Decomposition and Recomposition of Water. 337 
iron cap, in which a female screw is wrought so as to allow a 
large iron valve cock (C)-to be screwed to it. 
Upon the tubulures also iron caps are cemented, which are so 
wrought as, with the aid of appropriate screws, to constitute stuff- 
ing boxes. 
Through each of these a platina rod (D, d) is intense and 
fastened to plates of platina, to act as “ electrodes,” agreeably to 
the language of the celebrated Faraday. 
he tube being supported over the mercurial cistern, by means 
of a communication with an air pump, through the valve cock 
aud flexible leaden pipe, the bore of the tube is exhausted of air, 
So as to cause the mercury to take its place. 
The mercury is so far displaced by a solution of borax, con- 
sisting of equal parts of water and saturated solution of that salt, 
as to sink the surface of the column of metal in the tube about 
an inch or more below the “electrodes.” The projecting end of 
one of the rods (D, d,) to the other ends of which the “ electrodes” 
are severally attached, is bent at right angles outside of the tube, 
SO as to enter some mercury in an iron capsule, supported purposely 
at a proper height, and communicating with one end of my defla- 
grator of an handred pairs of Cruickshank plates of about eight 
inches by foureteen. Of course the rod of the other clectrode 
must have a communication with the other end of the deflagrator. 
Under these circumstances, if the circuit be eompleted by throw- 
ing the acid on the plates of the deflagrator, a most rapid evolu- 
tion of hydrogen and oxygen will ensue in consequence of the 
‘decomposition of the water, so that within a few — a eral 
cubic inches of gas will be collected. : 
The action being now suspended by shasteian: din anil. off the 
plates, and the foam being allowed to subside, the resulting gase- 
ous mixture may be ignited, and of course condensed, by com- 
pleting the circuit again as at first, and at the same time causing 
the ends of the “ iesiendedl to come into contact with each other, 
and thus to produce a spark. 
This contact is effected by causing a very slight movement in 
the rod, bent at right angles, and entering the mercury in the 
iron capsule. Of course the process may be repeated as often as 
can be reasonably desired. 
Vol. xxxvim1, No. 2.—Jan.-March, 1840. 43 
