I could wish to see that work, and hope to
get it sent down. Dr. Scopoli is physician to the wretches that work in
the quicksilver mines of that district.

When you talked of keeping a reed-sparrow, and giving it seeds, I could
not help wondering; because the reed-sparrow which I mentioned to you
(_Passer arundinaceus minor Raii_) is a soft-billed bird; and most
probably migrates hence before winter; whereas the bird you kept (_Passer
torquatus Raii_) abides all the year, and is a thick-billed bird. I
question whether the latter be much of a songster; but in this matter I
want to be better informed. The former has a variety of hurrying notes,
and sings all night. Some part of the song of the former, I suspect, is
attributed to the latter. We have plenty of the soft-billed sort; which
Mr. Pennant had entirely left out of his "British Zoology," till I
reminded him of his omission. See "British Zoology" last published, p.
16.

I have somewhat to advance on the different manners in which different
birds fly and walk; but as this is a subject that I have not enough
considered, and is of such a nature as not to be contained in a small
space, I shall say nothing further about it at present.

No doubt the reason why the sex of birds in their first plumage is so
difficult to be distinguished is, as you say, "because they are not to
pair and discharge their parental functions till the ensuing spring." As
colours seem to be the chief external sexual distinction in many birds,
these colours do not take place till sexual attachments begin to obtain.
And the case is the same in quadrupeds; among whom, in their younger
days, the sexes differ but little: but, as they advance to maturity,
horns and shaggy manes, beards, and brawny necks, etc., etc., strongly
discriminate the male from the female. We may instance still farther in
our own species, where a beard and stronger features are usually
characteristic of the male sex: but this sexual diversity does not take
place in earlier life; for a beautiful youth shall be so like a beautiful
girl that the difference shall not be discernible;

"Quem si puellarum insereres choro,
Mire sagaces falleret hospites
Discrimen obscurum, solutis
Crinibus, ambiguoque vultu."

HOR. ODES, II. od. 5-21, p. 131, orig. edit.

LETTER VII.

RINGMER _near_ LEWES, _Oct. 8th_, 1770.

Dear Sir,--I am glad to h