New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1854-01-23

guides attached to the cy finders parallel to the piston
rods, the better to control the ybratog movements.
Tie most convenient remA ming method would have
been to forge crank in thr paddleshait as near IS
practicable to the engines an, thus to have worked
pair OF sirpumps arranged IS ia the Golden Gaze The
single airpump OF the Edgar VIII steamer contained
tie rt American application Of this style Of engine
10 marine purposes, was worked IN tie manner last
indicated.
The importance of this portion OF tie mechanism viii
be best understood when the reader considers that all
the steam used in the engines is drawn either n the
form of water or yapor through the ar.pumps. II is
the FINAL means Of escape in fact for all the steam
which passes through the valves OF lOw-pressure
engine In case it is disabled the engines can only BE-
worked "high pressure or by forcing the steam out
against the pressure of the atmosphere The latter
pedient was resorted TO on the S1n Francisco, but
without smoke-pipes 8 sufficient pressure OF steam
could rot be maintained.
To work one or more air-pumps successfully, indie
pendent Of the main engines two engines might be
connected to an independent shaft acting st right angles
to each other or possibly simple arrangement Of
levers and links may be applied to single engine,
which in the cotton press and printing press, will
give the greatest purchase when it is most needed
But the effect of steam engine acting directly upon an
airpump without other load is necessarily imperfect
Tie whole capacity Of the pump is not nor should it be-
completely filed at each strske with water, portion
being invariably vacant filed with very thin air and
yapor The air-pump and engine Of the San Francisco
were both laid horizontally and in line with each other
tie air pun rcd being merely continuation of the
L, of
tie steam, which necessarily is at tie commencement
OF the stroke aud the greatest resistance which after
tie airpump bucket has compressed she saseous mt
ter md sIly met the resistance Of the water do not
correspond with each other in time, aad the result
must be series of kicks struggles aud Plunges sub
iec.nr the material to conclusions which 1t is almost
impossible to estimate in pounds. The difficulty was
anticipated and designed to be overcome BY the aid Of
b,ancewheel which could not, however, under the
circumstances be of sufficient Size to steady the motOn
and to this cause alone when driving the engines up to
pretty nearly their full capacity, may be ascrbed the
fracture of tie rod and the consequent gripping of this
portion of the machinery
This unfortunate steamship made several rather un-
satisfactory trial trips. The difficulty was not in the
boilers or in the engines but in the want of vacuum,
and this was undoubtedly due entirely to the ncapacy
and bad arrangement of the arpump The ship was fur
nshed at first with patent condenser, d. F. PRISONS
patent) to which the difficulty has been most com
pacenly ascrbed apparently without considering that
the same principle was successfully employed on the
keystone State and the unfortunate AbarOs and that
a precisely similar construction of condenser made
under the inspection of the patentee, is now EN-
ployed on the John Hancock, (RnggOld Expedition,)
the Augusta and the John J.. Stevens. But whatever
may be the merits dement's of this condenser which
consists Of tubes in which the steam is cooled without
mixture with salt water is worthy of especial remark
that the tubes were entirely removed vain attempt
to remedy the difficulty, and the ship went to sea with
a plain injection condenser of the usual Od-iashOned
and orthodox description.
The cylinders OF the San Francisco were 6 inches
in diameter and Of eight feet stroke. The airpump
26 inches diameter with solid piston of feet stroke,
and the steam piston impelling the airpump was 80
inches diameter and necessarily Of the same stroke
Tie fracture was in the connection Ofthe rod to the PTS
ton Of the arpump il having broken the slot or
keywsy The repairing Of this accident could under the
circumstances be done neither strongly snugly the
brass covering Of that portion Of the arpump rod haV
ing ceayed of in the conclusion and become irreriev
ably lost As mperfectly repaired however it served
TO work the pumps and keep the ship free Of water
without tie labor of bailing. But this was far from
sufficient to resume the navigation Of the ship even
after the wind had declined and the favorable.
We presume that 10 more engines will be built on
plan which has proved so disastrous and fatal.
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pVNgGXTVANIA AND THE WEST