394 Scientific Intelligence. 



5. On the formation of Ozone from. Oxygen. — An extended 

 series of experiments has been made by Shenstone and Peiest 

 on the production of ozone by the action of the electric discharge 

 upon oxygen, attention being paid especially to the effect of greater 

 or less differences of potential, of the rapidity of the discharges 

 and of the construction of the ozone generator. In producing 

 ozone in this way the chief points requiring attention are the fol- 

 lowing : (1) the ozone generator should be cooled, which is best 

 done with an apparatus of the Brodie form; (2) it should be 

 made of the thinnest glass that can be drawn of the requisite size 

 and uniformity; (3) its inner tube should fit fairly closely into 

 the outer tube ; (4) if a product rich in ozone be required, the 

 oxygen should be passed through the ozonizer very slowly, the 

 potential difference should not be too high and the breaks in the 

 primary current should not exceed 1000 per minute; (5) if how- 

 ever the oxygen is to be charged with ozone rapidly, a higher 

 potential difference may be employed, but the yield is less; (6) 

 the best results are given by a large induction coil if the rapidity 

 of its action be well managed. These experiments, the authors 

 think, throw some light on the nature of the process itself, by 

 which oxygen is converted into ozone. They show that unless 

 the path of the discharge be very short, the proportion of oxygen 

 converted into ozone, under given conditions as to temperature 

 and pressure, is for a given ozone generator practically indepen- 

 dent of the potential difference employed, provided that the range 

 is of moderate extent. In other words they show that the ulti- 

 mate effect of the discharge is conditioned only by the tempera- 

 ture and pressure at which the ozonizing is effected. Moreover, 

 these experiments show that any circumstance which is likely to 

 be opposed to the effective cooling of the gas (such as great fre- 

 quency of discharge, or the employment of* very high potential 

 difference with a short path for the discharge) causes a falling off 

 in the proportion of ozone formed ; whilst any circumstance which 

 promotes the efficiency of the refrigerating power of the ozone 

 generator (such as employing the discharges at a low rate of fre- 

 quency, or using an ozone generator the tubes of which fit closely, 

 together with low potential difference) raises the proportion of 

 ozone considerably. The authors regard these facts as support- 

 ing distinctly the -view that the direct effect of the discharge is 

 not to produce ozone but to resolve a greater or less proportion 

 of oxygen molecules into atoms, and that the ozone is produced 

 after the discharge by the recombination of these atoms ; since if 

 the formation of ozone depends on the recombination of the atoms 

 of oxygen after the discharge, we should expect the proportion of 

 ozone formed to be largely influenced first by the refrigerating 

 efficiency of the generator and secondly by the temperature 

 employed. — J. Chem. Soc, lxiii, 938, July, 1893. g. f. B: 



6. On Nitrocopper. — The compound called by Sabatier and 

 Senderens nitrocopper, is obtained by passing nitrogen tetrox- 

 ide (peroxide) over finely divided metallic copper at 25-30°, this 



