326 Scientific Intelligence. 



From the variety of solvents experimented with by the authors, 

 they have given the preference to alcohol ; whence substituting 

 its molecular mass for m, we have 



M= «.*.»• 



100 s" 



From the results obtained with this method, the authors give the 

 following values, the numbers in brackets being the true molec- 

 ular mass: nitrobenzene (123) 122, 12V; acetamide (59) 58; 

 ethyl benzoate (150) 137 and 143; benzoic acid (122) 107, 108; 

 picric acid (229) 264; diphenylamine (169) 153, 146; atropine 

 (289) 275, 250; hyoscyamiue (289) 263; formamide (45) 49, 50 ; 

 ethyl salicylate (166) 187, 189; urethane (89) 87, 91; carbamide 

 (60) 60, 61; vanillin (152) 130, 135; acetovanillon (a new body 

 not yet described OH . C 6 E 3 (OMe) . COMe) (166) 144, 165, 157, 

 156. Since the new method requires three weighings only and is 

 independent of delicate thermometric readings, it is obviously a 

 very convenient method in practice. — Ber. JBerl. Chem. Ges., 

 xxii, 1084-1092; J. Chem. Soc., lvi, 820, Sept. 1889. G. r. b. 



3. On the Boiling point of Ozone and the Solidifying point of 

 Ethylene. — The experiments of Hautefeuille and Chappuis have 

 proved that ozonized oxygen condenses to a dark blue liquid 

 under a pressure of 125 atmospheres and at the temperature at 

 which ethylene evaporates under the atmospheric pressure, namely 

 — 102 '5°. Since the ozone remains in a liquid state after the pres- 

 sure has been reduced to that of the atmosphere, it follows that 

 the boiling point of ozone cannot be very much lower than that 

 of ethylene. Consequently Olzewski attempted to obtain liquid 

 ozone by cooling ozonized oxygen to —150° at the ordinary atmo- 

 spheric pressure. But though the receiver was cooled to —157° 

 by liquid ethylene, no liquefied ozone was obtained, the result be- 

 ing due evidently to the large quantity of oxygen with which it 

 mixed. But by using liquid oxygen at atmospheric pressure in 

 place of ethylene, the temperature being now — 181"4° the ozone 

 was easily obtained in the form of a dark blue liquid. If by in- 

 jecting the ozonized oxygen into a tube thus surrounded with 

 liquid oxygen at this temperature, a drop of liquid ozone was 

 formed, the author observed that on allowing the oxygen to evap- 

 orate, the influx of gas being stopped, the ozone remained liquid 

 until the whole of the oxygen had evaporated. When this point 

 was reached the temperature would be about —150°. At the 

 boiling point of oxygen, the ozone remained a liquid, which was 

 transparent in thin layers but almost opaque in a layer 2 mm thick. 

 To determine the boiling point of the ozone, the tube containing 

 it was placed in liquid ethylene at — 140°. The ozone remained 

 liquid until the ethylene had nearly reached its boiling point, 

 when the temperature of its evaporation was noted on a sulphu- 

 rous oxide thermometer and found to be —109° corresponding to 



— 106° on the hydrogen thermometer. Hence this temperature 



— 106° may be taken as the boiling point of liquid ozone. On 



