MECHANICS AND USEFUL ARTS. 101 



some hours; one-half of chlorliydric acid and three-fonrths of sul- 

 phide of zinc must then be added, and the whole heated from 81° to 

 89° C. during 10 or 12 hours. This compound does not gelatinize ; 

 if simply allowed to settle it is ready for use. — Chemical News. 



New Glue Preparations. — A German chemist has discovered that 

 if glue or gelatine be mixed with about one-quarter its weight of 

 glycerine, it loses its brittleness, and becomes useful for many pur- 

 poses for which it is otherwise unfit, such as dressing leather, 

 giving elasticity to parchment or enamelled paper, and for book- 

 binding. 



Water-proof Glue may be made by boiling 1 pound of common 

 glue in 2 quarts of skimmed milk. This makes an excellent glue 

 for articles which are exposed to the action of the weather. 



Bromo-iodized Ruhher. — The following process of treating rub- 

 ber and other gums without the use of sulphur has lately been 

 patented by J. B. Newbrough and E. Fagan, New York City. By 

 adding to iodine one-half its weight of bromine, proto-bromide of 

 iodine is formed, and this, when combined with rubber, or equiv- 

 alent gum, will produce a composition which will harden on being 

 subjected for about an hour to a heat of 250° F. Owing to the 

 volatile properties of proto-bromide of iodine it cannot be applied 

 without difficulty to practical purposes. To obviate this difficulty, 

 we treat both the bromine and iodine, prior to combining the same, 

 with oil of turpentine, or similar oil, which has previously been 

 mixed with about one-fourth its weight of sulphuric acid, to pre- 

 vent the formation of an explosive composition. 



The pasty mixture, produced as above described, is combined with 

 caoutchouc, or equivalent gum, in the proportion oif about 3 ounces 

 of the paste to a pound of gum, the proportion of gum being in- 

 creased if a more elastic product is desired. After the gum and 

 paste are thoroughly incorporated, the composition may be hard- 

 ened by subjecting it to a dry heat (of from 200° to 320° F.), for 

 from 10 minutes to 1^ hours, the time being lengthened to increase 

 the toughness of the product. 



The product thus obtained may be applied to many useful and 

 ornamental purposes, and any desired color may be imparted to 

 the material by combining with the composition, before it is 

 hardened, any suitable mineral or earthy coloring matter. — Sci- 

 entific American. 



Sponge for Textile Fabrics. — A. Paraf, of Mulhouse, France, 

 has lately obtained a patent in this country, in which we find the 

 following : — 



"The best quality of sponge is gathered in the Mediterranean 

 Sea ; but an excellent quality, as well as an inexhaustible quan- 

 tity, is found upon the rocks of the Bahamas and the coast of 

 Florida. The sponge, when torn from the rocks to which it ad- 

 heres, appears at first as a heavy, black-looking mass, having a 

 strong and offensive odor. In order to clean the sponge it is 

 buried in the earth for some weeks, at the end of which time all 

 the organic matter will be decomposed, only the pure fibrous 

 skeleton remaining. 



"The sponge, when purified, is liable to become exceedingly 

 9* 



