Scientijic Intelligence. 169 



Gold prepared in the same way becomes incandescent only at about 

 ihe temp, of 50° cent. 



Paper impregnated in the same manner with the nitrate of silver 

 becomes red between 120° and 130° cent. 



A current of per carburetted hydrogen, (olefiant gas,) renders pla- 

 tina incandescent at 100° cent, and the gas inflames from time to time. 

 Sulphuretted hydrogen produces the same effect at a temperature 

 somewhat higher. The sulphur which is deposited on the metal, must 

 be cleared by the action of nitric acid, prior to a second experi- 

 ment. 



The protoxide of carbon determines the incandescence of platina 

 at about 80° cent. 



The force of the combustion produced by a current of hydrogen 

 directed on platina is very great, since it requires the presence of only 

 an extremely small portion of oxygen. When the current is thrown 

 upon the metal in a vacuum, it produces no effect, which proves that 

 the effect is not due, as Dobereiner supposed, to the immediate action 

 of the hydrogen on the platina. But in letting into the receiver suf- 

 ficient air to support an inch and a half of mercury, the platina be- 

 came sensibly red, and a thermometer, which, in the vacuum shewed 

 no elevation of temperature, was broken by the heat, being incapable 

 of rising higher than 150°. The quantity of oxygen in this case 

 was not more than the 18th part of that which the receiver would 

 have contained under the common pressure. — Ann. de Chim. JVov. 

 1828. 



5. Preservation of hones, and the employment of gelatine.- — J. 

 BoRNAUD, manufacturer of gelatine, at Geneva, has furnished the 

 editors of the Bibliotheque with the following information. 



It is well known, that the best means of preserving bones, is to 

 pass them through a caustic ley, which removing the grease and odor 

 which they acquire, allows of their being kept in heaps even many 

 years. Bones may thus be preserved in pits, in the ground or under 

 water ; which latter mode is preferable, if they are to be employed 

 in a few months. 



From late experiments, it appears that one of the most econom- 

 ical uses of gelatine, consists in uniting it with bread in the form of 

 soup. If it be well deprived of grease, it makes no alteration in the 

 appearance of the bread, and prevents it from moulding so easily. 

 The bread thus prepared is exactly like biscuit, if it be left a little 



Vol. XVIL—No. 1. 22 



