Chemistry and Physics. 233 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Crystallized Hydrogen Peroxide. — It is announced by 

 Wilhelm Stadel, that, contrary to previous assertions, hydro- 

 gen peroxide crystallizes with ease and in a very distinct manner. 

 Its melting point is about —2°. A preparation containing 95 to 

 96 per cent of hydrogen peroxide remained liquid in a freezing- 

 mixture at —20°; but in a mixture of solid carbon dioxide and 

 ether it solidified to a hard mass. It appeared to be necessary to 

 cool the preparation to a temperature between —20 and —23° 

 before it solidified. If a trace of the solid material is thrown 

 into the liquid cooled to —8 or —10°, magnificent needle-shaped 

 crystals immediately form, which are as clear and transparent as 

 water, and which soon permeate the whole mass. By draining 

 the mother-liquor from these crystals and allowing them to fuse, 

 then repeating the crystallization, peroxide of hydrogen free 

 from water is obtained. 



A number of reactions were tried with the anhydrous sub- 

 stance: an extremely small quantity of platinum-black produces 

 catalytic action accompanied by a violent explosion; powdered 

 manganese dioxide, or a mixture of carbon and metallic mag- 

 nesium with a trace of manganese dioxide, takes fire immediately 

 when put in contact with the substance ; finely-divided metallic 

 iron is without action, but when a little powdered manganese 

 dioxide is added the iron burns and throws off sparks ; powdered 

 lead is ignited in the same manner ; a few drops of anhydrous 

 hydrogen peroxide, when thrown upon wool or moist sponge, 

 immediately bursts into flame ; concentrated sulphuric acid can 

 be mixed with it if this is done at a low temperature, but if 

 the temperature is allowed to rise too high, oxygen very rich in 

 ozone is given off. 



It appears that the problem of preparing anhydrous hydrogen 

 peroxide on a large scale has been solved by the process which 

 has been described, while the pure product thus produced shows 

 an unexpected degree of stability. A well-packed sample was 

 carried on an ordinary truck for seven days over a distance of 50 

 or 60 kilometers without undergoing more than a slight change 

 under these unfavorable circumstances. — Zeitschr. angew. Chem., 

 1902, 642. h. l. w. 



2. Famarole Gases from Mount Pelee. — Moissan has analyzed 

 samples of gas carefully collected by Lacroix from a fumarole of 

 the Blanche River after the catastrophe of May 8th, 1902 and 

 before the eruption of Aug. 30th of the same year. It is reported 

 that pieces of lead placed in the mouth of the fumarole melted 

 rapidly, while zinc remained solid, so that it is assumed that the 

 temperature was about 400°. It is stated that the opening was 

 in conglomerate, and that an abundance of sulphur and ammo- 



