110 THE AMEEICAN MONTHLY [May, 



the general name for lacquer. An inferior kind is obtained from the 

 branches when the trees are cut down. The branches are soaked in 

 water for several months, then taken up and slightly warmed, when a 

 small quantity of sap exudes. This is seshime-urushi. The lacquer 

 is strained thi^ough cotton cloth to free it from bits of wood and dirt, 

 tirst being thoroughly stirred to break up lumps and make a uniform 

 mixture. The product thus purified is known as seshime-urushi ; but 

 this name, which has already been used to designate the lacquer from 

 the branches has now a diftbrent meaning, and is applied to the cheaper 

 kinds of raw lacquer, such as are used for the first coats in lacquering. 

 These lacquers have usually lost some of their water by stirring in shal- 

 low receptacles exposed to the sun. They have undergone no further 

 preparation. 



Many varieties ai"e prepared for special purposes, ranging in price 

 from one or two to six or seven dollars per kilogram. These differ in 

 quality and color. There is a famous black lacquer prepared by the 

 addition of iron, which forms a chemical combination to be mentioned 

 further on ; while red, green, yellow, and other colors are imparted by 

 the addition of various pigments, as cinnabar for red, orpiment and 

 indigo together for green, orpiment for yellow, etc. Certain lacquers 

 have a small proportion of drving oil (perilla oil) added to them. 



The most impoitant and abundant constituent of lacquer is urushic 

 acid, which occurs in the form of minute spherules. The acid is ob- 

 tained by evaporating the alcoholic solution to a syrupy liquid. The 

 evaporation must be carried on over a water bath. If too much heat 

 be applied, a tough, black, rubber-like substance is obtained, which 

 onlv strong nitric acid would affect in the slightest degree. Although 

 the drying, or rather the hardening, properties of lacquer are doubtless 

 due to the oxidation of urushic acid, the product extracted by alcohol 

 possesses no drying qualities. This fact was first observed by Professor 

 Rein in 1874. More recently Professors Korschelt and Yoshida have 

 found that a peculiar albuminoid of lacquer effects the drying by a di- 

 astatic or fermentive action. The fact seems to be that the lacquer 

 hardens only when the albuminous substance is present. If heated 

 above 60° C, or above the temperature at which albumen coagulates, 

 the lacquer will not dry. Besides urushic acid and the albuminoid, 

 raw lacquer contains a gum resembling gum arable, which doubtless 

 imparts some useful properties to the lacquer, and a volatile acid to 

 v.'hich Professor Rein ascribes the poisonous effects of lacquer. 



A portion of raw lacquer, about 16 pounds, is poured into a large 

 circular wooden vessel, and vigorously stirred with along-handled tool 

 for five or six hours, while the heat of a small charcoal furnace is in- 

 geniously thrown upon the surface to evaporate the water. During 

 the stirring certain ingredients may be added from time to time. The 

 roiro, the fine black lacquer already mentioned, is made by adding iron 

 at this stage. In Tokio a soluble salt of iron is used, but the Osaka 

 manufacturer objects to that, asserting that it injures the quality of the 

 lacquer. The material used in Osaka is fine iron dust collected ft-om 

 the grinding of knives. This is added in quantities of about a teacup- 

 ful of powder mixed with water at a time until the desired color is ob- 

 tained. When the work is finished the lacquer is poured into a vessel 

 to settle, and is afterwards drawn off" from the sediment. 



