130 



SOURCES OF HEAT AND COLD. 



communication is preserved between it and the beak, by means of G 

 tube sliding through a stuffing box, C, which surmounts a larger tube 

 to which the beak is soldered."* 



4. A new modification of the Blowpipe by Alcohol. 



11 This figure represents an improv- 

 ed blowpipe, by alcohol. In the ordi- 

 nary construction of that instrument, 

 the inflammation is kept up, by pass- 

 ing a jet of alcoholic vapor through 

 the flame of a lamp, supported, as is 

 usual by a wick. The inflammation 

 of the jet cannot be sustained with- 

 out the heat of the lamp flame ; since 

 the combustion does not proceed with 

 sufficient rapidity to prevent the in- 

 flamed portion from being carried too 

 far from the orifice of the pipe ; and 

 being so much cooled by an admix- 

 ture of air, as to be extinguished. 

 By using two jets of vapor in opposi- 

 tion to each other, I find the inflam- 

 mation may be sustained without a 

 lamp. If one part of oil of turpen- 

 tine, with seven of alcohol be used, the 

 flame becomes as luminous as a gas 

 light." 



" In order to equalize and regulate 

 the efflux, I have contrived a boiler like a gasometer. It consists of 

 two concentric cylinders, open at top, leaving an interstice of about 

 one quarter of an inch between them ; and a third cylinder, open at 

 bottom, which slides up and down in the interstice. The interstice 

 being filled with boiling water, and alcohol introduced into the inner- 

 most cylinder, it soon boils and escapes by the pipes. These pass 

 through stuffing boxes in the bottom of the cylinder. Hence their 

 orifices, and of course the flame, may be made to approach to or re- 

 cede from the boiler. It must be obvious that the introduction of the 

 alcohol requires the temporary removal of the intermediate cylinder.'' 



* "Stuffing box is the technical name given by mechanics to a small hollow me- 

 tallic cylinder, in which, by means of another cylinder acted upon by screws, some 

 cotton, tow, leather, or other elastic substance, is packed about a rod, 50 as to allow 

 it to move to and fro without permitting any fluid to escape from the vessel into which 

 it may enter/" 



