Intelligence and Miscellaneous Articles, 319 



to develope. Relying on the exact knowledge of this spectrum of 

 aqueous vapour, I calculate on soon being in a position to pronounce 

 on the presence of this principal element of organic life in the atmo- 

 spheres of a the planets and other stars. I can at once announce 

 that this vapour forms no part of the solar atmosphere. — Comptes 

 Rendus, August 13, 1866. 



ON THE PRODUCTION OF OZONE. BY M. G. PLANTE. 



The inoxidizable metals, such as gold and platinum, have hitherto 

 been regarded as those which alone can be used as electrodes in 

 obtaining ozone by the electrolytic decomposition of water. I have, 

 however, found that ozone can be obtained as well by electrodes of 

 lead as by electrodes of platinum, and even in greater quantity. 



This can be readily established by taking two voltameters, one 

 with platinum wires, the other with lead wires of the same length 

 and diameter, and passing the same current through them. By sus- 

 pending iodized starch-paper in open tubes placed over the positive 

 wire of each voltameter, both are at once seen to become blue, but 

 that placed over the lead wire more rapidly and with greater inten- 

 sity than that over the platinum wire. 



When ozonized oxygen is simultaneously disengaged in similar 

 solutions of iodide of potassium, the solution in which is the lead 

 wire becomes yellow more rapidly than that in which is the platinum ; 

 and taking the quantity of iodine liberated in the latter as unity, 

 that furnished by the ozone of the voltameter with lead wires is ap- 

 proximately equal to 1*5. In other words, the quantity of ozone 

 from the platinum is only two-thirds of that from the lead. 



In the smell also, and in the rapidity of the oxidation of silver, 

 there is also an appreciable difference. 



This greater abundance in the production of ozone from electrodes 

 of lead than from electrodes of platinum is a difficult fact to explain 

 in the present state of our knowledge of ozone. When ozone is pro- 

 duced by statical or induced electricity, the nature of the electrodes 

 between which the spark passes has no appreciable influence. But 

 when prepared by means of the pile, the nature of the electrodes 

 exerts a preponderating influence. In the present case a metal more 

 oxidizable than platinum produces the ozone. The oxidation, it is 

 true, is merely superficial ; the thickness of the layer does not appre- 

 ciably increase as the current continues, and the volume of oxygen is 

 not diminished as compared with that produced by platinum under 

 the same conditions. Yet this layer of oxygen serves a double pur- 

 pose ; it is the source of a secondary energetic current, and at the 

 same time it facilitates the production of ozone. 



To account for the manner in which it acts in the latter case, we 

 can only make hypotheses, useless now to dwell upon. I shall limit 

 myself to saying that at present, to prepare ozone by the electrolysis 

 of water, wires of lead must be used instead of those of platinum. — 

 Comptes Rendus, July 23, 1866. 



