348 Chemical Contributions. 
little or no danger of breaking it, when connecting it with other pie- 
ces of apparatus. 3. That whereas Welther’s tube projects far 
above the apparatus to which it is attached, and is constantly in the 
way, and in danger of being broken on that account: this is included 
within, without however at all interfering with, or preventing the suc-. 
cess of tlie process that is going’on ; or contaminating the substances 
that are there. In the case of hydrogen, it is not necessary that the 
funnel should rise at all-above the nozle of the bottle. It has also an 
advantage in‘procuring the gases, over a simple funnel with a long 
stem, reaching very nearly to the bottom.of the bottle, and dipping 
into the fluid that is introduced, such as is recommended by Orfila, 
and figured in his chemistry—because with that some of the gas gen- 
erated will escape into the room. If any chemist should dislike the 
trouble of making the instrument here proposed, himself, it is obvious 
that the glass blower may take the business off his hands; that the 
tube may in fact be made so as to constitute but a single piece, and 
ground into the bottle, before it comes to the laboratory. . 
When a two necked bottle is not at hand, a common gas bottle with 
an orifice an inch across, will answer the purpose very well. 
tubes pass through. the same cork as is represented in Fig. 5, (the 
cork itself being inclosed in a glass jacket that is ground into the bot-: 
tle, after the manner described in the note,) one for the conveyance” 
of the gas that is generated—the other receiving a small funnel into 
its top, and entering itself through a cork into a test tube, having # 
hole cut in its side and performing the office of a tube of safety. 
_ A tube of the kind here proposed, the funnel only being omitted, 
may be-ground into the middle orifice of a set of Woulfe’s bottles, oF 
into the tubulare of the retort, when the gas that is passing through 
them is generated and answers every purpose of Welther’s tube of 
safety, besides having some. advantages over it. For it is evident that. 
it need not project at all above the apparatus with whieh: it is- con- 
nected, and that if the diameter of the interior tube be small with 
regard to that of the exterior, (and it is quite unnecessary that it. 
should be large,) the included gas may be safely kept under @ pres- 
sure of some half dozen inches of mercury, and the absorption in this 
way promoted. Of its other applications [I will notice but’ a sid, 
one. Dr. Marcet’s fine instrument for experiments on high steam, fig- 
. ured in the supplementary volume of the Philadelphia edition of Hen- 
_Fy’s chemistry, and in Brande, is now very well made in New York; 
and upon the plan there exhibited, except that instead of two hemis- 
