LIME. 



day, and require nearly one of coal for every 

 two measures of lime burnt. In a country sale 

 of lime, the quantity sold every day is liable to 

 great fluctuations : two or three cart-loads will 

 sometimes only be required from an establish- 

 ment which, the day before, supplied forty; and 

 as lime is known to be a commodity, when ex- 

 posed to the action of air, which becomes more 

 bulky and heavy, and in that state does not ad- 

 mit of being carried to a distance without addi- 

 tional labour, it has been an object of import- 

 ance with me to find out a construction of a kiln 

 which will allow of lime being kept for several 

 days without slaking, and at the same time to 

 prevent the fire escaping at the top of the kiln, 

 if the kiln stands 24 hours without being em- 

 ployed, especially during the autumn and win- 

 ter, when the air is cold and the nights long. 

 I now employ kilns of an egg shape, and also 

 oval; the oval-shaped kilns are divided by 

 aivhrx across the kiln, descending 4 feet from 

 the top; the object of the arches across the 

 kiln is to prevent the sides of the kiln falling 

 in or contracting, and also to enable you to 

 form circular openings for feeding in the stone 

 and coal at the mouth of the kiln ; upon this 

 plan, a kiln of any length might be construct- 

 ed with numerous round mouths. In the model 

 of the kiln sent to the Highland Society, Book- 

 er's conical cover may be seen revolving upon 

 an iron ring placed upon the circular mouth, 

 and having placed a lid to the cover, I am en- 

 abled to prevent the escape of heat at the top, 

 and by cast-iron doors at the bottom the air is 

 prevented passing through the kiln ; so that, 

 by these precautions, the lime burner can regu- 

 late the heat, and prevent its escape for several 

 days, when the fire would be extinguished at 

 M>n in the course of 24 hours. This is 

 an object of great importance, as it enables the 

 lime to be burnt as well, and with as small a 

 quantity of fuel in the winter as the summer 

 se;<v,,;i, and to supply the farmer with as well 

 burned lime, and at any time of the year, which 

 cannot be done in the common construction of 

 kilns, open both at top and bottom, for the rea- 

 sons I have before stated. From the great ex- 

 pense attending the driving of fuel from a dis- 

 tance of 25 miles from my own coal-pits, I have 

 adopted the practice of coking the coal, which 

 is a saving of eight-twentieths of the weight; and 

 I find that an equal measure of coal and coke 

 furnish the same quantity of heat in burning 

 lime, which is somewhat paradoxical, but not 

 the less true. The coal is found to have little 

 effect upon the stone till it is deprived of its 

 bitumen, or is coked in the kiln ; for, during the 

 time the smoke is emitted from the top of a 

 lime kiln, little or no heat is evolved. A kiln 

 in which coke is the fuel employed, will yield 

 near a third more lime shells in a given time 

 than when coal is the fuel ; so that coke may 

 be used occasionally when a greater quantity 

 of lime is required in a certain time than usual, 

 as it is well known to lime burners that the 

 process of burning is done most economically 

 when the kiln is in full action, so as almost 

 constantly to have a column of fire from the 

 bottom to the top of the kiln, with as short in- 

 tervals as possible in working the kiln. 

 "In working a kiln with narrow circular 



LIME GRASS. 



mouths, the stone and coal should be carefully 

 measured, so that the workmen can proportion 

 the fuel employed to the quantity of stones, and 

 it is obvious that the quantity of coal to be 

 used must depend upon its relative quality and 

 the hardness of the stone to be burnt. If this 

 measure was adapted to kilns of any con- 

 struction, the lime snells would be found better 

 burnt. 



"Circular kilns are constructed with similar 

 ! eyes or openings at the bottom, and not more 

 than 8 feet wide at 18 feet from the base, and 

 contracted to 4 or 5 feet wide at top. In light- 

 ing the kiln at the commencement of burning, 

 j some care should be taken not to allow the fire 

 j to remain below the upper grate. There are 

 two iron grates at the bottom of the kiln : the 

 upper grate consists of iron bars 8 or 10 inches 

 distant from each other across the kiln, be- 

 tween which the pieces of burnt lime fall down 

 upon a lower grate with iron bars one inch 

 from each other, which allows the lime ashes 

 to fall through them into an ash pit; these 

 lime ashes are found very useful as a top- 

 dressing for grass ground, and are a clear gain 

 to the proprietor of lime-kilns for public sale. 

 As a burner of lime for agriculture in an ex- 

 tensive district of country to the extent of 

 150,000 imperial bushels annually, the value 

 of the lime ashes which fall through the lower 

 grate amounts to more than 150/. annually; 

 the lower grate is 3 feet above the ground, and 

 the upper grate is the same distance from the 

 lower one. The kilns I employ at Closeburn 

 are upwards of 30 feet high, and nearly per- 

 pendicular, which is the cause of the great 

 heat in this construction of kiln, and which is 

 found to burn lime more equally than circular 

 kilns of large dimensions. {Trans. High. Soc. 

 vol. ii. p. 127.) 



The limestone quarries of Scotland are de- 

 scribed by Mr. Carmichael (Ibid. vol. v. p. 57) : 

 he observes, when speaking of the uses of this 

 valuable earth, "how sterile must have been 

 the soil, how cheerless the dwellings, and how 

 scanty the resources of Britain before lime 

 came into general use." And on the method 

 of calcining limestone in some of the limestone 

 quarries in Scotland there is a paper. (Ibid. 

 p. 441.) 



Limestone Gravel. There are some traces of 

 this manure in the Isle of Anglesea; but in ge- 

 neral, it is seen in quantities only in Ireland, 

 where it is very common. It is in appearance 

 only common gravel, of a blue colour, mixed 

 with stones as large as a man's fist, and also 

 with loam or clay : it has a strong effervescence 

 with acids, and, when used, is attended with the 

 usual effects of marl or lime. For bogs, it ex- 

 ceeds every other manure, as its weight assists 

 in the improvemont of that loose and spongy 

 soil. Upon strong clays, the use of it is unri- 

 valled, for it has all the effect of a dressing of 

 lime, and gives friability yet more than chalk 

 does. It destroys moss infallibly. Upon whar- 

 ever soil it is used, it is found very durable, 

 lasting, in many instances, in great heart, from 

 twenty to forty years. In limestone counties, 

 all blue gravels should be examined; for it ta 

 an invaluable treasure, wherever found. 



LIME or LYME GRASS. See ELTMUS, 



723 



