Chase. ] 108 [July 20, 
Comparing the positions of inter-Uranian planets which are most cor- 
rectly represented in the foregoing tables, and taking the geometrical 
means for the five positions of each planet, we find : 
- 
oO. he (T-O) + T. 
h 9.521 9.512 —.0009 
yo 5.197 - 5.196 —.0002 
3 «ALB L6 1.517 +.0014 
® 999 1.001 +.0021 
Q 722 721 —.0012 
bs .380 .380 +.0001 
Mean 3.567 3.567 +.0002 
A similar closeness of accordanee is shown by comparing the positions 
of the intra-Nepturian planets which appear to be most typical : 
O. ame (T-O) + T. 
1 
SB; 19.184 =a et idles +0001 
h, 10.848 ay SG, 00.340 —.0004 
Us 5.427 ()> Ge 5.429 +.0008 
1 
d's 1.524 won 1.524 +.0002 
if 
QD, .966 ees 965 —.0009 
o, 749 @)* Ss 749 —.0005 
¥ AVY (ay er ATT —.0008 
Mean 2.473 2.478 —.0002 
The variation of the nucleal radius as the 2 power of the atmospheric 
radius,* may furnish an explanation of results which seem to have been ob- 
tained nearly simultaneously, by Silas W. Holman (A. A. A.S. June 14, 
1876 ; P. Mag, Feb., 1877; p. 81), and E. Warburg (Pogg. Ann. clix, 415 ; 
communicated 9th July, 1876). Holman concludes, from the results of a 
number of careful experiments, that the ‘‘ viscosity of air increases propor- 
tionally to the 0.77 power nearly, of the absolute temperature, between 0° 
and 100° C.’’ The extreme range of his results is .738 to .799. Warburg, 
from experiments both with hydrogen and with air, deduces the exponents 
between 20° and 100°, .76 for air (the extremes being .74 and .76), and 
‘‘about 2’’ for hydrogen (the extremes being .57 and.65). The closeness, 
the narrow range, and the mutual confirmation of these independent re- 
sults, as well as the new analogy between molar and molecular forces, 
which seems to be indicated by the atmospheric exponents, are all interest- 
ing. The viscous particles, so far as they are affected by the same move- 
ments, may be compared to the rotating particles of a solid nucleus ; the 
thermal undulations, in a supposed ethereal medium, present a like analog 
to the motions of an elastic atmosphere. The well known anomalies in 
the elasticity of hydrogen are in accordance with its viscosity. War- 
* Ante, xiv, 305 et. al. 
