TEREDO. 143 



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 efficacious. 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 some other metal, a composition now superseded by 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 



