Feb. 14, 1878] 



NATURE 



307 



signs of much activity of late. First we hear of a small 

 planet detected by M. Perrotin at Toulouse, on January 

 29, position at loh. in R.A. 8h. 43m. 13s. N.P.D. 71° 41 

 twelfth magnitude, which appears to have been inde- 

 pendently discovered by Herr Palisa at Pola, on P"eb- 

 ruary i : by an observation at Pola, January 27, it seems 

 this object is not to be confounded with Rliodope, No. 

 166, of which a corrected ephemeris is given in the 

 Circular of the Berliner yahrbuch, No. 84, but it is there 

 conjectured that it may be Urdu No. 167, found by Prof. 

 Peters 1876, August 28. Calculating from the elements 

 of (Jrda in Circular No. 64, for the time of the Berlin 

 observation of M. Perrotin's planet on February 3, it 

 results that with the correction 8M = + 5° 24' 9 the com- 

 puted and observed longitude will agree, but there is a 

 difference of — 1° 38' from the observed latitude which, 

 in the present case, throws doubt upon the presumed 

 identity. Again, on February 2, M. Cottenot, at Mar- 

 seilles, detected a planet, tenth magnitude, position at 

 I3h. 2m. in R.A., loh. 2m. 293, N.P.D. , 78° 51', which was 

 also found by Prof. Peters at Clinton, U.S., on February 

 4 ; this object is probably new. Finally, on February 6, 

 Prof. Peters met with another planet, also of the tenth 

 magnitude, in R.A. loh. i6m. N.P.D. 76° 17', which he 

 notified to the Paris Observatory through the Smith- 

 sonian Institution by cable ; it is probable, however, that 

 the presence close to this position of his previously- 

 discovered planet Antigone, No. 129, has escaped his 

 attention, and as its brightness would also be about equal 

 to that of stars of the tenth magnitude, it is most likely 

 to be the object observed. 



The number of minor planets appears now to have 

 reached 180, and possibly 181. 



The Supplement to the Berliner yahrbuch, for 1880, 

 contains ephemerides for the present year, of the small 

 planets to No. 172 inclusive, excepting only Dike and 

 Scylla, for which the necessary materials are not avail- 

 able. Polyhymnia in opposition on August 30, in 11° S. 

 declination, is distant from the earth 088 ; Atalanta in 

 opposition October 27, declination 37° N., is distant 098, 

 and Felicitas in opposition November 1 1, declination 

 30° N., is distant 0*92 ; these are the three cases of 

 nearest approach during the year. Of the minor planets 

 discovered since 1845, Hebe attains the greatest bright- 

 ness — 7'4 m. in the miJdle of November, 1878, while in 

 the neighbourhood of c Eridani. 



METEOROLOGICAL NOTES 



Atmospheric Movements. — A first paper on this 

 subject, by Mr. Ferrel, has been published by the United 

 States Coast Survey Office, in which the inquiry is limited 

 to an investigation into the mechanics and general motions 

 of the atmosphere which are dependent on wide-spread 

 and periodically-recurring disturbances. In consideration 

 of the enormous difficulties in the way of investigating the 

 effects of friction, the author adopts the only course open 

 to him, viz., to introduce unknown functions into the equa- 

 tions representing the resistances from friction in the direc- 

 tion of the co-ordinates, leaving these to be determined ap- 

 proximately from a comparison of the final results deduced 

 from the equations with observation. From a mathematical 

 examination of the question it is concluded that in what- 

 ever direction a body moves upon the surface of the earth, 

 there is a force arising from the earth's rotation tending 

 to deflect it to the right in the northern but to the left in 

 the southern hemisphere ; and that this deflecting force 

 is exactly the same for motions in all directions, so that if 

 any sensible effects of this sort arise in the case of rivers 

 or of railroads running north or south, the very same 

 effects must take place where they run east or west or 

 in any other direction. The amount of this deflecting 

 force is exactly double of that which is obtained in 

 accordance with the principle adopted by Hadley. An 



elaborate examination is made of the distribution of tem- 

 perature over the earth, the most important of the results 

 being that the mean temperature of the whole surface of 

 the earth is 60° 2, the mean for the northern hemisphere 

 being 59° 5, and that for the southern hemisphere 6o°*9. 

