AS APPLIED TO DENTISTRY. 145 



The result of my visit to London, in 1857, only 

 made the fact more evident, that dentists must 

 have in their own workshops a small and con- 

 venient apparatus, or that the public must be 

 debarred from enjoying the benefits of the system. 



Members of this Society will remember the 

 promise I made on the eve of my departure from 

 England, to return again in 1858, with an appa- 

 ratus so perfected as to meet their demands ; and 

 they are now my censors if I have not done so. 



To answer many inquiries relative to the use 

 of dry heat for vulcanizing, I give (by your per- 

 mission) a synopsis of some experiments made 

 immediately after my return to New York from 

 London, in October, 1857. 



I first constructed two cylinders of sheet iron, 

 one within the other (a model of which I present). 

 A cover upon the small cylinder, in which a ther- 

 mometer was arranged. 



The flasks containing the work were put into 

 the inner cylinder and surrounded with asbestos 

 to make the heat even. Sand and pulverized 

 soap-stone were also used for the same end. 



That some moisture might be constantly sur- 

 rounding the work, a reservoir of water was 

 formed upon the top, with an aperture at the 

 bottom to allow a steady supply to a coil of pipe 

 or worm placed over the gas flame. 



The coil of pipe was kept constantly red hot, 

 and the water forced throusrh it into the small 



