
THE 
PHYSICAL REVIEW 
A JOURNAL OF EXPERIMENTAL AND 
THEORETICAL PHYSICS 
American Physical Society 
EDWARD L. NICHOLS 
ERNEST MERRITT, AND FREDERICK BEDELL 

Twentieth Volume Begins JANUARY 1905 
PUBLISHED MONTHLY ANNUAL SUBSCRIPTION $5.00 
SAMPLE COPY UPON REQUEST 
THE MacMILLAN COMPANY, 
66 FIFTH AVENUE, NEW YORK 
THE AMERICAN JOURNAL OF SCIENCE 
` Established by BENJAMIN SILLIMAN in 1818 



The Leading Scientific Journal in the United States 
Devoted to the Physical and Natural Sciences, with special ee to PE 
and Chemistry on the one hand, and to Geology eut: Mineralogy 
Editor: EDWARD S. DANA 
Sennat Editors : eigen GEORGE L. GOODALE, JOHN TROWBRIDGE, 
S, of 

W.G. 
Prorzssons A. E. VERRILL, HENRY S. WILLIAMS, and L. V. PIRSSON, of New Haven; 
Prorsssor G. F. BARKER, of Philadelphia ; FESSOR JOSEPH S. AMES, of Baltimore 
Mz. js. DILLER, 3 Washington. 
wo volumes annually, in monthly numbers of about 80 pages. im 
es Journal ended its fe series of 5o volumes as a quarterly in uer : d second series — ree 
of 50 volumes as a two-monthly in 1870; its Zhird series as a mon thly en ded -Decamber,: = 
1895. A FOURTH ind commenced in January, 1896 m 
Subscription price $ j porki the United. 
States; $6.40 to foreign subscribers of countries in the Po stal pube "A few sets on sale of 
the frst, second, and third series at reduced prices. Tenvolume index n umbers m an 
for the second and third series. = 
-THE AMERICAN JOURNAL OF SCIENCE - 
NEW HAVEN, CONI 



