BE 
es 
Dr. Hare's Improved Eudiometers. 73 
Let us suppose that this Eudiometer has been thoroughly 
filled with mercury, the sli rod being drawn out to its 
greatest extent; and that it is ‘firmly fixed over a mercurial 
cistern in the position if which it is represented in the draw- 
ing, the little funnel-shaped part at the bottom, des ending 
into the fluid to the depth of half an inch. Abave this part 
is seen a cock (C), the key of which, in addition to the per- 
foration usual in Legon has another, at. right angles. to, and 
oe in, the ordinary, perforation. When the lever 
(L) attached to the key of this cock is “ines as it 
is seen in the drawing, the tube ye the sliding 
‘rod communicates with “the recipient, but not with the mer- 
cury of the reservoir. Supposing the lever anil through a 
‘quarter of a circle, to the other side of the glass, the tube in 
which the rod — will communicate at the same time vibe 
_ rahavins the reservoir. By means of the 
), the passe ‘between the gauge and the: recipient | is 
opened. at shut at pleasure. 
sidiary to this Sidiocoa, sioner te provided with 
fod and aang i §! similar,* excepting its being 
shovter: (See fig 
* In order to ensure. accuracy in the measures of gas, made by the 
subsidiary Eudiometer, it is necessary to attend to the following ‘pre- 
first i 
cautions. ce, the instrument must d air t, 
‘thet Botionagter tor me sath the =n ee ae — en 
Me hese he ei 
of the tubes, always on 
ble of air, the effect is very much augmented. The E 
be introduced into the vessel whence the gas is to be mw abet ten 
‘per cent. more than is necessary being drawn in by opening the orifice 
and duly ae out the rod. The Eudiometer being lifted from the 
th as little change of position as possible, the red may be 
hg 
Vo. X,—No..1. om : 
