266 REPORTS ON THE STATE OF SCIENCE. 
‘ dissociation,’ though this term appears to have been first used by 
Deville in 1857. 
One of his most interesting experiments Grove describes as 
follows * :— 
‘I was now anxious to produce a continuous development of mixed 
gas from water subjected to heat alone . . . and for this purpose the 
apparatus shown in Fig. 9 was constructed ; a and b are two silver tubes 
4 inches long and 0°3 inch diameter ; they are joined by caps to a plati- 
num tube, c, formed of a wire one-eighth of an inch in diameter, drilled 
throughout its length with a drill the size of a large pin; a is closed at 
Deville’s Apparatus. 
for 
Diffusion Experiment. 
A PP PP PP IPP PPP PP PA PLP IPP A SL PP 
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IT SE TE PE A DP A PLP AL PFS 
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Outer glazed porcelain lube. \ 1 
Fig. 9 
Groves A ppara lus 
the extremity, and to b is fitted . . . the bent glass tube d. The whole 
is filled with prepared water, and having expelled the air from a by heat, 
the extremity of the glass tube is placed in a capsule of simmering water. 
Heat is now applied by a spirit lamp, first to b, then to a, until the 
whole boils; as soon as ebullition takes place, the flame of an oxy- 
hydrogen blowpipe is made to play upon the middle part of the platinum 
tube, c, and when this has reached a high point of ignition, which 
should be as near the fusing-point of platinum as practicable, gas is 
given off, which mixed with steam very soon fills the whole apparatus 
and bubbles up from the open extremity either into the air or into a gas 
collector. . . . I experienced a feeling of great gratification when, on 
applying a match to one of the bubbles which were ascending it gave 
* Phil, Trans., 1847-48, p. 12. 
