346 Chemical Contributions. 



The beak of a broken retort, of a suitable size, is ground with em- 

 ery into one of the necks, till it is found to be perfectly air tight, and 

 reaches very nearly to the bottom of the bottle. The part project- 

 ing above, is cut oiF with a hot iron, at a small distance above the 

 nozle.* The lower end is then closed by means of the blow-pipe ; 

 or when it is so thick as to render this method inconvenient, it is 

 filled with a glass plug ; the lower or round part of the stopper of a 

 tincture bottle or retort, (and such articles are apt to accumulate in ev- 

 ery laboratory) of a suitable size, is cemented with sealing wax to the 

 end of a glass or wooden rod, and ground into the tube with emery, 

 till it fits it accurately, and is nearly at its lower extremity, (&, fig. 1.) 

 the grinding being from the larger towards the smaller part, that 

 there may be no danger of its falling out. A hole is now cut with a 

 round file in its side, (an operation that is soon finished ; and if the 

 file be kept wet during the process, it will answer a great number of 

 times) so as to be just within the botde, wdien the tube is put into its 

 place, (a, fig. 1.) All that is now necessary, is to pass the stem of 

 a small funnel — the stem itself being five or six inches long, through 

 a cork : insert the cork into the upper end of the tube, and intro- 

 duce the tube into the nozle of the bottle. f The funnel itself may 



* Mr. Faraday has devoted four pages of his recent work on chemical manipulation, 

 to an account of the methods of cutting glass with a hot iron. Kis directions are val- 

 uable to the young chemist, because they are drawn out into that minuteness of de- 

 tail, which alone can make them of any use ; and yet he has omitted one precau- 

 tion, which I have found important in cutting large tubes, vials, etc. — that of not 

 making the iron too hot. It should be heated to a redness barely visible in day light. 

 If in this state, it be caused to vibrate a few times around the tube, along the track 

 where the division is to be made, and a drop of water put upon the spot, a simple 

 fracture, without side Jlaws, will be obtained. By pursuing this method, especially 

 if a trace be made beforehand, with a hie, a long tube may be cut up into sound, 

 well defined, and nariow rings, without a single instonce of failure. 



t Instead of making the cork apply itself directly to the side of the oriiice that is to 

 be closed, I have found it of advantage, not only in this case, but in many other sim- 

 ilar ones — in fitting in the tube that is to convey away the gas from the other nozle ; 

 for instance, to cut a glass jacket for the coik which is made to enter by grinding. 



A large tapering glass tube, such as (he beak of a retort, is cut with a hot iron, at 



a point where it is not greater — where it is perhaps a little less, than the orifice to 



11 be closed ; and the larger part is cut a .second time, at the distance 



?of two or three inches from its smaller end ; forming, in fact, a ta- 

 pering lube, two or three inches in length, and having the diame- 

 ter of its larger end a little greater than that of the orifice. This is 

 easily ground into the opening, so as to fit it accurately, and make 

 it perfectly tight. A coiK, consideral>ly shorter than Ihc tube, is lit- 



