540 American Philosophical Society. 



below the water, when at a somewhat less distance from the bell, 

 were unable to hear its sound. 



On the 24th of August, the vessel having proceeded to the Gulf- 

 stream, experiments were made with the view for which the voyage 

 was undertaken ; that is, to ascertain whether an echo would be 

 returned through water from the bottom of the sea. Some diffi- 

 culties were at first presented in exploding the gun under water, 

 but these were at length overcome. The hearing-tube was bal- 

 lasted so as to sink vertically in the water. The observers then 

 went with this instrument to a distance of about 150 yards from the 

 vessel, and the petard was lowered over the stern, about three 

 fathoms under water, and fired. The sound of the explosion, as 

 heard by Mr. Bonnycastle, was two sharp distinct taps, at an in- 

 terval of about one-third of a second. Two sounds with the same 

 interval were also clearly heard on board the brig ; but the charac- 

 ter of the sounds was different, and each was accompanied by a 

 slight shock. Supposing the second sound to be the echo of the 

 first from the bottom of the sea, the depth should have been about 

 160 fathoms. 



To ascertain the real depth, the sounding was made by the or- 

 dinary method, but with a lead of 7.5 pounds weight; and bottom 

 was distinctly felt at 550 fathoms, or five furlongs. The second 

 sound could not, therefore, have been the echo of the first ; and 

 this was proved on the following day, by repeating the experiment 

 in four fathoms water, when the double sound was heard as before, 

 and with the same interval. 



The conclusion from these experiments is, either that an echo 

 cannot be heard from the bottom of the sea, or that some more ef- 

 fectual means of producing it must be employed. 



Oct. 5, 1838. — The Committee on the solar eclipse of the 18th of 

 September, made a further Report in part. 



This portion of the report embraced the observations made in the 

 vicinity of Philadelphia, of which the following are the principal 

 results, arranged in the order in which they were received, and with 

 one exception, in mean time of the place of observation ; the longi- 

 tudes being reckoned from Greenwich. 



No. 16. by Robert Treat Paine, Esq., at the west front of the 

 Capitol, Washington. Latitude 38° 53' 23", as determined by Mr. 

 Paine with his Troughton's sextant. Longitude 5h. 8m. 8s. west. 

 With 3i feet equatorial, green screen glass. Time by three chrono- 

 meters, regulated by eastern and western altitudes of sun and stars 

 with his Troughton's sextant. 



Beginning 3" 6'" 9^-58 



Formation of ring 4 24 28-15 



Rupture of ring 4 30 18-55 



End 5 39 54 -89 



Duration of eclipse 2 33 45 -31 



Do. of ring 5 50 -40 



" ITie ring formed instantaneously, and broke nearly so. No 

 beads were seen, nor the dark lines mentioned by Mr. Baily, nor 



