1885.] CHEMISTRY. 209 



Chemistry. 



THE EXTRACTIOX OF TANNIX FROM OAK- WOOD. 



ACCOIiDING tu the Revue ties Faux ct Forets, oak-wood is a 

 drug in France as well as with ourselves. But industrial 

 chemistry appears to have opened there a new market for its 

 profitable nse in the extraction of tanning material. M. E. Henry 

 describes in the J\Iay number of our contemporary how M. Luc, an 

 extensive tanner in Nancy, has developed on the commercial scale a 

 new patent process by which the old stumps and larger branches of 

 the oak are made to yield to profit the chemical necessary for his 

 industry. Saplings and the younger branches are rejected, but the 

 other refuse material, cut into a shape like firewood, and having, 

 contrary to the recommendation of the patentee, the bark retained, 

 is placed in large cisterns, similar to those used as lye-washers in 

 chemical works, in ■which boiling water circulates, becoming, as it 

 follows a systematic course, more and more charged with tannin and 

 other soluble material in the wood. When it has thus cjone through 

 four of such caves, this concentrated material is subjected to a cooling 

 process, in this case a serpentine of cold water, the temperature is 

 reduced to 30 to 35 degrees Cent., and blood with a small quantity 

 of sulphuric acid added : the gums, mucilages, and solid matters 

 which have mingled with the tannin in the solution are thus 

 precipitated ; and the clarified juice is concentrated in a vacuum pan 

 until the extract stands at 20 to 25 degrees of the aerometer, and 

 in this state it is preferred by tanners to the more dilute extracts 

 ordinarily used. The spent wood is used as fuel. 



GAS FROM FIR SHAVINGS. 



ME. GEOEGE WALKEE, of Desoronto, Ontario, has obtained 

 from this material, on the commercial scale, no less than from 

 20,000 to 30,000 cubic feet of capital illuminating gas per ton of 

 dried shavings. The retorts used are similar to those in use for the 

 distillation of ordinary gas coal. But the bye-products are diiferent. 

 While coal-tar and ammonic sulphate go so far as they do to make 

 up the profit side in the balance-sheets of our gas companies, 

 resinous woods, though yielding a superior gas, will not be employed. 

 But may not this new manufacture pave the way for the utilization 

 of gas engines for many estate purposes ? It struck us as a lack at 

 the late Forestry Exhibition that one of several gas engines shown at 

 work, should not have been driven by gas from wood refuse. 



