528 



been dried at 212° F., was in some cases mixed with 

 chromate of lead, and the analysis conducted in the ordinary 

 manner ; in other cases, the substance was mixed with black 

 oxide of copper, and some chlorate of potash having been 

 placed in the end of the analysis tube, the operation was 

 conducted in the usual way to near the termination, when 

 the chlorate of potash being heated, a stream of oxygen gas 

 passed through the apparatus, and burned out the last traces 

 of the organic substances. 



These two modes gave almost identical results with the 

 same fuel, and there is no necessity for distinguishing 

 amongst the analyses, of which the results follow, those that 

 were done in the one way or in the other. 



It was found, however, that the anthracite could not be 

 perfectly analysed by either of these modes : the difficulty 

 of burning away the last portions of the carbon was so great. 

 Hence a totally different plan was adopted for that variety 

 of fuel. An analysis tube of Bohemian glass having been 

 taken about a foot long, the substance to be analysed was 

 placed in a little boat of platina foil, and introduced into the 

 tube near one end. To this end was fitted a tube containing 

 dry chloride of calcium to collect the water; then the potash 

 absorbing apparatus, then another potash absorbing appa- 

 ratus, and finally a tube containing dry potash. These three 

 were for the purpose of separating the carbonic acid perfectly 

 from the excess of oxygen, and also to prevent the oxygen 

 from carrying away any moisture from the potash liquor. 

 The other end of the tube was connected with a gazometer 

 full of pure oxygen gas, which, streaming over a large sur- 

 face of fused chloride of calcium, was rendered perfectly 

 dry. The apparatus being so adjusted, the analysis tube 

 was heated to redness by charcoal, so that the oxygen gas 

 passed through five or six inches of red hot tube before 

 coming to the ignited anthracite. The analysis was thus 

 conducted, as it were, with the hot blast, and the combustion 

 was in all cases quite par feet. This kind of process wouKl 



