Voi,. 7, 1921 RESEARCH COUNCIL PUBLICATIONS 
361 
Number 6- Data relating to X-ray spectra. By William Duane. November, 
1920. Pages 26. Price 50 cents. 
Number 7. Intensity of emission of X-rays and their reflection from crystals. By 
Bergen Davis. Problems of X-ray emission. By David L. Webster. De- 
cember, 1920. Pages 47. Price 60 cents. 
Number 8. Intellectual and educational status of the medical profession as repre- 
sented in the United States Army. By Margaret V. Cobb and Robert M. 
YerkES. February, 1921. Pages 76. Price $1.00. 
i 
Volume 2 
Number 9. Funds available in 1920 in the United States of America for the encourage- 
ment of scientific research. Compiled by CalliE Hull. March, 1921. Pages 
81. Price $1.00. 
Number 10. Report on photo-electricity including ionizing and radiating potentials 
and related effects. By Arthur Llewelyn Hughes. April, 1921. Pages 87. 
Price $1.00. 
Number 11. The scale of the universe. Part I by Harlow ShaplEY. Part II by 
HebER D. Curtis. May, 1921. Pages 47. Price 60 cents. 
Number 12. Cooperative experiments upon the protein requirements for the growth 
of cattle. First report of the Subcommittee on Protein Metabolism in Animal 
Feeding. By Henry Prentiss Armsby, Chairman. June, 1921. Pages 70. 
Price $1.00. 
Number 13. The research activities of departments of the state government of Cali- 
fornia in relation to the movement for reorganization. By James R. Douglas. 
June, 1921. Pages 46. Price 60 cents. 
Number 14. A general survey of the present status of the atomic structure problem. 
Report of the Committee on Atomic Structure of the National Research Council. 
By David L. Webster and Leigh Page. July, 1921. Pages 61. Price 75 
cents. 
Number 15. A list of seismological stations of the world. Compiled by Harry O. 
Wood. (In press.) 
REPRINT AND CIRCULAR SERIES OF THE NATIONAL RESEARCH 
COUNCIL 
(To November, 1921) 
Number 1. Report of the Patent Committee of the National Research Council. 
Presented for the Committee by L. H. BaekELAND, Acting Chairman. Feb- 
ruary, 1919. Pages 24. Price 30 cents. 
Number 2. Report of the Psychology Committee of the National Research Council. 
Presented for the Committee by Robert M. Yerkes, Chairman. March, 
1919. Pages 51. Price 60 cents. 
Number 3. Refractory materials as a field for research. By Edward W. Washburn. 
January, 1919. Pages 24. Price 30 cents. 
Number 4. Industrial research. By F. B. JewETT. 1918. Pages 16. Price 25 
cents. 
Number 5. Some problems of sidereal astronomy. By Henry N. RussELL. Octo- 
ber, 1919. Pages 26. Price 30 cents. 
Number 6. The development of research in the United States. By James Row- 
land Angell. November, 1919. Pages 13. Price 25 cents. 
Number 7. The larger opportunities for research on the relations of solar and ter- 
