Chemistry and Physios. 69 



with twelve faces. In convergent polarized light, some crystals 

 showed no coloration, while others showed feeble colors though 

 less intense than is sometimes seen in natural crystals. Hence the 

 author thinks it probable that carbon like iodine and arsenic, 

 changes at the ordinary pressure and at a sufficiently high tem- 

 perature from the solid to the gaseous state but under a very high 

 pressure can be liquefied and remain in surfusion taking a crystal- 

 line form when it solidifies. — C. JR., cxviii, 320; J. Chem. Soc, 

 lxvi, ii, 189, May, 1894. G. v. b. 



8. JElectrical Condition of the air in high altitudes. — The re- 

 sults of experiment by Weber, Elster and Geitel appear to con- 

 firm the hypothesis of Peltier that the earth has a negative charge 

 and is also surrounded by an electrostatic field. The equipoten- 

 tial surfaces are approximately parallel to the earth's surfaces, 

 and the positive charge increases with the height as far as 

 previous observations have extended. The amount of vapor in the 

 air, the presence of clouds modifies notably this electrostatic field 

 of the earth. Various measures of the potential of the air at 

 different heights have been made in balloon ascensions. Thus 

 Lecher found at 440, 550 and 660 meters height a potential of 

 193 voltmeters, while at the surface of the earth 92'2 voltmeters 

 was obtained. Tama obtained at the height of 410 meters, +40 

 voltmeters and at a height of 1900 meters +70 voltmeters. R. 

 Bornsteiu has made, however, two balloon ascensions and obtained 

 results which appear to disprove the theory that the potential 

 increases with the height. The first ascension was made August 

 18, 1893, near Berlin on a clear day, with still air. The height 

 of 3790 meters was reached, and the electrometer indicated a 

 potential between +88 and —52 voltmeters. The instrument 

 showed marked variations and on the whole, diminution of the 

 potential with the height. At 3000 meters, the potential difference 

 was too small to measure. The results of this ascension however 

 may have been complicated by unusual atmospheric conditions, 

 possibly by the prevalence of an aurora. A second ascension 

 was made from Charlottenburg, September 29. The height of 

 3943 meters was attained. The potential varied somewhat, 

 attaining a maximum value of +100 voltmeters, and did not 

 reach negative values. It decreased as the balloon rose, at 3300 

 meters it was not measurable, but became greater as the balloon 

 sank. Feb. 17, 1893, Baschin attained a height of 4000 meters, 

 and also noted a diminution of the potential with increasing 

 height. At a certain height measures were no longer possible. 

 Similar results were obtained in August, 1 893, by French observers. 

 Bornstein remarks that five observers, thus independently of each 

 other, have found that the potential decreases with increasing 

 height. The observations seem to point to the conclusion that 

 masses of electricity of positive sign are present in the atmos- 

 phere. In the discussion of Bornstein's paper Professor Bezold 

 pointed out that our knowledge of atmospheric electricity can be 

 gained better from balloon ascensions than from observations 



