38 



PORTER & JOURNAL, 



Joseph Andrews, sprained ancle. 

 Thomas Carroll, chronic rheumatism. 

 Midshipman Tittermarj, abscess of the knee. 



As some of our people had, contrary to orders, sold their 

 clothes, (at Port Praya,) and as we had not a very large sup- 

 ply of summer clothing on board, (as well with a view of 

 punishing them, as to make our supply hold out,) I did not 

 until now permit their summer clothes to be issued. 



The oppressive heat here is, I presume, occasioned by the 

 coast of Brazils, which runs at right angles with the direc- 

 tion of the trades, and occasions an interruption of their 

 course 5 as it is well known, that winds never blow home (as 

 seamen term it) on a high coast. Added to this, the land 

 breezes, which blow off at night, break in on the regularity 

 of the current of air, and produce the light and baffling 

 winds and calms that we have experienced in this place. 



From the accounts I have received from several persons 

 on board, who have been trading on this coast, it appears, 

 that the land-breezes blow very regularly at night, and 

 extend a considerable distance to sea. They serve to fa- 

 vour the passage of vessels bound from St. Salvadore and 

 otfier ports to the northward, as they stand off shore with 

 the land until they, meet the sea-breeze, which enables 

 them to make a considerable slant to the northward. 



We, however, were too far off shore to feel the land- 

 breeze, but not too far to experience its effects. 



The land-breezes may owe their existence to the follow- 

 ing cause. The action of the sun produces, in the day, by 

 rarefying the air, a considerable elevation of the atmo- 

 sphere, and where the sun's rays are strongest the greater 

 elevation is produced. Between the tropics, but more parti- 

 cularly under the line, this effect is most observable, and 

 wljiere the sun's rays are reflected back by the land, it is 

 still more heightened. When the cause of this extreme 

 elevation ceases, when the sun has set, a general fall of the 

 atmosphere takes place, like water returning to its level to 

 restore the equilibrium ; in its fall, should it meet with high 

 land or mountains, it follows the obliquity of their sides, 

 rushing in torrents down through the valleys until it is 

 borne off to the sea, where it spends itself, under the name 

 of the land-breeze, at the distance of a few leagues. On 

 the rising of the sun a new elevcition takes place, and a 



