Or, Walking, Swimming, And Flying.

With a Dissertation on Aeronautics.

By J. Bell Pettigrew, M. D., F. R. S., F. R. S. E., F. R.C. P.E.

I vol., 12mo......Price, $1.75.

"This work is more than a contribution to the stock of entertaining knowledge, though, if it only pleased, that would be sufficient excuse for its publication. But Dr. Pettigrew has given his time to these investigations with the ultimate purpose of solving the difficult problem of Aeronautics. To this he devotes the last fifty pages of his book. Dr. Pettigrew is confident that man will yet conquer the domain of the air."-N. Y. Journal of Commerce.

"Most persons claim to know how to walk, but few could explain the mechanical principles involved in this most ordinary transaction, and will be surprised that the movements of bipeds and quadrupeds, the darting and rushing motion of fish, and the erratic flight of the denizens of the air, are not only anologous, but can be reduced to similar formula. The work is profusely illustrated, and, without reference to the theory it is designed to expound, will be regarded as a valuable addition to natural history." - Omaha Republic.

D. Appleton & CO., Publishers, 549 & 551 Broadway, N. Y,

Opinions of the Press on the "International Scientific Series."