Dr. Ure on Chloride of Lime. 15 



trived for favouring the combination of chlorine with slacked 

 lime for the purposes of commerce. One of the most ingenious 

 forms was that of a cylinder, or barrel, furnished with narrow 

 wooden shelves within, and suspended on a hollow axis, by 

 which the chlorine was admitted, and round which the barrel 

 was made to revolve. By this mode of agitation, the lime-dust 

 being exposed on the most extensive surface, was speedily im- 

 pregnated with the gas to the requisite degree. Such a me- 

 chanism I saw at MM. Oberkampf and Widmer's celebrated 

 fabrique de toiles peintes, at JoUy, in 1816. But this is a costly 

 refinement, inadmissible on the largest scale of British manu- 

 facture. The simplest and, in my opinion, the best construc- 

 tion for subjecting lime-powder to chlorine, is a large chamber 

 eight or nine feet high, built of siliceous sandstone, having the 

 joints of the masonry secured with a cement composed of pitch, 

 rosin, and dry gypsum in equal parts. A door is fitted into it 

 at one end, which can be made air-tight by stripes of cloth and 

 clay lute. A window in each side enables the operator to judge 

 how the impregnation goes on by the colour of the air, and also 

 gives light for making the arrangements within at the com- 

 mencement of the process. As water-lutes are incomparably 

 superior to all others, where the pneumatic pressure is small, I 

 would recommend a large valve, or door, on this principle to 

 be made in the roof, and two tunnels of considerable widlh at 

 the bottom of each side wall. The three covers could be simul- 

 taneously lifted off by cords passing over a pulley- without the 

 necessity of the workman approaching the deletereous gas, 

 when the apartment is to be opened. A great number of 

 wooden shelves, or rather trays, eight or ten feet long, two feet 

 broad, and one inch deep, are provided to receive the riddled 

 slacked lime, containing generally about 2 atoms of lime to 3 

 of water. These shelves are piled one over another in the 

 chamber, to the height of five or six feet, cross-bars below each 

 keeping them about an inch asunder, that the gas may have 

 free room to circulate over the surface of the calcareous 

 hydrate. 



Tiie alembics for generating the chlorine, which are iisiially 



