Apparatus Proposed by Flandin and Danger
This apparatus consists of a wide necked jar A (Fig. 7) for the generation of the gas, the mouth of which is closed with a cork having two openings. The safety tube S, which is funnel-shaped at its upper extremity and has its lower end drawn out to a point, passes through one of these apertures; the other opening contains the small delivery tube B, open at both ends, and terminating in a point at its upper extremity: it is also provided with lateral openings, in order to prevent the solution being carried up to the flame. The second part of the apparatus is the condenser C, 0.03 metre in diameter, and 0.25 metre in length. This terminates at its lower extremity with a cone, and connects at the side with the tube T, slanting slightly downwards. In the interior of the condenser, the cooler E is contained, the lower end of which is nearly in contact with the sides of the opening O. The combustion tube D, 0.01 metre in diameter, is connected by means of a cork with the tube T; it is bent at right angles, and encloses the tube B, in such a manner as to allow the evolved gas to burn in its interior. The dish F is placed beneath the opening O. If the gas which burns in the combustion tube contains arsenetted hydrogen, water and arsenious acid are produced. A portion of this acid is retained in the tube D, the remainder is carried over, with the aqueous vapor, into C, where it condenses, and finally falls into the dish F. Both portions are subsequently examined by means of reactions necessary to establish the presence of the acid. If the ignited gas contains antimonetted hydrogen, water and an intermediate oxide of antimony are formed. The latter compound is entirely retained in the tube D separated from the greater part of the arsenious acid, if this body be present, and can be brought into solution by means of a mixture of hydrochloric and tartaric acids. A fluid is then obtained which can be introduced into Marsh’s apparatus, or otherwise examined for antimony.