464 ScUntifit Intelligence. [Dec, 



Article XV. 



SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS 

 CONNECTED "WITH SCIENCE. 



I, On the Ignition ofPlatinOy Sfc. by Hydrogen Gas, 



I have, says Prof. Dcebereiner, already proved that the protoxide 

 of platinum obtained by Edmund Davy's method, has the property 

 of causing alcohol, placed in contact with it, to attract oxygen gas, 

 and to become converted into acetic acid and water ; and that this 

 property is likewise possessed by the oxidized sulphuret of platinum, 

 prepared by treating a solution of that metal with sulphureted hydro- 

 gen, and exposing in a dry state the sulphuret formed by that means, 

 to the action of atmospheric air for some weeks. In this very remark- 

 able process, 1 atom (= 46) of alcohol combines with 4 atoms 

 (=4- X 8 = 32) of oxygen, and forms with it 1 atom (=51) of 

 acetic acid, and 3 atoms (= 3x9 = 27) of water; that irj so say, 

 equal volumes of the vapour of alcohol and oxygen gas, become 

 equal volumes of acetic acid and aqueous vapour ; for 1 atom of water 

 is requisite to the isolated existence of acetic acid. The respective 

 proportions in which acetic acid and water appear in this case, are 

 exactly the same as those which they bear to each other in crystallized 

 sugar of lead, and also in the subacetate of copper ; the quantity of 

 water in acetate of soda is exactly double that which is contained in 

 each of the former acetates. 



After having finished my experiments on this process of the forma- 

 tion of acetic acid, I took the opportunity of ascertaining the rela- 

 tions of the two above-named preparations of platinum to different 

 elastic fluids. The results of the experiments instituted for that pur- 

 pose are interesting ; for I found, 



1. That neither oxygen nor carbonic acid gas was absorbed by the 

 protoxide, or by the oxidized sulphuret of platinum ; but that those 

 substances absorbed every inflammable gas. 



2. That 100 grains of protoxide of platinum absorb from 15 to 20 

 cubic inches of hydrogen gas, during which absorption so much ca- 

 loric is evolved, that the protoxide becomes ignited, and the hydrogen 

 burns with detonation, if it had been previously mixed with oxygen 

 or with atmospheric air. 



The preparation of platinum, charged with hydrogen, has the pro- 

 perty of greedily attracting as much oxygen gas as is requisite for 

 the saturation of the hydrogen it contains. If atmospheric air, there- 

 fore, be suffered to enter the tube containing it, it instantly deprives 

 it of its oxygen, and even forms ammonia with a portion of the resi- 

 dual nitrogen, if there be not sufficient oxygen present for its satura- 

 tion. By this agency the oxide of platinum is reduced, and thereby 

 loses its remarkable property of disposing alcohol to become acetic 

 acid, and also that of condensing hydrogen gas ; but, what is very 

 remarkable, it retains the property of determining the latter substance 

 to the state in which it combines with oxygen gas, and becomes 

 water ; and so much heat is evolved during this combination, that if 

 the hydrogen gas be mixed with pure oxygen, and the volume of the 



