[ 545 ] 

 LXV. Intelligence and Miscellaneous Articles. 



ON THE PASSAGE OF HYDROGEN GAS THROUGH SOLID BODIES. 

 BY M. LOUYET. 



M. LOUYET has made a curious observation connected with the 

 history of hydrogen : he found that when a horizontal current of this 

 gas, emitted from a capillary orifice, was directed upon a sheet of 

 ])aper held vertically and perpendicularly to the gaseous current, the 

 fluid passes through the jjaper without being sifted, as might be ex- 

 pected, but retaining the form of a current, and so perfectly that it 

 may be inflamed behind the paper, absolutely as if it did not exist. 

 Spongy platina placed behind the paper became incandescent, and it 

 is to be observed that the pressure under which this phsenomenon 

 is produced does not exceed that of 40 to 48 inches of water. 



M. Louyet has also stated that hydrogen gas passes in the same 

 manner through gold, silver and tin leaf, even double, and also 

 through thin membranes of gutta percha, such as are obtained by 

 evaporating a solution of this substance in chloroform. 



Lastly, the author has observed that the same gas does not sen- 

 sibly pass through pellicles of glass obtained by strongly blowing a 

 bulb at the end of a tube, however thin they may be. — Ann. de Ch. 

 et de Phys., Septembre 1849. 



QUALITATIVE AND QUANTITATIVE DETERMINATION OF PHOS- 

 PHORIC ACID. BY M. LECONTE. 



The importance of phosphoric acid in vegetable and animal physi- 

 ology is well known, and, in this point of view, the utility of detecting 

 the presence and determining the quantity of this acid in food, ma- 

 nures, &c., has been duly appreciated, particularly in those manures 

 intended to fertilize the soils in which wheat is grown. 



For twelve months several chemists have been occupied with this 

 question, which appears a proof both of the interest and difficulty at- 

 tached to solving it. M. Raewsky's process by acetate of peroxide of 

 iron, and that of M. Cotterau by nitrate of silver, have been described. 

 M. Leconte states that he has found the soluble salts of uranium to 

 be the most certain for detecting and determining the quantity of 

 phosphoric acid, on account of the absolute insolubility of the phos- 

 phate of uranium, and the facility with which this salt precipitates 

 notwithstanding the presence of other saline substances, acids, &c. 



The quantitative determination of phosphoric acid in soluble phos- 

 phates is very simple. A solution of nitrate of uranium is prepared, 

 of which every cubic centimetre precipitates Ogr.'OOI of phosphoric 

 acid ; a known weight of the phosphate to be analysed is taken and 

 dissolved in a known bulk of distilled water, taking care to neutral- 

 ize it ; fifty cubic centimetres of this liquor are boiled in a flask, and, 

 by the aid of a graduated tube, nitrate of uranium is added to it, till 

 the liquor standing over the precipitate becomes limpid. It must be 

 boiled for a second after each addition of the test solution. — Journ. de 

 Ch. Med., Novembre 1849. 



Phil. Mag. S. 3. No. 239. Suppl. Vol. 35. 2 N 



