THE rXILGTJRATOE. 
103 
our ornaments, constituting our assurance that our mental activity- 
does not flag. 
I have said that our neglected opportunities are the themes of 
our saddest reflections. Impressed with this feeling I intreat you 
to lend your best energies to sustain the character of this Institu- 
tion, to give it that aid which it will require at your hands to 
enable it to maintain its position as the habitation of the intellec- 
tual activity of Plymouth, and to insure for it a career in the 
future which shall be chakacteeistic of the intellectual peogeess 
OF the times. 
THE rULGUEATOR 
A NEW ELECTRICAL APPARATUS FOR PRODUCING ELECTRIC SPARKS OF VERT 
GREAT LENGTH. 
By J. N. Hearder, f.c.s. 
Read at the Conversazione of the Plymouth Institution at the Anniversary 
Meeting, held May 2nd, 1870. 
About forty years ago, I contrived and exhibited to the members 
of the Plymouth Institution an arrangement of Leyden jars by 
which I was able to convert quantity into intensity, and thereby 
obtain sparks of greatly increased length. This was effected by 
charging a number of insulated jars of equal size separately, and 
then arranging them in consecutive order, so that the nob of one 
jar should touch the outer coating of the other. The first and last 
jars exhibited the terminal intensities of the arrangement, the one 
by its nob, and the other by its outer coating, the free electrical 
states of which were so exalted that on making a connection 
between the coating of the last jar and the nob of the first, sparks 
nearly a foot in length were obtained from four or five jars. As 
there was a limit to this intensity, when the jars were charged 
singly and placed in consecutive order on account of the tendency 
of the free electricty to escape in a brush discharge from the front 
nob when it attained a certain point, I had recourse to a new 
arrangement. 
The jars and their insulating stands were all placed on turn- 
tables which were fixed on a frame, and connected by levers with 
one common bar, which moved the whole at once. 
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