‘hr. Hare's Improved Eudiometers. 69 
cf 
rps 
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 calori- 
motors; also between all their zinc surfaces and the other fur- 
row. The acid for exciting the plates is contained in the jug 
below, which may be so uplifted as to surround with acid 
either of the calorimotors. Hence, while one is in operation, 
‘the others are by repose, recovering their igniting power. 
Or by using a vessel (Fig. 3.) large enough to receive, and 
containing acid enough to excite, two of the calorimotors at 
once, the igniting power may be doubled. The vessels for 
holding the acid are made of copper, covered with a cement 
of rosin, rendered tough by an adequate admixture of mutton 
suet. 
