( 416 ) 



reduction has not been carried out, as it is better to take this tem- 

 perature as standard temperature instead of — 135^71. Here the 

 reduction wouhi liave to be made for a comparatively large diiference of 

 temperature, and would becoujc inaccurate. It is, therefore, j)referable to 

 leave the values of table XIX for this temperature intact, and if 

 necessary apply the reduction to those of series 1, which are much 

 less reliable. The temperature — 1 64°. 14 has been adopted as new 

 standard temperature. 



The determinations 5 and 9 as well as 14 and 18 of table XIX 

 have been united to a mean. 



§ "20. Conipaiisuih of the .^ieries I (Uid [I with tlie control-dcter- 

 minatmis. 



For reasons mentioned in § J7 the points of series I and II have 

 been doubly determined in a mutually perfectly independent w^ay. 

 They can be easily compared with the control detei-minations of 

 IV and Y by reducing (hem to the same density and temperature by 

 means of virial coefiicients. If in this way for — 103°. 57 Nos. 2, 3 

 and 4 of series I (see table XII) ai-e compared with 1, 2 and 3 of 

 series IV (see table XXI), we lind for the differences of pi: a for 

 IV — I respectively : 



-I- 0.00001 , + 0.00007 , — 0.000J9 

 and for -139°.88 for IV (5,6) — I (2,3): 



— 0.00085 , — 0.00036. 



Dealing in the same way with the series II and V fsee tables 

 XII and XX), we tind resjiectively for the temperatures — 182°.81, 

 — 195°.27, — 204°.70, and — 212°.82, 



V(l,2) —11(2,3) =-1-0.00007,4-0.00010 



V (4, 5, 0) — II (2, 3, 4) =: -f 0.00012, -f- 0.00026, + 0.00017 



V (7, 8, 9) — II (2, 3, 4) == 4- 0. 0020, -f 0.00019, -f- 0.00034 



V (10, U, 12) — II (2, 3, 4) =: + 0.00013, -(- 0.00008, + 0.00021 



The dilferences ai'e to be ascribed chietly to condensation of 

 impurities, as they diminish with increase of the temperature. This 

 was considered as sufficient ground to reject the results of the series 

 I and II for the further calculations as less i-eliable. This was also 

 done for — 104 , though the series I and IV harmonize very well 

 for this tempcralure. When we disregard the intluence of the 

 probable condensation the \ery regular course in the situation of 

 the points is an indicaliou about the accuracy of the measurements 

 themselves also for the other isotherms. 



