MERCURY 



233 



1439 



j%. 1441 represents the exterior, but only one half, which is enough, as it resembles 

 exactly the other, which is not shown. In these three figures the following objects 

 may be distinguished : figs. 1439, 

 1440, a, door of the fire-place; b, 

 the furnace in which beech-wood is 

 burned mixed with a little fir- wood ; 

 c, door of the ash-pit, extended be- 

 neath ; d, a space in which the ores 

 are deposited upon the seven arches, 

 1 to 7, as indicated in figs. 1439 

 and 1442 ; e e brick tunnels, by which 

 the smoke of the fuel and the va- 

 pours of mercury pass, on the one side, into successive chambers /yfc. 



fg h ij k I are passages which permit the circulation of the vapours from the furnace 

 abed, to the chimneys II. Figs. 1439 and 1440 exhibit clearly the distribution of 

 these openings on each side of the same furnace, and in each half of the apparatus, 

 which is double, us fig. 1440 shows; the spaces without letters being in every respect 

 similar to the spaces mentioned, below. Fig. 1440 is double the scale of fig. 1439. 



1445 



mm', fig. 1440, are basins of reception, distributed before the doors of each of the 

 chambers f Jcf k'. The condensed mercury which flows out of the chambers is con- 

 veyed thither, n n' is a trench into which the mercury, after being lifted into the 

 basins m, is poured, so that it may run towards a common chamber o, in the sloping 

 direction indicated by the arrows, o leads to the chamber where the mercury is 

 received into a porphyry trough ; out of which it is laded and packed up in portions of 

 50 or 100 Ibs. in sheep-skins prepared with alum. 

 pp', fig. 1439, are vaulted arches, through which a 

 circulation may go on round the furnace b c d, on the 

 ground level, q j' are the vaults of the upper stories. 

 r f'lfy- 1441, vaults which permit access to the tunnels 

 e' e",fig. 1442. 



ss' and it', fig. 1441, are the doors of the chambers 

 fk and fk'. These openings are shut during the 



1441 



distillation by wooden doors faced with iron, and luted with a mortar of clay and 

 lime. ' uu' is the door of the vaults 1 to 7 of the furnace represented in fig. 1439. 

 These openings are hermetically shut, like the preceding, v v,fig. 1439, are superior 

 openings of the chambers, closed during the operation by luted plugs ; they are 

 opened afterwards to facilitate the cooling of the apparatus, and to collect the 

 mercurial soot. xyz,fig. 1442, are floors which correspond to the doors u it', of the 

 vaults 1 to 7, fig. 1441. These floors are reached by stairs set up in the different 

 parts of the building which contains the whole apparatus. 



On the lower arches the largest blocks of metalliferous rock are laid, over these 



