



THE 
PHYSICAL REVIEW 
A JOURNAL OF EXPERIMENTAL AND 
THEORETICAL PHYSICS 
American Physical Society 
BY 
DWARD 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 reference to € 7 see 
and Chemistry on the one hand, and to Geology and Mineralogy on the 
: Editor: EDWARD S. DANA 
Associate Y an r GEORGE L. Ba JOHN TROWBRIDGE, 
and V bridge; 
PRorzssons A. E VERRILL, HENRY S. WILLIAMS, d E V. PIRSSO 
PRorEsso FESSOR G. F. BARKER, hiladelphia R JOS OSEPH S. AMES, of 
ud > S. cde. of ‘Washington. 

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of 50 volumes a monthly in 1870; is third series as a mon 
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THE AMERICAN JOURNAL OF SCIENCE - 
NEW HAVEN, | CONN. 7 
N, of New a = 8 
volumes as a peu ie pee iti coed series — — 
ded December, 
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