364 Researches in Magnetic Electricity. 
stone, merely from its external characters. All the rocks in Ohio, 
except the tertiary and recent deposits, belong, in my opinion, to 
the transition of Buckland, which would include the coal meas- 
ures and the mountain limestone, the oldest visible rock in Ohio. 
Those rocks which the Doctor has mistaken for new red sand- 
stone belong to the sandstone of the coal measures. I think I re- 
mark in my review, (I have not a copy,) that I regard those rocks 
in the eastern part of the State, as the most recent, aside from the 
superficial deposits, since the dip is E.S. E., and unbroken. At 
Wheeling, two beds of coal crop out, which extend into Ohio. 
For these reasons, I think that neither the new red sandstone, 
nor the lias, nor the oolite, is to be found in Ohio. I was desirous 
to discuss this point, as the impression has gone abroad, that the 
new red sandstone is found here. | 
Art. XI.—Researches in Magnetic Electricity and new Mag- 
netic Electrical Instruments ; by Cuar.es G. Pace, M. D. 
eS Scan Electro-Magnets for the Magnetic Electrical 
spark, shock and decomposition.—In the last number of this Jour- 
nal, I announced this new form of magnet, as decidedly superior 
to the common solid electro-magnet, for exhibiting magnetic elec- 
trical phenomena. I have since performed a variety of experi- 
ments, with reference to the best mode of constructing these mag- 
nets, and arrived at some beautiful results and important conclu- 
sions. I find that the magnet made of flat plates of thin hoop 
iron, answers best for lifting power and sparks; but those made of 
fine annealed iron wire, answer nearly as well, and (for reasons, by 
and by to be mentioned) will in some cases be found preferable to 
the flat bars. Sixteen magnets were made of soft iron wire, in bun- 
dles of various lengths and diameters. Thirteen were made of No. 
26 wire, two of No. 16, and one of No. 8. For lengths within ten 
inches and diameters within one inch, the very fine wires answet 
best. But for longer and larger magnets than these, the larger 
iron wires answer equally well. Each of these magnets were 
tried with one, two, and three coils of No. 16, copper wire, (wound 
each the whole length of the bars and siperpowed by a single 
