2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



and gyroscope phenomena. There are indications that Babinet 

 and others at that time applied his results to the mechanics of 

 the atmosphere. But the modern study of this subject is properly 

 traceable to the influence of Prof. William Ferrel in America and 

 Prof. William Thomson in England, both of whom cooperated to 

 put our knowledge of the subject on a firmer basis than was 

 before possible. Meanwhile a profound Russian scholar, Brasch- 

 mann, and the equally profound German scholar, Erman, were 

 independently working over the same ground, though their publi- 

 cations have been scarcely noticed by technical meteorologists. 

 The neglect of Erman 's work in dynamic meteorology seems 

 remarkable, but has been atoned for by the enthusiastic activity 

 of Sprung and his successors at Hamburg and at Berlin. 



The works of Espy, 1840, on the Philosophy of Storms; Thom- 

 son, 1862, on the Convectional Equilibrium in the Atmosphere; 

 Peslin, 1868, on the Thermodynamics of Moist Air; Ferrel, 1857, on 

 The Motions of Solids and Fluids, and his subsequent important 

 memoirs; together with Sprung's Lehrbuch, 1885, mark the tran- 

 sition from ancient to modern meteorology. 



The modern sounding balloon has assured us of the intimate 

 connection between the lowest stratum of air and that which is 

 20 miles above us; but the conditions above this latter level are 

 doubtless of equally great importance to our surface climatology 

 and these can be made known to us only by the study of meteors, 

 auroras, spectrum lines, and refractions. I have, therefore, included 

 a memoir by Kerber on the limit of the earth's atmosphere, that 

 avoids some of the difficulties attending every application to the 

 outer atmosphere of our knowledge of the kinetic theory of gases. 



All students will gladly welcome the translation by Waldo of 

 the memoir by Guldberg and Mohn, first published in two parts, 

 1876 and 1880; it was revised by the authors in 1883 at the per- 

 sonal request of Prof. Frank Waldo who expected its prompt 

 publication, and to him we owe the privilege of including in the 

 present collection this new edition of that classic paper. 



The series of papers by Von Bezold were revised by himself in 

 1906, for publication in his collected memoirs and as thus revised 

 they are now reproduced by permission of his heirs and publishers. 



The study of strictly adiabatic changes that was so greatly 

 facilitated by the Hertzian diagram published in the preceding 

 collection of translations is now advantageously replaced by the dia- 

 grams of NeuhorT, 1900, which adapt themselves to any atmospher- 

 ical condition. 



