148 ON THE VULCANITE BASE 



drawing, which was thereupon deposited in the 

 Patent Office, is now before you. 



I soon found, however, that the apparatus 

 was sufficiently perfect to satisfy all demands 

 for dentistry, without the self-regulating attach- 

 ment, and consequently it has been left off en- 

 tirely. 



So many of your members are now familiar 

 with the working of this apparatus, that I need 

 not detain you Avith the details of its description. 



I state, however, that its small capacity gives 

 great facility and safety in its use, and that in 

 vulcanizing, the pressure required is only about 

 sixty-six pounds to the square inch ; also that it 

 is, I believe, the opinion of all engineers, that 

 pressure on a square inch by steam is the same, 

 in all respects, as leverage pressure ; therefore, as 

 steam pressure is equal in all parts of a cylinder 

 containing it, we have only to consider its capa- 

 city, and then the strength of the cylinder itself. 

 For instance, steam with a pressure of 200 

 pounds or more to the square inch, may be used 

 with safety in a very thin pipe of one inch dia- 

 meter, from the fact, that the capacity is so small, 

 very little force is exerted upon it. 



Machines which I have been permitted to in- 

 troduce to your notice have been subjected to a 

 pressure of over 200 pounds to the square inch, 

 and the manufacturer informs me that they can 



