334 Statistical Accoiini of 



parallelogram form, well moimted with iron, capable of ton-* 

 taining seven or eight hundred weight of ore: a hydraulic wheel 

 with double power, which a workman stops or puts in motion 

 \vhen ordered, gives the impulse to a capstern on which a cable 

 rolls and unrolls. The water which moves those two wheeh 

 comes from a canal which takes its rise in the Idrixa, and which 

 feeds two wells, as well as the workshops and washing-houses. 



The entrance of the mine by wliich the workmen descend, as 

 "well as the travellers from various parts of Europe to visit these 

 immense caves, is inclosed within a building in the town, which 

 also c iitains the room in which the workmen are collected pre- 

 viously to going upon duty. It is in this room (named in German 

 gesehtube) that the workmen are called over and paid their 

 Wages, &:c, by the controllers. 



There is al-^o an inclined opening or stair-case of stone and 

 wood steps, by which persons may descend into the mine for 150 

 yards. But in order to get lower there are wooden ladders 

 placed, and some of these are riveted perpendicularly against 

 the wall; which makes the descent very inconvenient to those 

 unaccustomed to such expeditions. 



Nine stages of g:illories or horizontal borings (including inter- 

 mediate ones, with their numerous ramifications,) constitute the 

 whole of these vast subterraneous works. Most of these galleries 

 ■are walled up with much art and skill, in order to prevent the 

 falling in of the earth so frequent in these kinds of works. The 

 arches and walls are very smiple and oeconomical, and yet very 

 iolid : they are of brick. 



The galleries are generally about seven feet high, and as 

 many broad, hi general they are all well aired, currents being 

 established between them and the main pits. Some of them, 

 however, particularly towards the centre, are not so well aired. 



The temperature is variable in the interior of the mine. In 

 fact, it may be easily conceived that it ought to be higher in re- 

 gions where it is not possii^le to establish currents easily. I have 

 made a great number of thermometrical observations ; and I re- 

 marked that in countries where there are great beds of rich ores, 

 or in their vicinity, the heat raised Reaunmr's thermometer 

 from 24° to 28* above zero. I have also observed the tempera- 

 ture at 21"', where the strata were blackish schists, very poor in 

 ■mercury. 



Compelled to work in an atmosphere of which the heat is 

 "veiy considerable, the air rarefied, and the atmosphere often 

 loaded with carbonic acid gas coming from the combustion of 

 the oil used by the workmen in their lamps, the health suffers 

 greatly. 



The working day at I^iia consists of eight hours : but when 



digging 



