542 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



of dyeing. Among the large number of chemical agents pat- 

 ented for the destruction of the vegetable matter, sulphuric 

 acid alone was found to answer in practice. Experiments 

 made by allowing certain portions of wool simply to drain 

 after the steeping in the acid, wringing out other portions, 

 and treating others in the centrifugal machine before placing 

 them in the heated chamber for carbonizing the vegetable 

 matter, showed that the employment of the centrifugal ma- 

 chine is necessary, not only for the most perfect preservation 

 of the wool, but also for the best results in the subsequent 

 operations of dyeing. A study of the relations existing be- 

 tween the degree of concentration of the acid, the tempera- 

 ture of the carbonizing chamber, and the time of exposure in 

 the latter, with different kinds of wool, indicated that within 

 proper limits no difference whatever in treatment is rendered 

 necessary by differences in fineness or character of the wool. 

 The particular degree of concentration of the acid in any case 

 within the tolerably wide limits established, however, varies 

 inversely as the temperature of the carbonizing chamber and 

 the time of exposure in the latter. The color assumed in 

 dyeing by wool thus treated was found, in general, to be 

 nearer that of wool not thus treated the more dilute the acid 

 employed, the lower the temperature, and the shorter the 

 time required in the carbonizing chamber; but below certain 

 limits it was normal and uniform, while above them it was 

 pale, without brilliancy, and wanting in uniformity, though 

 in different degrees with different colors ; and it is a singular 

 fact that thoroughness of washing after removal from the 

 acid did not prevent the unfavorable effect of the use of too 

 concentrated an acid upon the color. The results of these 

 experiments were also confirmed by several other independ- 

 ent investigators. 13 C, May 1, 1874, 590. 



CARBONIZATION OF HALF-WOOL STUFF. 



Two processes, the so-called dry and wet, are employed 

 for the removal of the cotton from half-wool material in the 

 manufacture of shoddy. The first consists in bringing the 

 material, in a suitably constructed iron carriage with a coarse 

 sieve bottom, running on rails half-way up, into a closed fur- 

 nace constructed of granite, the bottom of which is heated by 



