162 GOODYEAR ON GUM-ELASTIC. 



of uniform strength, in which form it is vulcanized, which form 

 it retains with this advantage over any natural wood of the same 

 bulk or weight, that it is harder, more elastic, and firmer. See 

 plate , fig. 



WHALE-BOATS, YAWLS, JOLLY-BOATS, AND ROW-BOATS. 



All these various kinds of boats are made of the same mate- 

 rials, they are manufactured in the same way, and the same ad- 

 vantages appertain to them all in a greater or less degree, there- 

 fore the following description of the manner of their construc- 

 tion, with the plates, will serve to give an idea of the whole. 

 The gunwale knees and keel are made either of wood or iron, 

 and covered with thin whalebone board, or they are formed of 

 tubes made of thick whalebone board. They are cemented to 

 the boats after they are formed in the following manner : — The 

 sheets of vulcanized caoutchouc whalebone board being made 

 from one to two yards in width, and of any length desired, are 

 cemented together upon the outsides of a form or model of the 

 boat, in the same way as a shoe is formed upon a last, the keel 

 being cemented on afterwards. The boat is then taken off and 

 placed inside another form or mould of the same shape, when the 

 parts before described are cemented to it, the whole is then vul- 

 canized in the mould. See plate , figs. 



LONG-BOATS. 



Boats of large dimensions, and ships' long-boats, may be made ' 

 stronger of these materials by first forming the whalebone board 

 into tubes of from two to four inches in diameter, or of such 

 dimensions as are best suited to the size of the boat. When put 

 together, the tubes are shaped upon a model to the form of the 

 boat, and cemented together. They are also cemented to the 

 stem and stern pieces, each tube being made separately water- 



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