Phenix gazette. [volume] (Alexandria [D.C.]) 1825-1833, 1827-07-18
From the Baltimore american.

DQHsfNOTS s1WeTJCuu
in the Franklin Journal for June, is highly
interesting letter from Mr. Perkins, in London,
on his "High Pressure, Safety, Steam Engine"
Grea, doubts have been expressed as to his even.
tual success, and among the res; by the editor OF
the Franklin Journal himself Perkins declares,
in the above letter, his complete success and
that orders have been given for his engines, with
The guarantee of saving half the fuel, and three
fourths of the weight an built, with less liabili-
~ Of arrangement, than in ordinary engines
An engine is now making, which will not oc-
cupy more than one sixth Of the room, nor ex-
coed one-sixth of the weight, of the ordinary
Bolton and Watts engine, OF the same power.
81 hope" says Perkins, "to take my seat by the
side Of generator sustaining pressure OF
5000 lbs. TO the square inch, this being The
pressure OH the generator, required to produce
a working power Of 1000 lbs. 10 the square
inch. on the piston" The discovery asserted
by this ingenious man, that steam is often SO
generated as TO indicate high degree Of tempe
nature, without corresponding increase OF pow
err, and that on waters being injected into the
super-heated steam, there would suddenly be
formed highly elastic steam,-is oil the great
est importance 10 safety as well as economy, as
to this principle 10 be imputed the tremen'
dous explosions which take place in low as well
as in high pressure boilers. He mentions va
riety of instances of explosions in low pressure
boilers, and asserts that more persons have been
killed by them than by high pressure ones. For
these explosions he accounts In the following
manner:
GAS long as water is not heated above 2l2
degrees, it will simply boil and give oil atmos-
pheric steam, without the water having any ten
dency to rise with 1t, but as 1t becomes more
and more elevated in temperature, It's DISPOSE.
ton 10 rise with the steam becomes more ana
more apparent AS the steam presses on lac
surface of the water, in the. same ratio as the
water increases in temperature, 1t only Dolls
without rising, as when at atmospheric pres
sure: bu, if the steam should be drawn off fast
err than il IS generated, this artificial pressure
would be taken oil, and the water would rise
with the steam in proportion to the suddenness
and rapidity Of its escape. The water and
steam in this mixed state, thus filling every part
of the boiler, the excess OF caloric In the sur
charged steam, as well as the extra heat from
the boiler, will be instantly taken up by the wa
ter which rises with the steam, by which means
the steam becomes sufficiently dense Cor power
full TO produce the fatal effects too often expe-
rienccd, not only from high but from low pres
sure boilers. If, for instance, the water as mas
before been noticed) should be suffered 10 get
below any part of the boiler, which is exposed
TO the fire, the steam will soon become sur
charged with heat If boiler thus circun-
stanced, should have the weight taken from the
safety vale, or small rent be effected in the
boiler from its giving way by the pressure oil
the steam, an explosion will be sure TO follow
A remedy for this kind of explosion, which aP,
pears to be the only serious one, Is that OF no!
allowing the water TO subside below any part o'
the boiler which is exposed to the lire
Perkins has been engaged by the French go
yernmen, to build steam artillery and muskeny
A niece of ordnance is to throw sixty balls, OF
four pounds each, in minute, with .he correct
ness Of the iifed musket. a musket is 10 DC
attached to the same generator, for discharg-
ING stream Of lead from the bastion OF fort;
il IS to throw from one hundred to thousand
bullets minute, as occasion may require. A
series OF satisfactory experiments has taken
place at Greenwich, attended by the French en-
gineers appointed for the purpose oy the LUKE