216 ' Voyage to the Western Coast of' Africa. 



mercury sinks to 29-70, and even as low as 29.35 *. Should 

 the mercury become stationary between these intermediate points, 

 it will most certainly blow from the south-west (which is the 

 pampeso wind) ; and during the period I served in the River 

 Plate, I never knew this instrument err. But the most remark- 

 able phenomenon which it presents, is the rapidity with which 

 it rises on the squall reaching the ship. I have often observed 

 the mercury rise upwards of a tenth of an inch in less than five 

 minutes after the gust had reached us. It will then rise very 

 gradually, if the weather is to continue fine; or should it rise 

 to 29.90, and again fall, the weather will continue boisterous 

 for some days. Whenever the mercury is below 29.94, the 

 weather becomes unsettled ; and when between that point and 

 29.8O, it generally prognosticates lightning, with little or no 

 wind. 



With an easterly wind the mercury rises to 80.20 and 

 30.28 ; when it obtains that height it generally blows strong, 

 and varying from NE. to SE. 



A northerly and north-west wind has the least effect upon the 

 mercury, and I have often observed it to blow with great vio- 

 lence without its being materially changed. 



Private Journal of a Voyage to the Western Coast of Africa^ 

 including Observations on the Preservation of the Health on 

 that station. Communicated by the Author. 



Dear Sir, November 1829. 



J.N conversing with you some time ago upon the unhealthy 

 climate of the Western Coast of Africa, and the precautions I 

 used to adopt in preserving the health of my ship's crew when 

 on that station, you requested me to favour you with my pri- 

 vate journal kept at that period. I send you, therefore, the 

 following extract, which will sufficiently point out the method I 

 followed, and the success with which it was attended. It may 

 afford a few useful hints, derived from experience and observa- 



• The lowest range of barometer I observed while in the River Plate was 

 29.35, and these remarks relate entirely to that place. 



