W. G. Mixter — Carbon and its Heat of Combustion. 437 



I. II. Mean. 



Acetylene carbon taken.. 1*1485 1*3838 gram 



Carbon 99*93 99*96 99*95 per cent 



Hydrogen 0*04 0*03 0*03 " 



The weight of the substance, corrected as already described, 

 multiplied by 0*9995 was taken to be the amount of carbon 

 burned in the calorimeter. The specific heat of both oxygen 

 and carbon dioxide at constant volume is very nearly 0*15. 

 Hence the product of this number by the total weight of the 

 carbon and oxygen is included in the water equivalent of the 

 calorimetric system. The observed weight of the water in the 

 calorimeter was reduced to weight in vacuum. The tempera- 

 ture observed the instant before an explosion was taken as the 

 initial temperature and it was assumed that the gain and loss 

 of heat were equal during the first minute after an explosion, 

 and correction was made for the loss during the four minutes 

 following. Thermometer No. 172863, described in the paper 

 on " The Heat of Combustion of Hydrogen,"* was used in this 

 first series of experiments. 



Experiment 1. — Carbon 1*3740, hydrogen 0*0004, iron 0*070, 

 oxygen 10*2 grams. 



Water 2190* grams 



Water equivalent of calorimeter. 258*6 " 

 " " carbon dioxide 

 and oxygen ._ 1*7 " 



2450*3 " 



Minutes. Temperature. Temperature interval. 



18*700 



23*124 — 18*7+0*04 = 4*464° 



Heat observed, 2450*3x4*464 — 10938 c 

 " of oxidation of iron — 1 1 2 C 



« « « hydrogen — 14 c 



1 



18*700 



2 



22*5 



3 



23*115 



4 



23*139 



5 



23*133 



6 



23*124 



7 



23*113 



8 



23*102 



9 



23*092 



10812 c 

 For 1 gram of carbon 7869 c 



The water with which the bomb was washed after the 

 experiment was free from silver. 



Experiment®.— Carbon 1*0318, hydrogen 0*0003, iron 0*030, 

 oxygen 10*5, water and water equivalent 2543*4 grams. 

 * This Journal, xvi, 214. 



