Annual Report of the Consulting Chemist. 
193 
which occurred last July in hauling, by means of a locomotive 
engine, a waggon laden with artificial manure and nitrate of 
soda from the Tunbridge Railway Station to a farm in the 
country. This accident illustrates the danger of a spark of fire 
.coming in contact with bags containing nitrate of soda and 
with wood or other combustible materials. 
Mr. Thomas Aveling, my informant, wrote to me as follows : — 
" Dear Sir, " Rochester, July 2Gtli. 
" The following are the particulars of the nitrate of soda fire case. On 
the 8th instant, a road locomotive engine, belonging to Mr. Whitfield, was 
employed hauling waggons laden with artificial manures from the Tunbridge 
Railway Station to the farm of Mr. Rales at Hadlow. Immediately the 
engines started, the first waggon, containing two tons of nitrate of soda, was 
observed to be on fire. Volumes of smoke, accompanied by a considerable 
hissing noise, burst from the bags, and so quick was the combustion that it 
was found to be impossible to save the waggon, which was entirely burnt. 
The soda became a burning liquid, as it ignited and flowed some yards over 
the road. Water had no effect in extinguishing the fire. The engine-driver 
was rendered insensible by the fumes in his endeavour to detach the engine 
from the train. Would any mixture of lime, &c, with the nitrate of soda 
cause spontaneous combustion, or is the accident to be attributed solely to a 
spark from the engine ? I send a specimen of the residuum. 
" Yours faithfully, 
" Dr. A. Voelcker." " Thomas Aveling. 
On examination of the specimen sent to me by Mr. Aveling, 
I found it to be chiefly fused nitrate of soda. 
Nitrate of soda is a readily fusible salt, and, like ordinary 
saltpetre, is a strong supporter of combustion, for at an elevated 
temperature it gives off a large quantity of oxygen. The 
nitrate of soda bags are necessarily impregnated with this 
salt, and are in much the same condition as touchpaper or a 
fusee. A single spark from an engine or a lucifer-match care- 
lessly thrown amongst a lot of nitrate of soda bags, under 
favourable circumstances, may kindle the bags, and any com- 
bustible matter, such as wood, upon which they are placed ; and 
when once the fire is started, the heat will soon become so high 
as to fuse the nitrate of soda, which in this fused state, as 
described by Mr. Aveling, will spread like liquid fire, and 
render its extinction by water extremely difficult, if not im- 
possible. 
During the last twelve months numerous samples of Peruvian 
guano passed through my hands. The former supplies from 
Guanape and Macabi islands, containing on an average about 
12 per cent, of ammonia, being exhausted, the deposits in the 
South of Peru have been taken in hand by the contractors for 
the sale of Peruvian Government guano. The Southern de- 
posits are now and will be the main, if not exclusive, sources 
from which Peruvian guano will be supplied in future. 
VOL. XIII. — S. S. 
