60 



THE AMEKICAN MONTHLY [March, 1880.] 



LIVERPOOL (ENG.). 



The second ordinary meeting of the 

 twelfth session of this Society was held 

 at the Royal Institution, on February 6th, 

 i88o. Dr. J. Sibly Hicks, the President, 

 in the chair. 



Robert Dempsted was elected an ordi- 

 nary member of the Society. 



Rev. W. H. Dallinger exhibited and ex- 

 plained Col. Woodward's Illuminator, ma- 

 nufactured by Messrs. Powell and Lea- 

 land, by means of which any angle of the 

 illuminating ray is secured and registered. 



Dr. Drysdale exhibited and explained 

 the oil-immersion condenser of Messrs. 

 Powell and Lealand, showing with it 

 the dotted markings on the diatom Navi- 

 cula lyra through a ^-inch objective. 



Rev. W. H. Dallinger read the paper of 

 the evening entitled " Microscopical Notes 

 on the Order of Minute Insects known as 

 Thysanura (Spring-tails) with a special 

 study of these scales," illustrated with 

 transparencies and the lime-light. 



GRIFFITH CLUB, MICH. 



Mr. E. H. Griffith of Fairport, N. Y., 

 read a very interesting paper on diatoms 

 before this club, but we cannot reproduce 

 it or condense it in our overcrowded issue. 

 The paper was printed in one of the Detroit 

 newspapers and we doubt not that any 

 reader who is sufficiently interested in the 

 subject can obtain a copy by writing to 

 Mr. Griffith. There are several valuable 

 suggestions contained in the paper, parti- 

 cularly those relating to the cleaning of 

 diatoms. 



CAMDEN, N. J. 



At a recent meeting Dr. Walter M. 

 James delivered a lecture on dust, from 

 which we make the following extracts : 



The Doctor opened his lecture by a des- 

 cription of the various kinds of dust, the 

 sources whence they originate, and the 

 important part it plays in the diffusion of 

 light, citing the well-known fact that a 

 ray of sun-light entering a darkened room 

 through a chink or crevice, would be invi- 

 sible from a side view were it is not for 

 the infinitesimal particles of dust floating 

 in the atmosphere, for light travels only in 

 straight lines, and unless the eyes directly 

 opposed its rays, its presence would be 

 unperceived. Much of the dust we see in 

 the air is composed of the pollen of 

 plants wafted abroad to fulfill its mission 

 in the propagation of its species, and fre- 

 quently gives rise to diseases of the hu- 

 man system which prevail in the Autumn, 



especially those called coryza or hay 

 asthma, hay fever, etc. 



The experiments of Tyndall, showing 

 how fermentation in various liquids may 

 be prevented, if excluded from contact 

 with the atmosphere, were fully explained, 

 and the formation of those fungoid growths 

 called mould, which occur so frequently 

 on articles of food and clothing, in moist 

 places, were traced to the multiplication of 

 the plants from spores carried by the at- 

 mosphere. 



Various moulds were exhibited under 

 the instruments and the curious branching 

 of the PeiiiciUiuvi glaucum, the cells of 

 the yeast-plant, vibriones and various 

 pollens were well shown by Messrs. Brown, 

 De LaCour, Kain and Derousse, with high 

 powers. 



Exchanges. 



[Exchanges are inserted in this column without 

 charge.] 



Polyzoa, Palates of Mollusca, Foraminifera, Sponge 

 and Holothurian-Spicules, Synapta-Anchors, Chirud- 

 ota-Wheels, Echinus-Spines, Minute Sea Shells, in ex- 

 change for Polyzoa, Foraminifera, Histological and 

 Pathological preparations, etc. Also, a quantity of 

 Sea Shells in exchange for Land and Fresh-Water 

 Shells. 



F. M. HAMLIN, M. D., Auburn, N. Y. 



J. J. B. Hatfield, Arsenal Avenue, Indianapolis, 

 Indiana, will exchange Bleached Plant-Sections for 

 good Diatomaceous material. List furnished on ap- 

 plication. 



For fine specimens of Tingis hyalina. send a 

 stamped envelope to ALLEN Y. MOORE, 



i86 Dodge St., Cleveland, Ohio. 



Pleurosigmas and other unmounted Diatoms, both 

 Fresh Water and Marine ; also Marine Algae, Ferns, 

 and a large quantity of miscellaneous microscopical 

 material in exchange for good mounted objects. 



M. A. BOOTH, Longmeadow, Mass. 



To exchange, well-mounted Slides of Hair for 

 mounted or unmounted specimens of hair from the 

 rarer animals ; lists exchanged. WM. HOSKINS, 



2o8 S. Halsted street, Chicago, 111. 



Nicely mounted Slides (opaque) of the Coal-tar 

 Derivatives, chemically prepared, crystalline in form, 

 showing their beautiful colors, in exchange for other 

 well-mounted material. Chemical name and formula 

 attached to each Slide. About a dozen varieties on 

 hand. F. L. BARDEEN, M.D., 



30}^ Meigs street, Rochester, N.Y. 



Vanadate of Ammonia, (N H *) '^ V O "^ Slides for 

 the Polariscope in exchange for other Slides. 



H. POOLE, Practical School, Buffalo, N. Y. 



Slides mounted from injected Frog's Gall-bladder, 

 Liver, Kidney, Stomach, Intestine and other parts, 

 exchanged for other good and interesting prepa- 

 rations. C. BLASDALE, M. D., 



Jericho, Queens Co., N. Y. 



