VOL. LXXXIV.] PHILOSOPHICAL TRANSACTIONS. 435 



As this acid is destructible by fire (f) (g) (1), and as it affords carbon (f), it must 

 be referred to the animal or vegetable acids. 



From the precipitation of tartrite of pot-ash (m, 8) resembling tartar, this 

 acid might be supposed to be the tartareous ; but as this precipitate is not again 

 dissolved on adding pot- ash ; as it has no sour taste (c) ; as it evaporates in 200" 

 of caloric (b) : as the combination with lime is readily soluble in water, and de- 

 composed by pot-ash (g) (m, l) ; and as the combination with soda is a deli- 

 quescent salt (k), this acid cannot be considered to be the tartareous. Nor does 

 this liquid appear, from the above experiments, to be any one of the other known 

 vegetable or animal acids. The other properties, shown by the experiments, 

 except the precipitation of tartrite of pot-ash, and the peculiar smell above- 

 mentioned, are either those common to every species of acid, or are possessed 

 by several of them. For though this acid possesses several properties common 

 to all acids, and some properties which belong to a few species only, there is not 

 any one of the already known acids that has the smell, when heated, above-men- 

 tioned ; that precipitates tartrite of pot-ash, but does not serve to compose aci- 

 dulous tartrite of pot-ash ; that, besides having these properties, is vapour in the 

 temperature of 200° without decomposition, has not a sour but a bitterish taste, 

 and forms a soluble compound with lime, which is decomposable by pot-ash. 



The precipitation by oxalic acid, it is probable, was occasioned by a small 

 quantity of lime which the undistilled liquid of white lac contains. The other 

 phenomena in the experiments I do not refer to, because they are produced by 

 acids in general. Whether the above liquid from white lac be a new acid, or 

 one of the acids already known, but disguised by mixture or union with other 

 bodies, I leave to the decision of future experiments, and to the judgment of 

 learned chemists. 



f^I. Remarks and ConcltLsions from the preceding Observations and Experiments. 



1. White lac being unctuous when in a fluid state; having little or no smell 

 and taste, unless heated ; being insoluble in water ; being inflammable in oxygen 

 gaz ; and decompounded by fire alone, in close vessels, before evaporation ; it 

 seems to belong to the genus of fat, or fixed oils : — but it differs from them, and 

 resembles the volatile oils and resins, in being brittle and semi-transparent ; in 

 being soluble in alcohol ; in composing an imperfect soap with fixed alkalis ; in 

 dissolving readily in sulphuric ether. 



2. As bees-wax and white lac seemed to be alike in many properties, I exten- 

 ded the comparison by some experiments on bees-wax. Bees-wax when first se- 

 creted is, I believe, always white, and it is often white when made into the 

 comb. It remains white after being melted. White lac becomes yellow on 

 purification by melting and straining. Bees-wax has a peculiar smell when cold. 



3k2 



