d to the tested water.

3. In general the salts of iron are more adapted for positives, and
weak pyrogallic acid solutions for negatives; say one and a half grain
of pyrogallic acid, twenty minims of glacial acetic acid, and an ounce
of distilled water.]

* * * * *

Replies to Minor Queries.

_London Fortifications_ (Vol. ix., p. 174.).--In last week's Number is an
inquiry as to "London Fortifications" in the time of the Commonwealth.

There is a Map by Vertue, dated 1738, in a folio _History of London_; there
is one a trifle smaller, copied from the above; also one with page of
description, _Gentleman's Magazine_, June, 1749. I subscribed to a set of
twenty etchings, published last year by Mr. P. Thompson of the New Road;
they are very curious, being facsimiles of a set of drawings done by a
Capt. John Eyre of Oliver Cromwell's own regiment, dated 1643. The drawings
are now I believe in the possession of the City of London.

A CONSTANT READER.

[The drawings referred to by our correspondent are, we hear, by
competent judges regarded as _not genuine_. Such also, we are told, is
the opinion given of many drawings ascribed to Hollar and Captain John
Eyre, which have been purchased by a gentleman of our acquaintance, and
submitted by him to persons most conversant with such drawings. Query,
Are the drawings purporting to be by Captain John Eyre, drawings of the
period at which they are dated?]

_Burke's Domestic Correspondence_ (Vol. ix., p. 9.).--In reference to a
Query in "N.& Q." relative to unpublished documents respecting Edmund
Burke, I beg to inform your correspondent N. O. that I have no doubt but
that some new light might be thrown on the subject by an application to Mr.
George Shackleton, Ballitore, a descendant of Abraham Shackleton, Burke's
old schoolmaster, who I believe has a quantity of letters written to his
old master Abraham, and also to his son Richard, who had Burke for a
schoolfellow, and continued the friendship afterwards, both by writing and
personally. When Richard attended yearly meetings in London, he was always
a guest at Beaconsfield. Burke was so much attached to Richard, that on one
of these visits he caused Shackleton's portrait to be painted and presented
it to him, and it is now in the possession of the above family. I have no
doubt but that an application to the above gentleman would produce some
testimon