Chemical Contributions. S47 



either be manufactured by grinding two or three glass rings together, 

 so that they will fit accurately one within the other, or obtained from 

 the glass-house. 



The mode of operation is obvious. We have a quantity of gran- 

 ulated zinc in the bottle. The dilute-acid is poured into the funnel, 

 passes down, and rises in the tube, till it reaches the orifice (a.) ; 

 when it flows over into the interior of die bottle. The gas can es- 

 cape through this nozle only by depressing the fluid in the tube quite 

 to its bottom, and thus creating a column in the stem of the funnel 

 five or six inches in height. 



The advantages of this construction are, 1. Its cheapness and sim- 

 plicity ; it is what every chemist can make for himself. 2. There is 



ted into it, so as to occupy its middle part, and leave a vacant space at both ends ; is 

 bored, and has the conducting tube passed through it, in the usual way. There is 

 then on each side of the cork, a vacant chamber, into which any kind of lute or ce- 

 ment, such as the fat lute, made by beating fine clay and drying oil together, may 

 be introduced under such circumstances, as to retain its place with great firmness, 

 and at the same time be perfectly impervious to any gas or vapor. 



I am thus minute, because I do not recollect to have seen this mode of fitting up 

 gas-bottles, noticed in any of the books, and I have found it very convenient. In- 

 deed, for making the four gases specified above, hydrogen, nitric oxide, carbonic 

 acid, and sulphuretted hydrogen, I do not believe it possible to contrive any ar- 

 rangement better than that here proposed. A two-necked bottle, standing upon a 

 shelf made to receive it, by the side of the pneumatic cistern, with the substitute for 

 Welther's tube, here described, in one of the nozles, and the glass jacket, holding 

 the cork and conducting tube, ground into the other. The solid materials are read- 

 ily introduced, and the resulting liquid as easily withdrawn : the acid is added as 

 there is occasion for it : not a particle of gas can escape, except along the conduct- 

 ing tube ; and finally, the apparatus is not one which we shall be likely to break. 

 If there be occasion to shew the absorption of the gas by a liquid ; as of the nitric 

 oxide by the green sulphate of iron, there may be two tubes, with their corks and 

 glass jackets fitting the same orifice; one for delivering the gas at the pneumatic 

 cistern, and the other bent twice at right angles, for passing it through the liquid ; 

 one of which may be exchanged for the other in a moment. The stem of the fun- 

 nel of the safety tube, must however be made a little longer in this case, than where 

 the object is merely to collect the gas in jars. It will require the labor of half a day 

 to fit up a bottle in this way, but when once finished, it may be used for any length 

 of time. 



The method of grinding, which is involved in this mode of fitting up apparatus, 

 has so many advantages, that it seems strange it is not more strongly recommended 

 in the books, and more frequently employed. AVe can in many cases make a close 

 joint in this way, in as little time as it would take to fit in a cork, and where the sur- 

 faces in contact are not wide enough to resist a considerable pressure of a gas that is 

 endeavoring to escape ; a very minute quantity of lute pressed down between them, 

 will make all perfectly close and secure. 



