L. Lesquereux on the Coal Formations of N. America. 63 
relief which has before been sought in vain, and what will be still 
more useful, to give permanence to the sort of molecular arrange- 
ment which the tilings take, when exposed to magnetic influence. 
Instruction can hardly fail to be derived from the use of these 
means, by aid of which it will be possible to study the figures 
more advantageously, which are, in some sense, the visible ex- 
pression of the force animating bodies endued with polarity de- 
veloped by magnetism. 
Nancy, March, 1860. 
Art. IX.—On some Questions concerning the Coal Formations 
of North America; by LEo LESQUEREUX. Continued from 
Vol. xxviii, p. 
Geographical Distribution of the Coal Flora. 
lem which is at present discussed by the authority of the highest 
scientific names. I allude to the theory of the origin of species 
by Mr. Darwin. It evidently concerns ie great problem of the 
inmost nature of man, and thus forces every naturalist to seek, 
in the sum of facts gathered up by his researches, either con- 
firmatory or contradictory evidence of views which cannot but 
preoceupy his mind. Thus it is apparently advisable to change 
the order of examination of the flora of the coal measures of 
orth America, studying it now in its stratigraphical and geo- 
ke distribution, and leaving for another opportunity the 
Iscussion concerning the nature of its vegetation and the spe- 
cific and generic value of its representatives. : | 
* 
entitled, Electromagnets and Magnetic adhesion, and accordingly treats of electro- 
have also to make known a great number of new facts respecting the laws and 
Eecwtics of electro-magnets, to say nothing of what we wrote upon this point in 
98 (v. Am, Jour, [2] vol. xv, p. 881, and vol, xx, p. 100). 3. N, 
