Proceedmgs 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. 



Dr. Demme 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 Stuttgartiae," 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. 



Dec. 18. — The committee, consisting of Dr. Patterson, Prof Bache, and 

 Mr. Lukens, to whom was referred the communication 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- 

 tion, which was ordered accordingly. 



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- 

 viously 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- 

 ris, the recently hatched larva penetrates to the centre of the straw, where 

 it may be found of a pale greienish-white semi-transparent appearance, in 

 form somewhat resembling a silk-worm. From one to six of these have 



* We omit the abstract of tliis paper, as it will appear in full in this Journal. 

 Vol. XL, No. 2.~Jan.-March, 1841. 49 



