METEOROLOGY 335 



will find many applications in the atmospheric movements. [Nature.^ 

 xxiiT, p. C27.) 



265. An anonymous article in Nature expresses some views on the 

 upper currents of the atmosphere, and suggests certain liues of research 

 into some of the more striking optical phenomena. [So far as the dy 

 namic problems are concerned there seems a little confusion as to the 

 cause.] {Nature, xxix, p. 154.) 



266. Dr. H. Hertz, of Kiel, presents an elaborate and important conven- 

 ient graphic method for determining the changes in the adiabatic condi- 

 tion of moist air. [The translation of this in full will, it is hoped, be pub- 

 lished for the benefit of American students.] The author states that 

 the condition of moist air, after being compressed or expanded without 

 addition of heat, has to be considered daily by the meteorologist ; he 

 desires therefore to offer to the student the means of solving the various 

 questions withont recourse to complicated formulae. At present it is cus- 

 tomary to use the little table published by Professor Hann in 1874, but 

 he thinks that we can achieve more complete solutions with equal ease 

 by employing the graphic methods and the engraved table of curved 

 lines that he has prepared. He proposes nothing especially new in ad- 

 dition to the publications of Hann, Guldberg, and Mohn, but accom- 

 plishes the equally important result of making their formulae easily 

 available in daily use. {1). M. Z., i, p. 121.) 



VIII. — Barometric pressure and its variations. 



267. A. M. Pearson, of Bombay, compares the barometric changes of 

 monthly means at Zanzibar, Belgaum, and Bombay for three years, and 

 shows there are evidences of the movement of barometric waves east- 

 ward through these stations, the time of transit being 4.9 months from 

 Zanzibar to Bombay, with numerous smaller coincident deflections. He 

 verj' properly claims that the atmosphere must have vibrations and 

 waves originating in various ways, of which these barometric phenomena 

 are the results. Similar studies, by J, Allan Broun, have lately been 

 published by the Manchester Philosophical Society. {Nature, xxviii, 

 pp. 354-377.) 



268. In a note of September 4, 1883, Mr. Pearson affirms that the at- 

 mospheric waves have been traced regularly since 1869 ; and that the 

 reason why they have a movement in troijical and sub-tropical regions 

 westward more rapid than eastward is owing to their combination with 

 the westward movement of the air in those latitudes, but as to the reason 

 why the amplitude is greater at eastward stations he advances the hy- 

 pothesis that the westward component proceeds from the tropics, where 

 all great movements originate. {Nature, xxviii, p. 562.) 



269. A. Schomrock, of St. Petersburg, has comi)ared the occurrence of 

 small, sudden, irregular variations of atmospheric pressure as recorded 

 on the barographs at St. Petersburg and Pavlosk. These have an an- 

 nual periodicity, being most frequent in November, December, July, and 



