( 772 ) 



ure. The different points on one and the same isotherm must 

 show smaller discrepancies inter se than corresponds with the 

 said mean error. The mean error namely, for a determination, apart 

 from the errors in the determination of the normal volume and the 



1 1 



calibration of the large volume is ± from — — to ± — — . 



Jd\) \)\) Z4UU 



All this does not apply to the isotherms of — 103°. 57 and 

 — 135°. 71. These belonging to series I arc the earliest determina- 

 tions and for different reasons less accurate than the later ones. 



§ 12. Provisional individual virial coefficients. 



If the temperatures had not been given as readings on the hydrogen- 

 thermometer of constant volume at 1100 mm. pressure, but on the 

 absolute scale, the coefficients Aa, Ba etc. calculated from the equation 



B A C A D A E A F A m 



pv A =A A -\ + _ + _ + _ + _ . . . (1) 



v A v*a v A v* A V s a 



with the values of pv A from table XII, could be immediately com- 

 pared with those derived in Comm. N°. 71 x ). However, this is not 

 the case, because the latter relate to the absolute scale of tem- 

 perature. From the outset it has been our purpose to derive the 

 correction of the hydrogen scale on the absolute scale experimentally 

 from our measurements themselves. This might be attained by first 

 neglecting the correction, and by calculating provisional values 

 A' At B' A , Oa etc. for each of the isotherms, which serve then for 

 finding provisional corrections for the hydrogen-thermometer; after 

 this the calculation is repeated with the corrected temperatures, etc., 

 till further repetition would not bring about any change. A similar 

 treatment has been applied for the determination of the corrections 

 of the readings of the hydrogen-thermometer to the absolute scale, 

 where we purposed to draw through the observations for every isotherm 

 a curve, which does not only correspond as closely as possible to 

 the observations, but also to the general equation of state. In this § 



l ) We must call attention to the fact that in the calculations of Comm. N°. 71 

 we began by taking 273°.04 by first approximation for the absolute zero-point ; 

 we should find the correction to this from the results of the calculations of iso- 

 therms, and then proceed to a second approximation. We have still retained 

 273 c .Oi in VI. 1 Suppl. N°. 8 and in VI. 2 Comm. N°. 92. Since then, however, 

 a set of coefficients VII. 1, which will be published in the following communi- 

 cation, have been calculated with the further approximation for the absolute tem- 

 perature, viz. the more accurate value 273°. 09, and corrections have, moreover, 

 been applied in critical quantities etc. 



