300 METEOROLOGY AND ALLIED SUBJECTS. 



Whence it appears that at 3000™ a uniform downward gradient pre- 

 vails from the equator to the pole, and that this gradient is stronger the 

 higher we ascend above that level. {Z. 0. O. 2L, XVI, 1881, p. 402.) 



A. Richter has studied the relations of the upper cirrus cloud move- 

 ment to the distribution of pressure and temperature at the earth's sur- 

 face, basing his studies upon the cloud observations of the years 1878- 

 1S80 at Ebersdorf, and the daily weather charts of the Deutsche See- 

 warte. He finds for the average of the three years that the upper clouds 

 move towards the azimuth S. 85° W. ; the angle by which the movement 

 of the cirrus differs from the barometric gradient averages 88°, and that 

 by which it differs from the corresponding temperature gradient is 75°. 

 The changes in these average results depending upon the seasons the 

 direction of the Avind, excessive gradients, &c., are also investigated 

 somewhat. {Z. 0. G. M., XYI, 1881, p. 37C.) 



L. Teisserenc de Bort, in a study upon atmospheric circulation in the 

 Iberian peninsula, says: "The simultaneous observations, day by day, 

 assume greater importance, but this new mode of research cannot wholly 

 replace studies by the method of averages in many of the problems that 

 meteorology ofiers us. Averages are, in fact, a powerful means of 

 bringing out the dominant character of phenomena, and they are aplica- 

 ble to the discussion of daily charts as well as to the so-called statisti- 

 cal researches. These latter do not show the accidental variations, but 

 they put in relief certain influences that play an important part because 

 of their continuous action, and that are too feeble to clearly stand forth 

 in the portrayal of the general condition that obtains at any moment. 

 {Z. 0. G. .¥., XVI, 1881, p. 265.) 



r. Chambers has discussed with much ability the record for 1873,' 74, 

 '75 of the anemograph, at Kurrachee, in a memoir of some length. (Z. 

 0. G. M., XVI, 1881, p. 172.) 



Ragona has published a memoir on the diurnal and annual variations 

 in the direction of the winds, basing his studies upon the hourly read- 

 ings from the self-register of the observatory at Modena. He finds four 

 daily maxima and four minima in the velocity of the wind during Jan- 

 uary, February, October, and December, three maxima and minima 

 during March, June, July, and August, September, and Xovember, and 

 two maxima and minima during April and May. The connection be- 

 tween diurnal periodicity in velocity and direction is so close that he 

 then finds almost a perfect parallelism in these two data. As to the an- 

 nual periodicity he finds for each wind direction two maxima and two 

 minima of frequency; he also finds Dove's law of rotation of the winds 

 confirmed for Modena. (Z. 0. G. 2L, XVI, 1881, p. 125.) 



VIII. — BAROMETRIC PRESSURE. 

 IX. — STORMS. 



Koppen, in a review of the extensive work of Toynbee on the " Meteor- 

 ology of the Xorth Atlantic during August 1873," gives a study of the 



