Institution of Civil Engineers. 527 



the slightest avail in the Tropics, and vice versa ; it was thus ques- 

 tioned whether any generally applicable principle could be found for 

 the counteracting of that universal solvent of soluble matter. 



The conclusions arrived at were, that the ravages of the marine 

 worm were not prevented by any chemical application, and that 

 nothing but mechanical means could ever prove completely success- 

 ful : studding with broad-headed nails was considered to be the most 

 effectual remedy, and various authorities were quoted, proving its 

 success. The paper concluded with a list of places where wood, 

 prepared with various chemical ingredients, had been destroyed from 

 various causes. 



The discussion commenced by the Dean of Westminster, chiefly 

 remarking on the analogous action of the Pholas on stone, was 

 announced for continuation at the next meeting. 



Dec. 4. — The discussion on Mr. Paton's paper extended to such 

 a length as to preclude the reading of any original communication. 

 Numerous specimens were exhibited, and commented on, of timber 

 thoroughly perforated by worms ; whilst beside them, under the same 

 circumstances, the " Jarrow wood" from Australia was shown to 

 have remained completely free from injury. The reference to the 

 age of Homer, as an instance of the ancient ravaging habits of the 

 Teredo, induced a return to geological questions ; and it was shown, 

 that in the London clay remains had repeatedly been found of 

 timber perforated by sea-worms. The oolite and greensand forma- 

 tions also exhibited petrified wood filled with boring moiluscae. 

 This led to the consideration of the formation most likely to with- 

 stand the attack of the Pholas ; and it was shown that the Portland 

 stone was, from the quantity of silica it contained, least liable to be 

 attacked. The Pholas was shown to have been in active operation 

 upon certain rocks from the earliest periods, but never upon Port- 

 land stone. Hence it was argued, that kind of stone should be used 

 for breakwaters and other works exposed to the action of the sea. 



The early state of the Teredo was noticed ; when escaping from 

 the egg, in the shape of a free swimmer, it was drifted about with 

 the tide until it met with a log, a pile, or the side of a ship, to which 

 it attached itself, and making an inroad into it, became a non- loco- 

 motive animal of different form and habits, never again to leave 

 the habitation it had burrowed for itself in the body of the timber. 

 The question, of whether the boring operation of the marine worms 

 was carried on by chemical or by mechanical means, was lengthily 

 discussed. The thin shell, covered by its delicate membrane, was 

 instanced as not possessing strength enough to cut away timber; 

 but it was on the other hand shown, that the shape of the two shells, 

 forming the extremity of the animal, admirably adapted them for 

 powerful cutting or rasping tools, when moved rapidly in a circular 

 direction, as was evidently the case, from the uniformly cylindrical 

 character of the holes. The shells of the Pholas were also shown to 

 be used in that manner, and the opinion appeared generally to lean 

 to a mechanical cause for the effects observed. This bearing of the 

 discussion naturally induced remarks upon the ravages of the white 



