───────┬────────────┬───────────┬──────────┬────────────┬─────────────────┐ │Temperature │ │ Time of │ │ Coriin Dissolved│ Sample.│ of Drying.│ Remarks. │ Softening│ Remarks. │ by Salt │ │ │ │ in Water.│ │ Solution. │ ───────┼────────────┼───────────┼──────────┼────────────┼─────────────────┤ I. │ 59° F. │ In vacuo │ 24 hours│{Without }│ 1·68 per cent. │ │ (15° C.) │ │ │{mechanical}│ │ II. │ 71-1/2° F. │ In sun │ 2 days │{ work }│ 1·62 " │ │ (22° C.) │ │ │ │ │ │ │ │ │ │ │ III. │ 95° F. │{In drying-│} 5 " │twice worked│ 0·15 " │ │ (35° C.) │{closet │} │ │ │ │ │ │ │ │ │ IV. │ 140° F. │ " │ {Refused to soften }│ Traces. │ │ (60° C.) │ │ { sufficiently for }│ │ │ │ │ { tanning }│ │ ───────┴────────────┴───────────┴──────────┴────────────┴─────────────────┘ Hence it is evident that, for hides dried at low temperatures, short soaking in fresh and cold water is sufficient, and, except in warm weather, there would be little danger of putrefaction. With harder drying, longer time is required, and it may be necessary to use brine instead of water. A well-known tanner recommends a solution of 30°-35° barkometer (sp. gr. 1·035, or about 5 per cent. of NaCl). This will have a double action, not only preserving from putrefaction, but dissolving a portion of the hide-substance in the form of coriin. Although this is undoubtedly a loss to the tanner, it is questionable if there is any process which will soften overdried hides without loss of weight: since even prolonged soaking in cold water at too low a temperature to allow of putrefaction will dissolve a serious amount of hide-substance. Water containing a small quantity of carbolic acid has been recommended for the purpose, and will prevent putrefaction, while it has no solvent power on the hide, but, on the contrary, will coagulate and render insoluble albuminous matters. Concentrated carbolic acid, however, tans the grain and renders it incapable of colouring in the liquors. Borax has been proposed for the same purpose, and, in strong solution, certainly prevents putrefaction, but is probably too costly. Sodium sulphide and other sulphides seem to have considerable effect in softening dried hides, from their property of attacking hard albuminous matters, without injuring the true hide-fibre.