TEREDO. 148 



it would keep out the fry. He especially noticed a 

 balsam of wonderful virtue^ and kept a secret, which was 

 patronized by Peter the Great. Possibly this was the 

 resin now extracted by the Cochin Chinese from a gi- 

 gantic tree called "cay-dan/^ and lately noticed by 

 M. Mariot, a lieutenant in the French navy. Native 

 canoes, hollowed out from the trunks of this kind of 

 tree, are said never to be worm-eaten. Among other 

 means of protection that had been long in use and 

 were still in vogue in his day, were the following : — for 

 ships, an inner layer of calf-skins, cow-hair, pounded 

 glass, ashes, glue, chalk, moss, or charcoal ; for piles, 

 large iron nails driven in close together ; and for both, 

 hard and close-grained woods. By the first of these 

 methods, however (which is still partially made use of 

 by the Turks and Arabs in the Mediterranean) , the 

 ship^s course was apt to be retarded; and the latter 

 remedy was expensive and not always efiicacious. He 

 said that the application of pitch or coal tar to the sur- 

 face of the wood had been recommended by a Londoner 

 of some repute. We find in the ' Philosophical Trans- 

 actions ^ for 1666 an announcement by an anonymous 

 writer that " a very worthy person in London suggests 

 the pitch, drawn out of sea- coals, for a good remedy to 

 scare away these noisome insects." The late Lord 

 Dundonald little suspected that the boasted discovery 

 of his father had been so long forestalled. Nor did 

 Sellius overlook the patent, granted by Act of Parlia- 

 ment in the reign of Charles II. (1671) to Sir Philip 

 Howard and Major Watson for preserving the hulls of 

 ships from worms by a sheathing of lead mixed with 

 some other metal, a composition now superseded by 

 copper. The conclusion arrived at by Sellius was 

 that the surest remedy consisted in trying to propitiate 



