March 16, 1917] 



SCIENCE 



263 



The Earliest Fresh-Waier Arthropods: 

 diaries Seliueliert, Peabody Museum, Tale 

 University. If the eurypterids and limulids 

 arose in the fresh water we can explain why 

 they and the terrestrial scorpions do not pass 

 through a crustacean stage. It may well be 

 that the trilobites retaining the nauplius stage 

 do not give rise to these stocks. "We may look 

 for this ancestral stock in one still more 

 primitive, which seems to have permanently 

 invaded the rivers of the land either in Pro- 

 terozoic time or in Walcott's Lipalian time. 



Ohservations upon Tropical Fishes and In- 

 ferences from their Adaptive Coloration: 

 W. H. Longley, G-oucher College, Baltimore. 

 The observations here presented undermine 

 many speculative explanations of animal 

 coloration in terms of natural selection. 



Eeport of meetings of the ISTational Research 

 Council and of its Executive Committee. 



Address by Lieut. Colonel George O. Squier, 

 on Scientific Research for l^ational Defense as 

 Illustrated by the Problems of Aeronautics. 



Research Grants from the Trust Funds of 

 the Academy. 



Eeport of the Autumn Meeting. 



We may summarize the articles in Yolume 

 2 of the Proceedings as follows : Mathematics, 

 20; Astronomy, 29; Physics and Engineering, 

 23; Chemistry, 15; Geology and Paleontol- 

 ogy, including Mineralogy and Petrology, 33 ; 

 Botany, 9 (see also Genetics) ; Zoology, includ- 

 ing General Biology, 20 (see also Genetics) ; 

 Genetics, 10; Physiology and Pathology, 13; 

 Anthropology, 10; Psychology, 4; a total of 

 186 articles. 



The division of these articles between mem- 

 bers of the Academy and non-members is 63 

 and 123, respectively. 



The list of institutions which have contrib- 

 uted three or more articles is as follows : Har- 

 vard, 31; Carnegie Institution, 29, divided as 

 follows : Solar Observatory 19, Marine Biol- 

 ogy 3, Station for Experimental Evolution 3, 

 all other departments 4; University of Chi- 

 cago, 12; Johns Hopkins University, 11; Uni- 

 versity of California, 7; Yale University, 7; 

 Princeton University, 5; Maine Agricultural 

 Experiment Station, 5; Brown University, 5; 



Massachusetts Institute of Technology, 5; 

 U. S. Geological Siirvey, 4; University of 

 Illinois, 4; Smithsonian Institution, 4; Rocke- 

 feller Institution for Medical Research, 4; 

 Observatorio Nacional Argentine, 3. 



Edwin Bidwell Wilson 

 Mass. Institute of Technology, 

 Cambridge, Mass. 



NOTES ON METEOROLOGY AND 

 CLIMATOLOGY 



evaporation measurement 

 Loss of moisture from plant and animal 

 surfaces and from the soil interests the plant 

 physiologists, plant and animal ecologists;, 

 and students in agriculture and forestry; but 

 evaporation from a free water surface appeals 

 to irrigation and hydraulic engineers. On 

 this account, a type of instrument satisfactory 

 to the one group will not meet the require- 

 ments of the other. Although the rate of 

 evaporation depends primarily on temperature, 

 wind-velocity, humidity, it is a function of 

 the nature of the atmometer as well. For in- 

 stance, the size, shape, material and color of 

 the pan, the height of the projecting rim, and 

 sediment, color and depth of the water, and 

 the nature of the evaporating surface, affects 

 strongly the evaporation. This being the case. 

 Dr. B. E. Livingston says :^^ 



The ratio of the rate of the evaporation from 

 one kind of atmometer pan to that from another 

 kind remains constant only for some single set of 

 surrounding conditions. Thus the evaporation rate 

 from any atmometer varies with the relation be- 

 tween the internal complex of conditions (nature 

 of the instrument) and the external complex (the 

 surrounding conditions of the atmosphere). . . . 

 The exposure of several evaporating surfaces must 

 be alike if their readings are to be comparable. 



The readings of one instrument, therefore, 

 can not be reduced to terms of another. 



Although many evaporation observations of 

 various sorts have been taken in the United 

 States,^- this lack of comparability prevents 



11 Mo. Weatlier Sev., 43, pp. 126-131, 1915, "At- 

 mospheric Influence on Evaporation and Its Di- 

 rect Measurement. ' ' 



12 T. Eussell, "Depth of Evaporation in the 



