20 Experiments and Ohscrvatmis on Lac. 



Tlie proportions of the substances which compose the 

 varieties ot'lac, must however be subject to very consider- 

 able variations ; and we ought therefore only to consider 

 these analyses in a general point of view. Hence we should 

 state, that lac consists principally of resin, mixed with 

 certain proportions of a peculiar knid of wax, of gluten, 

 and of colouring extract. 



The relative quantity of the two latter ingredients very 

 considerably affects the characters of the lacs; for instance, 

 we mav observe that the glutinous substance, when present 

 in shell lac in a more than usual proportion, probably pro-« 

 duces the defect observed in some kinds of sealing-wax, 

 which, when heated and burned, become blackened by 

 particles of coal ; for the gluten affords much of this sub- 

 stance, and does not melt like the resin and wax. From 

 what has been stated, therefore, lac may be denominated a 

 icro-rts'ni, mixed with gluten and colouring extract. 



§ III. 



GeJieral Remarks. 



From the whole of the experiments which have been re- 

 lated, it appears, that although lac is indisputably the pro- 

 duction of insects, yet it possesses f(iw of the characters of 

 animal substances; and that the greater part of its aggre- 

 irate properties, as well as of its component ingredients, arc 

 such as more immediately appertain to vegetable bodies. 



Lac, or cum lac, as it is popularly, but improperly, called, 

 is certainlv a very useful substance ; and the natives of 

 India furnish full proofs of this, by the many purposes to 

 which they apply it. 



According to Mr. Kerr it is made bv them into rincr=!, 

 beads, and other female ornaments. 



When formed into seahng-wax, it is employed as a 

 japan, and is likewise manufactured into different coloured 

 varnishes. 



The colouring part is formed into lakes for painters : a 

 sort of Spanish wool for the ladies is also prepared with it j 

 and as a dvcing material it is in very general use. 



The resinous part is even employed to form grindstones, 

 by melting it, and mixing with it about three parts of sand. 

 For milking polishing grindstones, the sand is sifted through 

 fine niu-slin ; but those which are employed by the lapi- 

 daries are formed with powder of corundum, called by 

 them Corune*. 



• Ph-losophicil Transactions 1781, p. j8o. 



But 



