412 



Experimental Researches on the Depressions 



[July, 





Second series, from 



observations in Calcutta. 



















D— d 









t 



t' 



t" 



r~f 



I d 



d 



Tab. 



Err. 



6 Obs open air 



, 82.1 



79.4 



78.1 



.88 



2.7 



92 



.88 







6 Obs. ditto, 



84.6 



79.9 



76.7 



.78 



4.7 



86 



.80 



+02 



9 Obs. ditto, 



85.6 



79.7 



75.5 



.73 



5.9 



82 



.75 



+ 02 



15 Obs. ditto, 



87.7 



80.2 



74.6 



.66 



7.5 



79 



.70 



+04 



2 Obs. ditto, 



96.0 



85.6 



78.3 



.58 



ao.4 



74 



.64 



+06 



3 Obs. ditto, 



93.8 



82.9 



71.2 



.49 



10.9 



71 



.60 



+ 11? 



4 Obs. ditto, 



87. 3 



76.4 



67.3 



.53 



10.9 



68 



.58 



+05 



3 Obs. ditto, 



97.1 



80.8 



71.3 



.45 



16.3 



59 



.45 







6 Obs. ditto, 



97.3 



73.6 



55.5 



.26 



23.7 



41 



.26 







1 Steam pipe, 



19.0 



92.5 



74.3 



.04 



97.5 



6 



.04 







3 Vacuum-pip 



3 92.8 



80.8 



74.8 



.58 1 



12.0 



68 



.57 



—01 





Third 



series, 



extracted from other observations. 







7 Obs. by Her- 



















bert on ri- 



















ver Ganges, 



91.4 



82.1 



78.1 



.66 



9.3 



74 



.65 



—01 



6 Obs. by Ap- 



















john, 



70.0 



60.8 



54.5 



.60 



9.2 



64 



.52 



—08 



4 Obs. ditto, 



















(heated air,) 



93.2 



69.0 



53.7 



.28 



24.2 



35 



.22 



—06 



In the following series the air was dried to two fixed points of 

 hygrometric tension hy means of sulphuric acid, of which the drying 

 power was known beforehand by the table which I published, from 

 careful experiment, in my note on the hair hygrometer before alluded 

 to ; but I preferred verifying those determinations by fresh measure- 

 ment of its barometric tension, in the mode 1 had adopted to correct 

 the tables of aqueous tension during the past year ; namely, by mois- 

 tening a barometer tube with the acid solution, and mounting it in 

 the ordinary manner. The daily readings registered in my monthly 

 tables for May- June afforded a more accurate average than a cursory 

 trial could have yielded ; but the result was in perfect accordance 

 with my former determination*. 



Fourth series — current of air partially dried. 



Number of observations Temp, 

 in similar circumstances, of air. 



t 



2 Obs. with gasome- 

 ter current, Sulph. ° 

 acid, 1.344, .... 90.2 



2 Obs. ditto 87.2 



2 Obs. ditto, 90.3 



1 Obs. ditto, 96.4 



1 Obs. ditto 94.0 



2 Obs. sulph. acid, 

 1.48, 88.8 



1 Obs. ditto, 87.7 



1 Obs. shorter tube, 84.4 



2 Obs. brass tube,.. 87.8 



* It will be seen by the Meteorological Register for May 1836, that pure 

 sulphuric acid caused the barometric column to be higher even than a boiled 

 tube. This must be attributed to capillarity, which is negative with mercury, 

 but acts in an opposite sense with acid or water. No allowance is made for 

 capillarity in my registers. 



Wet- 

 bulb. 



Known 



cent. 



tension . 



Hair 

 Hygrom. 



Depres- 

 sion. 

 t — f 

 or, d 



Comple- 

 ment cent. 

 dep- 

 D — d 







Tabular 

 centes. 

 tension. 



o 





















75.3 



.45 



75 



14.9 



58 



.45 







72.1 



.44 



74 



15.1 



56 



.43 



—01 



74.4 



.44 



74 



15.9 



56 



.43 



—01 



79.4 



.44 



74 



17.0 



57 



.44 







76.6 



.43 



73 



17.4 



54 



.40 



—03 



65.2 



.18 



43 



23.6 



33 



.20 



+02 



61.1 



.18 



43 



26.6 



24? 



.12 



—06 



62.0 



.18 



43 



22.4 



32 



.18 







64.3 



.18 



42 



23.5 



30 



.17 



—01 



