(888 ) 
A de ena C Remarks : 
2150 27 28 79° 0.033 | Perfectly clear ice, formed from 
8. 2150 23 30 79° 0.030 (distilled water with very little 
| Na, SO,,. 
Perfectly clear ice, formed from 
distilled water with more Na,SO,. 
ll 
9. 2150 3380 0033 
10. 11507512 S28" SOF 0028 
bo 
ze 
In the former measurements we found for steel wire of this thickness 
'= 0.029. Here we find as an average (only for ice from distilled 
water) (’= 0.031. This difference is scarcely noteworthy, since the 
theoretical value is about 2.5 times greater. Moreover the values 
found are slightly too large here, since the fall caused by the piece 
of ice melting away as a whole, could not be taken into account 
as in the former experiments, because these pieces contained no 
bubbles. The ice from the Na, SO,- solution gives the same value 
for ;G 
In the former communication it was suspected that one of the 
causes why the calculated value differs from the theoretical one, 
would be found in a lateral escape of the melting-water. This induced 
me to observe the wire microscopically during its descent. The 
microscope used had a magnification of 80; the wire sank at a 
distance of a few millimetres from a terminal plane of the small 
ice column and was observed in the microscope with reflected or 
transmitted light. This at once shows the spots with a refractive 
power, different from the surrounding parts, mentioned by QUINCKE 
and explained by him as “solidified foam-bubbles of oily salt- 
solution”. I was able to state distinctly that these spots consist of 
liquid. Immediately above the wire and at the sides from halfway 
the height, i.e. where the water is released from pressure, one sees 
numerous small bubbles which are bright in reflected light and 
consequently reflect totally. These bubbles are vacua. They often 
grow and shrink rapidly. As a rule they disappear quickly, but 
sometimes they grow over a distance of as much as several tenths 
of a millimetre when the wire sinks, and then are more or less 
quickly compressed. Also they detach themselves from the wire, 
rising as globules until they are stopped at a place where by a 
difference in refractive power an edge is visible. Hence they are 
stopped by ice that has formed. In a few cases these bubbles are 
not compressed but remain in existence by being enclosed all round 
by ice, so that no liquid can flow in. Then they are also distinctly 
visible macroscopically. The vivid motion of these bubbles over a 
fairly long distance from the wire proves that liquid is found there 
caus, 
