To facilitate reference to the queries, I take them in the order of
publication:--

1. "What is the earliest known instance of the use of a _beaver hat_ in
England?"--T. Hudson Turner, p. 100.

The following instance from Chaucer (_Canterbury tales_, 1775, 8°. v.
272.), if not the earliest, is precise and instructive:

"A marchant was ther with a forked berd,
In mottelee, and highe on hors he sat,
And on his hed a Flaundrish _bever hat_."

2. "Has _Cosmopoli_ been ever appropriated to any known locality?"--John
Jebb, p. 213.

Cosmopolis has been used for London, and for Paris (G. Peignot,
_Répertoire de bibliographies spéciales_, Paris, 1810. 8°. pp. 116,
132.) It may also, in accordance with its etymology, be used for
Amsterdam, or Berlin, or Calcutta, etc. As an imprint, it takes the
dative case. The _Interpretationes paradoxæ quatuor evangeliorum_ of
Sandius, were printed at Amsterdam. (M. Weiss, _Biographie universelle_,
Paris, 1811 28. 8°. xl. 312.)

3. References to "any works or treatises supplying information on the
history of the Arabic numerals" are requested by "E.N." p. 230.

To the well chosen works enumberated by the querist, I shall add the
titles of two valuable publications in my own collection: