400 Miscellanies. 



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

 gous lo that of some other substances except that 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 cannot be the cause of the absorption, nor 

 is it more probable that it is so in the case of platina and hydrogen.^' 

 —Idem. 



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

 were wrapped in unsized paper and put carelessly iijto a pasteboard 

 box. Having been 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 rtie- 

 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 the 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 experiment been tried of causing dry powdered fresh charcoal to absorb 

 a portion of ammouial gas, and then to place it over mercury in a receiver filled 

 with muriatic acid gas ? would ignition ensue ? J. G. 



