Polynesian. [volume] (Honolulu [Oahu], Hawaii) 1844-1864, 1852-09-18

We have before stated that atmospheric air
IS hrst drawn INTO the supply cylinder, from
whence II is forced into a receiver, and that
from this it proceeds towards the working
| cylinder, before reaching which it passes
through the regeneration. This structure is
composed of wire net, somewhat like tha,
used in the manufacture of sieves, placed
side by side, until the series attain thick
most innumerable cells, formed by the inter-
section Of these wires, the air must pass, on
its way to the working cylinder. In passing
! through these, it is so minutely subdivided
that the particles composing it are brought
into close contact with the metal which forms
the wires. Now let US suppose, what actu-
ally takes place, that the side of the regene-
rator nearest the working cylinder is heated
TO high temperature. Through this heated
substance the air must pass before entering
the cylinder, and in effecting this passage, ii
takes up, as is demonstrated by the thermom-
eter, about 450a of the 4S0s of heat requir-
ed, as we before stated, to double its volume.
The additional 800 are communicated by the
fire beneath the cylinder. The air has thus
become expanded; it forces the piston up-
ward; it has done its work--valves open
and the imprisoned air, heated to 1902, pas
ses from the cylinder, and again enters the
regenerator, through which it must pass be-
fore leaving the machine. We have said
that the side of this instrument nearest the
working cylinder is hot, and it shouldbe here
stated that the other side is kept cool, by the
action upon it of the air entering in the op-
posite direction at each up-stroke of the pis-
tons. Consequently, as the air from the
working cylinder passes out, the wires alb
sorb its heat so effectually that, when il
leaves the Regeneration, it has been robbed Of
it all, except about 800. In other words, as
the air passes into the working cylinder it
gradually receives from the regenerator
about 45Oo Of heat; and as it passes out,
this is returned TO the wires, and is thus used
over and over, the only purpose of the fires
beneath the cylinders being to supply the 800
of heat we have mentioned, and that which
is lost by radiation and expansion. Extra
ordinary as this statement may seem, it is
nevertheless incontrovertibly proved by the
thermometer to be quite true.
When physical causes, productive Of un-
expected mechanical results, are carefully
examined, they will always be found ade-
quate to effect what, upon a cursory view
might appear marvellous or incredible. Thus,
after an examination of the reasons why this
compact regenerator so effectually absorbs
and transmits heat, its operation will cease
to create wonder, although it cannot fail to
excite profound admiration. We will state
the causes of its efficiency.
The regeneration, contained in the sixty
horse engine we have examined, measures
twenty-six inches in height and width inter-
nally. Each disc of wire composing it. con-
tains 676 superficial inches, and the net has
ten meshes to the inch. Each superficial
inch, therefore, contains 100 meshes, which,
multiplied by 676, give 1900 mesfes in
each disc, and as 2OO discs are employed, it
follows that the regeneration contains l3, $40
900 meshes, and consequently, as there are
as many small spaces between the discs as
there are meshes, we find that the air within
is distributed in about $4,000, 900 minute
cells. Hence, it is evident, that nearly every
particle of the whole volume Of air, in pass
ing through the regenerator, is brought into
very close contact with a surface Of metal,
which he6ts and cools alternately. The ex-
tent of this surface, when accurately esti-
mated, almos; surpasses belief
III
feet long, and that contained in the regene-
rator is consequently DDS, 900 feet, or Il I-2
miles III length, the superficial measurement
of which is equal to the entire surface of four
steam-boilers, each forty feet long, and four
feet in diameter; and yet the regenerator,
presenting this great amount of heating sur
face, is only about two feet cube-less than
l-l920 of the bulk of these four boilers.
Involved in this wonderful process, Of the
transfer and retransfer of heat is discovery,
which Justly ranks as one of the most re-
markable ever made in physical science
Its author, Captain Ericsson long since as
certained, and upon this is based the subli-
of his caloric-engine, that atmos-
pheric air and other permanent gases, in
passing through distance of only six inches
in the fiftieth part Of second of time, are
capable of acquiring, or parting with, upward
of four hundred degrees of heat. He has
been first to discover this marvellous property
of caloric, without which, atmospheric air
could not be effectively employed as motive
power The reason is obvious. Until ex-
panded by heat, it can exert no force upon
The piston If much time were required to
effect this, the movement of the piston would
be so slow as to render the ma
chine inefficient. Captain Ericsson has de-
however, that heat may be COM
municated to, and expansion effected in, at
nospheric air, with almost electric speed;
and that it is, therefore, eminently adapted to
give the greatest desirable rapIdty of motion
% all kinds of machinery.
We here close our imperfect description Of
/ machine destined, as we believe, to work
revolution in the commerce of the globe.-f
t consumes but very small proportion of
he coal required for the steam-engine. Itis
Entirely free from every element Of explosion
II of danger. Watchfulness is not impera-
lively requged, as in the steam-engine. III
eft unatten0ed, the worst that can happen is,
hat after exhausting the heat Of its fires, and
q 4 l.