Defn: The region surrounding a moving body, such as the wing of a bird or a gliding aëroplane, within which cyclic or vortical motion of the air occur.
Defn: Of or pertaining to a vortex or vortexes; resembling a vortex in form or motion; whirling; as, a vortical motion.
It is spontaneously inflammable, owing to impurities, and in burning produces peculiar vortical rings of smoke.
On the contrary, they may and do move both towards the poles and downwards by circuitous and even vortical paths.
This return will then take the form of violent storms of wind, usually of a cyclonic nature, and affording direct evidence of the tendency of the air masses to pursue vortical paths in their movement towards lower levels.
But, however estimated, this involution seems to afford a measure of the air and vapor which finds its way to a higher elevation by means of the vortical movement in the body of the storm.
The Monades are obviously the simplest organized creatures, being mucous vesicles, which move, obtain their food by stirring upvortical currents in the water, and emit what is undigested again by the mouth.
The cilia also are perfected and lengthen into filaments, which no longer perform simply vortical movements, but now actually seize and convey the food self-substantially into the mouth.
Whence comes the vortical motion which has produced their forms?
The gradual establishment of a vortical motion such as we saw must eventually arise, and such as we at present see indicated in the spiral nebulae, is the gradual approach toward motion in one plane--the plane of greatest momentum.
That some of them exhibit clear marks of vortical motion is undeniable; and if this is so, the question arises--What is the degree of likelihood that there are two causes for spots?
Hence the whole assemblage of flocculi will break up into groups: each group concentrating towards its local centre of gravity, and in so doing acquiring a vortical movement like that subsequently acquired by the whole nebula.
Considering that they have so many characters in common, it is extremely improbable that their common characters are in some cases the concomitants of vortical motion and in other cases the concomitants of a different kind of action.
The gradual establishment of a vortical motion such as we at present see indicated in the spiral nebulæ, is the gradual approach towards motion in one plane.
