On Spontaneous Inflammations* 245 
importance to make them known, in order to guard 
against the danger of them. We have instances of fires 
produced by glass decanters filled with water and expo- 
sed to the sun in an apartment. When the form of the 
vessel is nearly similar to that of a lenticular or spherical 
glass, the rays are refracted, and produce, by uniting in 
the focus, a heat capable of setting fire to combustible 
bodies placed in it. 
8. Heat excited in non-combustible bodies . 
It is well known that quicklime immersed in water, or 
merely moistened, produces a considerable degree of heat. 
It has even been employed with success for heating at a 
small expense apartments, hot-houses, hot-beds, &c. 
This property which quicklime has of disengaging a 
great deal of caloric by contact with the air, and that no 
less dangerous of dissolving and corroding animal sub- 
stances immersed in it, require the greatest precautions 
where considerable depots of quicklime are formed. To 
preserve it, care must be taken to guard it from the con- 
tact of the air, and from moisture of every kind ; and 
particularly to remove from its neighbourhood all com- 
bustible bodies, such as wood, hay, straw, &c., which 
might inflame spontaneously should the lime contract the 
least humidity. The Journal de la Houte-Sadne gave an 
account last year of the burning of a barn, one of the par- 
titions of which being wood had caught fire, because a 
heap of quicklime, intended for repairing the farm-houses, 
had been carelessly throw n against it. 
A great number of similar phenomena take place in 
nature, where bodies, by changing their composition, or 
contracting new combinations, become so heated, or dis-, 
engage so much caloric, that other combustible substan- 
ces around them may be inflamed. 
