But putting aside economic and utilitarian considerations, there is to some of us a greater stimulus to solve the problems of nature. With the birds, and the insects and plants upon which they feed, we share a common heritage, and the more we learn of the life of these, our fellow workers, the nearer we approach solution of the great riddle of the Universe, the mysterious law-abiding scheme of Nature. The book of knowledge to which we may add some iota is marred with mystery, superstition and error, but each proved fact cleanses its pages. "Facts," says Laing, "are the spokes of the ladder by which we climb from earth to heaven." * * * * * BIBLIOGRAPHY 1. ALLEN, J. A. Cooke's _Some New Facts about the Migration of Birds_, _Auk_, xxi., 1904, 501. 2. ---- Gätke's _Heligoland_, _Auk_, xiii., 1896, 137. 3. ---- Walter's _Theories of Bird Migration_, _Auk_, xxv., 1908, 329. 4. BARRINGTON, R. M. "The great rush of Birds, etc." _Irish Nat._, xx., 1911, 97. 5. ---- _The Migration of Birds as observed at Irish Lighthouses and Lightships_, London, 1900. 6. BAIRD, S. F. "The Distribution and Migration of North American Birds." _Amer. Jnl. Science and Arts_, 2, 1866, xli. 7. BREHM, C. L. "Der Zug der Vögel," _Isis_, 1828, _Naumannia_, 1855. 8. BREWSTER, W. "Bird Migration." _Mem. Nuttall Orn. Club_ Cambridge, Mass. No. 1, 1886. 9. BROOKS, W. K. _The Foundations of Zoology_, New York, 1899. 10. _Bulletin of the British Ornithologists' Club. Reports on Migration_, vols. xvii., xx., xxii., xxiv., xxvi., 1906-1910. 11. CARPENTER, F. W. "An Astronomical Determination of the Heights of Birds," _Auk_, xxiii., 1906, 210. 12. CHAPMAN, ABEL. _Bird-Life of the Borders_, 2nd edit., London 1907. 13. ---- F. M. "Observations on the Nocturnal Migration of Birds," _Auk_, 1888, 37. 14. CLARKE, A. H. "The Migration of Certain Shore Birds," _Auk_, xxii., 1905, 134. 15. CLARKE, W. E. "Bird Migration in Great Britain." _Report of the British Association_, _London_, 1896. 16. ---- "Studies in Bird Migration," _Ibis_, 1902, 246, 1903, 112. 17. CLARKE, W. E. "The Birds of Fair Island; Native and Migratory." _Ann. Scot. Nat. Hist._, 1906, 4. 18. COOKE, W. W. "Distribution and Migration of North American Shorebirds." _U.S. Dept. Agric. Biol. Survey_, Bull, 35, Washington, 1910. 19. ---- "Routes of Bird Migration," _Auk_, xxii., 1905, 1. 20. ---- "Some New Facts about the Migration of Birds." _U.S. Dept. Agric. Year Book_, 1903, 371. 21. ---- "Our Greatest Travellers." _Nat. Geog. Mag._, 1911, 346. 22. ---- "The Migratory Movements of Birds in Relation to the Weather." _U.S. Dept. Agric. Year Book_, 1910, 379.