512 Prof. Schonbein on the Polarization of Oxygen. 



mercury, put them into a tumbler filled with dilute sulphuric 

 acid, stir up the metals with a glass rod, and you will soon have 

 a grossly-powdered amalgam. Now, after having washed that 

 metallic mixture with water, put it loosely into a funnel placed 

 upon a bottle ; let a very thin stream of distilled water run over 

 the amalgam, and by means of dilute paste of starch contain- 

 ing iodide of potassium, you will detect peroxide of hydrogen 

 in the water which has j^assed (in the manner indicated) only 

 once over the amalgam, if you add to a mixture of both some 

 drops of a solution of iron vitriol, &c. If you shake for a few 

 seconds the said amalgams together with air and 100 grms. of 

 distilled water, the latter will have the property of striking a 

 blue colour with the paste of starch on adding to it a couple of 

 drops of a dilute solution of any protosalt of iron. 



Water containing 1 per cent, of SO"*, under the same circum- 

 stances produces more HO^ than pure water does. You may 

 satisfy yourself with one instance. Take 100 grms. of a still 

 liquid amalgam of lead, shake it with 100 grms. of the mentioned 

 acidulated water and atmospheric air for from 5 to 6 minutes, 

 separate by filtering the sulphate formed from the water, add to 

 the latter some drops of a dilute solution of chromic acid, and 

 the liquid will be transiently turned azure-blue, — a proof of the 

 presence of H0-. If you shake one volume of the said acidu- 

 lated water, two volumes of pure ether, and some drops of a 

 dilute solution of CrO^ together, the ether assumes a still deeper 

 blue colour : the same acidulated water of course discharges 

 the colour of the permanganate solution. In saying so much 

 about this matter, I must not omit to add that the quantity of 

 HO^ formed under the circumstances soon reaches its maximum, 

 which does not go beyond -g-o^joth of the quantity of acidulated 

 water employed. The reason of this fact is obvious. I shall 

 not enter into any more details on the subject, hoping soon to 

 find an opportunity of sending you a paper containing all the 

 particulars about this highly interesting formation of HO*. 

 From the facts above stated, and others not mentioned, I am 

 led to conjecture that all the slow oxidations which take place in 

 the moist atmospheric air depend upon what I call " the chemical 

 polarization of neutral oxygen," i. e. that this act always pre- 

 cedes that of real oxidation. The oxidable matter being eager 

 to combine with 0, and water with to produce 110 + 0, de- 

 termine that mysterious polarization of in a similar manner as 

 HO^ is sometimes decomposed if placed between two substances, 

 one of which attracts the oxygen, the other the hydrogen of that 

 compound. But, be this as it may, the fact is now certain, 

 that in a number of cases of slow oxidation, the counter- 

 part or antipode of makes its appearance in the shape of 



