370 RECORD OF SCIENCE FOR 1887 AND 1888. 



These two tables contain a wealth of data for future deductions, but 

 as to the results that Loomis draws from them, Koppen promises a fut- 

 ure communication. 



III.— THEORETICAL HYDRO-DYNAMICS APPLIED TO THE MOTION OF 



THE AIR. 



(10) Koppen^ whose skill in studying? the mechanism of storms and 

 in handling masses of data has so frequently been shown, has con- 

 tributed to the Meteorological Zeitschrift of ])eceml)er, 1888, a study 

 " On the form of the isobars in reference to their dependence ui)on alti- 

 tude and the distribution of temperature." Assuming that isotherms 

 and isobars have been given by the daily weather chart, he then gives a 

 most convenient and rapid method of computing tables and deriving 

 the isobars for any elevation, such as 2,500 meters, by an inspection of 

 the tabular figures. Such upper isobars were first iniblished for a given 

 storm by Moller in the Annalen fiir Hydrog., April, 1882. The impor- 

 tance of such u])per isobars had been urged by nie in lS71-'72, and sam- 

 ple maps were drawn preparatory to their daily use, but subsequently 

 the introduction of departures and variations of departures in i)ressure 

 and temperature as auxiliary to sea-level isobars and surface isotherms 

 was decided on by General Myer. Koppeu's diagrams of ideal systems 

 are very suggestive. 



(11) Ferrel. — In 188G there appeared a treatise by Prof. William Fer- 

 rel, •' Eecent Advances in Meteorology," being Appendix 71, or part ii, 

 of the Annual Report of the Chief Signal Officer for 1885. This treatise 

 was originally designed as professional i^aper of the the Signal Service, 

 No. 17, but the abolition of that series of papers by order of the Secre- 

 tary of War caused a change in the method of publication. 



An abstract of the contents of this book was delivered in lectures by 

 Professor Ferrel to the second lieutenants of the Signal Corps, but the 

 abolition of the Signal-Service school of instruction at Fort Myer has 

 prevented its further use in that direction. The comi)lete volume being 

 easily obtained in this country, I need give only a short account of it. 



In this work Ferrel has collected the results of recent investigations 

 by many authors, adding to them many of his owmi demonstrations, and 

 combining the whole into a systematic treatise on meteorology under 

 the following seven chapters: (1) The constitution and physical prop- 

 erties of the atmosphere; (2) the temperature of the atmosphere and 

 the earth's surface; (3) the general motions and pressure of the atmos- 

 phere ; (4) cyclones ; (5) tornadoes ; (G) observations and their reduc- 

 tions; (7) ocean currents and their meteorological effects. In the first 

 chapter, after the sections on chemical constituents, pressure and 

 weight, there comes a section on the diffusion and arrangement of the 

 constituents, ihcluding the vapor atmosphere, followed by the ordinary 

 applications to the atmosphere of the thermodynamics of adiabatic 

 processes. In his section on the diathermancy and transparency of the 



