Febeuaey 26, 1897.] 



SCIENCE. 



359 



series. In this paper he discusses the species 

 commonly known as Orihis testudinaria, and con- 

 cludes that several separate forms are gener- 

 ally comprised in it and that the original species 

 has no typical American representative. 



Professor Jules Marcou finishes his review of 

 ' Eules and Misrules in Stratigraphic Classifi- 

 cation.' Especial application is made to vari- 

 ous members of the Orodovician, Mesozoic, 

 Tertiary and Quaternary. In a postscriptum 

 the three official geological maps of the State of 

 New York are compared in some detail. 



The extreme rapidity of weathering and 

 stream erosion in the artic latitudes is described 

 by Professor R. S. Tarr. The, abundant lichen 

 flora, the air and water and the great varia- 

 tions of temperature are the active agents. 



SOCIETIES AND ACADEMIES. 



NEW YORK ACADEMY OF SCIENCES, FEBEUAEY 



1, 1897. 



SECTION OF ASTRONOMY AND PHYSICS. 



The first paper was one postponed from last 

 month by H. Jacoby, ' On two Trailplates of 

 Circumpolar Stars, made by Anders Donner at 

 the Helsingfors Observatory.' 



It was explained that these photographic 

 negatives of circumpolar stars were taken with 

 the telescope stationary, and hence that each 

 star left a trail upon the plate, which, after 

 necessary corrections, would be an arc of a circle 

 around the true north pole of the heavens. The 

 exposure, which was for a few moments at 

 intervals of a half hour, extending over 14 

 hours, thus gave a series of short arcs extending 

 over a little more than a semicircle. This 

 method, if no unforeseen difficulties appear, 

 should give the position of the pole to within a 

 few hundredths of a second of arc and a sys- 

 tem of right ascensions differing from the 

 truth by a uniform correction. 



The paper was discussed by R. S. Woodward 

 and others. 



Mr. P. H. Dudley then presented a paper 

 under the following title : ' Investigations of 

 Undulations in railway tracks by his track 

 indicator, and the reduction of two-thirds of 

 the amount in the last fifteen years, by the use 

 of his stiff- rail sections. ' 



Mr. Dudley pointed out the causes and char- 

 acter of the inequalities in railroad rails, and 

 described his very perfect car for obtaining a 

 complete record of the condition of the track 

 while travelling at 20 to 25 miles per hour. 

 Among other records given is the summation of 

 the inequalities of the rail per mile. A dozen 

 years ago this total unevenness amounted to six 

 or seven feet even on the better roads ; now as 

 a result of the records of the car, and of new 

 designs and methods of manufacture of rails, 

 the total has been reduced to 18 to 20 inches. 

 It was shown that this remnant was due to 

 dents in the rails and could not be helped by 

 work on the road bed, but must be reduced by 

 further improvements in the manufacture of the 

 rails. 



Sections of rails and indicator records were 

 exhibited, and lantern slides shown to illus- 

 trate the above improvements on the New York 

 Central and Boston and Albany system. A 

 great proportion of the gain is due to the im- 

 provement in Mr. Dudley's improved rail sec- 

 tions, which give a maximum of rigidity and 

 wear, with a minimum of weight. 



R. S. Woodward pointed out the extreme 

 importance of many of the problems upon 

 which Mr. Dudley is working, and hoped that 

 the author's idea of a rail-rolling machine, 

 which would turn out a 60-ft. rail straight and 

 cold, would soon be put into operation. W. Hal- 

 lock remarked upon the advantages to science 

 which were sure to come from the author's in- 

 vestigation of many physical questions which 

 cannot be studied in a laboratory and need a 

 railroad to experiment with. 



J. J. Stevenson called attention to what the 

 community at large owes to Mr. Dudley's im- 

 provements. It means heavier engines, heavier 

 cars,longer trains, greater speed, reduced freight 

 and passenger rates, all of which greatly con- 

 tribute to the general welfare and the advance 

 of civilization. 



H. S. Curtis presented a paper on ' The ad- 

 vantages of long-focus Lenses in Landscape 

 Photography.' After referring to the unsatis- 

 factory results of photographing landscapes 

 with ordinary lenses, owing to false perspective 

 and lack of detail, he showed how this was 

 remedied by lenses of longer focus. A telescopic 



