270 PROFESSOR TAIT ON THE 



Pressure of C0. 2 in terms of Volume and Temperature (Amagat). 



At 0° C. and 1 atm. the volume is unity. After the experiments were completed the C0 2 was tested, and left 



O'000-l of its volume when absorbed by potash. 

 The interpolated columns are differences (or average differences, if in brackets) of pressure for 



10° at constant volume. 



Vol. -023S5 -01636 -013 -01 -00768 -00578 -00428 -00316 -0025 -002 -00187 



<5 



31 



o 



34-4 



7-4 





10 





10 





10 





10 



10 



34-4 



10 









307-5 



96-6 



10 



33 



o 



41 -S 



33 



44-4 



6-7 





11-9 





12 





12 



12 



44-4 



12 









404 



111! 



20 



35 





45-1 





51 -1 





56-3 





56-4 











56-4 





64 





300 



520 







2 





32 





5-4 





G-5 





11-9 





143 



14 3 





15 1 





45 



84 



107 5 



30 



37 





48-3 





55-5 





62-8 





68-3 





70-7 







71-5 





109 





384 



627 5 



32 



37-4 





49 





56-4 





64-1 





70 





73-7 





74-6 



77 













35 



38 





49-9 





57-6 





65-8 





72-6 





77-2 





79-5 



84-7 

















2 





3-1 





4 2 





5-8 





8-3 





12-4 



171 





26-5 





46 



86-5 



122 5 



40 



39 





SI -4 





59-7 





68-6 





76-6 





83-1 





87-8 



98 





155 





470-5 



750 







1-9 





31 





4 1 





5-9 





8-2 





11-6 



17-0 





27-3 





40 



S9-5 



106-i 



50 



40-9 





54-5 





63-8 





74-5 





84-8 





94-7 





104-8 



125-3 





201 





560 



856-5 







1-9 





31 





4-0 





5 7 





8-0 





11-5 



17-1 





28-5 





49-5 



91 



97 



60 



42-8 





57-6 





67-8 





80-2 





92-8 





106-2 





121-9 



153-8 





250-5 





651 



953-5 







1-9 





3-0 





4-0 





5-6 





7-8 





11-3 



17-0 





29-4 





48 



94 





70 



44-7 





60-6 





71-8 





85-8 





100-6 





117-5 





138-9 



183-2 





298-5 





745 









1-9 





2-9 





3-9 





5-5 





7-6 





11-3 



17-4 





28-3 





47-5 



88-5 





80 



46-6 





63-5 





75-7 





91-3 





108-2 





128-8 





156-3 



211-5 





346 





832-5 









1-9 





30 





3-9 





5-4 





7-8 





11-4 



17-2 





29 





48-5 



85-5 





90 



48-5 





66-5 





79-6 





96-7 





116 





140-2 





173-5 



240-5 





394-5 





918 









2 





3-0 





4-0 





5-6 





7-8 





111 



17-6 





30-5 





49 



80 





100 



50-5 



[1-73] 



69-5 



[2-8] 



83-6 



[3-7] 



102-3 



[5-1] 



123-8 



[7-2] 



151-3 



[10-6] 



191-1 



[16-4] 



271 



[28] 



443-5 



[46-8] 



998 





137-5 



57 



[l'Sl] 



80 



[2-6] 



97-5 



[3-7] 



121-5 



[5-3] 



151 



[7-2] 



191 



[10-9] 



252-5 



[17 1] 



376 



[29-4] 



619 



[48] 







198 



68 



[1-75] 



97 



[2-5] 



120 



[3-3] 



153-5 



[4-6] 



195 



[6-G] 



257 



[9-8] 



356 



[15-6] 



554 





909 









258 



78-5 





112 





140 





181 





234-5 





316 





449-5 















It is obvious, from a glance at the columns of differences, that the change of pressure 

 at constant volume, while the C0 2 is not liquid, is almost exactly proportional to the 

 change of temperature. M. Amagat expressly warned me that the three last tempera- 

 tures in the table are only approximate, as they were not derived from air-thermometers, 

 but simply from the boiling-points of convenient substances. 



They appear to indicate a slow diminution of dp/dt (v constant) as the temperature 

 is raised above 100° C, but this is beside our present purpose. 



Leaving them out of account, we find that in the range 31° to 100° C. the fluctuations 

 of the changes of pressure per 10° (at constant volume) are very small, and do not seem 

 to follow any law. These fluctuations besides are, especially when the volume of the gas 

 is small, well within the inevitable errors of observation in a matter of such difficulty. 

 Hence we take a simple average in each column ; and thus we have the following table :-- 



Average Change of Pressure per 10° of Temperature at Constant Volume, 

 v -02385 01636 013 -01 "00768 -00578 -00428 -00316 0025 002 -00187 



A/> 1-93 



30 



40 



56 



7-9 



11-5 



172 



28-5 



47-8 



877 



108? 



vAp -046 



049 



052 



•056 



•061 



066 



•074 



•090 



•120 



175 



•20? 



Calc. { 046 



•049 



052 



■056 



061 



•068 



•077 



•087 



















•061 



073 



093 



122 



•175 



■20 



