y cut down, and the plate is
then susceptible of a beautiful black lustre by polishing with the
buffer. The complaining operator could not succeed by his own method
with one of the plates; he would encounter all manner of clouds and
other unaccountable phenomena; he would imagine this plate entirely
worn out before it was half cleaned, and soon fix in his own estimation
the reputation of the heavy plate.

In making a choice of plates, therefore, it would appear to be a matter
of perfect indifference with an experienced operator what kind he would
use, except so far only as the labor required in cleaning them was to
be taken into consideration.

The distinction between a scale plate, a Scovill No. 1, S. F., heavy A,
star, crescent, eagle, or any other brand, consists in the superior
finish of some, and the thinness of the silver in the cheaper qualities.

Consequently, let the complaining operator but employ the diligence
inculcated in this article, to clean his plate thoroughly, so as to
bring it to a perfectly even and level surface, and he will seldom be
troubled with specks, clouds, dark patches, and the host of other
obstacles which heretofore have tormented him.

CHAPTER VI.

AN ACCOUNT OF WOLCOTT AND JOHNSON'S EARLY EXPERIMENTS, IN THE
DAGUERREOTYPE. BY JOHN JOHNSON.

[From Humphrey's Journal, vol. ii 1851]

As a general thing, however perfect any invention may be deemed by the
inventor or discoverer, it falls to the lot of most, to be the subject
of improvement and advancement, and especially is this the case with
those new projects in science which open an untrodden field to the view
of the artisan. Such has been, in an eminent degree, the case with the
discovery first announced to the world by Mons. Jean Jaques Claude
Daguerre, of Paris, in the year 1839, and which excited unbounded
astonishment, curiosity and surprise. It may be questioned had any
other than Daguerre himself discovered a like beautiful combination,
whether the world would have been favored with details exhibiting so
much care, patience and perseverance as the Daguerreotype on its
introduction. Shortly after, these details reached the United States,
by Professor S. F. B. Morse, of New York, who was, at the time of the
discovery, residing in Paris. By this announcement, the whole
scientific corps was set in operation, many repeating the experiments,
following carefully the directions pointed out by Daguerre, as being
necess