60 



than 5 grains or a 240th part of the whole mixture. The vial in which the 

 explosion was made had a glass lube about an inch & •§ long & ^^ of an inch in 

 bore fitted to its mouth, by way of contracting the orifice. 



I also tried the specific gravity of each of these parcels of distilled air in 

 my usual manner. 10,000 grains of the first distilled air being forced into a 

 bladder, which held 48,000 grains & had a brass cock fitted to it, the bladder 

 increased |- of a grain in weight on pressing out the air. So that, supposing 

 common air to be 800 times lighter than water, this air which was before 

 said to contain y^j of its bulk of common air should be about Jjrth part lighter 

 than common air ; & the pure factitious air without any mixture of common 

 air should be y^A or yjth part hghter than common air, or near 6| times 

 heavier than inflammable air from metals. 



21100 grain measures of the last distilled air being forced into the same 

 bladder, there was an increase of 12 grains on pressing it out; whence this 

 air appears to be lighter than common air in the proportion of 1 1 to 6, or 

 near 4 times heavier than the air from metals. 



The caput mortuum or matter remaining in the brass pot after the distilla- 

 tion was completed, consisting of the wood reduced to charcoal, weighed 134 

 grains. 



On the whole, the 400 grains of wainscot yielded with a heat less than suf- 

 ficient to make it red hot 9400 gra. measures of fixed air, whose specific gra- 

 vity was before found to be about If times greater than that of common air, 

 & 12700 of an inflammable air, which was about Jj parts lighter than com- 

 mon air, & which required to be mixed with more than 2ce its bulk of com- 

 mon air to make it explode. With a greater heat than that it yielded 5800 

 grains of fixed air, & 30700 of an inflammable air, which required to be mixed 

 with above 2i times its bulk of common air to make it explode, & whose den- 

 sity was -^ of that of common air. The weight of all this air together is 64 

 grains, id est, ^-^^ of the weight of the wood it was produced from, or near i 

 of the loss of weight which it suiFered in distillation. It must however be ob- 

 served that there was most likely more fixed air discharged than is here set 

 down ; as in all probability some of it must have been absorbed by the water. 



As this inflammable distilled air is much heavier than that from metals, & 

 requires to be mixed with a much greater proportion of common air to make 

 it explode, I at first imagined it might consist of an inflammable air exactly 

 of the same kind as that from metals, mixed with a good deal of air, heavier 

 than it, & which had a power of extinguishing flame like fixed air ; as I hinted 

 before with regard to the air produced from meat by putrefaction : but on con- 

 sideration, I fancy this must really be of a different kind from that of metals ; 

 for if it had been only a compound of that air with some of a different kind, 

 then a mixture of that compound with common air must necessarily, I think, 

 have exploded with less noise than a mixture of pure inflammable air with the 

 same proportion of common air; as it contains less inflammable matter than 

 the latter mixture, & that compounded with a substance which should rather 

 diminish than increase the explosion ; whereas the last distilled air was 

 found to make as great an explosion as the air from metals, when both were 

 mixed with 4 times their bulk of common air. 



