2 
PHYSICS: C. BARUS 
Proc. N. a. S. 
gradually but continuously vanishing; or of a spontaneous tendency of 
the wire to regain the original molecular condition, free from strain. An 
example of the observation taken in November is given in the figure, 
and it shows the deflection of the needle (left without direct interference) 
on successive days. 
As to the kinks in the curve which increase enormously (with the ad- 
vent of cold weather, the need of more heat increases), they may be due 
to thermal expansion in the supports of the telescope, or to radiant forces. 
But as they are always accompanied by a corresponding vibration of the 
needle, the latter cause must be in preponderance, so that radiant forces 
are not, even in case of these large masses, to be disregarded. 
Apart from the irregularities, the curve, as a whole, rises uniformly, 
because of the viscous detorsion specified, at a rate of about 0.08° of de- 
torsion per day, and it has kept this up uniformly for months. One may 
notice that in view of the large weight (over 3 kg.) suspended, the wire 
is kept at relatively low viscosity, i. e., full of unstable molecular con- 
figurations. Utilizing these, the torsional set obtains facility of exit. 
How the wire acquired this torsional strain is hard to see, unless it was 
reeled helically. This was probably the case, as the free wire, placed on 
a plane, shows a helical form, with a pitch of about 2 feet. That the 
strong tensile strain, which is also vanishing, should, in the suspended 
wire, make its exit torsionally is improbable, for there would be no reason 
for the sign of the twist; but the tensile strain probably developed the 
torsional strain in the lapse of- time on the reel. 
