Progress of Foivign Science. 157 



to examine. On the other side of this ball, draw out the tube 

 a little, and blow in it a second ball, somewhat smaller, after 

 •which bend the drawn part of the tube, in the manner shewn 

 in the figure DEFGH, (fig. 1). We must weigh the tube 

 first empty, and then with the substauce to be analyzed, to 

 learn the weight of the latter. 



For disengaging the chlorine, we may employ a vessel, A, 

 which has the capacity of 1, or at most 2 litres, (from 2 to 4 

 pints). We introduce into it a mixture of common salt and 

 oxide of manganese, and fill the vessel up two-thirds with water. 

 The orifice must then be closed with a cork, through which 

 pass an elongated funnel, B, and a small bent tube, which gives 

 issue to the gas. Fig. A B D, explains this arrangement better 

 than any description. From the bent tube the gas passes into an- 

 other tube, C, which contains small fragments of fused muriate 

 of lime, and from this tube it enters the small apparatus that 

 contains the powder to be analyzed. The joinings are made 

 by small tubes of caoutchouc firmly tied round the glass tubes. 

 The drawn-out tube, G H, descends perpendicularly into a 

 bottle, HI, two thirds filled with distilled 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, 

 through which the excess of chlorine escapes out of the 

 apartment by a window, or chimney. This arrangement is 

 shewn in the figure G H I K. The bottle can be placed at a 

 convenient height, by means of the screw, M. 



When every thing is thus arranged, we pour concentrated 

 sulphuric acid, by the funnel B, into the flask, till a disengage- 

 ment of gas begins to appear. We must, however, take care 

 that the mixture does not heat too much, which would cause 

 too rapid an extrication of gas. The disengagement of this is 

 sufficiently quick, when four or five bubbles rise every minute 

 into the bottle, H I. As soon as the greater part of the atmo- 

 spheric air is displaced by the chlorine, we set a spirit of wine 

 lamp at a little distance below the ball, E. We require but a 

 very small tlame, and we must avoid too great a heat ; for it is 

 diflficult to expel entirely, especially at the commencement, the 

 atmospheric air, by which a small part of the ore might pro- 

 duce arsenious acid, which would render the result inexact. 

 According as the mass becomes hot, we perceive an orange- 

 coloured liquid distil over, which condenses in the little ball, 

 F ; and as this fills, it runs off by the tube G H, and falls into 

 the water. 



During the operation there is formed muriate of peroxide of 

 iron (bichloride), which sublimes in red and transparent 

 spangles, and of which a small quantity is deposited even in the 

 tube ED. For this reason, it is proper to have the tube so 

 long, that the sublimed part may not pass ofl:'. Another part of 



