909 
of the observations '). This appears to be the case in the first place 
in the range of hydrogen temperatures: the curve which unites the 
experimental results crosses the curve calculated according to 
Desue (Fig. 10), in such a way that at 14° K. the specifie heat is 
greater, at 20° K. it is smaller than the value calculated with 6 = 88. 
These deviations continue in the lower part of the range between 
hydrogen and oxygen temperatures, and decrease again in the higher part. 
It is true that the drawing of a conclusion is made uneertain in 
this region by the interpolation, which the gold thermometer requires 
there. We do not, however, consider it probable, that the deviations in 
this region are to be ascribed to the inaccuracy of the interpolation: 
1. as they are a regular continuation of the deviations in the hydrogen 
region which are established with certainty, 2. as there are no indi- 
cations that the deviations have a different sign in one part of the 
region of interpolation than in the other, as would have been the 
consequence of an inaccurate interpolation with the method of inter- 
polation used ($ 3). 
We are therefore led to the conclusion that the specific heat of 
lead shows deviations from the curve calenlated according to Desun, 
which unites the determinations at oxygen and at hydrogen tempe- 
ratures in the best possible way (6 = 88), in the intermediate range 
of the temperatures, to the extent of about 4°/, at 30° K. (ef. also 
table VI). 
These deviations may presumably find their explanation in one 
or more of the following circumstances: a. that we did not observe 
with a homogeneous substance crystallized in the regular system, 
but with a micro-crystalline aggregate consisting of different phases, 
such as the two different states of crystallisation assumed in supra- 
conductors for the explanation of the micro-residual resistance (Comm. 
N*. 133 § 11), which perhaps also come into play in the experi- 
ments of Conen and HELDERMAN ®), who on the ground of their inves- 
tigations assume, that with lead we are dealing with a metastable 
complex of two or more modifications, 6. that the approximate sup- 
positions. concerning the elastic spectrum made in Depie’s theory 
1) At the points 7’=57.20, 6928 and 69.97 the irregularities mentioned in 
note 1 p. 905 in the determination of the sensitivity have presumably also occurred, 
though in a less degree. The first point has probably been calculated with too 
large. the last two with too small a value for the sensitivity. 
2, E. Cowen, These Proc. June 1914, p. 200; E. Conen and HeLpeRMAN, These 
Proc. Noy. ’14, p. 822. CoHeN |. c. quotes measurements of LE VERRIER according 
to which at 220 to 250°C. lead would pass into another modification with appreci- 
ably larger specific heat (al constant pressure). The measurements by P. Scniisen, 
Zs. f. anorg. Chem. &7 (1914), p. 81, do not, however, confirm this result. 
