8 THERMOMETRICAL EXPERIMENTS. [1843. 



the Cape de Verds to Sierra Leone, or to the coast 

 easterly, could always be anticipated, and that no re- 

 tarding calms, are to be met with on the verge of African 

 soundings. Vessels also from the African coast, seeking 

 Ascension for change of climate, find this remark appli- 

 cable, and it might be fairly assumed that if we could 

 reach the Equator under light airs and moderate breezes 

 in a less number of days than the average passage to the 

 twenty-fourth degree of West Longitude (the increased 

 distance being impeded by many days' calm), that by 

 crossing to the eastward of the tenth degree of West 

 Longitude, the westerly current would be avoided, and 

 we should be able to fetch to windward of Ascension, 

 or possibly sight St. Helena many hundred miles to 

 windward of the "beaten track." The result proved 

 as was anticipated. We experienced light and mo- 

 derate breezes with a south easterly current. Between 

 the 7th and 21st of March, or from Porto Praya to the 

 Equator on the ninth meridian of West Longitude, we 

 averaged eighty-one miles per day, and experienced no 

 more than ten hours' calm ! Here we passed over the 

 position assigned to the Island of St. Matthews ; the day 

 was beautifully clear and the radius of vision at least 

 twenty miles, but no traces of land were visible in any 

 direction, whilst any moderate elevations could readily be 

 seen at forty or more miles distance. 



Before the south-westerly breezes quitted us, we had 

 been carried as far as 8 west. On the 23rd of March 

 experiments were made with the water-bottle and ther- 

 mometers as low as 1,000 fathoms, as follows : 



