Sends four samples of dust blown on board his ship from the coast of Africa, nearly 400 miles away, during four days in March 1838. Gives careful descriptions and relates the tests he made of it [see Collected papers 1: 200].
H.M: Packet Brig Spey Falmouth
Although I have not the pleasure of being personally known to you— yet, I beg, you will be pleased to consider me, as a sincere friend to any science, that may tend towards the improvement of the human understanding—and, in my humble opinion;— I know of no other science, that can surpass Geology,—especially, since the discovery of so many wonderful fossil remains in the high northern Latitudes;
Permit me then Sir, to add my mite, in sending you a few papers of dust,—blown on board the Spey—from the coast of Africa—nearly four hundred miles distance— I almost despaired of being able to collect any at all— It was too light and too fine to get even a pinch of it—but a clean sponge and fresh water soon procured me as much as I wanted;
The Dust that I collected on the
10thof March 1838 was blown off to us in a SE & ESE wind
a smart top-gallant breeze— on the 6th—in the
afternoon, the Sympasometer kept rising and falling from 29o–
On the 7thin the morning it came on like a dense thick fog—to
the great astonishment and annoyance of every person on board— in the evening
I collected the contents of No
On trial by acids this substance produced no effervescence—but is is very probable, that the finer particles would give way to the stronger acids, of which I had none with me;
By the blow-pipe it glomerated quite easily—and on taking a small portion of the glomerate and exposing it to a strong heat—the fusion was complete— with this difference No 1 was less fusible—only giving a kind of green enamel—while No 2 melted into a black shining globule—
On the trial with Borax it indicated the presence of Iron—
On rubbing some of No 2 on a fine polished new silver spoon—with a piece of soft leather—the silver became a dull pale white—
With these results I send the four parcels— only
I have the honor to be | Sir | your obedient Servt
Cha's Lyell Esqr &c &c
- f1 405.f1CD had observed this phenomenon early in the Beagle voyage (see Journal and remarks, p. 4). James's letter is summarised in CD's paper ‘An account of the fine dust which often falls on vessels in the Atlantic Ocean’, read on 4 June 1845 at the Geological Society (Collected papers 1: 199–203).
- f2 405.f2CD's annotation on the cover refers to dates of observations of dust reported in various publications cited in his paper.