!;•' j*( !I■
closed, over the outside, 19 inches hy 9 inches
square.
BRo' 8 represents an apparatus tor preparing oxj/-
.-en, hy<li-o?en, or kuallgas, lor use in gas analysis.
I t is of the M-ell-kiioivii form of the lecture-apparatus
knotvii as ‘ Hofmauii’s tubes.’ I t consists of tivo
tubes. A and b, united at tlieir lower extremities by a
sliort'tube c, wbicli connects them at tlie same time
hy means of the tuhe n with
the reservoir E. At their
upper extremities A and n
terminate in capillary tuhes
provided with stopcocks E e.
Communication with the reservoir
can he made or interrupted
hy tiie stopcock g.
One of the tuhes A is provided
Avith two platinum
electrodes, the other, n, has
hut one. Bent delivery-tuhes
not sliown in the draAving fit
on the tuhes ahove the stopcocks
E E. When ahout to
he used, all the stopcocks are
opened and dilute sulphuric
acid poured in through tbe
F ig. S .-G a s-g en e ra tin g Apparatus.
reservoir until it has eliminated all air and is
running out at the delivery-tuhes. The stopcock g
is now shut, and the battery connected as circumstances
may require, either with the electrodes in a
or with one in A and one in B. Gas is allowed to
escape freelv until one can he sure that all dissolved
air is removed; the stopcocks E E are now closed
and G opened, and the liquid in a and b allowed to
sink until it just covers the electrodes, g is then
closed and e e opened, when the gases may he introduced
into the eudiometer in the ordinary way.
The Avhole apparatus is attached to a mahogany
slab II Avhich fits into the box K—shoAvn cut
through the middle in the draAving—either when
in use, as represented, or Avhen not in use, as a lid,
Fic:. 9.—Sea-going Sand-bath.
Avith the apparatus Avithin the box. The box thus
answers the double purpose o f a convenient stand
and a safe packing-case.
Bor evaporating or heating in flasks or beakers a
small sand-bath suspended on gimbals has heen found
very useful. . . a A (Big. 9) are iron brackets screwed
to the ship’s side; b is the outer frame, made of cast-
iron and moving on an axis parallel to the ship’s
length; c is tlie inner frame, also of cast-iron, and