1 52 Scientific Intelligence. — Chemistry. 



be placed in the liquid, the whole coat of platina adhering to the glass 

 dissolves, almost instantaneously. 



(c.) Tlie decomposition of the oxide of carbon, by the dry oxi- 

 sulphuret of platina, has always been observed by M. Dobereiner, 

 although others have doubted the fact. He has found, that from 12 

 to 15 grains of the oxi-sulphuret (obtained by exposing sulphuret of 

 platina prepared in the humid way to the action of the air during 

 several weeks) are sufficient to decarbonate a cubic inch of the car- 

 bonic oxide gas, and that there remains exactly, in this experiment, 

 half a cubic inch of carbonic acid gas, which proves (says M. Dobere- 

 iner) that the oxide of carbon is composed of equal volumes of car- 

 bonic vapor, and carbonic acid gas, — the protocarbonated and deuto- 

 carbonated hydrogen act differently j they are absorbed in great part 

 by the oxi-sulphuret of platina, and transformed Into acetic acid, 

 + widiout any influence of atmospheric air. 



{d,) The sub-oxide of platina affords an excellent method of dis- 

 covering the presence of alcohol, dissolved either in atmospheric air, 

 or in any liquid ; even the quantity may be determined by means of 

 it. Thus, putting a drop of alcohol into a vessel of the size of 3 or 4 

 cubic inches, and filled with djy air, and inserting into the vessel a 

 few grains of the sub-oxide of platina on a small plate suspended by 

 a platina wire, at the end of a few minutes it is observed that the 

 whole interior surface of the vessel becomes moist, and that this 

 moisture collects into small drops which make litmus paper red. 

 This experiment succeeds well, particularly under the influence of 

 light, and tlie sub-oxide becomes hot, although the acetic acid evap- 

 orates at the very moment of its formation. To determine the quan- 

 tity of alcohol contained in a liquid, as in wine, beer, &:c., a particu- 

 lar apparatus is to be employed, which communicates with a gradu- 

 ated glass jar filled widi oxygen gas. Li (his apparatus, small quanti- 

 ties of the liquid containing alcohol are rendered acid in a few hours ; 

 and from the volume of oxygen consumed, the quantity of alcohol con- 

 tained in the liquid subjected to experiment is calculated, (100 parts 

 of absolute alcohol combine with G9.5 parts of oxygen to pass into the 

 state cf aceuc acid-) M. Dobereiner promises ample details respect- 

 ing his apparatus, to which he gives the name of Acetogenator 

 Idem. 



16. Process for Preserving Milk ^ for any length of time. Bulb 

 des Sc. Agric.) — ^This process, invented by a Russian chemist named 



