50 MR, hatchett's experiments 



nevertheless be advantageoufly employed in analytical opera- 

 tions, when alternately ufed with alcohol. 

 Boracic add 9. A faturated folution of boracicacid in water, diflblves the 



fcarcely aftj on colouring extracl ; but, as the efFeft does not furpafs that of 

 water alone, we may conclude that lac is little, if at all, adled 

 upon by boracic acid. 

 Borax renders it 10. It has been already Hated, that fub-borate of foda or 

 rotable in water. borax has a power f u i e ff e & on \ ac> f as to ren der it foluble in 

 water; and, as the preceding experiments prove that boracic 

 acid alone fcarcely a£ts upon lac, there is every reafon to be- 

 lieve, that the excefs of foda prefent in borax is the aclive fub- 

 ftance; and this conclufion will be confirmed, by the refults of 

 fubfequent experiments made with the alkalis. 

 Froportion, &c. In order to render lac (efpecially (hell lac) foluble in water, 

 about j- of borax is neceflary ; and this may be previoufly dif- 

 folved in the water, or may be mixe^d and added together with 

 the lac. 



The beft proportion of water to that of lac is 18 or 20 to 1. 

 So that 20 grs. of borax, and four ounces of water, are, upon 

 an average, requifite to diflblve 100 grs. of (hell lac ; but more 

 water may be occasionally added, to fupply the lofs caufed by 

 evaporation during the digeftion, which mould be made nearly 

 in a boiling heat. 



This folution of (hell lac is turbid, and of a reddifli-brown 

 colour; when confiderably diluted with water and agitated, a 

 weak lather is formed ; it is decompofed by acids, and the lac 

 is precipitated in yellow flocculi, which do not apparently 

 differ from the lac originally employed. 

 The rotation is The general properties of the folution fliew, that it is a 

 aToap of difficult f a p onaceous compound, which, being ufed as a varnifli or 

 vehicle for colours, becomes (when dry) difficultly foluble 

 in water, although this was the liquid employed to form the 

 folution. 



A white thick fcum or cream collects on the furface of this 

 liquid, after it has been Suffered to remain tranquil for fome 

 time, and is found to be produced by a fort of wax, which I 

 fhall more particularly notice when the analyfes of the va- 

 rieties of lac are defcribed ; but, in the prefent cafe, this wax 

 appeared in fome degree to be converted into an almoft info- 

 luble foap by the alkali of the borax, and may be regarded as 

 the principal caufe of the turbidnefs of the folution. 



11. The 



