BY K. O. DAVIDSON. 
Philosophy, in the highest and most appropriate meaning of the 
term, is the key (to employ a simple metaphor) with which wise 
men unlock the doors leading into the occult recesses of Nature's 
limitless empire, where alone can be discovered her elemental prin- 
ciples ; the secret germs of her countless organisms ; the vis inertia 
of her grand systematic revolutions, and the laws of her simple motions^ 
But, it is quite certain that there is about an equal portion of truth 
and error mixed up in the mass of philosophy, so called ; and gener- 
ally, it is as difficult to detect and remove old errors, as to discover 
and establish new truths throughout the vast fields of physical and 
metaphysical science. And among the great number of prominent 
subjects which, hitherto, have claimed the attention of philosophers, 
there is none which is so constantly open to view, and that has been 
so long and attentively observed, with the discovery of so little of 
truth, as that of our present inquiry— ^Ae flight of birds. 
The cause of this, I imagine, is to be found in the nature of the 
various circumstances connected with the production of this motion, 
consisting chiefly in the great velocity of the animal on the wing ] 
his remoteness from the observer ; the airy and unsubstantial medium 
in which it Occurs ; and the peculiar form, flexibility and celerity of 
motion of the organs by which alone it is, seemingly, produced. At 
any rate, from these or some other cause, it is certain that men of 
science, and all others, have utterly failed to solve the lofty problem, 
" the way ef an eagle in the air." 
There are several varieties or modifications of this motion, each of 
which occurs under, and is controlled by, particular circumstances ; 
such as that of ascending, progressing on horizontal lines, and de- 
scending under the action of the wings ; and the exhibition of similar 
