( 781 ) 



The kuier may be reduced to the error in />*'„ and the difference 

 of the pressure-coefficients used for the density =0 and that at 

 0° and 1090 mM. If for the mean error in B'„ we compare the 

 values of B\ which may be derived from the data of Comra. N 08 . 70 

 and 78 and from those of Chappuis, a mean error of ± 0.000034 

 (about agreeing- with the error per cent derived for t Fie pv in § i\ 

 of Comm. N". 97") follows from their deviations inter se, which 

 corresponds with a mean error of =t 0°.008 at — 100° and of 

 ± 0°.003 at — 200° for A t. 



We may further assume that the mean error in the pressure- 

 coefficients 0.0036618 and 0.0036629 amounts to one unit of the 

 last decimal for the first and to two units for the second, which 

 corresponds with a mean error in Lt of ± 0°.003 and ± 0°.006 at 

 — 100° and of ± 0°.005 and ± 0°.011 at — 200°. 



If we further put the mean error in B't equal to that of B' 0) a 

 mean error in At corresponds to this of =t 0°.006 at — 100' and 

 of db 0°.002 at — 200°. 



The total mean error in consequence of all these mean errors 

 together will amount to ±0°.012 for — 100° and ±0°.013 for — 200°. 



§ 4. Comparison of the results with those which have been theore- 

 tically derived. 



Table XVII contains the corrections concerning the normal hydrogen 



53* 



