462 Dnj-Rot in Ships. — CartwrlglU's Pedo-motive Machine. 



must be instructed like children, who begin to make the first 

 efforts to articulate. 



M. Deleau informs us, that he is constructing an instrument, 

 which will afford the happy facility of finishing the operation in 

 three niiimtes, bv which its success will be rendered more certain. 

 By means of tiiis instrument he will raise on the tympanic n^em- 

 brane enough of sul)stance to prevent the necessity of introducing 

 probes into the perforation during from thirty to forty days, lie 

 is of opinion, that he can restore the hearing of all those who 

 have been deprived of it by the obstruction of the Eustachian 

 organ, and by the obesity of the membrane of the tympanum. 



DRY-KOT IN SHIPS. 



Col. Gibbs, of the United States, is of opinion, that the rea- 

 son why the dry-rot is so much more frequent now-a-days than 

 it was formerly, is, that in consequence of the great consumption 

 of wood during the last century, for naval and architectural pur- 

 poses, all the old wood has been consumed, and nothing is now 

 left for these purposes but comparatively young wood, in which 

 the alburnum bears a much greater proportion to the heart than 

 in old trees. He mentions some facts that have been stated to 

 him by Colonel Perkins, of Boston, and which seem entitled to 

 attention. Several ships built at Boston have been salted, or 

 filled in between the timbers with salt, while on the stocks, and 

 after the lapse of 10 or 15 years the timbers have in every case 

 been found to be perfectly sound. A large ship belonging to 

 Col. Perkins, which had been salted (14 years old), required re- 

 pairs, new decks, and new iron work. Considering the age of 

 the ship, it was important to examine the frame in every part. 

 The ceiling was therefore ripped up, and a complete examina- 

 tion took place. The result was, that the timber and plank were 

 found completely sound in every part. A vessel of .500 tons re- 

 quired 500 bushels of salt ; and two years after being built, 100 

 bushels were added to fill up the space of the salt dissolved. — 

 American Journal of Science and the ArlSy ii. 114. 



DR. CARTVVRIGHt's PEDO-MOTIVE MACHINK. 



In announcing th^ invention of this machine (sec Phil. Mag. 

 June 1819) Dr. Cartwright observed, '• 1 should not despair of 

 seeing, were I to live but a few years longer, carriages of every 

 description travelling the public road without the aid of horses." 

 The ingenious Doctor's expectation has been already in some 

 degree realised. A letter in The Star, signed " A Traveller," 

 states, that on the road between Tunbridge and Hastings he had 

 met a cart loaded with coals, and travelling without hordes, being 



im])ellcd 



