SELF-PACKING VULCANITE APPARATUS. 307 



the time requisite for each. [Mr. Dewar pro- 

 ceeded to heat the apparatus, by connecting it by 

 means of an elastic tube with a small copper boiler, 

 placed over a suitable gas-burner, preparatory to 

 demonstrating the process which he was explain- 

 ing to the meeting. The apparatus was a very 

 ingenious one, and excited considerable admira- 

 tion amongst the members present.] We ascer- 

 tain that the flask is sufficiently packed by the 

 rubber showing itself at the two side gates. There 

 is one point of interest here which is worthy of 

 attention. The first case which I succeeded 

 in packing was put into the machine to be vul- 

 canized ; on taking it out, after giving it the usual 

 time, I found a long worm coming out of each side 

 from either gate. I consequently feared I should 

 find a cavern, as it were, in the rubber ; so much 

 of it had come out of the gates that I presumed 

 the case must be hollow. On opening it, how- 

 ever, I found it perfectly solid, thereby showing 

 either that I had put in more rubber than was 

 required, or had put it in so condensed a state, 

 that in heating it, it had expanded, packing its own 

 case, as it were, still more thoroughly, and the 

 superfluous rubber had escaped by these two 

 gates. In every subsequent case that I packed 

 by this process I have noticed a great density in 

 the rubber, and uniformity in its appearance; 

 there is no difference in any one portion of it from 

 any other. A question may be asked. Do we get 



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