22 Dr. Hare’s improved Eudiometers. 
having proved insecure, a new and unobjectionable method 
has been adopted. 
In the instrument represented by the preceding cut, the ig- 
niting wire is soldered into the summits of the two brass wires 
(WW), which pass through the bottom of the socket (S), 
parallel to the axis of the glass recipient (G), within which 
they are seen. One of the wires is soldered to the socket; the 
other is fastened by means of a collar of leathers packed by 
a screw, so that it has no metallic communication with the 
other wire, unless through the filament of platina, by which 
they are visibly connected above, and which I have already 
called the igniting wire. The glass has a capillary orifice at 
the apex (A), which by means of a lever and spring (apparent 
in the drawing) is closed, unless when the pressure of the spring 
is counteracted by one of the fingers of the operator. The 
sliding rod (seen at R) is accurately graduated to about 320 
degrees. 
So easy is it to manipulate with this instrument, that any 
number of experiments may be performed in as many minutes. 
The ignition of the platina wire is caused by either of four 
calorimotors, each consisting of four plates of zinc, and five 
of copper. ‘They are all suspended to one beam, as may be 
seen in fig. 2 following. 
Two furrows are made in the wood of the beam, one on each 
side. ‘These are filled by pouring into them melted solder, 
after having caused a metallic communication between one 
furrow and all the copper surfaces of all the four calorimo- 
tors: also between all their zine surfaces and the other furrow. 
The 
