138 On the Construction of De Lwe’s Columns. 
derstood from the following figure; which represents the disks, as 
eompressed, in due order, within a glass tube, by spirals of wire. - 
Each of the wires of which these Sri were formed, at the ends 
enclosed in the tube, being unaltered throughout the remaining por- 
tions of their length, were passed through corks closing the orifices _ 
of the tube. The series thus prepared, is to be placed in the situa- 
tion of the electric column, appended to the instrument agreeably to 
Fig. 1, being in like manner suspended from the rods outside of the 
vessel] by means of the projecting wires already mentioned. Thus 
situated, if there be any adequate degree of electromotive power in 
the series under trial, and the atmosphere sufficiently dry, the excite- 
ment of the poles will be communicated to the knobs, and be indica- 
ted by the consequent vibrations of the gold leaf, suspended between 
them 
When a larger series is ond, such as that represented at DD, 
Fig. 1, the vibrations will be discontinued, only in consequence of 
the adherence of the leaf to one or the other ofthe knobs. This adhe- 
rence usually ceases, on touching with a finger the little brass ball at 
the vertex of the instrument, to which the forceps holding the leaf is 
affixed. The finger being removed, vibratory pulsations will recom-. 
mence, to be sooner or later arrested in the same manner as at first. 
When duly connected with the poles of a voltaic battery, of seven 
hundred pairs, excited merely by pure water, the pulsations of the 
leaf are quick and incessant. It serves in this way to indicate the 
electric intensity,.but does not furnish any criterion of the divellent, 
igniting, or electro-magnetic powers of ‘a voltaic series. 
It may readily be perceived, that the electrometer, constructed as 
herein described, constitutes an electrical indicator, which may en- 
able us to discover the electromotive powers of various substances 
arranged as disks in a series, or as coatings to disks. I have already 
ascertained that aurum musivum spread on the naked surface, of the 
tinned paper produces an electromotive series. 
The piling of the disks was facilitated by using a punch excava- 
ted so as to leave a point in the center, by which the center of each 
disk was punctured. By means of the puncture thus made, it was 
easy, even for an unskillful operator, to string them concentrically 
