PHILIPPINE COALS AS FUEL. 307 



The average readings on all of these tests are, for the steam-gauge 

 pressure 7.4601 kilograms per square centimeter (106 pounds per square 

 inch), for the upper thermometer 166° (330°. 8 P.), and for the lower 

 thermometer 109°. 4 (229° F.) ; the ranges for the thermometers being 

 from 161° to 169° and from 108° to 110°.5, respectively. The normal 

 for 166° may be taken as 139°. 5 and the average cooling below this point 

 is 30°. 1. In order to compute the amount of moisture from the loss of 

 heat shown, the number of degrees of cooling is divided by the coefficient, 

 which depends upon the specific heat of steam, representing the number of 

 degrees of cooling due to 1 per cent of moisture. 30°. 1 divided by the 

 coefficient given by Barrus ^ for 166°, which is 11°. 66 (21° F.), gives 

 2.58 per cent. No correction has been made for the moisture produced by 

 radiation from the apparatus itself. 



Denton " has shown that it is seldom possible to operate a condensing 

 calorimeter with the degree of exactness calculated for the instrumental 

 error, namely, 1 per cent. There has always been found to exist ac- 

 cidental variation considerably in excess of the theoretical instrumental 

 error, even Eegnault's experiments, the results of which are presented in 

 tabular form in most publications upon the properties of steam, being 

 no exception in this respect. He has also shown that jets of steam show 

 unmistakable change of appearance to the eye when steam varies less 

 than 1 per cent, either in the direction of wetness or of superheating, 

 from the condition of saturation. When a Jet of steam flows from a 

 boiler into the atmosphere under such conditions that very little loss of 

 heat occurs through radiation, etc., the quantity of water if not too 

 large, may be estimated from the color of the steam. If the jet is 

 transparent close to the orifice, or is even a grayish-white color, the 

 steam may be assumed to be so nearly di-y that no portable condensing 

 calorimeter will be capable of measuring the amount of moisture in it. 

 If the jet is strongly white, the quantity of water, if it does not exceed 

 2 per cent, may roughly be estimated, but an amount in excess of this can 

 be determined only with a calorimeter. Careful observations roughly 

 corroborated the results given in Table I. 



Analysis of the flue-gases. — The flue-gases were analyzed and for this 

 purpose were drawn from the flue by means of a sampler such as is shown 

 in the following figure : 



'Trans. Am. Soc. M. E. (1890), 11, 795. 

 'Ibid (1899), 10, 326. 



