Chemistry and Physics. 251 



and permanent, i. e., not convertible into the prismatic form. 

 On treating them with silver-oxide, neutralizing the filtrate with 

 hydrochloric acid and evaporation, the hydrochloride was ob- 

 tained partly in needles and partly in octahedra. Hence there 

 are two hydrochlorides of this compound ammonium as there are 

 two platinochlorides, the prismatic form of the hydrochloride 

 being the more stable. — C. M., ex, 144, 1890; J. Ghent. Soc, 

 lviii, 475, May, 1890. G. f. b. 



3. On the production of Ozone and the formation of Nitrites 

 in Combustion. — Ilosvat has confirmed the observation of Leeds 

 that no ozone is formed by the action of concentrated sulphuric 

 acid upon potassium permanganate, the supposed reaction of 

 ozone being due to chlorine contained as an impurity in the per- 

 manganate, or even in the absence of chlorine, to the direct 

 action of the promanganic oxide in the form of a violet vapor. 

 With four or five grams of promanganate, the action proceeded 

 satisfactorily. But on attempting to use 20 grams, a strong de- 

 tonation resulted, due no donbt to the decomposition of the an- 

 hydride by the heat generated. Oxygen prepared by the action 

 of concentrated sulphuric acid on potassium dichromate also con- 

 tains no ozone. 



The author has also explained the products of the combustion 

 of coal gas under modi6ed conditions. In one case the Bunsen 

 flame was allowed to strike down, much air being mixed with the 

 gas; in a second, carbon dioxide was admitted to the Bunsen 

 flame ; and in a third, a flame of air was obtained in the gas. 

 The products of combustion were carried through a dilute solu- 

 tion of sodium hydroxide and the presence of nitrous acid was 

 detected in four or five minutes in the first and second cases, and 

 in 25 or 30 minutes in the third. Oxygen and nitrogen dioxide 

 were then mixed with the air burning in the illuminating gas. 

 The flame was more brilliant and cyanogen was observed among 

 the products of the combustion. Since ammonia had also been 

 observed among the products of the combustion of air in coal 

 gas, the author regards these facts as proving the affinity of 

 nitrogen at high temperatures for hydrogen and carbon as well as 

 oxygen. 



In other experiments the author observed the production of 

 nitrites but not of ozone when air is passed over platinum heated 

 to 200° to 300°. In the case of platinum gauze the action begins 

 at 280° and continues up to 350° ; but the property is lost after 

 an hour and a half. With platinum black the action begins at 

 180°, reaches a maximum at 250° and diminishes above 300°. 

 After repeating the experiment three or four times, the power of 

 effecting the combination is lost. With platinum sponge, the ac- 

 tion begins at 250° and is strongest at 300° ; at 350° it becomes 

 feeble and in thi'ee or four hours disappears entirely. Since the 

 activity of the platinum when lost is not regained by heating in 

 hydrogen, the author concludes that the loss of its power is due 

 to a chancre in its molecular structure, and not to a condensation 



