ments, “ A eudiometer double scales, double measure, -£ 4-4-0” , but Van Marum
records its arrival on 19 June as: “Fontana’s Eudiometer door en onder opsicht van
Ingenhousz” (MV). This is number 52/3 in the Inventory. On 19 November, 1790,
Van Marum sold some of his own apparatus to the Directors of Teyler’s Foundation,
which included a Volta eudiometer forJ)2i (MV).
Fontana (1779); Volta (1816) iii, II, fig. 1,7; Wheatland (1968) 168.
Inv. 32/1
183 EUDIOMETER: Volta’s e.1782 if 1134) Fig. 163
Overall height 290, diameter of globe 106, diameter of funnel 124. A small glass globe,
brass bound and mounted, has a brass stopcock and a funnel at one end for filling
under water. At the other end is a brass cap, under which is. a pair of electrodes. This
piece of apparatus looks as though it came from the same workshop as the Volta
eudiometer described under Cat. 182. It closely resembles the lower part of an instrument
illustrated by Volta, where the upper part is a long, calibrated glass tube. As it
now stands, it could be used to show the condensation effect only.
Volta (1816) iii, II, fig. 6.
184 EUDIOMETER, DEMONSTRATION 4/4 18th C. (1146) Fig. 164
Overall height 550, diameter of base 170, diameter of globe 210. A large glass globe,
brass bound, is mounted on a hollow brass bracket fixed to a brass pillar on a
mahogany base. There is a stopcock in the pillar, and communication with the inside
of the globe is via the hollow bracket. At the top of the globe is an ivory plug with
a brass electrode running through it.
This apparatus was used to demonstrate the condensation that results from detonating
hydrogen and oxygen in a container by means of an electrode. This method
is used in the Volta eudiometer. The instrument has no scale attached, as its
purpose was to show the condensation effect only. See Cat. 182, 183.
Inv. 40/4
C H E M I C A L A P P A R A T U S
185 WATER MAKING APPARATUS 1790-1791 (219) Fig. 165
Overall height of apparatus 1,860, width 1,570, depth 360; height of brass water-holders
(without top) 1,210, diameter 155; height of glass gas-holders between brass rims 590,
diameter 300; diameter of glass combustion chamber 360.
This apparatus for the experiment ofmaking water by continuous combustion of oxygen
with hydrogen consists of:
1) Pair of glass gas-holders, each on three levelling screws, with three stopcocks and a
thermometer (pg281/2°R: 32°-g6°F) in the cap. An ivory scale, 0-1,640, is secured
to the side of each gas container.
2) Pair of brass water cylinders, filled from above, with glass tubes mounted on the
inner side, for reading the water level. In the outer side of each cylinder are three
taps.
3) Glass combustion chamber on tripod. In the brass cap are two stopcocks and
a glass tube, which contains platinum conductors and an adjustable spark gap for
igniting the hydrogen. The U-tube inside the chamber is of silver.
All these pieces of apparatus are linked by tubing, of brass or glass.
This was Van Marum’s first design for the apparatus which he later modified and
simplified. It is itself his improvement on the apparatus of Lavoisier, which Van
Marum found expensive and difficult to acquire. On 31 October, 1788, Van Marum
was given permission to spend f 600 to have made apparatus for demonstrating the
composition of water (MVji A-t various times from this date he records buying small
items for these chemical experiments. A detailed account of Van Marum’s chemical
apparatus and experiments has been written by Dr. T. H. Levere.
Lavoisier (1789)411790); Van Marum (1798) chap. 1, I, II; Levere (L & W i 1969)
chap. 4.
Inv. 37/1I 40/1
186 COMBUSTION CHAMBER, HYDROGEN 1790-1791 (220) Fig. 166
Overall height 430, base area 360 x 280; diameter of globe 250. A mahogany stand
with two pillars is used to support a glass globe on a brass tripod. There is a glass
bowl below, and a pair of brass taps is mounted on each pillar.
The purpose of this apparatus is to produce water by continuous combustion of
oxygen and hydrogen. The globe, having been filled with oxygen, was quickly placed
over a bowl filled with mercury, to act as a seal. A small quantity of hydrogen was
admitted from a gas-holder and lit with a candle. As combustion took place within
the globe, further amounts of oxygen and hydrogen were admitted through the two
glass tubes from gas-holders placed on either side of the apparatus. Water collected
in the bowl on top of the mercury.
The purpose of the stand and the two stopcocks on each pillar was to enable the
experiment to continue over a longer period, because an alternative supply of gas
could be quickly applied.
Van Marum (1798) chap. 2, III, fig. 2; Levere (L & W i 1969) fig. 30.
Inv. 4012