TOL. LXXXIV.] PHILOSOPHICAL TRANSACTIONS. 449 



various experiments, by which I found that it contained barytes, calcareous 

 earth, and carbonic acid. 



One hundred grs. of this substance were dissolved in marine acid, during 

 which 15 grs. of carbonic acid were separated; the solution was gently eva- 

 porated, and exposed to crystallize. The crystals were then exposed for some 

 time to air in a funnel, during which part of the crystals had deliquesced. When 

 no more deliquescence was observed, the whole liquor was diluted with a suffici- 

 ent quantity of distilled water, and diluted sulphuric acid was then added, by 

 means of which 2 grs. of barytes were separated. The filtered liquor was then 

 decomposed by alkali, and 12 grs. of calcareous earth were separated. The dry 

 crystals remaining on the funnel were then dissolved in distilled water, and also 

 decomposed by alkali, by means of which 68 grs. of barytes were obtained. 



According to these experiments, 100 grs. of this crystallized substance yielded 

 by decomposition 70 grs. of barytes, 15 grs. of carbonic acid, and 12 grs. of cal- 

 careous earth. The difference of the 3 remaining grs. may be accounted for by 

 the water, by the small loss which was observed when the crystallized substance 

 was exposed to a strong heat, and also from the crackling which was perceived 

 when exposed to a sudden heat. Whether this crystallized substance is different 

 from that specimen which Dr. Withering analyzed, or whether the calcareous 

 earth escaped his observation during his experiments, I cannot decide, as he does 

 not mention that he employed the substance in a crystallized state for his 

 experiment. 



XKV. Account of a Spontaiieous Inflammation. By Isaac Humfries, Esq. 



p. 426. 

 " On going into the arsenal a few mornings since, I found my friend Mr. 

 Golding, the commissary of stores, under the greatest uneasiness in consequence 

 of an accident which had happened the preceding night. A bottle of linseed oil 

 had been left on a table, close to which a chest stood, which contained some 

 coarse cotton cloth ; in the course of the night the bottle of oil was thrown 

 down, and broken on the chest probably by rats, and part of the oil ran into the 

 chest, and on the cloth : when the chest was opened in the morning, the cloth 

 was found in a very strong degree of heat, and partly reduced to tinder, and the 

 wood of the box discoloured, as from burning. After a most minute examina- 

 tion, no appearance of any other inflammable substance could be found, and how 

 the cloth could have been reduced to the condition in which it was found, no one 

 could even conjecture. The idea which occurred, and which made Mr. Golding 

 so uneasy, was that of an attempt to burn the arsenal. Thus matters were when 

 I joined him, and when he told me the story and showed me the remainder of 

 the cloth. It luckily happened that in some chemical amusements, I had occa- 



VOL. XVII. 3 M 



