improved Syphons. 317 



into the naphtha, the cock is opened till the hydrogen begins to es- 

 cape in bubbles. The escape of the bubbles is kept up to prevent 

 the naphtha from entering the tube, and to evacuate the bag. Before 

 this is quite accomplished, the orifice of the tube is to be approxima- 

 ted to the surface of the potassium as nearly as possible without en- 

 tering it, and just as the last of the gas is expelled, is to be merged 

 in the metal. The cock is at the same time to be closed, and the 

 pressure of the hand on the bag discontinued. The cock being in 

 the next place very cautiously opened, the elasticity of the bag coun- 

 teracts the pressure of the atmosphere within the tube ; and the li- 

 quid potassium is forced to rise into it. This effect may be controll- 

 ed by the cock, which is to be closed when the column of the metal 

 has attained a satisfactory height. After being removed, cooled and 

 separated from the cock, the tube may be closed by a covering of 

 sheet gum-elastic, such as is procured by the inflation of bags soften- 

 ed by ether. Any portion of the contents thus preserved may be 

 extricated by cutting off and fracturing a portion of the tube, ade- 

 quate to yield the requisite quantity. 



In order to guard against accidents the apparatus was heated in 

 this process by a bath of naptha ; in a bath of hot water. For the 

 object last mentioned, the vessels ordinarily used for the solution of 

 glue were employed, the naphtha being placed in the inner vessel usu- 

 ally occupied by the glue. 



I have long been in the practice of filling tubes with phosphorus by 

 a similar process. 



Art. XIII. — Improved Syphons ; by R. Hare, M. D. Professor of 



Chemistry in the University of Pennsylvania. 



Subjoined are engravings of two Syphons, which I have found use- 

 ful in my laboratory. Of these, one represents the more complete 

 method of execution; the other, that which can be more easily 

 resorted to by Chemists in general, who have not easy access to skil- 

 ful workmen. 



The construction last alluded to, is represented by fig. 1. A cork 

 is perforated in two places parallel to the axis. Through one of the 

 perforations, the longer leg of the syphon passes : into the other, one 

 end of a small lead tube is inserted. In order to support this tube, it 

 is wound about the syphon until it approaches the summit, where a 



Vol. XXIV.— No. 2. 41 



