May 26, 1905.] 



SCIENCE. 



809 



In this transformation a large fraction of 

 onr whole atmosphere is involved ; the gen- 

 eral conditions of the air as to temperature, 

 moisture, pressure and wind in distant 

 regions atfect this Asiatic whirl and it itself 

 affects other distant regions. The monsoon 

 rains of India depend on the intensity of 

 the winds, the moisture of the air and the 

 exact direction in which and date on which 

 it moves over the country. It may, there- 

 fore, be said to depend mainly on the dis- 

 tribution of atmospheric pressure over an 

 immense area, perhaps one third of the sur- 

 face of the globe. But it may also depend 

 ultimately on the intensity and quality of 

 the radiation that we received from the 

 sun, since that may exaggerate the differ- 

 ence of temperature over land and water 

 or over equatorial and polar regions and 

 thus cause slight deflections in the general 

 currents of air. A relatively small dis- 

 tui'bing cause may cause a deflection that 

 will turn the southwest monsoon aside and 

 cause it to pass by or over India or fall 

 short of reaching it and thus cause a failure 

 of the monsoon rains and of the crops that 

 depend on them. 



On the Construction of Isoharic Charts for 

 Upper Levels and their Dynamic Im- 

 portance in Dynamic Meteorology : Dr. 

 J. W. Sandstr()M, of Stockholm. (Pre- 

 sented by Professor Abbe.) 

 Dr. J. W. Sandstrom, of Stockholm, has 

 long been a student of the atmosphere 

 under the guidance of Professor Victor 

 Bjerknes, of Stockholm, Sweden, and his 

 eminent father the late Professor C. A. 

 Bjerknes, of Christiania, Norway. These 

 mathematicians have developed Kelvin's 

 theorem of circulation within a fluid mass 

 and have shown how to apply it to the 

 earth's atmosphere, provided we have ac- 

 curate values of the temperatures and pres- 

 siires at various altitudes. To their work 



Dr. Sandstrom now adds an important 

 practical consideration, i. e., that the study 

 of the motions of the upper atmosphere 

 can best be made by drawing isobars and 

 isotherms on successive level surfaces of 

 equal gravity rather than on surfaces of 

 equal height above mean sea level, as has 

 hitherto been customary. In his memoir 

 'On the Construction of Isobaric Charts 

 for Upper Levels and their Dynamic Im- 

 portance in Dynamic Meteorology' Sand- 

 strom gives formula? and tables for this 

 method of study and shows its advantages. 

 It affords a peculiarly powerful method of 

 utilizing the observations made at the 

 seventeen kite stations occupied by the U. 

 S. Weather Bureau in 1898, and his illus- 

 trative computations refer especially to 

 these observations, as they were the first 

 ever made that spread over so large area 

 of country as to make it worth while to de- 

 velop a method that is peculiarly suitable 

 to them. At present this method also finds 

 its most important application in studying 

 the international aerial work now carried 

 on by simultaneous ascensions to great 

 heights once or twice monthly in Europe at 

 fourteen balloon stations, seven kite sta- 

 tions, combined with twenty-five mountain- 

 top stations and thirty-five or forty cloud 

 or nephoscope stations. In this work the 

 only American station at present contribut- 

 ing is the Blue Hill Observatory, but it is 

 hoped that the U. S. Weather Bureau will 

 eventually join in the great undertaking. 

 On the Straight-line Concept: Professor 



F. A. Lambert, of Bethlehem, Pa. 



Precision is given to the straight-line con- 

 cept not by experience or experiment, but 

 by assumptions or axioms. These assump- 

 tions determine whether the straight line 

 is that of the space of Euclid, of Lobat- 

 sehefski or of Riemann. Cayley's theory of 

 measurement causes much of the apparent 

 mystery of these three spaces to vanish. 



