ON SUPERHEATED STEAM. 190 



The first mode is the one which has for the 

 most part been adopted, in some cases by cylin- 

 ders from the boiler, in others by side chambers, 

 and in others by top chambers to the boilers (the 

 vessels, as shown in the diagram Fig. 25, by Wright 

 and Fouche, would answer the purpose) ; and 

 most excellent results have been arrived at; but 

 the materials hardened or vulcanized are generally 

 in substance, and not with solutions, when done 

 in this way. When in woven fabrics and with 

 thin layers of rubber, then the mode adopted for 

 vulcanizing is generally by ovens, or dry heat, as 

 it is termed. One advantage of the dry heat 

 insisted upon by some persons, is the power of 

 continuously vulcanizing, as trays of paste or 

 cakes are continuously baked, by putting in and 

 taking out all day, without any unscrewing lids, 

 &c. For neither of these modes, as a principle, 

 can a patent exist, as both have been used and 

 described for more than thirty years. Patents for 

 either the one or other must be for a particular 

 kind of apparatus only. The third mode of 

 hardening and vulcanizing is by superheated or 

 sub-saturated steam. The principle of this is 

 patented by myself. The form of apparatus, 

 which is before you (Fig. 26), and which is called 

 " Childs' Vulcanizer," I must, with your per- 

 mission, now allude to. That it bears my name 

 will arm you against over-estimating what I say 

 of it; but as it contains a new and novel applica- 



