

373 GOODYEAR ON GUM-ELASTIC. 



preserve fruits and other perishable articles from decay. For 

 this use the air must be exhausted from them by means of an air- 

 pump, a tube being attached to them for this purpose. An iron 

 rim is also attached to the mouth of each part of the envelope, 

 one or both of which has a soft gum-elastic packing cemented 

 upon the edge of it. When the contents are of such a kind as 

 to be liable to injury, from atmospheric or other pressure from 

 without the envelope, it becomes necessary to keep off this pres- 

 sure, by first placing the contents in a strong box or barrel, or 

 they may be protected by an iron frame within the envelope. 

 See plate fig. 



IMPROVED FRUIT PACKAGE ENVELOPE. 



This is made for the same use as the one above described, and 

 in the same way, except that the package is made to fold like self- 

 inflating air work, and is so constructed as to keep pressure 

 off the contents by means of rims or discs of iron or whalebone 

 board cemented in between the section, and by supports or 

 braces, which prevent the envelope from collapsing in the other 

 direction. See plate , fig. . 



PORTABLE BOATS AND PONTONS. 



Boats were among the first things that were attempted to be 

 made of India rubber, not only in the United States, but also 

 in Europe. But so far as the writer can ascertain, the experi- 

 ments for this purpose have been chiefly confined to bags of 

 air of various forms. Among these may be noticed the pon- 

 ton made first for the United States Government, by the Rox- 

 bury Company, in 1836, of unvulcanized gum-elastic, and a con- 

 siderable number made of vulcanized gum-elastic in 1847, which 





