548 PHILOSOPHICAL TRANSACTIONS. [anNO 1721. 



which tow, are subject to the inconveniencies of the common way of towing, 

 by losing two thirds of the time; and besides, they cannot act all together: 

 and the vessel that is towed, pulling them back after the oar has made its 

 stroke, they have so much of the space to regain by the next stroke. Besides, 

 the cable by which they tow, sinking into the water by its own gravity, the 

 resistance the water makes to its return, is to be overbalanced ; all which cir- 

 cumstances together considerably diminish the towing force. 



M. de Chazelles might have added, that the chaloups that tow, are in close 

 fight liable to be sunk by the enemy's cannon, and are exposed to the waves by 

 having so little height above water. 



M. Arnoult was ordered to examine the new oars; and he made his report 

 to the court, that the officers of the galleys found, that they interfered with 

 the use of the sails in a galley, but might be of use in other vessels and bomb- 

 ketches. 



Part of a Letter from the Rev. Mr. Rowlands^ to the Rev. Mr. Derham, F.R.S, 

 Concerning the stocking of the River Mene with Oysters. N° 36g, p. 250. 



The river Mene, that divides Anglesea from Caernarvonshire, has at present 

 the bottom of its channel, for some miles in length, all bedded with good 

 oysters, in such plenty, that in the season several boats are daily employed to 

 dredge them up, and have done so these 8 or 9 years last past, to their great 

 profit; but what I recommend as observable, is, that about 24 years ago, we 

 have good assurance that there were none to be found on that bottom : but that 

 a gentleman about that time, caused 3 or 400 large oysters to be dropped into 

 the channel, just under his land; from the spat or seed of which, it is most 

 probable, the flux and reflux of tides dispersing it, all the bottom at length, 

 where small stones and a large cultch received the sperm, became covered with 

 oysters. And what favours this conjecture that they are a brood of oysters begun 

 at that time, is, that at the first finding, they appeared young and small, but 

 have since yearly increased in bulk and plenty, though prodigious quantities of 

 them have been taken up. 



END OP VOLUME THIRTY-FIRST OF THE ORIGINAL. 



