xl GENERAL SUMMARY OF SCIENTIFIC AND 



Au excellent contribution to our knowledge of the chromatic dis- 

 persion of gases has been made by Lorenz, of Copenhagen ; and his 

 investigation of the coefficient of refraction of aqueous vapor will 

 find an important application in the spectroscopic study of the at- 

 mosphere. 



Hennessey has engaged in an elaborate work on the atmospheric 

 lines of the solar spectrum. His observations were made among the 

 outlying hills of the Himalaya Mountains at an elevation of 1700 

 feet. In this region, near sunset, atmospheric lines are remarkably 

 well developed, and the effect of aqueous vapor is truly startling. 

 There can be no doubt that in the hands of skillful observers the 

 spectroscope must become an invaluable meteorological instrument, 

 and will perhaps eventually give quantitative as well as qualitative 

 indications. 



Two very elaborate memoirs are to be found in the official publi- 

 cations of the Italian Meteorological Office. One is due to Denza, on 

 the distribution of rain and barometric pressure in Italj'^ ; the other, 

 by Ragona, is on the distribution of temperature. 



Professor Reynolds has made a further communication to the Roy- 

 al Society on the refraction of sound by the atmosphere, fully con- 

 firming the positions previously advanced by himself and by Pro- 

 fessor Henry. Interesting relations seem to exist between these phe- 

 nomena and the state of the atmosj^here before or during storms, etc. 



Jordan, of Carlsruhe, contributes to the theory of atmospheric re- 

 fractions an article in the AstronomiscTie Nachrichten^ in which he 

 shows that, without making any assumj^tion as to the decrease of 

 temperature with altitude, we may, by a general assumption as to 

 the curvature of the ray of light, obtain simpler tables and better 

 results than by any of the tables now in use.' Inversely, then, the 

 average temperature of the air can be determined from refraction 

 observations, as others have done from barometric observations, and 

 thus valuable new meteorological results arrived at. 



An interesting paper, both in a theoretical and practical point of 

 view, is that by Dr. Von Lang, of Vienna, on experiments on the fric- 

 tion between water and air. These experiments were made by 

 measuring the amount of air drawn along after a falling column of 

 water. The friction of air slipjDing over the surface of water and 

 causing it to slowly follow is one of the important elements in ter- 

 restrial physics, and is directly involved in Von Lang's experi- 

 ments, which have also a direct bearing on the origin of the gust of 

 wind that precedes falling rain and hail. 



The severe storm of March 12, 1876, has been the subject of a 

 memoir by Quetelet, according to whom it was the severest that 

 has been observed at Brussels since the period of exact observa- 

 tions at that place. 



Montigny contributes an investigation into the law of diminution 



