MAIL-BAGS. 351 



caps, ruffles, &c. ; also for a life-preserver, being made quite 

 impervious to air and water. 



The same form of bag, when made of heavier materials and 

 vulcanized upon a block or last, will keep its shape so as not to 

 require inflating with the tube. 



A convenient form of incompressible bag is made as repre- 

 sented by fig. , having the body of a trunk or box united with 

 the upper part or mouth of a bag. A similar article is made 

 with a box which shuts or folds like an accordion. See plate 

 , fig. . 



PORTMANTEAUS. 



Portmanteaus are manufactured of perforated gum-elastic 

 fabrics, in combination with those which are not perforated, as 

 represented by plate , fig. . 



SADDLE BAGS. 



These are manufactured of the same material as the portman- 

 teaus, and may be recommended on account of their water- 

 proof qualities and safety in fording rivers, particularly when 

 they are made water-tight at the mouth. See plate , fig. 



M A I L - B A G S . 



If there is any one purpose for which it is desirable to sub- 

 stitute gum-elastic for leather, on account of its water-proof 

 quality, it is for mail-bags. The value of their contents, and 

 their exposure to damage and loss by water, being generally 

 known and often commented upon, led many persons, at a very 

 early period, to suggest to the writer that this would be a useful 

 application of gum-elastic. 



On these accounts the first premature attempts to make mail- 

 bags, were made before the vulcanizing process was at all under- 

 stood or rendered practicable to any extent. 



?. 4 



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