118 Experiments in Electro-Magnetism. 
Art. VIII.—Experiments in Electro-Magnetism ; by Dr. Cuartrs 
G. Pace, of Salem, Mass. 
TO PROFESSOR SILLIMAN. 
Dear Sir—I notice in the July No. of the Franklin Institute . 
Journal, an announcement of the discovery of the thermo-electric 
spark by an Italian philosopher, and also the subsequent exhibition 
of the spark by Prof. Wheatstone to Faraday and others ; the date 
of the discovery is not given. On referring to my notes I find that 
I obtained the spark in August last, but not the shock. The spark 
and shock were both obtained Dec. 2d, 1836, and exhibited to a 
number of friends, and announced in your last No. It appears that 
the European philosophers have not yet obtained a current of suf- 
ficient magnitude to afford a shock by the multiplier, although they 
use in the experiment a great number of pairs. In my experiment 
only a single pair is used either of bismuth and iron, bismuth and 
zinc, or bismuth and antimony, and yet the induced or lateral shock 
given by the multiplier is very distinct by acupuncture. ‘The par- 
ticular arrangement of the thermo-electric elements to produce such 
powerful effects, I do not wish to describe at present, as I hope ere 
long to announce it as a substitute for galvanic batteries m many 
experiments. 
On the disturbance of Molecular forces by Magnetism. 
A short article on this subject appeared in the last No. of this 
Journal, under the caption Galvanic Music. The following experi- 
ment, (as witnessed by yourself and others not long since,) affords a 
striking illustration of the curious fact, that a ringing sound accom- 
panies the disturbance of the magnetic forces of a steel bar, provided 
that bar is so poised or suspended as to exhibit acoustic vibrations. 
An electro-magnetic bar four and a half inches in length, making five 
or six thousand revolutions per minute near the poles of two horse 
shoe magnets properly suspended, produces such a rapid succession 
of disturbances, that the sound becomes continuous, and much more 
audible than in the former experiment, where only a single vibration 
was produced at a time. 
On the application of Electro-Magnetism as a moving power. 
Late in the fall of last year, (November,) I commenced the inves- 
tigation of this subject, not knowing that any thing more had ever 
