The daily exchange. [volume] (Baltimore, Md.) 1858-1861, 1858-05-05
SC1EN AND ART

NAUTICAL lNvENTIoNS.-Two or three inventions
OF nautical character have late been brought for
ward, and which, from their ingepiousness and
novelty, we here make mention of. 1t is well known
that wooden masts soon decay about the head and
down to the hounds and truss hoop, in consequence
OF Judgments OF moisture at such parts induced by
the cap, the rigging and the top. 1t is also known
that iron masts are objectionable on account of
their rigidity, the difficulty of cutting them away
to save ship &c These objections it is proposed
TO oovlate by making the top of the mast from the
cap TO the truss hoop, in the form of a tube of
wrought iron, similar to an ordinary iron mast
and continuing the metal downwards, in the
form OF four tapered arms; the lower part of the
mast is entirely of wood, and the upper end of
1t Is flled into the tube as far as the hounds
where it abuts against strong iron cross plate
formed in the tabe the tapered arms fit close to the
wooded portion of the mast, to which they are Sc
curely liked by iron hoops or otherwise, Some i'm
portant experiments with signal lights for ships in
distress have recently been exhibited They are de-
tonating and luminous signals and differ from 9th
ers in use in the brancy Of their light and the ex
pense OF manufacture. The composition is inclosed
in metal tubes, and the light shows itself so bril-
liant and difused at the distance of five or six miles
from the point OF observation, to present the ilu
sion of ship on fire. A lieutenant in the French
navy has invented new steam screw propeller
which he calls the futed screw. The Improvement
is founded on very nice observation of the direc
tons taken by the particles of the water displaced
and repealed by the screw The result of an official
trial has shown gain of seventeen per cent in
dIsagreeabe vibration usual in screw steamers
PREVENTING Explosions IN Coal MINEs-A wri-
ter in the Mining journal, London, proposes a
unique and simple plan for preventing explosion
In coal mines The plan il, to introduce into the
coal mine basin containing muriatic acid, which
when the lid was raised, readily CASTLES as gas is
the peculiar natural condition of muriatc acid; on
escaping from the basin it quickly combines with
the hydrogen and nitrogen of the mine, for which
TINS acid has the greatest affinity, and neede-like
crystals of muriate of ammonia are deposited on
the sides and surface of the mine. For agreeable
ness, the lid may be partially raised during the dav
For greater security wire is introduced through
the mine, connecting with electro-g alvanic bat
terry, on the bank of the mine, and every evening
when the miners are absent, current of electricity
is passed through the mine, which causes the gases
more easily and quickly to combine and by probing
the mine ensures no aggregation Of fire damp, be-
yond that accumulated in day,
SaoKELEss SrovE.-A stove of very novel con-
st1 uction has been invented by NJ. Chamber of
Paris, and for which invention he has received the
large gold medal of the Society for the ENCOURAGE
ment of National Industry. The object of the in
ventor was to constr uct stove which should dfuse
a uniform heat, and at the same time consume its
own smoke. BY NJ. Chambers system, the front of
the hire place covered with metal plate and there
is no cavity for fuel as in the ordnory stove In
place OF such receptacle sort of iron basket is fixed
about eight inches above the hearth stone; beneath
this is grating by which air is admitted to cham
Der behind the plate and above the latter is anoth-
er chamber communicating with that underneath
and which can be opened shut at will by the aid
OF two registers. The grating under the basket
can also be opened or shut by means of lever
worked by handle fixed in the upper part of the
plates and the combustion of the fuel is quickened
or sackened in proportion as the grating below and
the registers above are made to act When the re-
gisters-which are simply small iron doors about
SIX inches square-are closed and the grating is
open, the flame and smoke of the fire are reversed:
and when the registers open and the grating
closed, the snake and fame pass into the upper
chamber as in an ordinary stove, with this excep-
ton, that the combustion is more active If the re-
gisters and grating be partially open the smoke is
burnt in the open chamber. Heat and ventilation
are provided by means of a zigzag traversing pipe
which passes behind the plate and emits stream
OF hot air through apertures provided in the chin
ney for that purpose. Metal pipes may be fixed to
those apertures, and thus a continuous stream of
warm air can be circulated through the room.