250 



If ammonia is added to an aqueous solution of a nickelsalt, we get 

 the blue coloured solution of the complex nickel-auinionia compound. 

 As with these solutions the strong evaporation of the ammonia 

 makes it impossible to determine with sufficient accuracy the correction 

 for the magnetic susceptibility of the air, these measurements were 

 carried out under an atmosphere of hydrogen and ammonia, which 

 was obtained by leading the hydrogen through an aqueous NH, -solution 

 of about the same NH, -concentration as the solution to ite investigated. 

 The magnetic susceptibility of this atmosphere is so small, that it 

 may be taken equal to zero, thus formula (I) becomes, as with these 

 measurements the water measurements also were made under a 

 hydrogenatmosphere ; 



'f'L^ -rf-water (I) 



h 



The calculation of Xxi salt fiom Xl with the ammoniacal solutions 

 is performed analogous to the calculation of Xni shU from Xl with 

 the aqueous solutions. However not only the susceptibility of the 

 water but also that of the ammonia must be taken into account. 



The measurements of aqueous ammonia solutions gave for Xfjtf, : 



— 0,947.10-G 



— 0,950.10-6 



— 0,942.10-6 



— 0,954.10-6 



Average : — 0,948.10-6 



while Pascai, gives: Xnhj = — 0,881.10-6. 

 Instead of formula (II) we get: 



(100 — .B — y) Xwatei- + y XnH, + X Xni salt ,^,,, 



Xl = ^^ . . . (//) 



where x. indicates the percentage of nickelsalt, y that of ammonia. 



As from some experiments in the beginning it was evident, that 

 with a ci'rtiiln concentration of the nickelsalt within the limits of 

 expenmenial accuracy a fixed value was found for X^; s,^it calculated 

 wiih formula (11) for «////'(j/wi^ NHj-concenlrations, the conclusion may 

 l)e drawn that Xnh, has the same value no matter in what degree 

 llie aiiimoiiia is bound to the nickelsalt or finds itself free in 

 I e sniiiiioii. fiie .su.sceptibility therefore maj' be assumed as an 

 additive |)roperiy and the correction for the ammonia may be 

 deduced from the whole ammonia quantity. 



The following table gives the results obtained with the ammonical 

 solutions : 



