The customary method of liming is simply to lay the hides flat in milk of lime in large pits. Every day, or even twice a day, the hides are drawn out ("hauled"), and the pit is well plunged up, to distribute the undissolved lime through the liquor. The hides are then drawn in again ("set"), care being taken that they are fully spread out. How much lime is required is doubtful, but owing to its limited solubility, an excess, if well slaked, is rather wasteful than injurious. Great differences exist in the quantity of the lime used, the time given, and the method of working. Lime, as we have seen (p. 140), is only soluble to the extent of about 1·25 _grm._ per _litre_, or (as 1 cub. ft. of water weighs about 1000 oz.) say 1-1/4 oz. per cub. ft., or, in an ordinary lime-pit, not more than 1/4 lb. per hide. Only the lime in solution acts on the hide, but it is necessary to provide a surplus of solid lime which dissolves as that in the liquor is consumed. Jackson Schultz prescribes 1 bush. (56 lb.) of fresh lime to 60-70 hides, and 3-4 days as sufficient time to unhair and plump them; while a well-known English tanner states that, after working for 6-10 days through a series of old limes, the hides (presumably wet-salted South Americans) should have 4 days in a fresh lime, made with 3-12 lb. of lime per hide. It is obvious that if the American authority is right, the English process is wasteful in the extreme, both in hide-substance and lime. Much depends on the amount of hauling which the hides receive, and the more frequently they are moved the better. It is probable, however, that it would be found impossible to unhair and flesh hides, to suit the English market, in cold limes with the quantity and time mentioned, and if the limes are steamed, it is quite likely that the destructive action on the pelt may be even greater than by the longer and slower process in the cold. Most likely a compromise between the two is the most desirable, but about 2-4 lb. of lime per hide, according to weight, should be amply sufficient; while a week for market hides, and 14 days for heavy salted, will loosen the hair and plump the pelt as much as is requisite. This is on the supposition that the limes are kept at a uniform average temperature of about 60° F. (15° C.) in winter and summer. If they are heated to 80°-90° F. (27°-32° C.), of course much less time is required; but there are no published experiments showing the relative weights made by the two processes, and, from the fact that warmed limes are principally used for descriptions of leather where weight and solidity are not of primary importance, it may be concluded that, in this direction, the results are unsatisfactory. Hides do not plump in warm limes.