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ship sailing obliquely from the land, dust of a very much finer character, like that which I collected off St. Jago, continued to fall. (The dust collected on the 9th in Lat. 19° 57' 17° 43 N. & Long 24° 5' 25° 54' W. is that, which prof. Ehrenberg finds *(a) (Back page) is almost composed of an Infusoria, identical with a species from Cayenne in S. America. Alter in accordance with P. Ehrenberg account, when the other with the wind from the SE,

In the direction of the SE wind on the 7th, the distance from of the land, on the 7th when it came dust fell, was only a little less [illeg] 7th than on the succeeding days when the fine dust fell, so that we must suppose that the coarser particles were borne along by a squall, which had on the succeeding days subsided into a moderate breeze by the some it had reached the ship with less carrying powers. The circumstance of particles of stone, above the 1/1000 of an inch square, being carried at least 330 miles by the wind is interesting, as showing how much further the smaller & lighter sporules of cryptoganius plants, or the eggs of infusoria might be wafted. (Considering that dust fell on the Princess Louisa, when exactly half way between the country north of the Senegal & Cayenne; is it not probable, that the Infusorian found living at Cayenne & in the dust which fell off the Cape Verd Isld., may have originally be transported from Africa to S. America?) Conclusion When we remember how many observers have described the hazy atmosphere & were discoloured sea far off near the coast of Africa, & how often dust in considerable quantities has been blown to great distance over the Atlantic during four or five months in the year, we can hardly doubt that the wind from the following observations of Prof. Ehrenberg, will consist in great part of Tasmania