MAEVDCE] GEOLOGY ROCKS EAST OF FEOXT EA^'GE LIGNITIC. 115 



The moisture, or uneombined v\-ater-ash and sulphur, in the above table 

 appear in the same manner as in the preceding table. The carbon 

 appears greater in amount because, besides the " iised carbon," it in- 

 cludes the carbon before contained in the " volatile products." 



The amou-nt of oxygen included in these volatile products now becomes 

 apparent. If combined with the associated hydrogen to form water, it 

 has thus akeady rendered one-eighth of its weight of hydrogen un- 

 available as a heat-producer. The resultant combined water (equal to 

 the oxygen plus one-eighth of its own weight of hydrogen) is given in 

 column 11, and this acts precisely as the moisture does in absorbing 

 heat. Mr. Eaymond, in spealiing of the first three columns of calorific 

 powers, which he gives, says : 



In each of these the amounts are expressed in centigrade heat units, and there- 

 fore indicate directly the pounds of water which could theoretically be raised from 

 zero to the boiling-point by the combustion of one hundred pounds of fuel. The first 

 column is obtained in the following manner : The anjouut of combined water is found 

 by adding to the oxygen one-eighth its weight in hydrogen ; the remainlug hydro- 

 gen is multiplied by 34,462, the number of heat-units evolved in the corubustion of 

 hydrogen ; and the amount of carbon is in like manner multiplied by 8,080, the calo- 

 rific modulus for carbon. The sum of these two products is the number of units gen- 

 erated by the complete combustion of one unit of the fuel, containing the given pro- 

 portions of carbon and available hydrogen. The heat units due the combustion of the 

 sulphur are disregarded, in view of the small amount of sulphur, its low calorific 

 capacity, (about 2,240 units,) and the circumstance that it exists partly in the form of 

 pyrites, the decomposition of which still further diminishes the amount of heat from 

 this source, and partly as sulphuric acid, causing a net loss. 



The second class of calorific powers is obtained by a similar calculation on the suppo- 

 sition that the moisture is absent. The third column gives the closest approximation 

 to the available heat, and is obtained by deducting from the figures in the first the 

 amount of heat-units required to vaporize the moisture and combined water. This is 

 537 units of heat for each unit of water. 



In reality, the results in column 14 (calorific power III) should be 

 still further reduced. 



We have seen that the full amount of hydrogen given in the analysis 

 cannot be realized as a heat-producer, as part of it already exists in the 

 form of water. Is the remaining hydrogen to be regarded as in a con- 

 dition to give out all its great heat energy ? It is, in fact, combined 

 with some of the carbon present, probably mostly in the form of marsh- 

 gas, (composed of one part by weight of hydrogen to three of carbon,) 

 and though the two ingredients are both combustible, yet they have to 

 be separated from one another in uniting with oxygen in the process of 

 burning. As the union of elements to form compounds produces heat, 

 so the separation of compounds in their elements absorbs heat, and 

 each unit of marsh-gas thus decomposed absorbs about 1,612 units of 

 heat. In other words, when a unit of marsh-gas is burned it produces 

 but 13,063 units of heat instead of the 14,675 units which would be pro- 

 duced if it were first separated into its components and these then 

 burned, as is implied in the preceding calculation of calorific power III, 



In estimating the calorific power of the fuel from this last point of 

 view, the amount of hydrogen rendered unavailable as a heat-producer 

 in the form of water remains the same as before. (Columns 6 and 11.) 

 The remaining hydrogen, (column 5,) if its combination with carbon is 

 considered to be in the proportion to form marsh-gas, which is approxi- 

 mately true, must take up tliree times its weight of carbon (column 4) 

 to form this gas, and the sum (column 4 plus column o) multiplied by 

 13,063 — its calorific modulus — will give the heat produced in its com- 

 bustion. The remaining carbon only, then, gives out heat in proportion 

 of 8,080 units to one of carbon, and the two products together give the 

 total amount of heat produced, from which, as before, the heat ab- 



