400 Mhccllanies. 



The absorbing power of finely divided plaiina appears to be analo- 

 gous to that of some other substances except tliat it acts so much more 

 powerfully on inflammable gases. Charcoal absorbs very little hydro- 

 gen, not so much even as dry wood. The effect in each case doubt- 

 less depends in a great measure on the relative dimensions or figure 

 of the molecules of the gas and of the Imbibing substance. Hydro- 

 gen contained over mercury in a receiver^ which has a crack in its 

 upper part, will gradually escape and the mercury will rise, in op- 

 position to its gravity- No other gas possesses this property. 



It would appear reasonable to ascribe the ignition of the spongy 

 platina in part to the extermination of latent heat, arising from the 

 affinity of oxygen and hydrogen, or in other words, to electrical ac- 

 tion. But charcoal absorbs both ammoniacal and muriatic acid 

 gases in equal proportions, when the electrical states are directly oppo- 

 site. Affinity therefore caimot be the cause of the absorption, nor 



is It more probable tliat it is so in the case of platina and hydrogen.* 

 ■Jdem. 



42. Reduction of nitrate of Silver. — Some fine crystals of this salt 

 were wrapped in unsized paper and put carelessly inio a pasteboard 

 box. Having beai found a few years after, the paper had acquired 

 as usual a deep violet color, but to the surprise of the manufacturer, 

 the crystals, without losing their form, had become converted into me- 

 tallic silver, which was very malleable. — Idem. 



43. Flesh of young calves.' — By a municipal law in Paris, it is 

 forbidden to expose for sale tlie meat of calves less than six weeks 

 old. The great profit arising from the sale of milk furnishes an in- 

 ducement to the violation of this law. Many thousands of cows 

 are kept and fed in cellars, within the walls of Paris for the sale of 

 the milk, and unless a cow yields a calf about once a year, she is 

 less profitable. 



The prohibition of the sale of very young calves, is deemed of 

 great importance to public health. At less than a month old, the 



*Has the experiuiOiit been tried of causing dry powdered ficdli charcoal to absorb 

 ft portiou of arumouial gas, and then to place it over mercury in a receiver filled 



with iL. .'atic acid ^as ? would ignitioQ ensue ? J' ^• 



) 



I 



