which are evolved in Coal-Mijies, 320 



licle, which had been deposited from the gas after it had passed 

 through the sulphuric acid, had a peculiar empyreumatic smell. 



The sulphuric acid also had a strong empyreumatic odour, 

 which, however, as the acid became diluted with water, was 

 diminished, so that at last only a feeble sweetish smell, as 

 when sulphuric acid and alcohol are united, remained behind. 



The diluted acid was neutralized with carbonate of potash. 

 The evolved carbonic acid had also a sweetish smell. The 

 solution had a light brownish colom\ After it was filtered, a 

 brown coating remained behind on the filter, which, however, 

 was too inconsiderable in quantity to admit of its examination. 

 The filtered liquid likewise had still a feebly brownish tint. 



As the preceding experiments had proved, that peculiar 

 carburetted hydrogen compounds can be produced when in- 

 flammable pit-gas is transmitted through a heated porcelain 

 tube, and that these compounds, at least in part, are also ab- 

 sorbed by sulphuric acid, I performed an experiment to ascer- 

 tain if these combinations are also absorbed by alcohol. I 

 made use of precisely the same apparatus, but filled the ab- 

 sorbing apparatus with alcohol of 92°.5 per cent. 



In the first ball, viz., that turned towards the porcelain tube 

 of the absorbing apparatus, there soon appeared, after the gas 

 passed through the heated porcelain tube, white vapours, which 

 were condensed into brownish-yellow small drops. Afterwards 

 there was formed on the cooler side of the ball a yellow co- 

 vering, in which were perceptible many small yellow drops. 

 The alcohol gradually assumed a wine yellow colour, and the 

 colour increased. In the tube which was fixed in the cork of 

 the porcelain tube, there was condensed a light brown scaly 



bf was united with the collecting apparatus. These two tubes entered a 

 small glass-receiver r, in which quicksilver was poured up to c d, so that the 

 openings of the tubes were above the level of the metal. I have employed 

 such an arrangement for several years, in all experiments with gases which 

 require an apparatus composed of several parts, as, for example, in the ana- 

 lysis of organic substances. The connection is, of course, perfectly air-tight, 

 i easily made, and easily again removed. I prefer it in most instances to 

 the connection by means of caoutchouc tubes, which must always be proved 

 regarding their air-tightness, and which often remain air-tight for a short 

 time onlv. 



