362 
POPULAR SCIENCE REVIEW. 
CHEMISTRY. 
Glycogen in the Tissues of Molluslcs. — Signor Rizio presented a paper on this 
subject to a recent meeting of the French Academy. This observer not only 
detected an amyloid substance, which he believes to be glycogen, in the 
tissues of various species, such as the oyster, the mussel, the razor-shell, and 
the scallop ; but he has shown a very curious fact in connection with the 
presence of this substance ; viz., the rapidity with which the amyloid 
substance gives rise in these mollusks to lactic acid fermentation, so that in 
those species in which this matter is abundant the lactic acid produced is 
sufficient to preserve the animal from putrefaction. From this it follows 
that the more or less easy preservation of the body of the animal may enable 
us to judge of the relative quantity of amyloid substance contained in it. — - 
Comptes Benclus, April 2. 
Oxidizing Action of Air on Coal. — The recently published observations of 
Varrentrapp upon the oxidation of coal by atmospheric air have disclosed 
some curious results. The coal which he experimented on was gas coal from 
certain mines in Westphalia. The coal was dried and pounded, and the 
powder, which passed through a quarter of a millimetre sieve, was used for 
examination. The powder was next placed in a three-necked Woulffe’s 
bottle, one neck being for the entrance, and the other for the exit of the air, 
while the middle one gave passage to the bulb of a thermometer, which 
rested upon the coal in the bottom of the vessel. The air, rendered perfectly 
pure by potash, &c., was measured by passing it through a gas meter ; it then 
came in contact with the coal, and afterwards bubbled through baryta-water, 
the amount of carbonic beihg determined from the quantity of carbonate 
formed by a given amount of air. The coal was exposed to different 
temperatures by immersing the bottle in a paraffin bath ; air was passed for 
some time through the entire apparatus before each experiment. 530 
grammes of coal exposed for 30 days of 24 hours, at from 15° to 18° C., to a 
current of air gave off O' 109 gramme of carbon in the shape of carbonic acid. 
534 grammes were moistened with boiled water, and heated to 110° ; the 
coal only rose to 97°, and in 10 days gave off 0 - 529 gramme of carbon. 
Between 130° and 140° the first-mentioned quantity gave off 0’538 carbon in 
24 hours. Up to this time the temperature of the coal has been lower than 
that of the bath. When, however, the latter was heated to 160°, the 
thermometer in the coal rose to 170°, and R64 grammes of carbon were 
oxidized in 24 hours ; on heating the bath to 170 Q the coal showed a tempera- 
ture of 180°, and in 48 hours 2*74 grammes of coal were consumed. 
New Mode of preparing Oxygen. — This has been devised by Herr Fleitmann, 
and has recently been experimented on by Herr Reinsch. The latter rubbed 
up chloride of lime and water till they formed a cream, separated the lumps, 
and shook up the cream with water. Allowing the mixture to deposit, 
he then poured off the clear solution, and heated it, along with a piece of 
