41 



strument, 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 interval of about one-third of a 

 second. Two sounds, with the same interval, were also clearly 

 heard on board the brig ; but the character 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 ordi- 

 nary method, but with a lead of 75 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 

 fathom 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 effec- 

 tual means of producing it must be employed. 



Dr. Hare suggested the expediency of employing the Gal- 

 vanic fluid to fire gunpowder below the surface of water, in 

 experiments similar to those of Professor Bonnycastle. 



The President laid on the table for the inspection of the 

 members, an English and Japanese, and Japanese and English 

 Vocabulary, by the Rev. W. H. Medhurst, late of Batavia, now 

 in London, and a "Translation of a comparative Vocabulary 

 of the Chinese, Corean, and Japanese Languages, to which are 

 added the thousand Characters classic, in Chinese and Corean; 

 the whole accompanied by copious Indexes of all the Chinese 

 and English Words occurring in the Work," by the same author, 

 under the name of Philo-Sinensis. 



These two books, the President said, throw considerable 

 light on the various graphic systems of the Indo-Chinese 

 nations; they had been communicated to him by our associate, 

 Mr. Pickering, of Boston, to whom they must be returned: 

 he, therefore, recommended to the society to take measures to 

 procure them for the library. 



The recommendation of the President was then adopted, 

 and the books referred to, ordered by the society. 



