even when 
on account of the smallness of their quantity and the slowness of their 
operation no rise of temperature takes place. 
By exposing- fermentable bodies in pieces of the size of a nut to the 
mixed gases, M. de Saussure has arrived at the following conclusions : — 
The combination of hydrogen and oxygen gases may be effected without 
inflammation at the temperature of the air, by bodies submitted to slow 
fermentation. 
They usually produce this combination when they are accumulated and 
impregnated with a sufficient quantity of water to prevent their complete 
contact with the oxygen gas. If this contact be made by increasing the 
surface of the fermentable body, or by diminishing the quantity of water, 
the hydrogen gas, is not absorbed, and the oxygen gas disappears in other 
combination. 
The porosity of the fermenting body greatly contributes to the destruc- 
of the detonating mixture. 
Many observations prove that the hydrogen gas which disappears by 
fermentation combines with the oxygen gas, in the proportion of the ele- 
ments of water. The demonstration requires that the oxygen shall be 
employed only to form this water, and all the carbonic acid produced in 
the operation. 
The fermentable substances mentioned in the memoir do not effect the 
combination of the oxygen and hydrogen gases before they ferment, nor 
when the fermentation is stopped by an antiseptic. Soils and humus, 
mixed w r ith different earths, undergo a slow fermentation as soon as they 
are moistened, which gives them the power of destroying the mixture of 
oxygen and hydrogen gases. 
Gaseous oxide of carbon, and carburetted hydrogen gas, obtained by de- 
composing water with red-hot iron, were not destroyed by fermentation 
when they were substituted for common hydrogen gas, in the explosive 
mixture formed of two volumes of hydrogen gas and one volume of oxygen 
gas. Azotic, hydrogen and oxygen gases, added to the explosive mixture, 
do not present any remarkable obstacle to the destruction of an explosive 
mixture by a fermenting body, nor to that which is effected under the same 
circumstances by a plate of platina recently cleaned. 
Oxide of carbon, and olefiant gas and others, which prevent the combi- 
nation of oxygen and hydrogen by platina, are also great obstacles to the 
same result of fermentation. 
Nitrous oxide, added to the explosive mixture, was partly decomposed 
by fermentation, and did not prevent the combination of the hydrogen and 
oxygen gases. — Bibl. Univ, Feb, 1838. Sup, to Land, <$r Edin, Philos, 
Mag, 
