210 National Geographic Magazine. 
the actual motions of the particles of air as they flow inward 
below, whirl about the central core and flow outward above ; 
this may help to free the mind from an erroneous idea that may 
be suggested by thinking of or seeing the enormous, piled-up, 
apparently stationary mass that constitutes the barra, or cloud- 
bank of the hurricane, but which is really only the stationary 
and visible Jocws where the conditions are such that the whirling, 
rushing masses of humid atmosphere condense their tons of 
aqueous vapor and leave it, as they pass upward and outward. 
Sketch, in cross-section, to illustrate the cloud-formation, storm-wave, etc.. in a 
hurricane. The dotted lines represent the probable circulation of the upper 
atmosphete. 
Sketch, in perspective, to illustrate graphically the lower-atmosphere-wind- 
circulation in a hurricane. The inward spiral at the base is the surface wind. 
It is analogous to the cloud-cap, or banner, that hangs stationary 
over a lofty mountain peak, although if you visit the peak you 
may there find a living gale of wind. 
In both of these sketches my object has been to try to convey 
an idea of the marked individuality, symmetry, and intensity of 
a tropic cyclone, and its grasp upon and intimate connection with 
the ocean, which it joins to the upper atmosphere by a huge, 
hollow trunk, with widely extended roots and spreading branches, 
—no doubt an enormous and effective conductor of atmospheric 
electricity, too, whose power is quickly shattered and destroyed 
by contact with the land ; the notable absence of thunder (illus- 
