others; and indeed, as my collections have always been at the service of
my friends, very few indeed have been left in my hands, and those,
probably, of no material value.

I wish this system were generally adopted. Papers, occasionally of great
historical importance, and very often of archæological interest, would
thus be preserved, and, what is more, _used_, as they would thus
generally find their way into the right hands.

There are, I fancy, few classes of papers that would be so little likely
to interest archæologists in general, as those relating to mathematics;
and yet such are not unlikely to fall in their way, often and largely,
if they would take the trouble to secure them. I will give an example or
two, indicating the kind of papers which are desiderata to the
mathematical historian.

1. A letter from Dr. Robert Simson, the editor of Euclid and the
restorer of the Porisms, to John Nourse of the Strand, is missing from
an otherwise unbroken series, extending from 1 Jan. 1751 to near the
close of Simson's life. The missing letter, as is gathered from a
subsequent one, is Feb. 5. 1753. A mere letter of business from an
author to his publisher might not be thought of much interest; but it
need not be _here_ enforced how much of consistency and clearness is
often conferred upon a series of circumstances by matter which such a
letter might contain. This letter, too, contains a problem, the nature
of which it would be interesting to know. It would seem that the letter
passed into the hands of Dodson, editor of the _Mathematical
Repository_; but what became of Dodson's papers I could never discover.
The uses, however, to which such an unpromising series of letters have
been rendered subservient may be seen in the _Philosophical Magazine_,