AS API'LIKl) TO DENTISTRY. 147 



Work might appear and look as well as though 

 steam had been employed, yet it was invariably 

 destitute of the requisite solidity and strength. 



If the plaster moulds were first dried, then the 

 piece would be uniformly burned or porous ; if 

 not dry, then the inner part of the piece was not 

 in the least hardened, while the outer edges were 

 burned to a crisp. 



Such was my experience in all forms of dry 

 heat ; and it would be interesting to know what 

 success has been obtained by others in this espe- 

 cial point. 



In January, 1858, I constructed a steam appa- 

 ratus, to work automatically, viz., self-circulating 

 and self -regulating, — the greatest diameter 12 

 inches, and length 40 inches. 



It was soon successfully put into operation in 

 the presence of the late Professor Townsend (of 

 whom many of you,' no doubt, have pleasant recol- 

 lections) and Professor Austin, of the Baltimore 

 College of Dental Surgery ; eifecting in two hours 

 better results than were produced by my first 

 extensive steam apparatus in three hours, and 

 which the ponderous machine of Goodyear' s could 

 scarcely accomplish in twelve. 



The gentlemen just alluded to (though gene- 

 rally adverse to patents) urged me to patent 

 what seemed to them so useful, convenient, and 

 novel an invention, and a copy of the original 



L 2 



