308 SELF-PACKING VULCANITE APPARATUS. 



rid of all the wax ? I admit that there is still 

 an appreciable quantity of wax left in the flask, 

 but it has no bad efiFect upon the rubber. What 

 effect it might have when other than steam 

 apparatus is used in vulcanizing I cannot say; 

 but in using the steam process the vulcanite comes 

 out as perfectly where the plaster has absorbed 

 a considerable quantity of wax, as where great 

 care has been taken to render the plaster per- 

 fectly free from wax. Although steam is used 

 here it is simply for heating the rubber suffi- 

 ciently to cause it to soften somewhat to the 

 consistency of plastic sealing-wax. We never 

 get the rubber into a fluid state, it is simply 

 reduced to a plastic condition. [Mr. Dewar here 

 fixed the case on to the cylinder, which was 

 kept filled with steam, and proceeded to manipu- 

 late. After a short interval he succeeded in the 

 operation, and the case was sent round the room for 

 inspection.] 



He proceeded to observe : — I have succeeded in 

 packing with another form .of machine. The 

 model was so exceedingly rough that it would 

 hardly bear your inspection — it was merely the 

 model for a model ; however, I had a sketch made 

 of it, which I have much pleasure in showing to 

 the meeting. [The sketch was handed to the 

 members for inspection.] It is, you will see, 

 somewhat of an Archimedian screw revolving in a 

 cylinder — in fact, something like a sausage ma- 



