Memphis daily appeal. [volume] (Memphis, Tenn.) 1847-1886, 1871-07-23
SCIENTIFIC I GOSSIP.
Photography without Light.

may be thus briefly described: The
photograph Is taken On a sheet OF
geiatine; this sheet is fastened down
upon a plate Of metal, and after a lit
tie preparation, in which sponge and
water play a part, can be printed from
as If it were an engraved block. Or
binary printing ink, laid on with a
roller, Is used; and the sheet is print
ed In an ordinary printing press, and
with a remarkable preservation Of
the lights and half tones. Oil paint
ings, ~engravings, chalk drawings, and
anything, living or dead, that can be
photographed, may, by this process,
be reproduced and multiplied in a
permanent form and when a sufi-
Gent number of impressions has been
taken, the sheet Of gelatiue can be
lifted from the plate, and laid aside
for future use. This is obviously a
very Important addition to the re-
sources OF art; from three hundred to
four hundred impressions can be ia
ken in a day, quite independently Of
weather; and, if required, the picture
can be printed along with type in the
pages Of 9 book. Specimens were eX-
hibited at the conversations given by
the President of the Royal Society,
at Burlington House, including chalk
drawings by the old Italian masters,
landscapes, buildings, engravings, sea
pieces, maps, and a number OF shat
tered and wounded bones from the
recent battle fields in France, inten-
Eded to illustrate g work on surgery.
All these specimens were reproduced
with such skill that, in many cases, it
would have been difficult to distin-
guish them from the originals.
COMPRESSED AIR As A MOTOR.
The greatest progress in this direc-
ton yet made is due to q Mr.. Robert
Spear, of Portland, Me. From the
Boston Advertiser, we learn that ex-
periments made by Mr.. Spear, in
Portland, upon. compressed air as a
motive power, have made a very de-
cided sensation among men of all
classes-mechanics, manufactures,
capitalists andinventOrs. Its evident
that IN certain branches of manutac-
ture a complete revolution must fol-
low upon the general Introduction Of
this simple and economical substitute
for steam or water power. Whether
engines of very high pressure a be
successfully worked by this new
agency is still a debatabie question
among our intelligent mechanics. Mr..
Spear has invented a governor which
as easily controls the pressure as the
governor Of a steam engine. He
claims what seems Incredibly that
air can be compressed in the reservoir
to an extent double the power Of the
engine that congresses, thereby saw
ing a large per cent. in fuel. Also, that
the pipes can be extended almost in
definitely, and that the obstacle of
friction, which previous experiment.
ers nave found almost impossible to
deal with, is, by a simple invention Of
his, entirely overcome. The necessity
OF long lines OF shatting in largeshops
is thereby Obviated, and each work
man becomes, a il were, his own
engineer. This work OF keeping a
large engine running when, perhaps,
only asmalI part Of The machinery in
| q factory i sin use, is done away with.
MI. Spear afhrms that the tidal force
! at Tukey's Bridge alone is sufficient
to furnish compressed air for all the
machinery in the neighbOrhOOd, and
that the water-pOWer at the lower
falls Of the PesumpscOt. if applied for
the same purpose, would give a Sum-
cient power for q manufacturing city
Of hundreds Of thousands Of inhabi-
tauts. If these things be so, the time
viii seem to be near when the tidal
force of our seabOard cities shall be
utilized, as has long been desired,
while there is scarcely an inland town
but possesses sufficient W~ater-pOWer to
compress air sufficient to run all the
machinery of the vicinity. The fur
ther development OF this theory viii
be watched with great anxiety.
BEssEMER's PROBES.
In addition to the wonderful process
of producing, almost instaneOusly, the
purest quality OF steel from iron, Mr..
Bessemer announces that he has orig
mated a method Of conducting his pro-
cess under pressure, by means of
which sufficient heat IS produced to
retain complete fiaidity in the steel
until il is poured Into mOuids. For
this purpose, he makes the converting |
vessel of great strength, and rs air
tight as possible, and makes the mouth
of it circular instead Of oval, and of
smaller size than usual, lining this
mouth with a ring of well burnt fire.
clay, or a composition of clay and
plumbago. Mr.. Bessemer states that
for the conversion OF the pureT kinds
Swedish charcoal pig-irOn, and for mot
tied or hematite pig-irOn (White, 4
mixed with gray, a back pressure in
the vessel of from eight to fifteen
pounds on the square inch will give
good results, and in but a few cases
Will a pressure OF twenty pounds per
square inch be necessary; while q
pressure as low as three or four pounds
will be Of little practical advantage,
and below two pounds pe-rsquareinch,
he lays no claim to a useful effect.
PRESSED COAL DUST,
The use of pressed coal dust, COM
paeted into solid cakes convenient for
stowage and handling, has become
quite general on board the naval yes
sells Of different European countries,
and their value appears to be unques-
tionable. 1t is claimed that in the
carriage of the little bricks, there is a
loss Of only n per cent, instead of
six to ten per cent, as in the case of
lump coal; and when stored aboard
they are found, after two years expo
sure, to be scarcely at all injured. 1t
is claimed for them also that they are
free, or comparatively free, from ash,
and can be made from the refuse of
every kind Of coal, and in such
as to produce the best effect in
getting up and maintaining steam. /,
bricks, which are exceedingly
compact, are produced by hydraulic
pressure, and require but a small per
centage of e~xlraneous, gummy or re-
sinOus matter to make them stone
like and thoroughly durable. The
best approved process Of manufacture,
the one that is asserted to give the
best results, is briefly described as
The machine has sixteen
cylinders disposed rs the radi of a
in which the coalGslack, after
being heated to the requisite degree
by q current Of steam and mingled-I
by means of ingeniously adapted APP
paratus-With pitch, is pressed by pis- I
tons and formed into cylindrical or :
blocks of uniform length.
The plan might be tested with advsn- |
age. \
ANTHRACITE AND BrTUMIN0US COAL. /
The. comparative value of anthra- {
lite and bltuminens coal as a steam y
generator, has been experimental {
Upon by the superintendent of the !
States Armory, atSpringfeld, :
Mass. Each variety Of three different :
classes Of coal was used for six consec- I
tive days in raising the steam for l
he engine of the establishment, with T
he following reported RESULTS: Ofthe {
.sckawanna, or hard anthracite, 4.01 2
per horse power were used per I
,our; of the P~ittstOn, q softer authra- 8
lite, 4.02 pounds were used; and Of c
he Cumberland, or bituminOus coal q
# MARYLAND, 3.03 poands were used. Z