746 



SALT 



The evaporation is found to proceed at nearly the same rate with the weaker water, 

 and with the stronger, within the above limits. When it arrives at a density of from 

 1'140 to 1'16, it is run off into the settling-cisterns. M. Bcrthier calculates, that upon 

 an average in ordinary weather, at Moutiers, 60 kilogrammes of water (13 gallons 

 imp.) are evaporated from tho fagots, in tho course of 24 hours, for every square foot 

 of their surface. Without the aid of currents of air artificially warmed, such an 

 amount of evaporation could not be reckoned upon in this country. In the Schlotting, 

 or throwing down of the sediment, a little bullock's blood previously beaten up with 

 some cold brine, promotes tho clarification. When the brine acquires, by brisk ebulli- 

 tion, the density of 1-200, it should be run off from the preparation to the finishing or 

 salting-pans. The boilers constructed at Rosenheim, in Bavaria, evaporate 3 pounds 

 of water for every pound of wood burnt. 



Figs. 1750, 1751, 1752, represent the construction of a salt-pan, its furnace, and the 

 salt store-room of the works at Diirrenberg: fig. 1752, being the ground-plan, fig. 1751, 

 the longitudinal section, and fig. 1750, the transverse section, a, is the fire-grate, 

 which slopes upwards to the back part, and is 31 J- inches distant from the bottom of 

 the pan. The ratio of the surface of the grate to that of the bottom of the pan is as 

 1 to 59'5 ; that of the air-hole into the ash-pit, as 1 to 306. The bed under the pan 

 is laid with bricks, smoothly plastered over from b to c, in fig. 1750. Upon this bed 



the pillar d, d, &c., are built in a radi- 

 ated direction, being 6 inches broad at 

 the bottom, and tapering to 1J inch at 

 top. The pan is so laid that its bottom 

 has a fall towards the middle of 2^ 

 inches: see e, f, fig. 1751. The fire 

 diffuses itself in all directions under the 

 pan, proceeds thence through several 

 holes, g, g, g, into flues, h, k, h, which 

 run round three sides of the pan ; the 

 burnt air then passes through i, fig. 

 1752, under other pans, from which it is collected in the chimneys k, k, to be con- 

 ducted into the drying-room. At I, I, there is a transverse flue, through which by 



1751 



..._,., .: - T. 7 \ ,' \ ,-- ' 



means of dampers, the fire-draught may be conducted into an extra chimney, m. From 

 the flues k, k, four square iron pipes, n, n, issue and conduct the burnt air into tho 

 main chimneys in the opposite wall. 



Tho bottoms of the several flues have a gradual ascent above the level of tho fire- 

 grate. A special chimney, o, rises above the ash-pit, to carry off tho smoke which 

 may chance to regurgitate in certain states of the wind, p, p, are irou pipes laid 



