120 GOODYEAR ON GUM -ELASTIC. 



HYDRAULIC PRESSES. 



Gum-elastic compound felt and vegetable leather, are now 

 being successfully applied for hydraulic rams, presses, &c., as 

 a substitute for animal leather. Those who are acquainted with 

 the properties of these fabrics, will not require for them any 

 recommendation for such uses. 



FORCE PUMPS. 



The plan ol this article, answering to the diagram in plate , 

 fig. , to be made of caoutchouc, was given by another.* 

 This pump has not yet been applied to use, but it is obvious 

 that the great objection which exists in all mechanism, and 

 particularly in pumps, that of friction, is, in this case, almost 

 entirely removed, and in other respects it would appear that 

 this fabric must answer a good purpose for force pumps. 



WATER-WHEELS. 



These are made on the same plan as elevators before 

 described. They have not yet been practically applied to use, 

 but certain inferences may be drawn with regard to their utility, 

 from what is known from the use of the iron chain wheel, which 

 is operated on the same principle ; they may be built at so 

 great a reduction of cost, in comparison with other wheels, 

 that the invention appears to the writer to be an important one, 

 especially when it is considered that the size of all other wheels 

 is limited, and that these may be built of any height, to that of a 

 hundred feet or more; consequently, a large power might be 



* Mr. Edwin M. Chaffee, Rozbury, Mass. 



