Chemistry and Physics. 311 



4. On the Preparation of Alkali Nitrites. — It has been pointed 

 out by Divers that the common impression that in preparing 

 alkali nitrites by passing nitrous fumes into alkali solutions, a 

 method proposed by Fritsche in 1840, there is also produced 

 much nitrate, is erroneous. The nitrous gases are made from 

 nitric acid and starch or arsenous oxide, and are passed into the 

 concentrated solution of the hydrate or carbonate until neutrali- 

 zation is effected ; the vessel being loosely stoppered. The 

 strength of the acid and the temperature are so regulated that 

 the nitrogen monoxide is in excess of the dioxide. If the solution 

 is acid, it must be boiled until neutral before exposing it to the 

 air. Then the solution may be freely evaporated to crystalliza- 

 tion. Both potassium and sodium nitrites are slightly yellow in 

 color and are slightly alkaline. Sodium nitrite fuses at 2*71° and 

 at 15° five parts of it requires six parts of water to dissolve it. It 

 is moderately deliquescent, and its crystals are anhydrous. 

 Potassium nitrite is very deliquescent, is soluble in about one- 

 third its weight of water, and its crystals are reputed to contain 

 half a molecule of water. — J. Chem. Soc, lxxv, 85, January, 1899. 



G. F. B. 



5. On the Composition of American Petroleum. — By means of 

 a combined dephlegmator and regulated temperature still-head, 

 Young has succeeded in preparing from American petroleum 

 ether a number of nearly pure hydrocarbons. In some cases the 

 fractional distillation was preceded by treatment with mixed 

 nitric and sulphuric acids, in order to remove the benzene. Evi- 

 dence of the presence of the following has been thus obtained : 

 Isopentane B. P. 27-95°, normal pentane B. P. 36*3°, penta- 

 methylene B. P. about 59°, isohexane B. P. about 61°, normal 

 hexane B. P. 68*95°, methylpentamethylene B. P. about 72°, ben- 

 zene B. P. 80-02°, hexamethylene B. P. 80*8°, isoheptane B. P. 

 90-3°, dimethylpentamethylene (?) B. P. about 94°, normal hep- 

 tane B. P. 98-4°, methylhexamethylene B. P. about 102° and 

 toluene B. P. 110-8°. These results show that the same classes of 

 hydrocarbons, paraffins, polymethylene compounds or naphthenes 

 and aromatic hydrocarbons are present in petroleum from all 

 three sources, but that Russian petroleum contains a relatively 

 larger amount of naphthenes and in all probability, of aromatic 

 hydrocarbons than Galician, and Galician a larger amount of the 

 same hydrocarbons than American petroleum. — J. Chem. Soc, 

 lxxiii, 905-920, December, 1898. G. f. b. 



6. Electrical leaves along wires. — A. Sommerfeld has exam- 

 ined by means of elaborate mathematical analysis this subject, 

 and has calculated the rate of damping and the decrease ot 

 velocity for the case of wires of different diameters. In the case 

 of a copper wire 4 mm thick with a period of 10 9 per second, the 

 electric wave velocity was 8 kilometers below the velocity of 

 light. With a platinum wire of T -oVo mm - diameter, period 3*1 6 

 per second, the velocity falls to f of the velocity of light. The 

 ordinary experimental method, in which two parallel wires are used, 



