1813,] On the Specific Heat of the different Gases. 369 



Article IX, 



Memoir on the Determination of the Specific Heat of the 

 different Gases. By MM. F. Delaroche, M.D. and J. E, 

 Berard. 



(Continued from p. 292.) 



Section III. 



Determination of the Specific Heat of the Gases hj anothef 



Process. 



We might have repeated a greater number of times the expe- 

 riments which led us to the foregoing results ; but we conceived 

 that such' a repetition would have been useless. The agreement 

 which exists between those of the same kind, and which we 

 obtained in two experiments following each other, shows that 

 they were not influenced by accidental causes of error ; and if 

 they were subject to a constant cause of error, no advantage 

 would result from multiplying their number. It was therefore 

 more essential to endeavour to arrive at the same results by a 

 different process, susceptible of almost equal precision, and to 

 compare these results with the preceding. Count Rum ford has put 

 this in our power, by publishing the ingenious method by which 

 he determined the quantity of heat disengaged during the com- 

 bustion of certain substances, and which he had himself an- 

 nounced as fit for determining the specific heats of the gases. 



We therefore undertook some experiments of this kind, 

 employing the same apparatus which has been already described, 

 and which had been constructed long before we were acquainted 

 with the experiments of Count Rumford. It answered all the 

 conditions demanded by this celebrated philosopher. It was, as 

 has been already observed, a metallic vessel full of distilled 

 water, traversed by a flat serpentine, sufficiently long to allow 

 the gas while passing through it to acquire the temperature of 

 the water in the calorimeter. As the gas entered by the lower 

 end, it deposited there the greatest pait of its heat ; so that this 

 heat spread itself sufficiently equably through the whole water 

 that filled the vessel. We determined the temperature of this 

 water by means of a thermometer, the cylindrical bulb of which 

 wi's almosl as high as the calorimeter itself, and which gave us, 

 of course, the mean heat of the whole liquid. Our gazometer, 

 and the part of the apparatus for heating the gas, were equally 

 litted for the experiment. 



Leaving every thin as in the preceding experiments, 



set, pro g in the same manner, with this 



difference, that Instead o! waiting till the temperuture of the 



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