REPORT OF THE SECRETARY. 107 



Tlie composition and structure of meteorites compared witli that of terres- 

 trial rocks, by George P. Merrill. 14 pj)., 9 pis. (Publ. 2505.) 



Corals and the formation of coral reefs, by Thomas Wayland Vaughan. 88 

 pp., 37 pis. (Publ. 2506.) 



The correlation of the quaternary deposits of the British Isles with those of 

 the continent of Europe, by Charles E. P. Brooks. 99 pp. (Publ. 2507.) 



Natural history of Paradise Key and the near-by everglades of Florida, by 

 W. E. Safford. 58 pp., 64 pis. (Publ. 2508.) 



Notes on the early history of the pecan in America, by Rodney H. True. 14 

 pp. (Publ. 2509.) 



Floral aspects of the Hawaiian Islands, by A. S. Hitchcock. 14 pp., 25 pis. 

 (Publ. 2510.) 



The social, educational, and scientific value of botanic gardens, by John 

 Merle Coulter. 6 pp. (Publ. 2511.) 



Bird rookeries of the Tortugas, by Paul Bartsch. 32 pp., 38 pis. (Publ. 

 2512. ) 



Catalepsy in Phasmidae, by P. Schmidt. 5 pp. (Publ. 2513.) 



An economic consideration of orthoptera directly affecting man, by A. N. 

 Caudell. 8 pp. (Publ. 2514.) 



An outline of the relations of animals to their inland environments, by 

 Charles C. Adams. 28 pp. (Publ. 2515.) 



The National Zoological Park — A popular account of its collections, by N. Hol- 

 lister. 51 pp., 46 pis. (Publ. 2516.) 



The sea as a conservator of wastes and a reservoir of food, by H. F. Moore. 

 14 pp., 8 pis. (Publ. 2517.) 



0.iibway habitations and other structures, by David I. Bushnell, jr. 9 pp., 6 

 pis. (Publ. 2518.) 



National work at the British Museum — Museums and advancement of learn- 

 ing, by F. A. Bather. 15 pp. (Publ. 2519.) 



Leonhard Fuchs, physician and botanist, 1501-1566, by Felix Neumann. 13 

 pp., 7 pis. (Publ. 2.520.) 



In memoriam — Edgar Alexander INIearns, 18.56-1916. by Charles W. Rich- 

 mond. 14 pp., 1 pi. (Publ. 2521.) 



William Bullock Clark. 4 pp. (Publ. 2522.) 



KEPORT FOR 1918. 



The general appendix to the report for 1918, wliich was still in 

 press at the close of the year, contains the following papers : 



1. The discovery of helium, and what came of it, by C. G. Abbot. 



2. An account of the rise of navigation, by R. H. Curtiss. 



3. The tornadoes of the United States, by Robert DeC. Ward. 



4. Wind power, by James Carlill. 



5. A tribute. Samuel Pierpont Langley : Pioneer in practical aviation, by 

 Henry Leffmann. 



6. Modern physics, by R. A. Millikan. 



7. The experiments of Dr. P. W. Bridgman on the properties of matter when 

 under high pressure. Introductory note by C. G. Abbot. 



8. The problem of radioactive lead, by Theodore W. Richards. 



9. Sphagnum moss ; war substitute for cotton in absorbent surgical dress- 

 ings, by George E. NichoLs. 



10. History of military medicine and its contributions to science, by Col. 

 W. P. Chamberlain. 



