[Fig. 671 enlarged] (103 kB)
![[Fig. 671 enlarged]](#1185752912146279659_lg0815a.png.id-6615706460810604328.wrap-0.html.html){kind=link}
The grilles anglaises are similar to the sleeping tables used at Idria. The system of these en gradins is represented in [fig. 671.] There are 5 such systems in the works at Idria, for the sorting of the small morsels of quicksilver ore, intended for the stamping mill. These fragments are but moderately rich in metal, and are picked up at random, of various sizes, from that of the fist to a grain of dust.
These ores are placed in the chest a, below the level of which 7 grates are distributed, so that the fragments which pass through the first b, proceed by an inclined conduit on to the second grate c, and so in succession. (See the conduits l, o, p). In front, and on a level with each of the grates b, c, d, &c., a child is stationed on one of the floors, 1, 2, 3, to 7.
A current of water, which falls into the chest a, carries the fragments of ore upon the grates. The pieces which remain upon the two grates b and c, are thrown on the adjoining table v, where they undergo a sorting by hand; there the pieces are classified, 1. into gangue to be thrown away; 2. into ore for the stamp mill; 3. into ore to be sent directly to the furnace. The pieces which remain on each of the succeeding grates, d, e, f, g, h, are deposited on those of the floors 3 to 7, in front of each. Before every one of these shelves a deposit-sieve is established, (see t, u,) and the workmen in charge of it stand in one of the corresponding boxes, marked 8 to 12. The sieve is represented only in front of the chest h, for the sake of clearness.
Each of the workmen placed in 8, 9, 10, 11, 12, operates on the heap before him; the upper layer of the deposit formed in his sieve, is sent to the stamping house, and the inferior layer directly to the furnace.
As to the grains which, after traversing the five grates, have arrived at the chest x, they are washed in the two chests y, which are analogous to the German chests to be presently described. The upper layer of what is deposited in y is sent to the furnace; the rest is treated anew on three tables of percussion, similar to the English brake-sieves, also to be presently described.
After several successive manipulations on these tables, an upper stratum of schlich is obtained fit for the furnace; an intermediate stratum, which is washed anew by the same process; and an inferior stratum, that is sent to the system of stamps, [fig. 672.]
