22 BAROMETRICAL VARIATION. 



Tropical varia- On January 1 3, } 80 1, after we had cleared the river 

 ^^^°J^^^^"°'tloog]y, the mercury in the barometers began to perform 

 its motions with uniformity, which continued during the 

 pafTage to Bombay, until our arrival there on February 12. 

 The barometers being then placed on fhore, the mercury 

 inclined to a ftationary pofition, without evincing any pro- 

 penfity towards the equatropical motions from the 12th to 

 the 18th February, 1804-, as has been noticed in the fore- 

 going defcription, to happen frequently, on entering a har- 

 bour from fea. 



On February 18, 1804, the meteorological journal ceafes, 

 at which time it comprifes the obfervations of 22 months, 

 having commenced April 6, 1802, in Margate Road. 



I have taken the liberty of fending you this ablirad from 

 the journal, to exhibit the apparent difference of the mercury 

 in the barometer at fea, from what has been obferved on 

 ftiore, at thofe places mentioned in the precedmg defcription. 

 As I have not feen any account indicating the phenomenon, 

 I thought it might be interefling to you, or other gentlemen 

 of the Royal Society to forward this imperfect abftrad, the 

 journal itfelf beihg too cumberfome to fend home at prefent. 

 But as I am in expedlation of returning to England by the 

 Ihips from China next feafon, I hope I (hall be enabled to 

 prefent you with the meteorological fheets alluded to. 



I am, &c. 



J. HORSBURGH. 



P. S. Since I wrote the foregoing ahUra^, I have received 

 a letter from my friend Mr. Dalrymple, intimating that a 

 copy of the meteorological journal itfelf would be acceptable, 

 which has induced rae to tranfmit to him the original theets, 

 with a requeft to deliver them to you. I regret that I could 

 not find leifure time to make out a fair copy, to have fent 

 to you, in place of the original flieets in their rough ftate. 



Bombay, June 1, 1804. 



Second 



