410 



SCIENCE. 



[N. S. Vol. XX. No. 508. 



er, while those over which the same type of 

 pressure variation exists should have weather 

 of an abnormal but similar nature. 



VERTICAL TEMPERATURE DECREASE UP TO 10 

 KILOMETERS. 



A PAPER on the vertical decrease of tem- 

 perature up to altitudes of 10 kilometers, as 

 determined by balloon observations, was read 

 by Hann before the Vienna Academy of Sci- 

 ences on April 21, 1904. The object of the 

 investigation, the results of which were pre- 

 sented in this report, was to ascertain whether 

 the annual march of the temperature at great 

 altitudes in the free air can at present be 

 determined with fair accuracy on the basis 

 of the observations already made during bal- 

 loon ascents. The data employed were ob- 

 tained on 150 ascents up to seven kilometers, 

 and on 125 up to heights between seven and 

 ten kilometers. Among the most interesting 

 of Hann's results are those which concern the 

 rate of decrease of temperature vertically in 

 cyclones and anticyclones in winter and sum- 

 mer. These agree with Hann's conclusions 

 based on the Sonnblick observations up to 

 three kilometers, and with the results obtained 

 by de Bort for greater altitudes. The vertical 

 decrease of temperature in the lower air is 

 slower in anticyclones than in cyclones, but 

 at greater altitudes the relations change. The 

 lowest temperatures at great heights are found 

 in anticyclones. In the lower air, and above 

 eight kilometers, the minima are warmer, and 

 in the intermediate strata the maxima are 

 warmer. The excess of temperature in the 

 anticyclones reaches at its maximum about 

 9° in the stratum between two and three kilo- 

 meters. Similar differences were previously 

 found from the Sonnblick observations. The 

 general mean between one kilometer and ten 

 kilometers gives an excess of temperature for 

 the anticyclonie air, but definite conclusions 

 must be postponed until the publication of 

 de Bort's results. 



WEST INDIAN HURRICANES. 



As usual during the tropical cyclone season, 

 the 'Pilot Chart of the North Atlantic' for 

 July contains " an account of West Indian 



Hurricanes, by James Page (reprinted from 

 Hydrographic Ofiice Publication No. 86, Gulf 

 of Mexico and Caribbean Sea, Vol. I., 5th edi- 

 tion, 1901). This is an excellent brief ac- 

 count of the most important facts regarding 

 season and frequency; origin and develop- 

 ment; area and depth; direction of the wind 

 and bearing of the storm center; distance of 

 the center; weather changes during the ap- 

 proach of a tropical cyclone; the motion of 

 the storm center and the shifts of the wind; 

 and maneuvering. Pour figures show: (I.) 

 the generalized track and the direction of the 

 inflowing winds; (II.) tracks of the more im- 

 portant hurricanes during the ten-year period 

 1890-1899; (III.) barometric pressure and 

 wind at Havana during the hurricane of Oc- 

 tober 19, 1876; and (IV.) positions in which 

 vessels caught in a hurricane should ' lie to.' 

 Extra copies of this discussion on West Indian 

 hurricanes may be obtained on application to 

 the hydrographer. Navy Department, Wash- 

 ington. The August ' North Pacific Ocean 

 Pilot Chart' has a similar discussion of ty- 

 phoons. 



CLIMATE OF EGYPT. 



The ' Meteorological Eeport for the Tear 

 1901,' published by the Survey Department, 

 Public Works Ministry, Cairo, has recently 

 been received (Cairo, 1903). The usual inter- 

 national tables are given for seven stations 

 in Egypt and six in the Sudan, including 

 Omdurman, Wadi Haifa and Suakin. In a 

 personal letter to the compiler of these notes. 

 Captain H. Q. Lyons, director-general of the 

 Survey Department of Egypt, writes as fol- 

 lows : " I have this time published large dia- 

 grams of the daily observations, and it is in- 

 teresting to ' see the prompt effect of a Medi- 

 terranean depression passing near our African 

 coasts. I hope that a note on the Khamsin 

 winds will be published this year. These are 

 not a special spring effect, as has frequently 

 been said, but are our southerly winds which 

 we may have at any time, though their in- 

 tensity and sand-carrying power is greatest 

 in May." 



E. DeC. Ward. 



Harvard Univeesitt. 



