3o0 On \ffl I>I<<r<> of the Poles of the Atmosphaw. 



some from the shore, within reach of the salt spray and 

 occasionally washed by the waves, and some from a moist 

 inland cliff not far from the sea, close to the town, examined 

 in the manner described above, afforded similar results.* 

 Lesketh How, Ambleside, 

 August 30, 1852. 



^ , , , 1 , 



On the Place of the Poles of the Atmosphere ; and the Reid 

 Theory of Hurricanes. By Professor C. Piazzi Smyth. 



This is merely a notice on some of the recent discoveries and 

 generalisations, by Lieutenant Maury, U.S.N., on the motions of 

 the atmosphere. It had been clearly proved by the extensive re- 

 searches of Lieutenant Maury, that the trade- winds when rising at 

 the equator, do not, as previously held, return to their own poles, 

 but cross over to the opposite ones ; and thus traverse the extent of 

 the whole earth from pole to pole, in a curvilinear direction, on 

 account of the effect of the rotation of the earth. The whole atmo- 

 sphere thus partakes of a general movement, the upper half moving 

 towards the poles, and the lower towards the equator, or vice versa, 

 according to the latitude of the place ; the former occurring between 

 the parallels of 0° and 30°, and the latter between 30° and 90°. At 

 0° and 30° two nodes, so to speak, of the upper and lower currents 

 take place ; at the former ascending, and indicated by a low baro- 

 meter ; at the latter descending, and marked by increased barome- 

 tric pressure. At the point of 90°, the pole, or thereabouts, the re- 

 volution of the currents and their change of direction for N. and S., 

 and vice versa, with another node, takes place, and marked, Lieut. 

 Maury thought, by a calm region, as the two nodal zones of 0° and 

 30° most undoubtedly are. 



As to the place of this calm polar point, which we shall probably 

 long want observations to determine, Lieutenant Maury did not 

 place it over the poles of rotation of the world, but over the mag- 

 netical poles, without, however, sufficient reason. Indeed, he 

 much lamented that after the admirable developments made by 

 Lieutenant Maury of the motions of the atmosphere, he should have 

 thus brought in merely the name of magnetism to clear up one ob- 

 scure point. Meteorology pursued on the system of strict mechani- 

 cal and scientific inquiry was now disclosing a most interesting and 

 understandable series of phenomena, and promised a legitimate har- 



* In some instances, the black hue which I have attributed above to the de- 

 composition of the vegetable matter in transition to form peat, may be in great 

 measure the natural colour of the species of cryptogam ia covering the rock. 



