08 M. Berzelius on the [Junk, 



side of the bulb, draw the tube out a little, and blow a second 

 and smaller bull), after wliich, bend tlie drawn tube, as shown 

 by the fi^i^ure D E F G H. The tube is to be weighed at first 

 empty, and afterwards with the substance to be analyzed, in 

 order to determine its weight. 



To evolve the chlorine gas, a vessel, A, may be employed, 

 capable of holding from two to four pints ; a mixture of com- 

 mon salt and of oxide of manganese is to be put into it, and it 

 is then to be two-thirds filled with water; the orifice is then 

 to be closed with a cork, through which pass a long stemmed 

 funnel, B, and a small bent tube, which gives vent to the gas. 



Fig. A B D explains this arrangement better than any de- 

 scription. From the bent tube, the gas passes into another 

 tube, C, which contains small fragments of fused chloride of 

 calcium ; and from this it passes into the small apparatus, 

 which contains the powder to be analyzed. 



The joinings are made by small tubes of caoutchouc, firmly 

 tied round the glass tubes. The drawn tube, G H, descends 

 perpendicularly into a bottle, H I, one-third filled with dis- 

 tilled water , G H passes through a cork, which closes the 

 mouth of the bottle, and which contains also another tube, 

 from 24 to 36 inches long, by which the excess of chlorine 

 gas escapes, and by which it is conveyed out of the room by 

 the chimney. This arrangement is represented in the fig, 

 G H I K. The bottle is placed at a convenient height, by 

 means of the screw, M. 



When every thing is thus arranged, concentrated sulphuric 

 acid is poured by the funnel B into the vessel, until a disen- 

 gagement of gas begins to take place. Care must be taken 

 that the mixture does not become too hot, as it would occa- 

 sion too rapid an extrication of chlorine gas. The disengage- 

 ment is sufficiently quick w^ehn four or five bubbles rise every 

 minute out of the bottle H I. 



As soon as the greater part of the atmospheric air is dis- 

 placed by the chlorine gas, a spirit lamp is placed near the 

 bulb E. A very small flame only is requisite, and too great a 

 degree of heat must be avoided ; for it is difficult, especially 

 at the beginning, to expel the atmospheric air perfectly, and 

 this might produce arsenious acid in a small part of the ore> 

 -which would render the result inaccurate. 



As the mass becomes hot, an orange coloured fluid distills, 

 which condenses in the little bulb F ; and as this fills, it runs 

 through the tube G H, and falls into the water. 



The operation continues in this manner without recjuiring 

 any attention, unless to add a small quantity of sulphuric acid 

 every 2 or 3 hours, when the disengagement of gas goes on 

 slowly. No artificial heat is employed to assist the extrica- 

 tion ; for in that case it would take place too quickly. Each 

 bubble of gas which passes through the water in the bottle 



