492 



SCIENCE. 



[N. S. Vol. TV. No. 92. 



above 30 lamps, the gas may be profitably 

 burned in the gas-engine. Mr. Eeynders gives 

 an account of experiments with a differential 

 Watt-meter indicating the probably frequent 

 existence of errors in such work. Mr. Ferris 

 makes a valuable contribution to the draughts- 

 man's department in a collection of alphabets, 

 for use in marking drawings with the pen, 

 which have special value as illustrating the 

 practice of a number of distinguished and suc- 

 cessful manufacturing and other firms, whose 

 draughtsmen have reduced the production of 

 such alphabets to a most efficient state. 



There are few phases of modern scientific 

 and technical college work which have better 

 exhibited the progress made on that side of 

 education, in the last decade or two, than the 

 appearance and progress of these scientific jour- 

 nals. Each measures, in greater or less degree, 

 the standing of its source of publication ; al- 

 though, as a matter of course, care must be 

 taken to distinguish between the periodicals 

 published by students and those issued more 

 formally and under the more practiced hands 

 of professors and alumni. R. H. T. 



INORGANIC CHEMISTRY. 



Prof. Olszewski has published in the Bull. 

 Acad. Sci. de Cracovie for June an account of 

 his unsuccessful attempts to liquefy helium, 

 and a translation of the paper is given in Nature 

 of August 20th. In the first experiment the he- 

 lium was cooled by liquid oxygen boiling at 10 

 mm. pressure ; in the second by liquid air 

 tinder the same conditions. At the tempera- 

 ture of — 210° and 140 atmospheres pressure no 

 sign of condensation occurred, and on allowing 

 the gas to expand until the pressure was re- 

 duced to twenty atmospheres and in some cases 

 to one atmosphere, the gas remained perfectly 

 clear, and not the slightest trace of liquid could 

 be detected. Prof. Olszewski calculates the 

 temperature reached by this expansion to be 

 — 263.9° and that therefore the boiling point 

 of helium is at least 20° lower than that of hy- 

 drogen. He also points out that helium is an 

 ideal gas for a gas thermometer for very low 

 temperatures. 



In the Chemical News Profs. Ramsay and 

 Collie describe their attempts to separate argon 



and helium into two parts by fractional diffu- 

 sion through porous pipe clay. In the case of 

 argon the heaviest fraction gave a density of 

 20.01 and the lightest 19.93, showing the ap- 

 parent homogeneity of the gas. In the case of 

 helium the density of the gas first passing was 

 1.874 and of the gas remaining in the apparatus 

 was 2.133. Repeated fractionations did not 

 change these figures. From this it would ap- 

 pear that helium contains two constituents with 

 densities respectively 2.366 and 1.874 or of 

 2.133 and 1.580, according as the lighter or the 

 heavier fraction is the mixture. The spectrum 

 of both gases was the same, and the revolu- 

 tionary question is raised as to whether all the 

 molecules of an elemental gas necessarily have 

 the same weight. 



Dr. a. Angeli has described in a recent 

 number of the Gazetta Chimica Italiana salts of a 

 new oxyacid of nitrogen of the formula H2N2O3, 

 formed by the action of ethyl nitrate on an 

 alchoholic solution of free hydroxylamin. The 

 sodium and the barium salts are fairly stable 

 when dry, but in solution decompose readily on 

 boiling with evolution of nitrogen monoxid. 

 The sanLe gas is given off when solutions of the 

 salts are treated with acids. The acid appears 

 to be a nitro-hydroxylamin (NH. OH. NO2), 

 but is bibasic, the sodium salt having the for- 

 mula Na2N203. This compound possesses con- 

 siderable interest from a theoretical standpoint, 

 in view of the great extension in recent years 

 of the chemistry of nitrogen in its combinations 

 with hydrogen and oxygen. J. L. H. 



GENERAL. 



The British Association has approved the rec- 

 ommendation of the Council that on the occasion 

 of the meeting of the Association at Toronto the 

 President, Vice-Presidents and officers of the 

 American Asssciation be invited to attend as 

 honorary members for the year, and, further, 

 that all fellows and members of the American 

 Association be admitted members of the British 

 Association on the same terms as old annual 

 members — namely, on payment of £1, without 

 the payment of an admission fee. 



The ninth annual meeting of the Geological 

 Society of America will be held in Washington, 

 December 29-31, 1896. It is announced that 



