On the Vertical Currents of the Atmosphere. 421 
Among the meteorological notices, we find it stated that about 
three-quarters of an hour after the total eclipse, clouds approached 
the sun from the eastward, which harmonizes with what we have 
assumed above; it must not, however, be overlooked that in the 
morning rain-clouds came up from the west ; so that here, again, 
the direction of the current of the air remains undecided. 
It would be easy to gather from the reports before us on the 
total solar eclipses that have been observed, many more addi- 
tional hints that coincide with and support my explanation of 
the red prominences; but I confine myself to what has been 
stated above, and this the more from my being of opinion that 
decisive facts have first to be arrived at by future observations. 
It will be especially advisable to follow up the masses of vapour 
that condense in the cone of shadow,—and to do so not only at 
the moon’s edge, but likewise in the aureole as far outwards as 
the light extends, determining at the same time their magnitude 
and the direction of their motion; perhaps, indeed, it might be 
practicable to gain some information upon this head immediately 
previous to the disappearance of the sun, and immediately sub- 
sequent to its reappearance. The visibility of the masses of 
vapour depends mainly on their density; and that they are not 
unfrequently of considerable density is proved by the occurrence 
of prominences that are black, or which at least are bounded by 
a black border. 
LVI. On the Vertical Currents of the Atmosphere. By HENRY 
Hennessy, F.R.S., M.R.I.A., Professor of Natural Philosophy 
in the Catholic University of Ireland *. 
1. FT has long been recognized that, although currents of wind 
in a direction nearly parallel to the horizon are those which 
usually prevail, the atmosphere is frequently subjected to vertical 
and oblique motions among its particles. 
Under favourable conditions these motions may acquire such 
a development as to force themselves upon the attention of 
observers, and thus become objects for meteorological inquiry. 
The interesting researches of M. Fournet upon the vertical cur- 
rents of mountains, appear to have arisen from the opportunities 
enjoyed by that physicist of studying such phenomena among 
the Alps. Among the deep ravines and valleys, as well as along 
the elevated slopes and escarpments of the Alps, a regular 
periodicity in the action of vertical winds has frequently been 
observed during the course of twenty-four hours, which has led 
to the conclusion that their development depends upon changes 
* From the Atlantis, No. V. Communicated by the Author. 
Phil, Mag. 8. 4. Vol. 19. No, 129. June 1860. 2F 
