PHILIPPINE 'COALS AS FUEL. 309 



The solubility of carbon dioxide, tlae most soluble of the chimney gases, 

 is shown by the following data : 



Carbon dioxide was bubbled for twenty-four hours through water and a salt 

 solution under identical conditions, at 28° C. and atmospheric pressure. For 

 each part of water, 0.649 volume of gas was dissolved, while the volume for 

 each part of the salt solution was only 21 per cent of this amount. There can 

 be little doubt that these are the saturation values, for that obtained for water 

 agrees remarkably well with the results of other investigators. Calculated from 

 the interpolation formula of Naccari and Pagliani,* a=1.5062 — 0.036511* 

 +0.0002917*^ the value for water is 0.647. 



The chimney gases were never bubbled through the salt solution and 

 were in contact with the surface for a short time only, so that any 

 error must be slight. The same salt solution was used throiighout the 

 experiments and after several months intermittent use and exposure to 

 the air contained less than 3 per cent of the saturation value for pure 

 water. 



The exposed end of the glass tubing of the sampler was attached to the 

 aspirator, the siphon started and the gases gradually drawn off. Between the 

 aspirator and the sampler a Fresenius tower filled with cotton was imposed to 

 remove the soot. By means of pinclicocks the removal of the flue gases was 

 maintained at a constant rate. The aspirator was removed at will and a new 

 one put in its place. This operation was continued for any number of suc- 

 cessive hours. The various samples of gas thus obtained were analyzed and 

 reported as the average for that period. The analyses were made according to 

 standard chemical methods. The absorption medium for oxygen was an alkaline 

 pyrogallol solution." 



The unconsumed constituents of the flue gases — viz, carbonic oxide, 

 hydrocarbons and soot — may at times be great and represent a consider- 

 able percentage of the calorific value of a coal. However, the only 

 combustible gas determined was carbon monoxide (CO). Wlien this 

 gas is found in any quantity it is quite probable that hydrogen and 

 hydrocarbon gases are also present, but because of the difficulty of 

 determining these in small amounts their percentages have not been 

 ascertained. 



Chemical analyses. — Nitrogen in the coal was determined by the regular Kjeldahl 

 method and all other analyses were made according to standard chemical methods. 



Determination of the calorific value of the coal. — In the calculation of the 

 calorific value of the coal from the ultimate analysis, Dulong's formula in the 

 form as given in 1899 in the report of the Committee on Coal Analj'sis,'" appointed 

 by the American Chemical Society, was used as follows : 



Calorific power=8,080C-|-34,460 (H— JO) +2,250S. 



^Gazzetta chim. ital. (1880), 10, 119; AtH d. R. Ao. d. sc, Torino (1879-80), 

 15, 279. 



"It has been maintained (Franzen, H. Ztschr. f. anorg. Ch. (1908), 57, 359.) 

 since this work was done that this is not a satisfactory absorbent for analyzing 

 gases where oxygen is present in large quantities, for the oxygen acts on the 

 pyrogallol solution producing carbon monoxide (CO) which remains in the 

 gas-rest and changes its composition. Alkaline sodium acid sulphite is recom- 

 mended. 



'"J". Am. Chem. Soc. (1899), 21, 1130. 



