tmas-box which is to be the reward of his "early minstrelsy."

The curfew is rung at Bewdley in Worcestershire.

At Durham the curfew is rung (on the great bell of the cathedral) at nine
o'clock. It is therefore of the same use to the students of the University
of Durham as "Tom" is to the students of the University of Oxford, viz. it
marks the closing of the college gates.

CUTHBERT BEDE, B.A.

* * * * *

PHOTOGRAPHIC CORRESPONDENCE.

_Photographic Engraving._--I inclose a copy of a little book for your
inspection, which is remarkable only in this, that the illustrations are
produced by photography. The general theory of the method is this: a piece
of glass is covered with a uniform thin coating of some substance, so as to
be opaque or semi-opaque (the substance should be light coloured), and a
design is etched on it with a needle. From this _negative_ positive
pictures are printed photographically.

As to details, the prints of the mice (p. 46.) and the cat (p. 37.) are
from a glass coated with iodized collodion rendered sensitive, exposed to
faint light for a short time and developed. In this method, the glass
should be heated; and the collodion _burnished_ with the hand, to make it
adhere well.[5] The owl (p. 22.) and the stork (p. 10.) are from a glass
coated with iodized collodion "rendered sensitive" only, and not developed
so as to be only semi-opaque. On this high lights were put with opaque
white, and darks were etched out. This has the effect of a tinted
lithograph, but requires much more care in printing than the former method,
in order to hit the right tint; so much so, that I have usually printed the
stork faintly so as not to show the "tint" at all. The frontispiece is from
a paper negative, a method much more troublesome and tedious than either of
the others, both in preparation of the negative and in printing.

I have lately tried gilt glass to etch upon. This would be excellent, were
it not most painful to the eyes. And more than two years ago, I prepared a
negative by painting whites with water colour on transparent glass with
moderate success.

I have recently received from Rome a positive printed from a negative on
smoked glass, the subject being a mule's head. Of all the methods I have
tried, the best is the first mentioned; and it seems to me easier than any
species of engraving.

Query, What is the best coating for the glass; and what will be the cost of