143 



wliich lüonld cause V^a to rise from about 11 to 36. Tlie xaliie of 



fdn\ 



I — j at Ik will, tlierelore, be very great positive, and this will 



fdp\ 

 lower the value ofl — 1 at the critical temperature considerably. 



fT dp\ 

 Hence the value of f\=z\— ~~\ will also be considerably lomer than 



the normal value. In our case the expected value is diminished 

 from 9,6 to 6,5. 



As Tk is now found == 1172° abs. instead of 1260° abs., as I 

 calculated before, the ratios Tk: Tg and 7\ -. T,,. will also be 

 somewhat lower. For the former we find 1172:630 = 1,86, and 

 for the latter 5,0. So high a value for the ratio Tk : T/,. is only 

 found for He (5,2) and for Bismuth (5,5) of the elements calculated 

 by us up to now. But we shall soon see (in a following paper), 

 that Tk: Ttr is also = over 5 for tin, lead and the alkali metals. 

 A pretty high value of Tk : 2^s (i. e. ^ 1,7) is also found for Argon, 

 Kryptoa, Xenon, Niton (1 ,73—1,79), for the Halogenides (1,75 to 1,72), 

 for 0, (1,71), for P, Sb and Bi (1,75—1,77), but 1,86 was not 

 reached yet. Among the compounds we mention HCl (1,71), HBr 

 (1,78), HI (1,79), H,0 (1,71), H,S and H,Se (1,77), PH, (1,75), 

 CS, (1,71), CH, (1,75), H. COH (1,97), while the three mercury 

 halogenides, examined by Rotinjanz, give 1,69 to 1,71. 



5. In conclusion I will still point out that èjt :^ 150 X 10~^ does 

 not only ensue from the densities of the mercury halogen compounds 

 (see § 1), but also from the density of mercury itself. For it follows 

 from Dewar's determinations (1902), who found the value 14,382 

 for the density at 188° C, and those of Mallet, who gave 14,193 

 for the density at — 39°, that the limiting density i)„ at about 

 — 250° (below this no appreciable volume diminution takes place) 

 will amount to 14,46. 200,6 Gr. of mercury then occupy a space 

 of 200,6 : 14,46 = 13,87 ccm., i. e. = 13,87 : 22412 = 61,9 . 10-'^ in 

 so called normal unities. This is, therefore, />„ = v^,. Now according 

 to one of our formulae bk:b^:= 2y, hence bk = 61,9 : 10 -^ X 2,4 = 

 = 149.10-5, quite identical to the value which we found above 

 (^ 4) with ^9 := 180 atm. We may, therefore, put the value of ^a: for 

 mercury at 150 .10--^ with great certainty. 



The value of Dk is found from the formula Dk = D^ : 2(1 + y) = 

 = 14,46:4,4 = 3,3. 



Recapitulating we probably have for mercury : 



