ETHNOLOGY. 411 



workshops, and, although operating day and night, still nine and ten 

 years are sometimes consumed on one piece. The expense of executing 

 such works, joined to the original cost of the material, enhances the 

 cost of fine works in jade to an enormous sum. And besides, this stone, 

 so costly, if it be a little thin, will break like glass if let fall to the 

 ground. 



Some mineralogists are of the opinion that the Chinese and Indians 

 work the jade into shape before it becomes permanently hard; that is 

 to say, when it is brought fresh from the quarry ; and further declare 

 that it is their custom to subject it to a suitable degree of heat after the 

 work is finished, by which it is made still harder. This assertion ap- 

 pears to be very questionable, especially as it is in direct opposition to 

 the authors whom we have quoted, who wrote from what they saw with 

 their own eyes, and constitute now the best authority on the subject. 

 This error appears to have been propagated by a passage in Hoai-nau- 

 tseu, a Chinese historian of the eleventh century before our era, which 

 has been misunderstood or badly interpreted, in which that writer re- 

 lates that the yu of the mountain of Tchong was heated in a lime-kiln for 

 three days and three nights without any alteration in its color or luster 

 being observed. This does not assert, however, that the Chinese lapi- 

 daries submit to the operation of fire all the works which leave their 

 hands. This author only seeks to show, by the trial named, that the yu 

 is unalterable by heat or moisture. Besides, the methods employed in 

 India to cut this refractory mineral is strong evidence in favor of our 

 opinion. 



"At the Exposition of 1854," (London,) says Baron Charles Dupiu, 

 when reporting on this exhibition, " the perfection of the work as well 

 as the designs, which the stones cut at Lahore presented, were highly 

 admired/' They were executed by a method of which we give a descrip- 

 tion, obtained from Mr. Summer, resident at Cambay. The rough gem 

 is fixed upon the steel axis of a lathe and cut away until its form ap- 

 proaches that of a sphere ; it is then polished by meaus of a composition 

 of gum lac and corundum. (Granular corundum is the next hardest 

 mineral after the diamond ; emery, which the ancients called smyrris, 

 from the Hebrew word smir, being a variety of it. It is found in Ben- 

 gal, Ceylon, and especially in China, where its use as an abrading ma- 

 terial dates back to the earliest times. It is the mineral used in polish- 

 ing the diamond.) Cups or vases or other art objects are worked out 

 according to fixed designs by means of the lathe. The first polish is 

 obtained by friction with common polishing-stones. The concave part 

 is fashioned by the help of a pointed tool armed with a diamond, which 

 perforates to the depth of G millimeters over the whole surface, so as to 

 present the appearance of a honeycombed structure. These innumer- 

 able circular holes are afterward broken into one and the surface leveled. 

 This process is repeated for the purpose of deepening the cavity, C milli- 

 meters at a time, until the desired shape of the interior of the cup is 



