Proceedings of Scientific Societies. 381 
The two curves thus presented agreed remarkably in all their general 
features, showing, as a general’ result, similar motions of the needle at the 
two places in direction, though not always proportional in amount. They 
presented remarkable differences in the absolute times at which these 
movements had taken place at the two stations, the similar movements 
differing frequently five minutes, (with opposite signs,) and in a few cases 
as much as ten minutes in time; in other cases being simultaneous. The 
period at which the needle had attained, suddenly, its greatest deviation 
from the true meridian, was ten minutes earlier in absolute time at Cam- 
bridge, than at Philadelphia. py ‘ - 2 
- Demmé referred to the contents of a circular letter from Germany, 
in which it was stated, that a number of gentlemen of Stuttgart had uni- 
ted, under the name “ Societas Bibliophilorum Stuttgartie,” to publish 
historical and antiquarian works, which are either out of print, or have 
never been printed. 
The society at Stuttgart will begin to publish as soon as they have pro- 
cured five hundred subscribers, The subscription is one pound sterling, 
for which the subscriber will receive one copy; and no more copies will 
be printed than are subscribed for. ; ss: 
Dec. 18.—T he committee, consisting of Dr. Patterson, Prof. Bache, and 
Mr. Lukens, to whom was referred the commutication of Prof. Henry, 
entitled ‘‘ Contributions to electricity, No. IV., on electro-dynamic induc- 
tion,” reported in favor of publication, which was directed -accordingly.* 
The committee, consisting of Mr. Nuttall, Mr. Lea, and Dr. Coates, to 
whom was referred a communication by Miss Margaretta H. Morris, on 
the Cecidomyia Destructor or Hessian Fly, reported in favor of publica- 
_ Yon, which was ordered accordingly. 
y ; ra 
The committee express the opinion, that should the observations of Miss 
- Morris be ultimately proved correct, they will eventuate in considerable 
benefit to the agricultural community, and, through it, to the public. 
Miss Morris believes she has established, that the ovum of this destructive 
insect is deposited by the parent in the seed of the wheat, and not, as pre- 
Viousl y supposed, in the stalk or culm. She has watched the progress of 
the animal since June, 1836, and has satisfied herself that she has fre- 
quently seen the larva within the seed. She has.also detected the larva, 
at various stages of its progress, from the seed to between the body of the 
Stalk and the sheath of the leaves. In the latter situation it passes into 
the pupa or “‘ flaxseed state.” According to the observations of Miss Mor- 
Tis, the recently hatched larva penetrates to the centre of the straw, where 
it may be found of a pale greenish-white semi-transparent appearance, in 
form somewhat resembling a silk-worm. From one to six of these have 
ee, 
* We omit the abstract of this paper, as it will appear in full in this Journal. 
Vol. xz, No. 2.-—Jan.-March, 1841. : 
