L. TECHNOLOGY. 505 



the cellulose of the plant into glucose by boiling with from 

 seven to ten per cent, of the weight of the mass of hydro- 

 chloric acid by the aid of steam. The acid is then saturated 

 with chalk, and the saccharine matter brought to fermenta- 

 tion. Twenty pounds of the lichen will, it is asserted, yield 

 live litres of spirit, containing fifty per cent, of alcohol. 1 A, 

 July 8, 23. 



FILTERING ALCOHOL. 



The following method of filtering alcohol, or its solutions, 

 is said to be very satisfactory, and is used extensively in 

 Northern Germany, where it constitutes one of the secrets 

 of the trade. Clean, unsized paper (Swedish filtering paper 

 is the best) is to be torn into shreds and stirred into the liq- 

 uid to be clarified. The whole is then to be strained through 

 a flannel bag, when the resulting liquid will be found to pos- 

 sess the utmost clearness and limpidity. A filter may also 

 be made by spreading thin paper-pulp evenly upon stretched 

 flannel or woolen cloth. When dry, the cloth so coated will 

 be found to give better results than the felts, etc., commonly 

 employed as filters. 14 (7, 1871, vl, 513. 



PRESERVATION OF WINE BY TANNIN. 



Among the various improvements in the manufacture of 

 wine, the most important in many years past is that intro- 

 duced by Pasteur, of heating it to a certain temperature, 

 which is done for the purpose of destroying the fungus, the 

 development of which in wine causes it to become turbid, 

 and ultimately converts it into vinegar. This process, ap- 

 plied both to wine and to malt liquors, after having been bot- 

 tled and well corked, has been carried into almost universal 

 application, with a result of retaining the liquid in question, 

 for an indefinite period of time, at the precise point at which 

 it was when treated. In some instances, however, this pro- 

 cess is not applicable, and especially where means are not at 

 hand for doing the work on a suitable scale, and for securing 

 that particular temperature which has been found to be most 

 successful in accomplishing the object, and in such cases the 

 process of Parent becomes of great value. 



This consists in the addition of a small quantity of tannin 

 or tannic acid to the wine, which, perhaps, acts in a similar 



Y 



