2466.                                                             THE NEW ZEALAND GAZETTE.                                                              [No. 58

in. Employ the remaining time in examining the
drawing and in inking in any figures which may have
been before overlooked, and in checking the dimen-
sions.

14. Make sure that you will have sufficient room
    on the drawing-sheet to show all the necessary views.
    You can have another sheet of drawing-paper if
    necessary. All the paper used must be forwarded
    with the drawing.

(Specimen.)

SUBJECT FOR EXAMINATION IN ROUGH WORKING-
DRAWING.

Form Exn. 17a.

[Read the foregoing general instructions.]

A COMMON SLIDE-VALVE, with its spindle. Show
also an outline section of the ports at the
cylinder-face. Show the provision for connect-
ing the slide-valve to the spindle.

The candidate is requested to fill up the following,
and to attach this paper to his drawing.

Statement by the Candidate.

The accompanying drawing, made by me this day
without referring to any document, and without
the assistance of any person, is intended by me to be
sufficient for the new construction of the parts above
described, to fit the places of similar parts which are
to be removed. The construction is similar to what
I have been with in the steamer
, but the dimensions may be different.*

The diameter of the cylinder is .
The stroke of the piston is .
The travel of the valve is .
The cover at top end on steam side is .
The cover at bottom end on steam side is .
The lead at top is intended to be .
The lead at bottom is intended to be .
The inside cover is + or — .
The thickness of the face of valve is .
The thickness of the body of valve is .
The greatest opening for steam will be .
That gives an area equal to one th of the
piston.
The opening for exhaust when the crank is on the
top centre is .
That gives an area equal to th of piston.
† The length of the connecting-rod is .
† The valve will cut off steam on the downstroke
at .
† The valve will cut off steam on the upstroke
at .

It is required that all the parts shall be fully
dimensioned in ink, but, if owing to want of time, this
has not been done, the parts not fully dimensioned
must be stated, otherwise it will be understood that
the candidate considers the dimensions given suffi-
cient.

The parts not fully dimensioned are .

Dated at , this day of ,
191 .

Candidate.

• Run the pen through the words that do not apply.
  † The candidate may omit this part if he chooses.

APPENDIX D.

READING THE WATER-GAUGES.

Notwithstanding that the reading of the water-
gauge is made a special feature in the examination of
engineers, many boiler casualties result from the
engineer of the watch either not understanding the
construction of the water-gauge fittings or not satis-
fying himself by actual trial that the cocks, pipes, &c.,
are clear.

In one case two furnace-crowns came down in a
steamer that was just starting on a voyage. The
engineers were satisfied that there was plenty of water
in the boiler, because the water-gauge showed full
glass, and they called the attention of a Board of
Trade Surveyor to this fact as being conclusive evi-
dence that the casualty could not have resulted from
shortness of water. On examination of the fittings,
however, it was found that the cock between the
boiler and the steam-pipe leading to the gauge was
shut, having been carelessly left in that position on
the previous day, when the mountings were over-
hauled for survey. Directly the cock was opened the
water disappeared from the gauge-glass, and the
second engineer admitted that he had blown down
the boiler in order to lower the water-level, as the
glass was full.

Many steamers have had their furnaces brought
down at sea in a similar manner to the above through
what the engineers of the watch have called “false
water in the glass,” and which, on examination, has
been found to result from the top communication
being choked.

These casualties resulted from what, to say the
least, was bad management, not false water.

Unless a candidate under examination is able to
prove that he understands how to verify the indica-
tions of the water-gauge, he should not be passed in
practical knowledge; and, as failure in practical
knowledge involves the candidate going to sea for
another three months before being eligible for re-
examination, the Examiner should explain to such
candidate his error, after failing him, in order to pre-
vent further casualties resulting from his want of
knowledge on this subject.

The sketches, Figs. 1, 2, 3, 4, and 5, Plate I,
represent the usual methods of attaching water-
gauge mountings to marine boilers. The important
features in each gauge and the method of verifying
its indications are dealt with separately in the follow-
ing remarks.

Referring to Fig. 1 only.

In this case the water-gauge cocks are attached
direct to the boiler, and the accuracy of the gauge
when the boiler is under steam can be tested as
follows:—

First.—Let B remain open, then close cock D
and open cock E, and if steam issues it proves
that cock B and the passage through the top
fitting and gauge-glass are clear. If no steam
or water issues, either cock B or the passage
through the top fitting and gauge-glass is
choked, and the gauge cannot act properly
until the obstruction is removed.

Second.—Close cock B and open D and E, and
if water issues cock D is clear. If no water or
steam issues, either cock D or the passage
from the boiler through the lower fitting is
choked, and must be cleared before the gauge
can act properly.