The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1839-07-05 00:00:00

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EFFECTS OF SLEEP UPON THE ETES.—A due portion of
sleep is as essential to enable the eyes to perform their office
comfortably and effectively, as a due portion of rest is to ena-
ble the limbs wearied with toil, or the mind with reasoning
or other kind of exertion, to resume with alacrity their wonted
offices. But sleeping too long protracted, on the other hand,
is perhaps hardly less destructive of accurate and healthy
vision than when taken too sparingly ; for as in the one case
the organ is enfeebled by unremitting activity, without a
proper degree of repose, so in the other case, the eye, from
unfrequent or insufficient exercise, becomes torpid and dull,
and if inaction be persisted in, it is at length unfitted for its
functions.—Curtis on the Eye.
WATER AND ICE PRODUCE FlRE.—Throw a piece of po-
tassium, about as large as a peppercorn, on the surface of
water in a basin ; the instant the metal meets the water, it
bursts into flame, with a, slight explosion; It continues to
burn till the whole of the potassium is consumed, darting
from one side of the vessel to the other, or running to and
fro on the surface of the water very rapidly, in the form of a
red-hot fire-ball. If a piece of potassium be placed on ice,
it instantly takes fire, burns with a bright flame, and melts
a deep hole in the ice. This curious phenomenon is caused
by the great affinity which the potassium has to oxygen, in
consequence of which it decomposes water and ice, com-
bining with the oxygen with such intensity as to produce
heat and light, and setting fire to the hydrogen, which is li-
berated. The result of the combustion of the metal is the
alkali potassa, which is thus shewn to be an oxide of the
metal potassium.—Chemist.

A DISCOVERY IN THE ARTS.—One of the most import-
ant recent discoveries is the one applicable to the reprinting
of books, or reproduction of engravings. M. Dupont, a very
industrious printer, was seeking the means of saving the ex-
pense of stereotyping. With the assistance of a particular
ink he was already enabled to avoid the preservation of the
clichts, which require many materials, and much place and
money, by the means of the preservation of a mere printed
sheet which lithography afterwards reproduced whenever it
was wanted ; but doubting whether the ink used upon that
sheet would retain in course of time the same properties, he
consulted his brother, a very intelligent lithographer, and the
latter found what neither ventured to expect. This new pro-
cess is applicable not only to fresh printed sheets, but like-
wise to the oldest engravings, to the oldest books, and,
which is of far more interest, to Greek, Chinese, and Hebrew
books. It consists in two operations. oYer the page or en-
graving of which you want a copy you lay a particular com-
position. It is placed upon the lithographic stone and
pressed, and the stone reproduces, with scrupulous precision,
the original engraving or book. This impression could not,
however, serve such as it is. It is itself covered with the
same preparation, and it may then print thousands of copies
by the ordinary processes of every sort of lithography. Five
minutes suffice for both operations. The original engraving
may be restored to the portfolio which has supplied it, for it
has not been in the slightest degree injured ; the book, thus
wholly reprinted, may undergo another binding, and honour-
ably resume its place in your library. This new process ad-
mits of a reduction of 75 per cent upon the expense of print-
ing ; and as for engraving, that which on copper would have
cost 100 francs will now cost but 20 francs ! What conse-
quences will not this discovery yield ! It threatens the
graphic arts, engraving and printing, with a complete revolu-
tion. A man of the greatest talent in the arts lays claim to
priority in this discovery, as is always the case, when success
has been obtained claims come in. The wisdom of the cen-
tral jury and patent laws must decide the question. In the
MM. Duponts are manufacturing, which is always a great
point. On Monday the king, queen, Madame Adelaide, and
Princess Clementine, visited again the exposition, and ex-
amined the lytho-typographic produce of the brothers. His
majesty obserYing an engraved head of Albert Durer, of
1527, which was wanting in his collection of the-Palais Royale,
ordered a copy of it, and congratulated MM. Duponts upon
a discovery whereby there would be no longer any scarce en-
gravings or books.—Parb periodical.