November 2, 1906.] 



SCIENCE, 



571 



final means will be sufficient. These differ- 

 ences can best be shown by the following brief 

 table : 



White 



Yellow white 

 White yellow 

 Yellow, etc... 



+0.26 

 +0.23 

 +0.07 

 -0.06 



The most striking feature shown in this 

 table is the remarkable accordance in the mean 

 results at Bonn, Harvard and Oxford. In 

 each case there is a positive difference of about 

 a quarter of a magnitude for white stars, and 

 this quantity diminishes systematically to a 

 small negative value for the yellow-red red 

 stars. The systematic differences between the 

 Bonn, Harvard and Oxford catalogues are in- 

 appreciable. In all cases Potsdam makes the 

 white stars fainter and the red stars brighter 

 than the other three observatories. Between 

 these two extremes, however, somewhere be- 

 tween the whitish-yellow and yellow stars, the 

 differences disappear. The differences seem 

 difficult of explanation. On the one hand, we 

 have Potsdam with two observers and with 

 ZoUner photometers, and on the other hand, 

 Bonn, Harvard and Oxford, with eight ob- 

 servers and photometers of several kinds. The 

 differences concerned are small, however, and 

 it may well be regarded as remarkable that the 

 color scale of the different catalogues should 

 agree so closely that for stars of one color 

 the differences are positive, and for those of 

 another color, negative. 



Another relation is shown by arranging the 

 observations with regard to magnitude. We 

 may use for illustration Potsdam — PI. It 

 is thus found that the scale of magnitude of 

 the Harvard photometry lies, for stars of dif- 

 ferent color, on both sides of that of the Pots- 

 dam scale. Por white stars a full Harvard 

 magnitude equals about 1.05 of the Potsdam 

 scale; for yellowish- white, 1.03; for whitish- 

 yellow, 1.01; and for yellow and red stars, 

 0.94; and for all, about 1.00. Taking into 

 consideration the systematic differences which 



are found in the results of a single observatory 

 by different observers and instruments, as 

 shown in the present discussion for Potsdam, 

 and also the known influence of the Purkinje 

 phenomenon, the differences of scale between 

 Potsdam and Harvard are surprisingly small. 



Solon I. Bailey. 

 Harvard Coixege Observatory. 



BOTANICAL NOTES. 



BOTANY IN THE ST. LOUIS CONGRESS OP 1904. 



A LITTLE more than two years ago in the 

 Congress of Arts and Science of the Uni- 

 versal Exposition at St. Louis a considerable 

 number of botanical papers were read which 

 are now given wider publicity by being printed 

 in the fifth volume of the published proceed- 

 ings of that notable meeting. The following 

 papers on botanical subjects are printed in 

 this volume : ' Development of Morphological 

 Conceptions,' by Professor John M. Coulter; 

 ' A Comparison between Natural and Arti- 

 ficial Selection,' by Professor Hugo de Vries; 

 ' Plant Morphology,' by Professor Frederick 

 O; Bower ; * The Fundamental Problems of 

 Present-day Plant Morphology,' by Professor 

 Karl F. Goebel; 'The Development of Plant 

 Physiology under the Influence of the Other 

 Sciences,' by Professor Julius Wiesner ; ' Plant 

 Physiology — ^Present Problems,' by Professor 

 Benjamin M. Duggar ; ' The History and 

 Scope of Plant Pathology,' by Professor Joseph 

 C. Arthur ; ' Vegetable Pathology, an Eco- 

 nomic Science,' by Merton B. Waite; ' The 

 Position of Ecology in Modern Science,' by 

 Professor Oscar Drude ; ' The Problems of 

 Ecology,' by Professor Benjamin L. Robinson; 

 ' Relations of Bacteriology to Other Sciences,' 

 by Professor Edwin O. Jordan ; ' Some Prob- 

 lems in the Life-history of Pathogenic Micro- 

 organisms,' by Professor Theobald Smith. To 

 these may be added the two more general 

 papers — ' The Recent Development of Biology,' 

 by Professor Jacques Loeb, and ' The Problem 

 of the Origin of Species,' by Professor Charles 

 0. Whitman, and the brief introductory ad- 

 dresses by Professor Charles R. Barnes (plant 

 physiology) and Professor Charles E. Bessey 

 (plant pathology). Nor are these all that will 



