1880.] 



MICROSCOPICAL JOURNAL. 



59 



front of the former one, giving better and 

 sharper definition, and he termed the ob- 

 jectives thus constructed four-system ob- 

 jectives ; but, finding that term cumber- 

 some, changed it to " duplex." Four 

 systems had been made previously by 

 Ross and by Hartnack ; but not on the 

 same formula that was used by ToUes. 



Curiously enough, Mr. Wenham, after 

 contending for eight years that it was im- 

 possible to get through any objective 

 more than an angular aperture of 82" 

 now {J. R. M. Society, Dec. 1879) gives 

 up the point so far as his contention ap- 

 plies to the " duplex-fronts " of ToUes, 

 utterly ignoring the fact, or disputing it, 

 after repeated measurements of the aper- 

 ture of three-systems by Tolles, Wood- 

 ward, Keith and others. One of Tolles' 

 three-system had been in Wenham's own 

 hands, and was grossly mismeasured. 

 The same objective had just been meas- 

 ured with Zeiss' apertometer, a modifi- 

 cation of ToUes' of 1872, and gave a balsam 

 angle of 93°-(-, just as Tolles made it 

 in 1872. Carl Reddots. 



Boston, Feb. i8th, 1880. 



MICROSCOPICAL SOCIETIES 



WELLESI.EY COLLEGE, MASS. 



The regular monthly meetings have 

 been kept up with the usual interest dur- 

 ing the present college year. 



Only a few of the papers and exhibits 

 can be mentioned. 



Miss Nunn, Prof, of Biology, who spent 

 the Summer with the Zoological Expedi- 

 tion fitted out at the Johns Hopkins' Uni- 

 versity, for investigating the fauna of the 

 waters along the Southern States, gave an 

 interesting account of deep-sea dredging 

 and shore-collecting, and described some 

 of the life thus found. She exhibited from 

 specimens which she obtained, Synapta 

 squilla, and several varieties of sponges 

 and hydroids ; specimens of deep-sea 

 dredgings, from the North and South At- 

 lantic and the Red Sea, were also under 

 the microscopes. Miss Ida Brown, Presi- 

 dent of the Society, a student in Biology, 

 gave a pai)er on white and colored blood- 

 corpuscles, illustrated by slides showing 

 corpuscles and haemin crystals. A paper 

 on plant-crystals, embodying much indi- 

 vidual work, was given by Miss V. Smith, 

 illustrated by the following specimens 

 prepared by herself : crystal-prisms from 

 cactus, washed out ; stellate raphides from 



lily ; crystal prisms in onion-sheath ; 

 sphseraphides from begonia ; raphides in 

 calla ; crystals in pear, stained.' Miss 

 Whiting gave a ristani of the exercises of 

 the American Society in Buffalo, with an 

 abstract of the portion of the address of 

 Dr. Ward pertaining to the use of the mi- 

 croscope in the detection of forgeries and 

 the examination of gunpowder wounds. 

 Papers on the antennaj of insects, and on 

 the best methods of microscopic measure- 

 ments have been given. A demonstration 

 with Dr. Seller's section cutter, and an 

 exhibition with a new polari-microscope 

 of the remarkable phenomena exhibited 

 by minute crystals, in converging polarized 

 light, attracted much notice ; also the cir- 

 culation in the branchiee of the triton. 



The Society have formed a plan for 

 studying the fauna and flora of the waters 

 in the neighborhood of the College thor- 

 oughly. Drawings with descriptions are 

 handed in to the President, and those per- 

 taining to specimens not on the list already 

 presented to the Society, are presented by 

 the Secretary. Thus, in time, the history 

 of microscopic life in the region will be 

 complete. 



The regular meeting was held on Mon- 

 day evening, February 9th ; the President, 

 Miss Brown, in the chair. 



The leading paper was by Miss Free- 

 man, on the method of mapping absorp- 

 tion-spectra with the bright-line microme- 

 ter of the Sorby-Browning Microspectro- 

 scope. 



The instrument was described in de- 

 tail, and the method of constructing a 

 scale of reference by obtaining the posi- 

 tions of the principal Fraunhofer lines. 

 The bands in the spectra of different sub- 

 stances are mapped out on the same scale, 

 and thus compared. 



The paper gave details of the work of 

 the writer, especially on the spectra of 

 chlorophyll. 



Miss Whitney called attention to the 

 contents of the late journals, and read in- 

 teresting extracts. 



Some thirty varieties of ferns, mounted 

 for the Society's collection by Miss Painter, 

 were exhibited and greatly admired. The 

 following mounted objects were exhibited, 

 accompanied by drawings in detail : As- 

 pidium spinidosum, Dicksonia punctilo- 

 bula, Davallia pyxidata, and Cibrotiutn 

 Schtedii. 



The absorption-spectra of two prepara- 

 tions of chlorophyll were exhibited under 

 the microspectroscope. 



Ada I. Ayer, Cor. Sec. 



