KILN 17 



place of the sulphate of magnesia, formerly manufactured from dolomite, or from Grecian 

 magnesite, in cotton printing. Another portion of kieserite is converted into Glauber 

 salts, -which, on account of its freedom from iron, are highly prized by gas manu- 

 facturers. 



Manufacturers of ' blanc fixe ' employ kieserite, instead of sulphuric acid, to precipi- 

 tate the sulphate of baryta from chloride of barium, and in all similar cases -where 

 it is proposed to prepare a difficultly-soluble sulphate, the kieserite can be advan- 

 tageously used. Kieserite is recommended as a substitute for gypsum in agriculture, 

 as a top-dressing for clover, and is largely employed in England for this purpose. 

 It is proposed to use kieserite in the manufacture of alum. There is a mineral called 

 bauxite, which chiefly consists of the hydrated oxide of aluminium ; this is easily 

 dissolved in hydrochloric acid ; cheap potash salts and the calculated quantity of 

 kieserite are added ; alum crystallises out of the solution, and chloride of magnesium 

 remains in the mother-liquid. 



The uses indicated above are -wholly inadequate to consume the enormous quantities 

 now obtained from the Stassfurt mines, Millions of pounds of kieserite are annually 

 brought to the surface, and it is becoming a serious question to know what to do with 

 it. If it could be used as a substitute for gypsum in building materials and cements, 

 its cheapness would at once commend it to notice. Experiments looking to this appli- 

 cation have been tried. 



Two equivalents of kieserite and one equivalent of caustic lime were stirred to a 

 paste in water : the mass hardened, but remained granular and brittle. On calcining 

 it, however, again pulverising and moistening with water, it set to a solid marble-like 

 mass, which could be applied to many useful purposes. It is proposed to employ this 

 material for ornamental decorations in the interior of houses, and in general for the 

 manufacture of cements, and as a substitute for plaster-of-Paris. 



Kieserite appears likely to prove a valuable accession to our supply of useful 

 minerals, to be ranked by the side of kainite, a potash mineral also found at Stass- 

 furt, and now largely imported into the United States. 



XILBKICXEETITE. A variety of Geocronite from Kilbricken, Clare county, 

 Ireland. 



KILKENNY COAIi. A variety of anthracite. 



KXXiXiAS. The name given by the Cornish miners to the clay slate of that 

 district. It "varies very much in colour and character, being sometimes clay- 

 white, and at other times grey or blue. It is in one district soft ; in another compact 

 and hard. 



KIIiN, (Four, Fr., Ofen, Ger.) is the name given to a certain variety of furnace in 

 which substances can bo submitted to the influence of heat. In general, a kiln may be 

 described to be a structure of some considerable size, in which limestones, iron-ores, or 

 the like, can be calcined, bricks and cement stones burnt, pottery baked, or glass 

 annealed. 



The ordinary brick-kiln has been already described in the article BRICKS ; there 

 are, however, a few modern arrangements which demand some more especial des- 

 cription. 



Horizontal Close Kilns. These are employed very extensively on the Continent. One 

 is represented in fig. 1296. Although intended for bricks, it is often advantageously 

 used as an ordinary potter's kiln. A is the firing kiln ; B is the fuel-grate; c the ash- 

 pit, and D the chimney. The fire proceeds from the narrow end through the whole 

 length of the kiln to the chimney. Below the flue is the door b, which is bricked up 

 during every operation. The perforated wall a a separates the fire-hearth from the 

 burning chamber, and diffuses the flame uniformly over the whole front part of the 

 chamber ; the position of the fire-grate is found in practice to be exceedingly good, and 

 is recommended. The grate is inclined towards the kiln for the purpose of facili- 

 tating the addition of fuel. The curve in the roof conducts the flames, without 

 interruption, into the burning chamber. The fire-door, e, can be easily drawn up by 

 means of the weight o, and the chains passing over the pulleys nn. The flue p, and 

 a few others in the side of the kiln, tend to keep the brickwork dry, which is an 

 important point in getting up the heat. The heat in all furnaces thus constructed is 

 greatest in the neighbourhood of the wall a a ; and to prevent the vitrification of the 

 bricks, a certain quantity of lime is thrown into the front part of the kiln. In such a 

 furnace as this, the firing chamber is 3^ feet high and 10 feet long, and a full charge 

 is 6.000 bricks. 



Newcastle Kilns are arched kilns or ovens. These have been improved by Mr. C. G. 

 Johnson, who constructs a flue running along the back of a range of these kilns, and 

 instead of placing the chimney at the end farthest from the fire, he places it near the 

 fire. A communication is formed between the kilns of the flue running along the back 

 of the range. Suitable dampers regulate the heat, which can be drawn through any kiln 



VOL. III. C 



