62 Nofives respecting A'nt' Books. 



product, a gas is also expected and required to be collected, the 



^-^ ^^ ^ tube may have the accompanying 



/^^^^^^::^^y^ '°^*^IS^**--^'^ form given to it. If it be required 

 ^^^^^^:r!^ to distil the first product a se- 

 cond time for its further purification, it should at first be distilled 

 into a receiver of the second form, and that operation finished, the 

 retort is to be removed, a small flame applied by the blow-pipe to 

 the narrow part of the receiver at a, which when soft is to be 



drawn out and sealed hermeti- 

 cally. The second rectification 

 is to be made either by applying 

 heat to i, and placing another 

 receiver at c ; or by turning the 

 tube into the position it would take if this page were inverted, ap- 

 plying heat at a, and distilling into the bend at d. 



" A very convenient vessel, answering the purpose both of receiver 

 and bottle, may be made of tube. For this purpose a piece of tube 

 about the third of an inch in diameter, four inches long, and sealed 

 at one end, is to be softened in a flame at about an inch from the 

 open extremity, and when uniformly heated all round, it is to be 

 removed from the flame and drawn out, so as to form a long nar- 

 row neck. The substance to be distilled into it, such as sulphu- 

 rous acid, or chloride of phosphorus, is to be conducted by a fine 

 tube, similar to that already described, which is to terminate the 

 distillatory apparatus, being either drawn out upon the end of the 

 retort or joined with it by a caoutchouc connecter. When suffi- 

 cient fluid has been distilled into the receiver, the capillary neck of 

 the distillatory apparatus should be withdrawn, the 

 tube softened about a by a small flame and drawn 

 off, so as to leave the termination there with a fine 

 aperture ; then it is to be softened again at b, and 

 bent as in the second figure. The aperture at c is 

 easily closed by holding it for a moment in the edge 

 of a flame, and the contents of the vessel, however 

 valuable they may be, are securely retained. When 

 a portion is wanted for experiment, the extreme 

 point should be nipped off so as to make an aper- 

 ture, and the tube should be inclined until h be- 

 comes the highest part ; so much of the fluid as 

 may be required should be thrown by a little agi- 

 tation into the neck about b, where it will remain in 

 a short column ; but by applying the hand to the thicker part of 

 the tube, the air will expand andforce out the fluid in the neck, on 

 to any spot to which the aperture at c may have been directed. In 

 this manner the smallest quantity of the fluid, or the whole, may be 

 used at once ; and enough having been removed, the tube is again 

 to be placed in a more upright position, its extremity sealed, and 

 the whole put aside until again wanted. 



" These receivers are very useful for retaining valuable and^vola- 

 tile fluids, and are the best that can be used for such bodies as sul- 

 phurous acid. If that substance be confined in ordinary bottles, a 



great 



.0 



