20 



silver. The smelting is done either in clay-crucibles or directly in small hearth- 

 furnaces. 



With regard to copper, iron, lead, antimony, there is no regular assaying 

 process ; hut it is considered sufficient to treat certain quantities of ore in the. 

 usual manner, and then weigh the results. In this manner it of course is only 

 ascertained, how much metal can be extracted by the method used, not how 

 much the ore really contains. 



■ In weighing the grains of gold and silver, the ordinary small Japanese scales, 

 similar to the Roman balances, are used. 



As curiosum I may here mention, that of late Plattner's blow-pipe-scale is 

 used here and there in a somewhat hybrid form, that is in adopting it by 

 prolongation of the diverging lines, for the measurement of larger grains. 



The parts being placed in proportion to those on the blow-pip -scale, the 

 results obtained mu-t become too high. For an approximative test of the value 

 of gold-or silver-alloys, compositions of a fixed standard, corresponding to our 

 touch-needles, are also used. Thus for instance I have seen a collection of 100 

 pieces, in form of coins, strung on a wire, each of which represented a fixed 

 standard, in gold from to 100, and in silver from 100 to 0. The sample is 

 then with the aid of Lydian ttone and sulphuric acid compared with the stand- 

 ard alloy. The sampling is mostly done in a manner, which is far from 

 guaranteeing a correct average. 



SUBTERRANEAN SURVEYING. 



Still to mention another branch of the mining industry, the subterranean 

 surveying, it has always been the custom, to lay the main-galleries and- 

 worlüngs down ou a map. 



These drawings consist usually in a rather arbitrary combination of plans, 

 elevations and sections along the veins, showing at the same time often sketches 

 of the surface, rivers, villages, roads etc. as well as hints as to the geological 

 conditions. 



Eor plotting of works in different horizons either different colours are used 

 or smaller plans are in the proper places stuck on to the front or to the back of 

 the main plan, accordingly as the work in question is above or below the main 

 plan. The Japanese paper being semitransparent the perspicuity is not sensibly 

 interfered with by this proceeding. 



The instrument used for measuring horizontal angles is a sight-compass of 

 ca. 10 cm diam. Upon the limb are marked from right to left the twelve signs 

 of the zodiac : Rat, Bull, Tiger, Hare, Dragon, Snake, Horse, Goat, Ape, Cock, 



