BEDSTEAD CASTORS AND SHOES. 281 



UMBRELLA FRAMES. 



Some recent experiments in the manufacture of umbrella 

 frames from India rubber whalebone and ivory, give the writer 

 assurance that this is a valuable application of this substance. 

 An improvement is contemplated, and practically tested, so far 

 as to make specimens of umbrella frames, by making use of gum- 

 elastic in all the parts. The very great difficulty of making sub- 

 stantial joints with such slight materials as the frame of an um- 

 brella is made of, must be apparent to all. The extremely low 

 price of this description of work, will hardly allow the manufac- 

 turer to make them as carefully as they might be made. It 

 would not be possible to make them so that they would not easily 

 break or get out of repair, after the rivets and joints become 

 rusty. The experience of almost every one has taught them, 

 that loss and annoyance is the frequent consequence of these 

 defects. 



An improved umbrella is made by the use of caoutchouc 

 whalebone instead of whalebone for the bows, elastic compound 

 for the joints instead of wire and metal, India rubber fabrics for 

 the covers, and gum-elastic ivory for the sticks. 



BEDSTEAD CASTORS AND SHOES. 



The metal part of these castors is made of the common form, 

 with the difference that the wheel has a groove, into which a 

 ring or tire of elastic compound is fitted, as represented in the 

 plate , fig. . Shoes are also made for bedsteads, like the 

 chair shoes hereafter described. The design of both the above 

 articles is to prevent noise and the wear of carpets. 



