(3

larger, & much fine matter. The fact of particles of this size having been ca brought at least 330 miles from the land is interesting, as bearing on the transfer distribution of the sporules of cryptogamic plants & the eggs of some the ovules of infusoria. The dust which fell on the three succeeding days resembles in appearance, & action under the blowpipe that collected by myself off St. Jago, & was so excessively fine, that Lieut. James was obliged to collect it with a sponge moistened sponges with fresh water.

As the wind was continued nearly in the same direction during the four above mentioned days, & the distance from the land was only a little increased after the first day, we it would appear probable that the coarser dust was raised by a squall with which the breeze on this coast so often begin to begins commence blowing.)

(with respect to the direction of the wind when the during the falls of dust, in every case instance where recorded as may seen in the references, it was has been between NE and SE; generally between NE & East. In the case however given by the Rev. W. Clarke* (4), a hazy the  wind which which had blown for some time from East & South case, fell calm, & was succeeded for a few hours by a SW wind, during which the dust fell & then returned strongly to the East; during this whole time dust fell. With respect to the time of year, it has the falls have always occurred in the months of January, February, March & April; but in the case of the Princess Louise in 1840, as late as on the 9th of May. I may add that Baron Rosin, *(5) during his survey of the north-western African coast of the a little northward surface, that found, that whilst the wind keeps parallel to the shore, the haze & dust extend seaward only a short distance; but when during the above four specified months the

(A)

In the one year of 1839, it has chanced that dust has been recorded as having fallen in the Atlantic (as may be seen in the references) on the 14th and 15th of January, & on the 2nd, 4th, 9th, 10th, 11, 12 and 13 of February.