760 



SCIENCE. 



[N. S. Vol. XX. No. 518. 



tific work in agricultural science, and will 

 not include the results of the ordinary trial 

 of manures and varieties for demonstration or 

 commercial purpose. It is proposed to issue 

 the journal as material accumulates, aiming 

 at quarterly parts of about 100 royal 8vo 

 pages, four parts to constitute a volume. 

 Among those who have promised to support 

 the journal are : Professor H. E. Armstrong, 

 r.E.S., Professor M. J. E. Dunstan, Dr. Ber- 

 nard Dyer, Professor Liveing, Mr. A. E. Ship- 

 ley, Dr. J. Augustus Voelcker, and Professor 

 Marshall Ward. The first number will be 

 published in January, 1905. 



SOCIETIES AND ACADEMIES. 



PHILOSOPHICAL SOCIETY OF WASHINGTON. 



The 589th regular meeting was held Oc- 

 tober 29. 



Father Hagen, of the Georgetown Obser- 

 vatory, gave an account of ' Astronomy and 

 Mathematics at the International Congress of 

 Arts and Science,' speaking of the papers 

 read, the persons present, the exhibits in va- 

 rious parts of the grounds and the formal and 

 informal gatherings. Two great European 

 ■congresses held just previous to that at St. 

 Louis kept away many of the expected 

 visitors. 



Mr. C. E. Van Orstrand, of the Geological 

 Survey, then presented a paper on ' A Load- 

 Strain Function for Finite Strains.' The re- 

 sults of numerous experiments were summar- 

 ized as showing that the load-strain curve is 

 in general convex to the axis of loads, al- 

 though in some instances there is one point 

 of inflexion. Since matter is indestructible, 

 the ordinates of the curve between the points 

 of rupture for tension (a;,) and compression 

 ■{x^y are necessarily finite and positive. 

 Hence the load-strain function can contain 

 no zeros and no negative values between the 

 limits x^ and x,. There is a point of discon- 

 -tinuity at a;,, and for certain substances there 

 may also be a point of discontinuity at x . 

 Functions satisfying these conditions were de- 

 fined by means of the function-theory. A 

 ■special form of the most general equation is 



where y = strained length and x = applied 

 load. 



For the case of perfect elasticity, x^ = 

 4- oo , and a particular form of the equation is 



a relation which has previously been deduced, 

 but by a wholly different method.* It was 

 shown that this equation represents the data 

 of observation to a high degree of accuracy 

 within the limits ordinarily defined as per- 

 fectly elastic. The materials selected were 

 vulcanized India rubberf and various kinds 

 of metallic wires.:): 



A letter from Dr. Becker was read express- 

 ing his appreciation of Mr. Van Orstrand's in- 

 vestigation. 



Mr. C. W. Waidner, of the Bureau of Stand- 

 ards, gave the results of numerous determina- 

 tions by himself and Mr. G. K. Burgess, of 

 ' The Temperature of the Electric Arc' A 

 photometric method was used based on Wien's 

 law and the instruments were calibrated at 

 higher temperatures than had been done here- 

 tofore, so the uncertainty from extrapolation 

 was reduced; the results were very accordant 

 and gave about 3700° C. An increase of 70° 

 to 80° was found when the current forming 

 the arc was raised from 15 to 30 amperes. 

 Charles K. Wead. 



the geological society of WASHINGTON. 



The 158th meeting of the Society on No- 

 vember 9 had the following regular program: 



Mr. S. F. Emmons spoke of copper ores in 

 Carboniferous limestone in the region of the 

 Grand Canyon of the Colorado, some of 

 which he had an opportunity of visiting 

 during the past summer. Their origin had 

 been ascribed to the leaching of the copper 

 from the red sandstones which once overlay 

 them but are now eroded away. He used 

 these occurrences as a text to discuss the gen- 

 eral question as to whether the widespread 

 occurrences of copper in the Permian and 



* ' The Finite Elastic Stress-Strain Function,' 

 Dr. George F. Becker, Am. Jour. Sci., 1893. 



t Watertown, ' Tests of Metals,' 1893. 



j ' Ueber das Gesetz der elastischen Delinung,' 

 •J. 0. Thomson, Ann. d. Plujs., 3, 1891. 



