CHEMICAL SCIENCE. 253 



forcibly together in this manner for some hours more or less, accord- 

 ing to the nature and thickness of the hides the drums are thrown 

 out of gear, and the hides drawn out It is now ascertained that the 

 work of absorption and of partial drying has gone on vigorously, and 

 with uniformity, and that the hides not having yet attained the point 

 of saturation, are ready for another supply of the paste. Previous to 

 this, however, they are hung up in an airy part of the room, so as to 

 insure a more perfect uniformity of condition. They are then smeared 

 over with the paste again, returned to the drums, and the same process 

 repeated a second time, and afterwards, in general, a third time, when 

 a cut into the substance of the material displays a perfect uniformity 

 of color and of substance, proving that the conversion of the gelati- 

 nous mass has been equal and complete. They are now ready, after a 

 little more drying, fcr the operations of the currier, who finds that his 

 work is considerably lessened in amount by the effects of the above 

 process. 



This being the general nature of Mr. Preller's process, we have a 

 few facts to state which will show the principal characteristics of the 

 resulting leather, and the advantages which it possesses over ordinary 

 leather for a variety of purposes. One of the most remarkable qual- 

 ities of Preller's " H. B. Crown " leather is, that it is smaller in 

 weight and in thickness than leather produced by tanning. At pre- 

 sent there is a great prejudice in favor of stout and heavy leather for 

 purposes where great strength is desirable ; but this is fairly attributa- 

 ble, in part, to the action of moisture during the tan process, and in 

 part to the interest which the tanners have in producing weight. 

 Some of their processes, indeed, have been directed with this ob- 

 ject in view, while achieving which, the quality of the leather has, 

 to a great extent, been injured. The comparison of the two sys- 

 tems on the question of weight has been represented to be as fol- 

 lows: 100 Ibs. weight of "green" hide will yield by oak tanning 

 50 Ibs. of leather, and only 34 Ibs. by Preller's process. With weight 

 as a standard of excellence, therefore, the comparison would be ex- 

 tremely unfavorable to the new process, and we must therefore see 

 how they answer respectively the great purposes which arise in the 

 manufacture. In Preller's process the hide is left to the natural ope- 

 ration of the converting substance applied, without the intervention 

 of any mechanical means to hasten it, which could only lead to an in- 

 jurious result. It appears that the fibrous structure of the hide, and 

 the whole of it which is extremely important is preserved in a 

 condensed state, thus accounting for its great strength, and its greater 

 reduction of bulk. If a piece of oak-tanned leather be rent asunder 

 forcibly, the internal structure disclosed appears to be rather of a felty 

 character than otherwise ; but upon subjecting any piece of " H. B. 

 Crown " leather to the same test, all the fibers will be perceived to 

 be in close juxta-position, and with no sensible deviation from their 

 original parallelism. The comparison, in point of strength, gives 

 great superiority to the new process. It has been found that oak- 

 taniied leather, of -| of an inch in thickness, is incapable of resist- 



