MEGASS AS FUEL. 



FIG. 226. 

 hours' duration can be obtained. 



Analysis of the Flue Gases.- With perfect combustion, ie., 

 with no excess of air. the fuel gases should contain 20 per cent, of carbon 

 dioxide ; in actual practice 1 5 per cent, is a very high figure and an average 



of 10 per cent, cannot be con- 

 sidered unreasonable. The best 

 method for obtaining intermittent 

 analyses of the flue gases is 

 described below. 



Collection of the Sample. 

 Specially designed bellows may 

 be obtained from dealers, but the 

 writer prefers to use the aspirator 

 shown in Fig. 226 ; by adopting 

 means for regulating the flow 

 of water, a sample over several 

 The water in bottle a next to the flue is 

 covered with a layer of oil. Before collecting the sample of gas the tube 

 let into the flue should be well rinsed with the flue gases by means ot* 

 alternately lowering and raising the bottle b. 



For the analysis of the flue 

 gases the following solutions are 

 required : 



1. Caustic soda of density 60 

 Brix. For carbon dioxide. 



2. Twenty -five grms. pyrogallol 

 dissolved in 50 c.c. hot water and 

 mixed with 100 c.c. caustic soda of 

 density 50 Brix. For oxygen. 



3. Cuprous chloride in hydro- 

 chloric acid. Dissolve 35 grms. 

 cupric chloride in 200 c.c. hydro- 

 chloric acid of specific gravity 1'20 ; 

 add a quantity of copper turnings, 

 and preserve in a stoppered bottle 

 for 48 hours with occasional shaking ; 

 then add 120 c.c. of water. For 

 carbon monoxide. 



The apparatus (Orsat-Lunge) 

 shown in Fig. 227 is the most con- 

 venient form for analysis. The bulb b is filled with caustic soda up to the 

 mark on the neck, the bulbs c and d being filled in the same way with the 

 pyrogallol and cuprous chloride solutions. The filling is performed by first 



Fie. 227. 



421 



