390 RECORD OF SCIENCE FOR 1887 AND 1888, 



that the observed i^ressures agree with the preceding result, Oberbeck 

 then utilizes the terms on and n to separate the motions iu latitude aud 

 longitude. This process is more general than that which Ferrel ex- 

 ecuted in the case of the solutions given by him in 1859 iu the Mathe- 

 matical Monthly, so that the equations can be adapted to a wide range 

 of constants in the law of distribution of temperature at the earth's sur- 

 face. Oberbeck proceeds to apply it to the extreme seasonal c.iange 

 in the atmosphere as well as to the assumed mean. The whole memoir 

 will be given in my selected translations. 



(23) Eelmholtz. — In May, 1888, Helmholtz submitted to the Berlin 

 Academy the memoir on atmospheric movements that I have given in 

 full in the accompanying translations. He first shows that the results 

 of laboratory experiments on a small scale can not be directly applied 

 to larger atmospheric movements because of the fact that the inertia 

 and density of the masses, the forces of viscosity and gravitation, aud 

 the linear dimensions, length, area^ volume, angle and time, are not all 

 enlarged in the necessary ratios, so that certain results, especially vis- 

 cosity, become inappreciable in large natural phenomena. He then 

 studies the conditions of stability among masses having discontinuous 

 motions; thus if two ring vortices encircle the earth having different 

 latitudes and temperatures, stable equilibrium is possible only when 

 the warm ring is on the polar edge of the colder ring. If they have the 

 same latitude then the warmer must be above the colder. The unroll- 

 ing of the vortex-cylinders and rings destroys their integrity aud mo- 

 tions, mixes their own and the surrounding air together, determines the 

 actual average distribution of temperature and moisture iu the atmos- 

 phere, and is the important step in the history of all atmospheric phe- 

 nomena. Helmholtz announces his intention of further developing this 

 subject. 



(24) Diro Kitao — Comparable with the elegant analysis of Helm- 

 holtz and Oberbeck, and, in fact, reminding us remarkably of the work 

 of Kircljhoff, is the memoir by Kitao (professor of physics and mathe- 

 matics in the Imi)erial Academy of Agriculture of the University of 

 Tokio), entitled " Contributions to the theory of the movement of the 

 terrestrial atmosphere aud of whirlwind storms." 



A few years ago. Professor Kitao returned from studying in Germany, 

 and Japan is to be congratulated on possessing two such mathemati- 

 cians as Kikuchi aud Kitao, the former as able a pupil of the English 

 school as the latter is of the German. 



Kitao's memoir is published in two parts, iu vol. i, 1887. and vol. ii, 

 1889, of the Journal of the College of Science of the University Tokio, 

 and a further continuation is promised. But for its great length his 

 work would have been included in the appended collection of transla 

 tions, but awaiting its completion and eventual translation lean now 

 only call the attention of students to this extensive analytical memoir. 



