356 Experiments and Olservafhvs on Lac, 



The filtrated liquor is of a bright golden yellow ; and, 

 when saturated by anuiionia, changes to orange colour, 

 but docs not yield any precipitate, nor any traces of oxalic 

 or malic acid. 



This yellow nitric solution is converted, by evaporation, 

 into a deep vellow substance, which burns like resin, but 

 i:j soluble ii) boiling water. 



The alkalis and nme, l>eing added to this aqueous solu- 

 tion, do not produce any precipitate, but the yellow colour 

 is very considerably deepened ; and, by evaporation, an 

 orange-coloured substance is obtained, which is still easily 

 soluble in water, and consists of the deep yellow substance 

 abovemeutioned, combined with the alkali or lime, 



0. Muriatic acid dissolves the colourinir matter and 

 gluten of lac; but its action on these is feeble, unless the 

 resin has been previously separated. 



7. Acetous acid, in its eticcts, much resembles muriatic 

 acid. 



8. Stick lac, seed lac, and shell lac, are partially dis- 

 solved bv acetic acid ; and, if this be heated, a considerable 

 portion is taken up. 



The dissolved part consists of the colouring extract, of 

 resin, and of gluten: the wax being the only ingredient 

 which is insoluble in this njenstruum ; but a portion of the 

 former substances, being enveloped by the wax, is pro- 

 tected from the action of the acetic acid. 



The acetic solution of lac becomes tvu-bid when cold, 

 and deposits part of the resin ; a portion however remains 

 in solution, and niav be precipitated bv water ; after which, 

 the liquor retains some gluten and colouring extract, which 

 may be precipitated bv saturatinir the acid with an alkali, 

 and by subsequent boiling. 



For the reasons above stated, it would be difficult to 

 effect a conipictc solution of lac by means of acetic acid j 

 but this may nevertheless be advantageously employed ia 

 analytical operations, when alternately used with alcohol. 



9. A saturated solution of boracic acid in water, dis- 

 solves the colouring extract ; but, as the cflcct does not 

 surpass that of water alwie, we may conclude that lac is 

 little, if at all, acted upon by boracic acid. 



10. It has been alreadv stated, that sub-borate of soda 

 or borax has a powerful effect on lac, so as to render it so- 

 luble in water ; and, as the preceding experiments pro\'C 

 that boracic acid alone scarcely acts upon lac, there is every 

 reason to believe, that the excess of soda present in borax 



