434 PHILOSOPHICAL TRANSACTIONS. ^ANNO 1794, 



naked fire ; but on heating oxalic acid to a much less degree it evaporated, and 

 left not a trace behind, (g) Carbonate of lime (chalk) readily dissolved, with 

 effervescence, in the liquid (c). The solution tasted bitterish, did not turn 

 paper stained with turnsole to a red colour, and a copious precipitation ensued 

 on adding to it carbonate of potash (mild vegetable alkali). A little of this so- 

 lution of lime, and also of alkali, being evaporated to dryness, and the residue 

 being made red-hot, nothing remained but carbonate of lime, and carbonate of 

 pot-ash. (h) The above distilled liquid (c) did not render nitrate of lime tur- 

 bid ; but (i) it produced turbidness in nitrate and muriate of baryt. 



(k) To 500 grs. of the reddish coloured liquid obtained by melting white lac, 

 I added ley of carbonate of soda, till the effervescence ceased, and the mixture 

 neither reddened paper stained with turnsole, nor turned paper stained with tur- 

 meric to a brown colour. The quantity of dry carbonate of soda used in the 

 ley was 3 grs. A quantity of mucilaginous matter, with a little carbonate of 

 lime, was precipitated during this combination. The saturated solution being 

 filtrated and evaporated to a true degree, it afforded on standing, deliquescent 

 crystals. (1) A little of the crystallized salt (k) by exposure to fire left only a 

 residue of carbonate of soda, (m) The reddish liquid obtained by melting the 

 white lac being filtrated, the following precipitants were added ; namely, 



1. Lime-water, which produced a light purple, turbid appearance, and on 

 standing, there were just perceivable clouds. 2. Sulphuret of lime (calcareous 

 liver of sulphur) occasioned a white precipitation ; but I could not perceive the 

 smell of sulphurized hydrogen gaz, (hepatic air). 3. Alcohol of gall-nut (tinc- 

 ture of gall-nut) induced a grey precipitation. 4. Sulphate of iron (green vi- 

 triol) produced a purplish colour, but no precipitation ; nor did any precipitation 

 take place on adding to this mixture first a little vinegar, and then a little pot- 

 ash. 5. Acetiteof lead (sugar of lead) occasioned a reddish precipitation, which 

 re-dissolved on adding a little nitrous acid. 6. Nitrate of mercury (solution of 

 mercury in nitrous acid) produced a whitish turbid liquid. 7. Oxalic acid pro- 

 duced immediately a precipitation of white acicular crystals. 8. Tartrite of pot- 

 ash (soluble tartar) being added, a precipitation took place which much resem- 

 bled that which takes place on adding tartareous acid to tartrite of pot-ash ; but 

 the precipitated matter by the liquid from the white lac did not re-dissolve on 

 adding pot-ash. 



With respect to the nature of the liquid contained in white lac, it perhaps be- 

 longs to the genus of acids, because it changes turnsole to a red-coloured sub- 

 stance, and neutralizes fixed alkali and lime (g) (k). This acid liquid is most 

 probably secreted at the same time with the white lac ; and therefore the white 

 lac coccus, like the ant, and some other insects, has organs for secreting an acid. 



