SCIENTIFIC SUMMARY. 
365 
CHEMISTRY. 
Formation of Ozone during the Evaporation of different Liquids. — When 
it is desirable to show a number of persons that ozone is formed during the 
evaporation of a liquid, Bottger ( Polyt . Notizblatt, xxxv. 95) recommends 
letting fall on a piece of paper which has been uniformly saturated with a 
solution of starch and iodide of cadmium some drops of alcohol or ether, and 
the igniting of such solution. The paper in consequence of the ozone which 
is formed by the evaporation acquires a dark blue colour. 
Compound of Phosphoric Hydride and Chloric Hydride. — This compound 
is easily prepared according to Lemoine {Bull. Soc. Chim. Paris, xxxiii. 194), 
by placing the two gases in a U-tube, one end of which is closed, under a 
pressure of two atmospheres, produced by a column of mercury in an open 
tube and exposing the apparatus to the cold of liquid sulphurous acid, the 
evaporation of which is increased by a strong current of air. 
Silver Trioxide. — By the electrolysis of silver nitrate a curious body is 
formed, first described by Ritter in 1804, and later by Grothus, which was 
first regarded as silver dioxide, but has since been shown to contain nitric acid. 
Berthelot has since examined it ( Compt . Rendus, 1880, xc. 653). He employed 
a battery of four Bunsen elements during twenty-four hours, and obtained a 
gramme of the body. Washed and dried it presented the appearance of 
thick, short, flattened needles with metallic lustre, which soon fall to pieces 
and lose their lustre. It developes oxygen rapidly at 100°. Analysis gave 
the formula 4A g 0 3 , N0 6 A g , HO (old formula!). The longer it lies the 
higher rises the percentage of silver, and the composition approaches the 
formula N0 6 Ag + 4A g O. 
Salireton. — Experiments have been made by P. Giacosa {Journ. prakt. 
Chem. 1880, xxi. 221), to prepare glycosides synthetically, and led him to 
heat saligenin and mannite to 100°. In this way he obtained a new pro- 
duct of condensation of saligenin C 14 H 12 0 3 , which he has termed salireton. 
The same body is formed when glycerin or methylal is taken in place of 
mannite : and its formation is thus explained : 
2 C 7 H 8 0 2 - H 2 O - H = C 14 H 12 0 3 . 
The curious phenomenon that during the formation of this body, not only 
water but hydrogen also should be extruded, led the author to think that 
perhaps, in the first instance, a molecule of saligenin might be oxidized to 
salicylaldehyde, which then first combined with a second molecule of saligenin 
to salireton, water being extruded, as shown below : 
C 7 H 8 0 2 + C 7 H 6 0 2 = C 14 H 12 0 3 + H 2 O. 
Although when saligenin was heated with glycerin the odour of salicyl- 
aldehyde could not be recognized, the author heated equivalent quantities of 
salicylaldehyde and saligenin, just like the saligenin and glycerin, in closed 
tubes in boiling water. After many hours’ heating, the contents of the tubes 
were treated with water and distilled; with the steam almost the whole of 
the salicylaldehyde passed over ; the resinous residue remaining in the retort 
w r as boiled with a little water and filtered. From this filtrate the salireton 
separates: this is recrystallized, and when pure melts at 121 0, 5. The yield 
