252 On Spontaneous Inflammations . 
places, in turf, and in several kinds of white wood. By 
reducing these kinds of wood to charcoal there is some- 
times formed a small quantity of phosphorus, which may 
remain combined with the same bases which retained the 
phosphoric acid before the combustion : phosphorus, by 
contracting other combinations, may be no longer suscep- 
tible of producing any accident ; but it may happen also, 
by the concurrence of various circumstances, that char- 
coal impregnated with any phosphuret, when exposed to 
the action of warm and moist air, will disengage phos- 
phorated hydrogen gas, which by the contact of the at- 
mospheric air may kindle, and communicate inflammation 
to the mass of charcoal. 
Two instances of this kind of spontaneous combustion 
took place in the powder manufactory of Essone in the 
years 8 and 10. The first time the fire broke out in the 
box for sifting the charcoal, and the second time the char- 
coal repository took fire, without room being left for sus- 
pecting that it could arise from any thing but spontane- 
ous inflammation. The different reports on these two 
events were inserted in the public journals, but the ex- 
planations given were not sufficiently satisfactory. It 
appears very probable that they were occasioned by some 
phosphorus contained in the charcoal ; and this expla- 
nation is the more founded in reason, as the alder wood 
used at Essone as well as in most of the powder manu- 
factories, and which on many accounts deserves the pre- 
ference over other kinds of wood for the making of gun- 
powder, contains phosphoric acid ; at least that which 
grows in our neighbourhood does. 
Charred turf begins to be used in some manufactories, 
and for different operations ; but as it is much disposed 
to spontaneous inflammation, the use of it ought to be 
abandoned, or great care should be employed in preserv- 
ing it Magazines of this substance, both at Paris and 
