(3

on board soon became perfectly caked." Other authors *(7) describe the discoloration of the water at some distance from the coast further southward. From several statements (*8) it appears, that the dust which falls on vessels, even when at the distance of many hundred miles from the land, is considerable in quantity, & that the atmosphere is thus rendered quite hazy.

According to Roussin, # as long as the wind keeps parallel to the shore, the haze & dust extends only to a short distance, but when the harmattan prevails some from the N.E & ENE, during the months of January, February, March & April, the dust is spread through the atmosphere, & stars & other objects are hidden, when below going beneath within thirty degrees from above the horizon. Dust, however, was blown on Lieut James' vessel by a SE & ESE wind when between 300 & 500 miles from the land, & it was blown as late as on the 8th of May on the Princess Louisa, when a thousand miles from the continent & very nearly half way between Cayenne in S. Africa & the dry country north of the Senegal. in all the other recorded cases of dust having been blown to a great distance, it has occurred within the four above specified months.) The wind has been always all NE & SE.

The dust is not always of the same character: Lieut. James states in his M.S. account, that on the 6th of March a thick haze came on, & that on the next morning (when in Lat. 21° 40' N & Long. 22° 14' W; & 330 miles from the land, the deck was covered with fine sand. This sand consists of irregular, transparent, variously coloured particles & about the 1/1000 of an inch square, mingled with some few larger particles & many much smaller; it melts with difficulty into a grey bead. On the three succeeding days, the