III. ANALYSIS. 627 



266O. Apparatus for the determination of Water, Car- 

 bonic Acid, &c., principally for elementary organic analysis, 

 made by Dr. Geissler in Bonn. 



Dr. Drevermamii Hoerde* Westphalia. 



2556. Geissler's Apparatus for determining carbonic acid. 



Ch. F. Geissler $ Son, Berlin. 



258O. Collection of small Glass Apparatus for the Estima- 

 tion of Carbonic Acid. Dr. H. Geissler, Bonn. 



2402. Plattner's Diamond Mortar, in steel. 

 No. 1, with brass capsule. 



No. 2, without 



No. 3, A. fferbst, Berlin. 



2403. Freyb erg's Diamond Mortar, in steel. 

 No. 1, with brass capsule. 



No. 2, without 



No. 3, A. fferbst, Berlin. 



2574. Habermann's Air-bath. Julius Schober, Berlin. 



2574a. Water and Air Bath, with regulator. 



P. Waage, Professor of Chemistry at the University of 

 Christiania, Norway. 



(NOTE. For reference letters see photograph.) 



(A) is a water-bath heated by two Bunsen lamps, a compartment (If) in 

 which serves as an air-bath heated by a copper tube (c) coiled in the water 

 and opening 1 into the air-bath. 



A tube (d) keeps the air-bath in communication with the outer air. 



The regulator (B) consists of a U tube (e) half filled with mercury, and 

 the float (y) which rising or falling with the surface of the mercury, shuts or 

 opens the glass cock (h) by means of the lever (</). This movement can be 

 adjusted by the regulating screw (i). 



(7) is the drying tube filled, for instance, with chloro-calcium. 



(/?) is connected with an apparatus for exhaustion, for instance, a Bunsen's 

 pump. 



If the cock o and n are shut, whilst the cock m is open, and the air is ex- 

 hausted at p, the mercury rises in the long arm of the glass-tube, whilst it 

 sinks in its short arm. In this way the floating piece sinks and the cock h is 

 opened. Through i, the regulating screw, the floating piece may be placed 

 higher and loAver in such a way that the cock h admits the air into the appa- 

 ratus, in a greater or less state of rarefaction. 



If the cock m is shut, whilst the cocks n and o are open, and when these 

 cocks have been connected with c and d, through the india-rubber tubes r 

 and s, whilst the other end of the tube / ending in the air-bath, is connected 

 with the interior opening of the copper-tube d, then the air that enters 

 through the drying tube by the cock at a given rarefaction, will first go into 

 the copper coil at c, and then, having been heated to 100 C., will enter the 

 air-bath to be from thence exhausted by the pump through the cock o. 



The air-bath can thus be filled with warm dry air at any pressure that may 

 be desired. 



Besides, with the object just named, the regulator may also be used under 

 filtration with Bunsen's pump. In this case one of the india-rubber tubes, 

 for instance s, is brought into connection with the filtering apparatus, the 



R r 2 



