LACQUER WORK. 



347 



same as gum Arabic, and amounts to from 3 to 6'5 per cent, of 

 the whole. 



5. Lac-acId or Urushi-acid is the predominant and most im- 

 portant ingredient. Its quantity is usually between 60 and 80 

 per cent, of the total weight, and in the best lac of Yoshino amounts 

 to 85 percent. Analyses made by Korschelt from seven different 

 lac-samples, give the following result : 



The small quantity of oil found in several of the foregoing 

 analyses is not an original property of the lac itself, but came in 

 the process of obtaining it from the tree, as the tapster oils his 

 knife and spatula with E-no-abura (Perilla oil) in order to prevent 

 the lac adhering to the iron. 



The principal and most important constituent of the lac is the 

 already-mentioned lac- or urushi-acid, C14 H^g Oo which is distin- 

 guished by the microscope as little brown globules, and extracted 

 best in pure, warm alcohol. This formula ascertained by Korschelt 

 in an elementary analysis, is distinguished from that of the Borneo 

 camphor by 6 parts less of carbon. 



Lac-acid shares with resinous acids its solubility in alcohol, ether, 

 chloroform and other liquids, and in many cases the relation to 

 metallic bases also, but is much more active, inasmuch as its 

 alcoholic solution enables it to decompose nitrates and chlorates. 

 The reaction in sugar of lead solution is peculiar. It forms in 

 contact with lac-acid at once a grey, flaky precipitate of lac-acid 

 lead. Most interesting of all, however, is the conversion of the lac- 

 acid into an exceedingly steady neutral substance, oxylac-acid, 

 whose properties will be discussed further on under the lacquer 

 process. 



The Ki-sho-mi or purified lac, according to my observations, 

 when closely mixed with water added to it, takes it up gradually 

 and completely, especially if it previously contained proportion- 

 ably but little water. It loses in this way its fluidity, however, 