 With reference to this result Mr. Ferrel remarks that if 

 important data collected by Dr. Hann for the extreme 

 southern latitudes had been at hand while he was engaged 

 with the investigation, the results obtained for the mean 

 temperatures of the two hemispheres might have been 

 nearly equal. This result, which is essentially different 

 from the commonly received opinion, has, it is obvious, 

 important bearings on many questions of terrestrial 

 physics. The distribution over the globe of atmospheric 

 pressure is similarly examined with results of great im- 

 portance in their relations to meteorological theories. 

 The coefficient of the annual inequality of pressure in 

 North America amounts to only about one-third of that 

 of the interior of Asia, from which the important con- 

 clusion is drawn that the difference between Asia and 

 America in this respect does not depend so much upon 

 the difference in the extremes of temperature of the two 

 continents, which is inconsiderable, as upon the difference 

 in the extent of the two continents. The annual maximum 

 of barometric pressure for the United Scates, except the 

 Pacific coast, occurs about December 23, which is about 

 sixteen days earlier than in Europe. In both continents 

 the time is considerably earlier than the time of the 

 minimum of temperature. The distribution of tempera- 

 ture and pressure and the prevailing normal winds of the 

 globe are shown on seven well-executed maps. In suc- 

 ceeding papers Mr. Ferrel intends to investigate those 

 disturbances in the distribution of temperature and 

 humidity which are of a comparatively local character, 

 and which result in the locally developed phenomena of 

 cyclones and other storms ; and finally to apply the prin- 

 ciples of atmospheric mechanics thus developed to the 

 explication of oceanic currents. 



Climate of India. — We notice in a recent number of 

 the Isvestia of the Russian Geographical Society, an 

 interesting paper by M. Wojeikoff, being a sketch of the 

 climate of India according to the recent works of Mr. 

 Blanford, the reports of Mr. Wilson, and some notes 

 taken by the author during his recent visit. M. Wojei- 

 koff describes very clearly the main features of the 

 climate, and accompanies his description by some tables 

 which illustrate the prevailing and characteristic directions 

 of the winds. Besides, by a comparison of the tempe- 

 ratures of some places in India and South America, 

 situated the one in parts devoid of forests, and the others 

 in places where the forests are yet preserved, M. Wojei- 

 koff shows what a great influence forests have on climate, 

 and he arrives at the conclusion that the absence of great 

 heats and a continuous humidity of air are always met 

 with at those places which, however far from sea, are 

 situated in forest lands. He concludes, therefore, as to 

 the importance of preserving the forests in India, and 

 expects that detailed observations would yet more show 

 their importance as well as the beneficent influence of the 

 irrigation on climate. 



Low Barometric Reading in the Hebrides, 

 November 11, 1877. — We have received from Mr. 

 Buchan, Scottish Meteorological Society, a communi- 

 cation on this subject. The following readings of the 

 barometer, reduced to 32° and sea-level, were made by 

 Mr. Youngclause, the Society's observer, at Monach 

 Lighthouse (57° 31' N. lat., 7^42' W. long), on November 

 II, at 9 a.m., 28-330; II a.m., 28-120; 12.43 P-M., 

 28008 ; 1.30 P.M., 27-912 ; 4.20 P.M., 27-861 ; 8 P.M. and 

 9 P.M., 27752 ; and at 9 A.M. of the 12th, 27 968 ; and at 

 12-43 P-M> 28-038 inches. Thus for nearly twenty-four 

 hours the barometer at this place was under 28-000 inches, 

 and fell to 27-752 inches, the observer remarking that 

 the rise which followed proceeded at a very slow rate. 



