366 GOODYEAR ON GUM-ELASTIC. 



which it is inflated with air, although when vulcanized on forms 

 they retain their shape so as to be self-inflated sufficiently for 

 safety. 



They are manufactured from a variety of the gum-elastic 

 fabrics combined. See plate , figs. 



DOUBLE LIFE-PRESERVING TRAVELING BAGS. 



This bag is constructed from two bags of very nearly the 

 same pattern as the one last described. The two are united 

 together at the bottom, and are laced or buckled at the sides, as 

 represented, plate , figs. ; each bag is made air-tight by 



a separate slide. When laced together, a third compartment is 

 formed for the reception of coarse articles, boots, shoes, &c. 

 When unlaced, it may be used as a life-preserver, and is the 

 most convenient article of this sort for holding one up in the 

 water. 



LIFE-PRESERVING EXPANSION TRUNKS AND VALISES. 



These are manufactured in the same manner as the expansion 

 trunks and valises described in Chapter XXVIII. A spring of 

 elastic compound is inserted in the straps, by the elasticity of 

 which the two parts of the trunk are drawn together, and the 

 trunk made water and air-tight by compression against the 

 sponge in the top of the lid. 



