ELECTRIC COLUMN OF 20,000 PLATES, 
85 
each plate having a diameter of 5-8ths of an inch, occasions the pairs of 5-nths 
gold leaves in an electrometer, (whose cylinder is one inch and of an mch dia " 
v J meter, con- 
a half in diameter), to strike the sides, at intervals of from half stantly affect- 
a second, to two or three seconds, varying at different periods. ed the elec ' 
..... , r trometer, 
1 he extremities of the above column being connected with and charged a 
the opposite coatings of a Leyden jar, containing about 50 J ar ’ , 
square inches of coated surface, a charge was communicated to gaV<? aSi>ar * 
it capable of affording a very evident spark. The period of 
contact required for the production of this effect, was seldom 
less than one minute, and no advantage appeared to be obtained 
by its continuance beyond five minutes. 
The charge thus communicated, even at its maximum, pro- a?} d slight 
duced but a very slight shock, the sensation being. only percep- s5loek ‘ 
tible at the points of contact. 
Twenty Columns similar to the preceding were now arranged, Twenty co- 
r , 0 lumns, or 
so as to constitute a series of twenty thousand groups of silver 20,000 pairs, 
and zinc, separated by double discs of paper. In this apparatus, 
beside the two extremities, and a central point, there are 18 
intervening situations, at which an electrometer may be applied, 
the whole apparatus being insulated. s 
The power of the apparatus was such as to affect pith ball had a consi- 
electrometers ; several of these were employed with balls one- n J he p j tll 
fifth of an inch diameter, suspended by fine threads four inches ball electro- 
long. The electrometers at the extremities of the apparatus had meter > &iC ‘ 
their balls separated by its action, frequently to the distance of 
two inches and upwards, and their divergence was rarely less 
than one inch and a half J the electrometer at the centre was 
not affected. Electrometers applied at intermediate points, 
between either extremity and the water, exhibited various de- 
grees of divergence, diminishing in intensity in proportion to 
their proximity to the central point. 
When either extremity of the series was connected with the 
ground, that extremity became the neutral point, and the an- 
nexed electrometers divaricated, with progressively increasing 
intensity, towards the opposite end, where the original diver- 
gence was considerably increased j but the electro-motion in an The electio- 
apparatus of this extent is so slow, that some minutes are re- motion slow, 
quired to produce the maximum of effect. 
A communication between the opposite extremities of the Sparks seen at 
series 
