1816.] Scientific Intelligence. 479 
Col. Mudge ; so that several county maps will be ready for delivery 
almost immediately. ‘The maps of Cornwall, Devonshire, Dorset- 
shire,- Hampshire (including the Isle of Wight), Sussex, and that 
art of Kent which squares in on the Sussex side, with the general 
work, will be published in a very few weeks: and a separate map 
of the Isle of Wight is now on sale. The maps of all the con- 
tiguous counties north of these are in the hands of the engravers : 
and that of the whole county of Kent is re-engraving, and in a 
state of forwardness. When the several plots and portions now 
planning by the surveyors are finisked, at least three-fifths of Eng- 
land and Wales will be ready to be placed successively in the hands 
of the engravers; and the work will be carried on with all possible 
expedition consistent with accuracy. These maps are on a scale of 
an inch toa mile, a scale that admits of an attention to minutiz 
which must, of necessity, be disregarded in maps of smaller size. 
Hence it may not only be expected that the general outline, and 
the prominent physical circumstances, shall be correctly delineated, 
but that the minuter points and peculiarities, which are interesting 
to the topographer and the antiquarian, shall be permanently 
marked, and readily traced, in these maps. 
XIV. New Hygrometer ; and on the Mode of cutting Glass. By 
Mr. Robert Burrhard. 
(To Dr, Thomson.) 
MY DEAR SIR, . Waddon House, Marck 15, 1816. 
As you were kind enough to notice an article 1 sent you a short 
time since, J am induced to trouble you again, by sending the 
sketch of a hygrometer on a new construction. As I have but 
just made the above, L cannot as yet state the results; but I think 
it will be very sensible and permanent; at least, it will answer as a 
comparative instrument to make others. Should you consider it 
worthy a place in your Annals, 1 shall feel myself honoured by your 
notice, and remain, dear Sir, very respectfully, 
Ros. W. Borraarn. 
The above-mentioned instrument (Plate L., Fig. a,) consists of 
the segment, A, B,C, made by joining together three very light 
pieces of flat brass, of which the pin, e, is the centre, on which 
hangs the long thin wire, D, to the lower end of which is attached 
a large piece of sponge, F'. ‘The are, C, is to be divided decimally 
from 1 to 100. At g isa male thread, with a heavy nut, for the 
purpose of adjusting the pin, D, to 1; that is, to the beginning of 
ithe scale, or quite dry, At E is a common scale, beam, pin, and 
check, f, made with a fine bearing. If we suppose the sponge 
attached, and the instrument hung up, it must be adjusted by 
turning the heavy nut, g, either nearer or further from the point of 
bearing, f; until the line, D, with the sponge perfectly dry, comes 
exactly to the mark 1. The sponge must then be saturated with 
