CHEMICAL SCIENCE. 209 



placed under the same circumstances, and for the same oil under 

 different circumstances. 



2. That the height of the temperature exercises a very marked 

 influence on tlie rapidity of the oxidation. 



3. Tliat the intensity of tlie light also manifestly influences the 

 phenomena. 



•4. That light transmitted by colored glasses checks more or 

 less the resinifieation of the oils by the air. Starting from coloi*- 

 less glass as the term of comparison, the decrease of oxidation 

 is in tiie following order: Colorless, blue, violet, red, green, 

 yellow. 



5. That, in darkness, the oxidation is considerably retarded ; it 

 starts later and progresses more slowly than in light. 



6. That the presence of certain materials, and the contact with 

 certain substances, accelerate or retard this effect. 



7. That, in the resinifieation of oils, there is both a loss of cai'- 

 bon and hydrogen of the oil, and an absorption of oxygen. 



8. That the different oils, in oxidizing, furnish in general the 

 same products, — volatile acid compounds, liquid and solid fat 

 acids not altered, and an insoluble solid material, which apj)ears 

 to be a definite proximate principle. Oils oxidized in the air no 

 longer contain glycerine. 



9. The drying and non-drying oils ai'e not chemically distinguish- 

 able. All contain the same glyceric proximate principles, but in 

 different proportions. 



PEROXIDE OF HYDROGEN. 



Professor Schonbein has discovered a new and very ready 

 method of procuring the peroxide of hydrogen. It consists 

 simply in agitating, in a large flask, to which air has access, 

 amalgamated .zinc, in powder, with distilled water. Oxygen is 

 then absorbed by both the zinc and the water, with formation of 

 oxide of zinc and peroxide of hydrogen. The peroxide of h3'drogen 

 obtained by this method, unlike that obtained by the ordinary 

 process, is quite free from.- acid, and so may be kept for a long 

 time without decomposition. It does not contain, moreover, a 

 trace of either zinc or mercury, but is absolutely pure. This new 

 process has therefore great advantages over the old process of 

 preparing peroxide of hydrogen, both as being far simpler and 

 more expeditions, and as yielding a much purer product ; but it 

 is almost as far as the old process from yielding peroxide of 

 hydrogen cheaply enough for use in the arts. 



OZONE. 



The Paris correspondent of the " London Chemical News" 

 writes as follows : — 



" The rumor which you helped to spread abroad that Schonbein 



has succeeded in isolating ozone and antozone, attracted, it 



seems, the notice of the Scientific Association of France, and that 



learned body invited Schonbein to come to Paris and exhibit his 



18* 



