152 



SCIENCE. 



[N. S. Vol. XXI. No. 526. 



highest point reaching only 132 feet above the 

 sea. 



The flora is poor, embracing some 350 or 

 400 species, the relatively numerous cacti in 

 the genera Opuntia, Cactus, Melocactus and 

 Pilocereus emphasizing the desert-like condi- 

 tions prevailing on the islands. Five plant 

 areas were differentiated: (1) That of the 

 strand; (2) the scrub, where nearly all the 

 endemic species of the islands have been 

 found; (3) the white sand or white land, as 

 it is called locally, characterized by a species 

 of Coccothrinax; (4) the salinas, characterized 

 by the shrub Avicennia nitida Jacq., and (5) 

 the savannas, where Conocarpus sericea Forst. 

 is the characteristic shrub and Sporoholus vir- 

 ginicus the common grass. In the numerous 

 salt holes is found the only fern of the islands, 

 Acrostichum aureum. 



Excellent photographs were exhibited show- 

 ing the dwarfing effect of the sharp winds of 

 the southern coast, where the vegetation, else- 

 where six or eight feet tall, is reduced to a 

 foot or two in height and becomes widely 

 spreading. 



One of the results of Mr. Nash's trip was 

 the extension of the range of Pseudophoenix 

 sargentii about 350 miles to the southward; 

 another the collection of a number of new 

 species. 



Numerous photographs, and specimens from 

 each of the plant areas, illustrated the speak- 

 ers' various points. 



Edward W. Berry, 



Secretary. 



■II IK SCILNCK CLUB OF NORTHWESTERN 

 UNIVERSITY. 



The Science Club of Northwestern Univer- 

 sity held its regular monthly meeting Friday 

 evening, January 6, 1905. 



The program was furnished by the depart- 

 ment of mathematics of the university. Dr. W. 

 M. Strong, of Chicago, presenting a paper 

 on ' Some Points of Interest in Mortality 

 Tables.' 



Floyd Field, 



Secretary. 



DISCUSSlOy AND C0RRE8P0XDEXCE. 



THE EPIDIASCOPE. 



To THE Editor of Science: With reference 

 to Professor Todd's query in the last issue of 

 Science, ' Who saw the Epidiascope at St. 

 Louis ? ' I am happy to say that the apparatus 

 has recently been installed in the anatomical 

 laboratory of Brown University, a much ap- 

 preciated gift from physicians of Providence 

 and other cities. I had an opportunity of see- 

 ing the epidiascope in operation at Jena in 

 1903 through the usual courtesy of the Carl 

 Zeiss management. 



In actual use in the laboratory it surpasses 

 expectations both in respect to convenience in 

 handling and to range of capabilities. Lantern 

 slides or other transparent objects up to about 

 twelve inches in diameter and microscopic 

 slides are projected with good effect. The 

 new feature which especially distinguishes the 

 apparatus — the projection of opaque objects — 

 is of course the most remarkable. In this as 

 in other respects we find that the claims put 

 forth in the prospectus are, indeed, very 

 modest. The color, texture, motion and third 

 dimension of objects are beautifully repro- 

 duced. Colored lithographs in bound period- 

 icals or reprints may simply be placed upon 

 the carrier of the machine while the book is 

 held open with the hand, and the whole page 

 appears with the colors and lines of the figures 

 perfectly reproduced. It is a great advantage 

 that the image is not reversed. A manuscript 

 or page of text can be read from the screen 

 directly. Original water color or oil paint- 

 ings are reproduced altogether too faithfully, 

 for the effect is that received when standing 

 clo.se to the picture. Insects of various kinds 

 have been tried; they lose nothing in the re- 

 production. The metallic luster and irides- 

 cence of the beetles show better because of the 

 brilliant light than when viewed directly. On 

 the other hand, moths or butterflies with 

 bright colors and soft texture appear with as 

 much naturalness as do the beetles. Such 

 natural objects of course do not suffer from 

 the magnification of details. A small adder 

 and a newt when placed on the carrier ap- 

 pear on the screen as a boa constrictor and 

 a giant salamander. Embryos or dissected 



