144 ) -Dr. Pearson's Experiments and Observations 
my work on the Chemical Nomenclature; although 1 have 
heard of many persons,' and some of them experienced elec- 
tricians and chemists, who have made the attempt. But by 
labouring with Mr. Cuthbertson, since he came to reside 
in London, I have learned the circumstances on which the 
success of the experiment depends ; and 1 have received from 
him effectual aid in continuing a process, with the objects I 
had in view, the tediousness and even difficulties of which can 
only be conceived by those who have been engaged in the same 
pursuit. 
In the course of my experiments on this subject, Mr. Cuth- 
bertson invented a new method of disengaging gaz from wa- 
ter, by means of the electrical discharges, namely, by means 
of uninterrupted or complete discharges ; whereas the method of 
Mr. van Troostwyk was by interrupted discharges. The ra- 
tionale of the process according to these two methods, I appre- 
hend, cannot be understood without an explanation ; for I find 
books on electricity do not contain the necessary information. 
In the experiment of Mr. van Troostwyk, it must be con- 
sidered, that if in place of water the tubes be filled with air, 
the whole of the charge of the Leyden jar will pass, at each 
explosion, from the upper to the under wire, and no interrup- 
tion in the discharge will happen ; but if they are filled with 
water, then an interrupted discharge may be caused: by which 
is meant, that a part of the charge only passes at each explosion 
through the water from wire to wire, and with much diminished 
velocity. The residuary electricity in the Leyden jar is nearly 
one half, as may be accurately demonstrated. The reason of 
these differences must be assigned from the difference in point 
of density, elasticity, and conducting power, of the medium of 
