258 GOODYEAR ON GUM-ELASTIC. 



make them, as may be seen by any one who has an opportunity 

 to examine the internal construction of a bed, or cushion, of the 

 common kind. The odor of the goods, and their being uncom- 

 fortably warm, have presented, in addition to the cost, the 

 great objections to their use. 



By the use of the gum-elastic tube, which is cemented in so 

 as to form part and parcel of the article, the danger of leakage in 

 that part is completely removed ; and in the ventilated air- work, 

 the objection of warmth is wholly removed. By the new 

 method of manufacture by machinery, in the use of the laminated 

 fibrous fabrics, an entire change in the manufacture of air- work 

 is anticipated. The peculiar properties of these fabrics, and 

 method of manufacture alluded to, lead to the conclusion that 

 cheaper and better articles will be produced. And it may be 

 hoped that in consequence of the improvements here noticed, 

 and the reduction of the cost of the articles, they will eventually 

 come into as general use as was at first anticipated. 



The mechanical construction of air-work is chiefly of three 

 kinds. That which was first made, and was one of the earliest 

 manufactures of gum-elastic ; ventilated air- work, which has 

 been described. Vol. I., page , and the self-inflating air- work, 

 described as follows : 



SELF-INFLATING AIR-WORK. 



This is a style of work, some specimens of which were made 

 by the writer as early as 1838, but it could not then be made to 

 any advantage, in consequence of the gum peeling off" the woven 

 cloths, and causing the compartments to pull apart, and owing 

 to their want of suflftcient firmness. In consequence of the 

 improvements described in this work, it is believed that this class 

 of air- work may now be made with advantage. 



It is somewhat more expensive and difficult to manufacture 

 than other kinds of air- work described in this chapter, but it is 



