Daguerreotype . 
71 
DAGUERREOTYPE. 
Extract of a letter from Dr. Richardson to Sir Jolm Franklin, 
dated 5th February, 1840. 
... One of the most remarkable discoveries of modern times 
is the art of causing rays of light to act on oxides of silver, so 
as to give minute representations of objects placed in the focus 
of a camera obscura. The Daguerreotype, as the instrument 
has been called from its discoverer, or at least principal inventor, 
is so far improved that the images it produces are fixed ; and 
a further step has been made of engraving it, by means of 
galvanism ; so that, at a very moderate expense, the most 
minute representations of material objects may be multiplied 
and printed off. Plates of fossils have already been published, 
which bear inspection by a microscope. A common line en¬ 
graving on copper may also be reproduced, line for line, by 
galvanism. The process is rapid and simple. A cast is taken 
from the engraved plate in Paris-plaster. This is placed in a 
solution of blue vitriol, or sulphate of copper, as it is named, 
and a galvanic current of two metals being formed, the pure 
copper is rapidly separated from the sulphate, and deposited in 
the mould. In this way the engraving is represented in relief; 
a cast of this being taken is submitted to the same process, 
when a fac-similc of the original plate is formed. An hour or 
two suffices for the whole process; and, when I examined 
prints from the original and the copied plate, I could detect no 
difference. 
The speed with which electric fluid traverses a wire, far ex¬ 
ceeding the rapidity of light, has given rise to the idea of using 
an electrical apparatus for a telegraph. Professor Wheatstone 
has brought this to considerable perfection, so as to convey 
messages with great ease. The expense of laying down the 
wires, seven or eight in number, is about £300 a mile; but 
when once fixed they are not liable to decay, or much injury; 
and in an instant of time an intimation might be conveyed from 
one end of England to the other. 
Extract of a letter from Dr. Buckland to Sir John Franklin, 
dated 5th September, 1840. 
... I enclose for the edification of your Philosophical Society 
some novelties* not yet made known in London, and still under 
experiment, but of the greatest importance to science and art. 
* Three engravings. 1st. A thin section of a Madrepore, drawn with the 
oxyhydrogen microscope, magnified 1times, by the process of L. L. 
Boscuwen lbbetson, Esq., with the apparatus at the Polytechnic Institution, 
Regent-street. 2nd. Portrait of Lord John Russell engraved on a Daguer¬ 
reotype plate. 3rd. Silicificd Pcntagonaster from the green-sand of Black 
Down, Devon, drawn by solar light upon ft Daguerreotype plate, and thence 
transferred to stone. 
