Miscellanies. 193 



Wh 



ment is more complete. These plates once formed, may be convert- 

 ed into steel, on the plan of Mr. Perkins; after which they would 

 probably print from 10,000 to 20,000 copies without being materi- 

 ally defaced. An expert mechanic, with proper machinery, could in 

 a day or two, form a sufficient number of plates to print off 20,000 

 copies (500 pages) of an octavo volume. 



Other metals, as copper, brass and type metal with slight variations, 

 can all have letters transferred to them in the same manner, and can 

 be used as printing plates; but none of these will have the durability 

 of iron. 



19. Materials for paper. — By* a series of experiments I have 

 ascertained that paper, of an excellent quality, can be prepared 

 not only from the husks of Indian corn, but also from a pulp made 

 from various kinds of wood and bark, particularly from the bark of 

 several kinds of poplar, and from the wood of birch and some other 

 trees. — In conducting my experiments, my plan has been, first to se- 

 lect the vegetable matter, then, if it required whitening, to bleach it 

 in chlorine gas, and afterwards to reduce it to a fine pulp, by pound- 

 ing, and filing in water. When properly prepared, I would place a 

 small portion of the pulp, between polished steel plates, slightly warm- 

 ed, and strongly compress them by screw power; the degree of con- 

 sistency and polish, assumed by the pulp, under such compression, 

 would indicate the quality of paper capable of being prepared from 

 the vegetable matter used. I trust, that the time will soon arrive, 

 when rags, will not be considered as indispensable in the manufac- 

 ture of paper, and will be, when economy or convenience requires it, 

 superseded by different kinds of vegetable substances, which are so 

 cheaply, bountifully and universally furnished by nature. 



OTHER NOTICES. 



Notice of 



f Digestion. By Wi 



Beaumont, M. D., Surgeon in the U. S. Army. Pittsburgh, 

 1833, pp. 280. — This work of Dr. Beaumont, which has been for 

 some time announced, is, to say the least of it, equal in interest to 

 any one upon the same subject, that has ever been presented to the 

 public. The opportunity afforded to Dr. Beaumont, to institute ex- 

 periments upon the important and interesting subject of digestion, was 

 Vol. XXVL— No. 1. 25 



