334 On the Ebullition of Rotating Water. 



rotates as it nears the axis of rotation. This fact is also 

 evident from the inspection of the lines formed by the small 

 bubbles rotating near the base of the steam-column as already 

 mentioned. One might naturally expect that the outbursts 

 of e-team, (those which occur during the pulsation period), 

 would occur when the surface vortex was deepest, — instead of 

 which the exact opposite is the case. At times, too, large 

 bubbles of steam form suddenly in the water and condense, 

 without the surface-level of the water in the jar being simul- 

 taneously visibly disturbed : at any rate, if it be so — and it 

 would seem that it must be, considering the high elasticity 

 and incompressibility of water, — the disturbance is anything 

 but easy to observe. 



With respect to the cause of the pulsations already alluded 

 to, it may be well to state that by stirring cold water in a 

 beaker-shaped jar, having a small hole in its bottom through 

 which a stream of air-bubbles can be blown (to imitate the 

 generation of the steam, but not its condensation), there is 

 abundant evidence from the motion of small bubbles that 

 pulsations set in in this case also, and indeed there is some 

 evidence of a similar phenomenon when an ordinary glass of 

 water is stirred: hence it does not seem likely that in the case 

 of the hot water the pulsations are directly caused by either 

 the formation or condensation of the steam, although this 

 may reinforce them when once they have been set up. 



Lastly, the form of the steam-columns often presents an 

 unmistakable likeness to those of solar prominences, which 

 can scarcely be altogether fanciful ; for there is every reason to 

 believe that the latter are explosive emissions of gaseous matter 

 projected through and above the solar atmosphere. May not 

 their immediate cause be the diminution of pressure on the 

 sun's surface at and near the centre or centres of " depressions " 

 caused by violent cyclonic disturbances in the solar atmo- 

 sphere ? The enormous velocity with which such ejected 

 matter is seen to rise, and also the rapidity with which it is 

 dispersed, have their counterparts in the experiments which 

 have been described: no one who sees these last for himself 

 can fail to be impressed by the great velocity with which 

 the steam-column rises in the water, and by the suddenness 

 with which it condenses, and that, too, in water at, or at any 

 rate very near to, its boiling-point,— whilst the hanging fila- 

 ments such as appear in fig. 3 recall most vividly some well- 

 known drawings of solar prominences as they die out : the 

 fact that in both cases the filaments hang with their length 

 vertical, and do not lie horizontally, seems to the writer very 

 significant. 



