This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Take cow hides averaging from 25 to 30 pounds each; 35 hides will make a convenient soak for a vat containing 1,000 gallons of water, or 25 hides to a soak of 700 gallons. Soak 2 days or more, as required. Change water every 24 hours. Split and flesh; resoak if necessary. When thoroughly soft put in limes. Handle and strengthen once a day, for 5 or 6 days. Unhair and wash. Bathe in hen manure, 90° F. Work out of drench, wash well, drain 4
of 5 hours. Then process, using 45 pounds vitriol and 600 pounds of soft water to 700 gallons of water. In renewing process for second or consecutive packs, use 15 pounds vitriol and 200 pounds salt, always keeping stock constantly in motion during time of processing. After processing, drain over night, then put in tan in agitated liquors, keeping the stock in motion during the whole time of tanning. Pack down overnight. Use 200 pounds dry leather to each mill in stuffing.
For stuffing, use 3 gallons curriers' hard grease and 3 gallons American cod oil. Strike out from mill, on flesh. Set out on grain. Dry slowly. Trim and board, length and cross. The stock is then ready to cut. The time for soaking the hides may be reduced one-half by putting the stock into a rapidly revolving reel pit, with a good inflow of water, so that the dirty water washes over and runs off. After 10 hours in the soak, put the stock into a drum, and keep it tumbling 5 hours. This produces soft stock.
In liming, where the saving of the hair is no object, softer leather is obtainable by using 35 pounds sulphide of sodium with 60 pounds lime. Then, when the stock comes from the limes, the hair is dissolved and immediately washes off, and saves the labor of unfiairing and caring for the hair, which in some cases does not pay.