i W Harems Compound Blowpipe hy Alcohol 



surround them. In this way, the conductors are eflfectually 

 insulated, while the principal strain is borne by the wood- 

 en axes. 



I consider this mode of mounting an electrical plate pre- 

 ferable to any with which I am acquainted. The friction 

 arising from the band may render the working of the ma- 

 chine a little harder for one person, with one hand; but 

 then it affords the advantage, that two persons may be em- 

 ployed for this purpose, or one may use both hands at once. 

 The intervention of the band, secures the plate from being 

 cracked, by a hasty effort to put it into motion, when ad- 

 hering to the cushions, as it does at times ; and the 

 screws, by means of which the distance of the wheels is 

 increased, obviate the liability of the band to slacken with 

 wear. 



Art. XIV. — Description of an improved Blowpipe hy Alco- 

 hol^ in zohich the inflammation is sustained by opposing 

 jets of vapour, without a lamp : Also, of the means of ren- 

 dering the flame of Alcohol competent for the purpose of 

 Illumination. Illustrated by an Engraving. By Rob- 

 ert Hare, M. D. Professor of Chemistry in the Univer- 

 sity of Pennsylvania. 



In the ordinary construction of the blowpipe by alcohol, 

 the inflammation is kept up, by passing a jet of alcoholic 

 steam through the flame of a lamp, supported, as is usual, 

 by a wick — otherwise, the inflammation of the vapour does 

 not proceed with sufficient rapidity, to prevent the inflamed 

 portion from being carried too far from the orifice of the 

 pipe; and being so much cooled by an admixture of air, as 

 to be extinguished. By using two jets of vapour in oppo- 

 sition to each other, I find the inflammation may be sustain- 

 ed without a lamp. If one part of oil of turpentine, with 

 seven of alcohol, be used, the flame becomes very lu- 

 minous. 



In order to equalize and regulate the efflux, I have con- 

 trived a boiler, like a gasometer. It consists of two con- 

 centric cylinders, opening upwards, leaving an interstice of 

 about one quarter of an inch between them ; and a third cy- 

 linder, opening downwards, which slides up and down in 

 the interstice. The interstice being filled with boiling wa- 



