708 Transactions of the American Institute. 



face; and, although is was soon proved incorrect by a celebrated 

 mathematician, this statement has been the fruitful parent of many 

 fallacies. 



BULLET PROBE. 



Mr. Sylvande "Wilde has invented an instrument for extracting 

 bullets in wounds, which has been aptly called a sensitive artificial 

 finger, for its action depends on the actual presence of the bullet 

 sought for. It consists of two insulated steel wires, which are 

 connected with an electro-majjnet and a bell, so arranged that the 

 electric circuit will pass through the two wires whenever they are 

 connected by contact with the same piece of metal, which will 

 form a part of the conductor. The points of the probe are sheathed 

 in a sliding tube when introduced into the wound, and are not 

 uncovered until the supposed bullet is felt. The forceps have 

 curved points, and are not pallets or spoons. When the ends of 

 the probe are uncovered, on touching the bullet, the latter com- 

 pletes an electric circuit, which sets in motion a magnet, and by its 

 attraction compels the forceps to grasp the bullet; it is then ready 

 to be drawn out. 



PROCESS FOR PRODUCING HYDROGEN. 



M. Heurtebise describes in a late number of L^ Invention an eco- 

 nomical method of obtaining hydrogen gas. He places charcoal 

 in a retort, and raises it to a red heat; then passes. over it a stream 

 of carbonic acid, each molecule of Avhich absorbs two atoms of 

 oxygen, thus forming carbonic oxide (garat). Into another red hot 

 retort he passes a current of steam and the gaseous contents of the 

 first retort, and the products in the second retort, resulting from 

 the decomposition of steam, are carbonic acid and hydrogen gases 

 {garat and gal.), which are separated, and the carbonic acid is 

 again used in the first retort. The interesting process, described 

 as new in the French journal, has been long used in America, par- 

 ticularly by those experimenters who have aimed at mixing more 

 hydrogen with the large class of hydrocarbons which are very rich 

 in carbon, and therefore liable, from imperfect combustion, to give 

 off fine particles of unconsumed carbon in the form of smoke. 



UCHATIUS STEEL. 



The process of M. Uchatius, an officer in the Austrian service, 

 for making steel by mixing granulated iron and iron ore in proper 

 proportions in a crucible, -vvas patented here many years ago b}' an 

 American, and we believe before any simihu* plan had been tried 



