322 



SCIENCE. 



[N. S. Vol. I. No. 12. 



lumbia College. The second, held upon 

 March 14th, in the Galleries of the Ameri- 

 can Fine Arts Society, was much larger and 

 more successful than the first, including 331 

 separate exhibits, grouped under sixteen 

 branches of Pure and Applied Science. In 

 the South Galleiy were placed Physics, Elec- 

 tricity, Astronomy, Mechanics and Chemis- 

 try ; in the Middle Gallery, Photography, 

 Psychology and Mineralogy; and in the 

 Vanderbilt Gallery, Zoology, Palseontologj^, 

 Human and Comparative Anatomy, Bot- 

 any and Geology. Each branch was under 

 a Chairman who had entire control of the 

 the general arrangements, and while the 

 exhibits were largely from the educational 

 institutions and museums in and around 

 New York a number of most interesting ob- 

 jects were sent from considerable distances, 

 such as the photographs fi'om the Allegheny 

 and Lick Observatories. Among the very 

 large number of excellent exhibits it is only 

 possible to mention a few of the most novel. 

 Mr. Charles A. Post, of the Strandhome 

 Observatory, had charge of the astronomy, 

 in which he displayed photographs of star 

 spectra between F. and D. from the Alle- 

 gheny Observatory, glass positives of comets 

 and the Milky-Way from the Lick Observa- 

 tory, and a number of new spectroscopic 

 and other astronomical instruments. Pro- 

 fessor Mayer, of Stevens' Institute, had 

 charge of the physical section, in which 

 were shown his series of Chladni figui-es pre- 

 served in sand, illustrating the errors of 

 older figures and the accuracy of Lord Ray- 

 leigh's theoretical deductions. A number 

 of new physical instruments for spectro- 

 scopic and sound measurement were exhib- 

 ited in operation by Professor Hallock fi-om 

 the Columbia Physical Laboratory. Pro- 

 fessor Crocker had charge of electricity, in 

 which were shown Professor Pupru's ma- 

 chines for producing alternating currents 

 for multiplex telegraphy and other purposes, 

 also E. H. Dickerson's acetylene illuminat- 



ing gas produced from calcium carbide made 

 in an electric furnace. The mechanical ex- 

 hibit was in charge of Professor R. S. Wood- - 

 ward, and included models of the interna- 

 tional prototj^e metres and kilogrammes,and 

 several pieces of new mechanical apparatus. 

 In the mineralogical exhibit, arranged by 

 Dr. L. P. Gratacap, of the American Mu- 

 seum, was a series of Babylonian and Assyr- 

 ian cylinders, illustrating the different min- 

 erals employed between 4000 and 300 B. 

 C; also an extensive display of new tj'^pes 

 of American minerals. The photographic 

 exhibit, in charge of Dr. Edward F. Leam- 

 ing, besides new apparatus from Zeiss of 

 Jena, included all the recent applications of 

 photography in color printing, and the 

 combination of colors in lantern projection 

 shown by the inventor, Frederic E. Ives, of 

 Philadelphia. Dr. Leaming's micro-photo- 

 graphs of nervous and cellular tissues and 

 of bacteria formed an impoi'tant feature of 

 this exhibit. The exhibit in experimental 

 psychology was contributed by the depart- 

 ment of experimental psychology of Colum- 

 bia College. The apparatus has been re- 

 cently made for the college, and with the 

 exception of the harmonium was designed 

 by members of the department. The har- 

 monium was designed by von Helmholtz and 

 Ellis to give pure intervals in place of the 

 equal or tempered intervals used in musical 

 instruments with fixed keys. The other 

 apparatus shown was : (1) an instrument 

 which measures the duration, intensity and 

 area of lights, now being used for the 

 iuvestigation of after-images ; (2) an in- 

 strument which measures the time (to 

 0.0001 sec.) objects are exposed to view, 

 now being used to study the legibility of 

 letters and types, and in an altered form to 

 measure the perception, memory and atten- 

 tion of school children ; and (3) a new 

 chronograph of very high speed with fixed 

 drum and movable carriage. Phj^siology 

 was represented by a number of special ex- 



