for further portions of water to gain access to the interior of the powdery mass. On the other hand, if it is “drowned” by excess, the temperature is lowered, the process goes on slowly, and the mass does not readily fall into powder, and so fails to be utilised in the liming process. Of all methods of slaking lime, the ordinary one of tipping it direct into the lime-pits is perhaps the most irrational, leading to the formation of unslaked lumps which may burn the hides, and which, together with stones and dirt, rapidly choke the pits with useless matter. The best process is that adopted by builders and in many Continental yards, in which a large quantity of lime is slaked in a shallow tank by throwing on it sufficient water to thoroughly wet it, and after allowing it to heat and fall for 24 hours, adding enough water to convert it into a stiff paste. In this form it may be kept for months without material deterioration. When required for use, a suitable quantity of the paste is dug out, and well stirred with water in a tub or tank before running into the pit when the stones and sand remain in the tank. In this way all nuisance from dust is also avoided. If lime is stored unslaked, it gradually absorbs moisture from the air, falling, and soon becoming dusty and difficult to slake completely, while the traces of carbon dioxide in the air gradually convert it into useless carbonate. [69] Bull. de la Soc. d’Encouragement, 1895, x. pp. 52-62; Journ. Soc. Chem. Ind., 1895, p. 575. The solubility of lime in water is very limited, and the figures determined by different chemists do not agree very satisfactorily. The following table gives the result of determinations made by Mr. A. Guthrie in the Author’s laboratory, and is probably one of the most accurate[70]:-- 100 c.c. of saturated lime water at 5° C. contain 0·1350 grm. of CaO. „ „ 10° „ 0·1342 „ „ „ 15° „ 0·1320 „ „ „ 20° „ 0·1293 „ „ „ 25° „ 0·1254 „ „ „ 30° „ 0·1219 „ „ „ 35° „ 0·1161 „ „ „ 40° „ 0·1119 „ „ „ 50° „ 0·0981 „ „ „ 60° „ 0·0879 „ „ „ 70° „ 0·0781 „ „ „ 80° „ 0·0740 „ „ „ 90° „ 0·0696 „ „ „ 100° „ 0·0597 „ [70] Journ. Soc. Chem. Ind., 1901, p. 224.