OF ARTS AND SCIENCES. 265 



mens which he exhibited to the Academy. He also, in reply 

 to inquiries proposed by Professor Henry B. Rogers, stated the 

 result of his observations in regard to the different depths in- 

 habited by Echinoderms in the ocean. 



Three hundred and forty-seventh meeting. 



May 6, 1851. — Monthly Meeting. 



The President in the chair. 



Mr. Everett read a part of a letter from Sir John Herschel, 

 expressing a high opinion of the power of the astronomical 

 telescope belonging to the Cambridge Observatory, and of Mr. 

 Bond as a skilful observer ; and ascribing to him priority in 

 the discovery of the new ring of Saturn. 



Mr. Guyot gave an account of some recent discoveries re- 

 lating to the geography of the interior of Africa, and ex- 

 pressed his views at considerable length in regard to the gen- 

 eral configuration of the African continent. Remarks upon 

 the same subjecf were made by the President, Mr. Everett, 

 Judge Shaw, Professor Horsford, and Professor Caswell. Mr. 

 Guyot presented to the Academy a pamphlet in the German 

 language by C. Ritter, relating to the same matter. 



Dr. W. F, Channing offered some remarks respecting Fou- 

 cault's pendulum experiment, and suggested the idea of sup- 

 porting the pendulum b^r magnetic attraction or upon an agate 

 in an exhausted receiver, as a means of obviating the effects 

 of friction and the resistance of the air. 



Mr. J. H. Abbot communicated and explained the results 

 of a new experiment in Hydraulics. He stated that, — while 

 water flowing from a cistern through a straight, horizontal, 

 cylindrical tube, escapes, if small lateral holes are made in it, 

 through those holes in jets, contrary to a proposition laid down 

 by Bossut, — the opposite effect takes place, if the end of the 

 tube is made conically divergent, and small glass tubes de- 

 scend from the holes into vessels containing water. In this 

 case, water ascends and is discharged into the horizontal tube, 



VOL. II. 34 



