16 Experiments afid Olservalions on Lac. 



of the cluten, were dissolved; the wax was obtained m a 

 pure stAte, and a separation of the resin from the gluteri 

 was afterwards easily effected by the method which has 

 been described. As therefore acetic acid is capable of 

 dissolving resin, gluten, and many other of the vegetable 

 principle^', it certainly may be regarded as a very useful 

 solvent in the analysis of bodies appertaining to the vege- 

 table kingdom. 



From tlie results of the preceding analyses it appears, that 

 the different kinds of lac consist of four substances, namely, 

 extract, resin, gluten, and wax, the separate properties of 

 which shall now be more fully considered. 



Properties of the colouring Extract of Lac. 



1. When dry it is of a deep red colour, approaching to 

 purplish crhnson. 



2. Beint^ put on a red-hot iron it emits much smoke, 

 with a smell somewhat resembling burned animal matter, 

 and leaves a very bulky and porous coal. 



3. Water, when digested with it in a boiling heat, par* 

 tiallv dissolves it ; but the residuum was fousid to be ab* 

 aolutely insoluble in water. 



4. Alcohol acts but slowly on it, and, in a digesting 

 heat, dissolves less than water. The colour of the solution 

 is also not so beautiful ; and a considerable part of the re- 

 siduum loft by alcohol was, when digested with water, 

 found to be soluble, although this was not the case when 

 the residuum left by water was treated with alcohol. 



5. It is insoluble in sulphuric ether, excepting a very 

 small portion of resin, which appeared to be accidentally 

 iuixed with it. 



6. Sulphuric acid readily dissolves it, and forms a deep 

 hrownish-red solution, which, being diluted with water, 

 and saturated with potash, soda, or ammonia, beconies 

 thanked to a deep reddish-purple. 



7. "Muriatic acid dissolves only a part : the solution is of 

 the colour of port wine, and, by the alkalis, is changed to 

 a deep reddish-purple. 



6. Nitric acid speedily dissolves it : the solution is yel- 

 low, and rather tuVbid ; but the red colour is not restored 

 bv the alkalis, for these only deepen the yellow colour* 

 This nitric soluti.m did not afford any trace of oxalic acid. 



<j. Acetic acid dissolves it with great ease, and forms a 

 deep brownish-red .-olutlon. 



10. Acetous acid docs not dissolve it quite -so readily, 

 kut the solution is of a brighter red. Both of the above, 



when 



I 



