TABLE IV +-------------------+------+------+------+------+ | | A | B | C | D | | | S.P. | S.P. | S.P. | S.P. | +-------------------+------+------+------+------+ |_Salt-acid Tan_ | C. | C. | C. | C. | |Australian Opossum | 49° | 49° | 55° | 50° | | | | | | | |_Chamois Tan_ | | | | | |Mink | 59° | 67° | 69° | 70° | +-------------------+------+------+------+------+ A--500 c.c. water plus 5 c.c. formaldehyde for 1 hour B--500 c.c. water plus 5 c.c. formaldehyde for 12 hours C--500 c.c. water plus 10 c.c. formaldehyde for 3 hours D--As in C, but treated with 500 c.c. water plus 5 c.c. ammonia, instead of water alone. TABLE V +-------------+------+------+ | | A | B | | | S.P. | S.P. | +-------------+------+------+ | | C. | C. | |Persian Lamb | 44° | 54° | |Astrachan | 47° | 55° | +-------------+------+------+ A--Before dyeing B--After dyeing As a result of these experiments it may be concluded that the maximum temperature for drying salt-acid tanned skins should be 40° C., while for chamois tanned skins the temperature may be permitted to reach 45° C. without any danger of the leather being affected. Moreover, in the case of pickled skins, the matter of extraction of the tanning agent, as well as that of the leather becoming “burned” may be effectively counteracted by brushing some oil or fat on to the leather side before dyeing the pelt. The shrinking points of skins dressed by the various tanning methods are constant within certain limits, depending on the nature of the skin and on the conditions of tanning, and it is possible by observing the shrinking point, in conjunction with other characteristics of a given pelt, to determine what method of tanning was used. CHAPTER VI FUR DRESSING DRYING AND FINISHING One of the most important operations of all the fur dressing processes is the drying of the skins. For even when all the previous steps have been successfully completed, there is still a great possibility of the skin being injured if the drying is not properly and carefully carried out. The essential requirements for good drying are proper temperature, uniformity and rapidity. The leather part of the fur cannot, in the moist state, resist temperatures exceeding about 45° centigrade, for when dried, the skin turns out hard and stiff, and cracks easily. The furs must therefore be dried at an initial temperature of 25° to 30° centigrade, and as the moisture is gradually removed, the temperature may be raised, for the less water that remains in the pelt, the less is the leather affected by the heat, and the more difficult is the removal of its aqueous content.