§ 363-365. 



EASTING OF THE TRADE- WINDS, ETC. 



171 



Number of Observations and Mean Height of the Barometer {temperature 32°) between 

 the Faralkls o/36° S. and 50° N. 



(1) From 50° N. to 36° S. the observations are the mean of S3,.^34 taken from "Maandelijksche 

 Zeilaanwijzingen van Java naar het Kanaal Koninklijk Nederlandsch Meteorologisch Instituut, 185D." 



(2) Greenwich ; mean of 4 years' observations. 



(3) St. Petersburg ; mean of 10 years' observations. 



(*) Dr. Kane ; 12,000 observations (mean of 17 months' observations). 



(5) Hobart Town; mean of 10 years' observations. (6) Sir J. C. Ross; ''Erebus and Terror." 



863. The diagram of the winds (Plate I.) has been constructed 

 More atmosphere in SO as to show bj its shadcd bordcr this unequal 

 till Tou\hTrn* hTm^ distiibution of the atmosphere between the two 

 *'^^'^'"^" hemispheres. Have we not here proof that the 



southern hemisphere (§ 261) is indeed the boiler to this mighty 

 atmospherical engiiu / The aqueous vapor rising from its waste 

 of waters drives the air away from the austral regions, just as the 

 vapor that is formed in the real steam-boiler expels the air from 

 it. This difference of atmosphere over the two halves of the 

 globe, as indicated by the barometer, is very suggestive. 



361. Admiral Fitzroy has also reduced from the abstract logs 

 A standard of com- in thc Mcteorolos^lcal Department of the Board of 



parison for the ba- ^ . "^ ^ . 



rometer at sea. 1 radc lu Loudou a great number of barometrical 

 observations. He claims to have discovered that about 5° N. 

 iu the Atlantic Ocean the pressure of the atmosphere is so uni- 

 form as to afford navigators a natural standard by which, out 

 there at sea, they may, as they pass to and fro, compare their ba- 

 rometers. This pressure is said to be so uniform, that after al- 

 lowing for the six-hourly fluctuations, the mariner may detect 

 any error in his barometer amounting to the two or three thou- 

 sandth part of an inch. 



365. According to the views presented in § 358 and Plate YII., 



