488 



C. Barus — Fluid Volume and its 



Experimental Results. 



15. The bulk of the present experiments were made as de- 

 tailed in § 6, earlier data being rejected. Throughout the 

 tables L is the length of the thread of substance, at the tem- 

 perature d; v/Vis the corresponding volume-decrement due 

 to the burden of p atmospheres. Finally, ft is the mean com- 

 pressibility between the initial pressure p and the pressure 

 given. Values marked, observed and calculated will be dis- 

 cussed below § 30. 



16. Ether. — The results for ether are given in table 4. 

 Manipulations were made very difficult, because of traces of 

 sulphur retained by the liquid. This destroys the cohesion of 

 the mercury thread, probably by reducing its surface tension. 

 Above 100° the thermal expansion increases enormously, so 

 that I found it necessary to operate with two threads, a long 

 one for low temperatures, and a short one for 310°. Since the 

 initial pressure could not be kept at 20 atm., the tubes not 

 being long enough, I reduced all data to the uniform pressure 

 j? o =100 atm. Table 5 shows the corresponding expansion 

 data. It may be noted that supposing the given conditions 

 to hold linearly, ether would cease to expand at 1100 atm. 



Cf. §3& 



Table 4. 



Compressibility of Ether, referred to 100 Atm. 







Observed 





Comput'd 









e, l 



P 



4uxl0 3 



/3xl0 6 



^-xlO 3 



Diff. x 10 8 



#xl0 6 



tfoxlO* 







V 





V 









29° 



100 



o-o 





o-o 











200 



15-6 



156 



15'4 



+ •2 



165 



194 



14.317cm 



300 



28-9 



145 



28-9 



•0 









400 



40-8 



136 



40 9 

 O'O 



— -1 







65° 



100 



00 











200 



20-T 



207 



20-5 



+ •2 



226 



282 



15-18 cm 



300 



377 



189 



37-8 



— •1 









400 



52-8 



176 



52-8 



±0 







100° 



100 



o-o 







o-o 



.__ _ 









200 



30-5 



305 



29-9 



+ '6 



343 



497 



16-25 cm 



300 



53-6 



268 



53-4 



+ •2 









400 



72-2 



o-o 



241 







72-8 



-•6 





♦ 



185° 



100 



o-o 









20'08 cm 



200 



74-1 



741 



71-5 



+ 26 



1005 



10060 





300 



115-5 



577 



114-7 



+ '8 









400 



143-5 

 



478 



145-6 



-2-1 







310° 



100 



• . « - 



o-o 



. - - - 







*14-59 cm 



200 



382 



3820 



383 



-1 



34250 







300 



462 



2310 



460 



+ 2 









400 



502 



2510 



503 



-1 







* Second sample. 



