OF ARTS AND SCIENCES. 



220 



on the results of Regnault. Assuming, then, for the specific gravity 

 of oxygen gas referred to air the value 1.10562, as obtained by Re«- 

 nault and corrected by Crafts, and dividing this value by each of the 

 values for the specific gravity of hydrogen gas given above, we have 

 the following values for the specific gravity of oxygen referred to 

 hydrogen. 



BNo.l 

 B No. 2 

 BiNo.3 

 Average 



Average of chemical method 



Value found by Lord Rayleigh 



15.892 

 15.907 

 15.873 

 15.891 



15.882 



15.884 



Density of Carbonic Acid. 



For the weight of carbonic acid gas held in the balloon at different 

 temperatures and pressures we have the following data. 



B No. 1, weight of C0 2 at 756.73 mm. and 22°.40 9.0334 gr. 

 C No. 1, " « 760.50 " " 25°.56 8.9821 « 



C No. 2, " « 759.13 " " 26°.60 8.9348 " 



Taking now the average value of the weight of air held in the bal- 

 loon at 300 d. in. = 761.99 mm. and 27° (viz. 5.8586 grams), and re- 

 ducing this weight to what it would have been under the condition at 

 which each of the four weights just given was observed, and then divid- 

 ing each of these weights (corrected as by previous note) by the 

 weight of air under the same conditions, we obtain the following 

 results. 



Specific Gravity of Carbonic Acid. Air = 1. 



Taking lastly the average value of the weight of hydrogen held in 

 the balloon at 761.99 mm. and 27° (viz. 0.4076 gram), and dividing 

 the several weights of carbonic acid by this weight reduced to the 

 same conditions, we have, — 



