On Spontaneous Inflammations . 103 
stances and tied up ; the compound remained cold and 
quiet. 
Russian fir-black, mixed with equal parts of oil of 
turpentine, aud bound up, exhibited not the least re-ac- 
tion or warmth. 
Birch-oil, mixed with equal parts of Russian fir-black, 
and bound up, began to grow warm and to emit a vola- 
tile smell ; but the warmth soon went off again. 
From the experiments of the Admiralty, and of Mr. 
Georgi, we learn, not only the decisive certainty of the 
self-aecension of soot and oil, when the two substances 
are mixed under certain circumstances, but also the fol- 
lowing particulars. 
Of the various kinds of soot, or lamp-black, the expe- 
riments succeeded more frequently and surely with the 
coarser, more unctuous, and heavier, like Russian pain- 
ter’s black, than with fine light German rahm , or with 
coarse chimney-soot. In regard to oils, only those expe- 
riments succeeded which were made with drying oils, ei- 
ther raw or boiled. The proportions of the soots to the 
oils were, in the successful experiments, very various ; 
the mixture kindled with a tenth, a fifth, a third, with an 
equal, and likewise with a double, proportion of oil. In 
general, however, much more depends on the mode of 
mixture, and the manipulation ; and, as Mr. Georgi often 
observed, on the weather : for, in moist weather, the bun- 
dles, after becoming warm, would frequently grow cold 
again. 
It is in all respects remarkable, that it should never 
till now have been observed, that a mixture which has 
been made millions of times, in all proportions and quan- 
tities, for painting of ships, and the outsides of wooden 
houses, and sometimes intentionally, sometimes acciden- 
tally, left covered or open, a longer or a shorter time, 
should be capable of kindling of itself. It is highly pro- 
