att 
ee 
= 
of this object, of which we e have any record, was made by Mr. 
_ try who produced a rotary electro-magnetic machine. Since the 
106 ~—— Ellectro-Magnetism, as a Moving Power. 
ees 
Arr. VL—On- Ele ct eed netism, as a Moving Pusal 3 by 
Cuartes G. Pace, M. D., Washington City, D 
Arter the first successful magnetization of soft iron by the we 
«vanic current, and more especially on the announcement of Prof. 
Henry’s signal experiment, the suggestion naturally occurred to 
every enquiring mind, cannot this immense attractive power, 80 
easily developed and ps ie be rendered available as a me- 
chanical agent?» The first successful step towards the attainment 
William Sturgeon, a distinguished philosopher of E gland. 
next original invention by which an independent motion was ob- 
tained from electro-magnets, was the oscillating apparatus of Prof. 
Henry, described in a previous No. of this Journal. The next 
invention of any note, was that of Dr. Ritchie, now very well 
known as Ritchie’s revolving magnet. "This ingenious and sim- 
ple contrivance, will always be regarded as a superb philosophical 
apparatus. It does not exhibit that lishing rapidity of rota- 
tion, as if its poles were changed by the use of solid conductors, 
but as an instrument is more pleasing, as it shows at the same 
time the magnetic rotation, the vivid sparks, and in the dark a 
beautiful optical illusion. Some time after the announcement of 
this instrament in this country, Mr. Davenport of Vermont pub- 
lished in this Journal a partial description of an electro-magnetic — 
engine of considerable power. It appeared that Mr. Davenport 
had for a long time been occupied in the subject, an * 
‘Sa ORES Nesiieaie ae 
time prior also to this period, some interesting experi 
described in this Journal, by Dr. Edmondson of Baltimo 
indeed, this gentleman appears to have been the first in this coum= 
announcement of Mr. Davenport’s invention, the innumerable ex- — 
periments which have been performed in this country, in Eng- 
land, on the continent of Europe, and even in the East Indies, é 
have all contributed to prove that the smallest engines which a 
have been made, have had by far the greatest proportionate power. # 
Since I first gave the subject any attention, I have had sixteen 
different models constructed, — involving distinct principles. 
From all these experiments the inference is still the same, viZ- 
