C171 
990 kilom. per sec. In another case, also observed by Fúxvr (July 
15% 1889), in the course of 10 minutes the ascending velocity 
passed through the values 72, 6, 65, 24, 154 kilometers per second; 
and with the prominence of Oct. 6, 1890, in 30 minutes’ time 
iheoneh the valués 33,8;..79,8, 67,6,-72,7, 127,7 275,5, 249.3. 121. 
57,3 kilom. per sec. 
Considering the problem from the new point of view we see the 
difficulties disappear in consequence of the observation, that, properly 
speaking, we have not to do with velocities at all. We 
may speak of the velocity with which matter moves or with which 
a disturbance is transmitted by a medium; but neither of these cases 
is met with here. Wherever the whirling sets in, it results from local 
conditions and cannot be considered as directly transmitted from places, 
where whirling was going on a little earlier. Though it is true that, 
as a rule, the breaking of a wave begins in those parts of a surface 
of discontinuity, that are nearer to the Sun’s axis, and from there 
proceeds outwards, yet this does not involve that we should have a 
right to call this process a transmission of matter or of motion in 
the direction of the vortex-cores. And where there is no transmission, 
there is no velocity. 
When at the sea-shore a wide wave approaches and breaks, now 
here, then farther and farther, nobody will speak of the velocity” 
with which the foam or the whirling is moving alone the coast. 
Every body knows, that the foam, the visible token of the whirling, 
is successively formed at different places. Such about is the case 
with the prominences, the visible spots in the breakers of the solar ocean. 
Chemistry. — Professor Losey pr Bruyn communicates a paper 
by himself and Mr. J. W. Drro. “The botlingpoint-curve of 
the system: hydrazine + water”. 
In a previous report’) Mr. Drro has communicated the results of 
determinations of the densities of mixtures of hydrazine and water; 
the figures showed that a maximum density corresponds exactly (or 
nearly so) with the composition N, H,-H,O. At the end of that note 
it was stated that we would endeavour to determine the boiling- 
point-curve of the system: hydrazine + water. 
We have lately been engaged with that determination; the result 
is given in the following table and annexed curve, 
1) Proc. of April 19, 1902, p. 838. 
