320 The Microscope. 



CORRESPONDENCE AND QUERIES. 



Paw Paw, Mich., Sept. 15, 1887. 

 The Microscope, Detroit, Mich. : 



Please give, through the cohimns of The Microscope, directions 

 for cleaning diatomaceous earth, and also for mounting the cleaned 

 diatoms without matting. Yours truly, 



E. B. DUNNING. 



Per J. C. D. 



[We shall publish, at an early date, an interesting paper on col- 

 lectino' and cleaning diatoms, by Mr. K. M. Cunningham, of Mobile. 

 Mattincf may be prevented by the method given in Technology, p. 

 151, May, 1887.— Editors.] 



EXCHANGES 



This department is for the benefit of .subscribers who have microscopical apparutiis. 

 jnaterial or books ivhich they wish to exchange, and such zvants ivill be given one insertion 

 FREE OP CHARGE. Dealers are referred to our advertising department. 



FOR SALE— Beck Popular Binocular with complete outfit, 3-in., 1-in. and H ob. polari' 

 scope parabola, double nose-piece, 3 sets ej-e-pieces, etc , in perfect order, only 

 tarnished. Price, 5f80. Address WM. H. SE.AM AN, Patent Offlc-, Washington. D. C. 



ANTED — To buy the numbers of tiae American Journal of Microscopy for July, 1876, 

 and May and September. 1881. Will pay 2.i cents each for them. Address 



C. C. MELLOR, 75 Fifth Ave , Pittsburgh, Pa. 



w 



WANTED— B. eye-piece (to fit Bausch & Lomb's smaller stands), a camera lucida, a stage 

 mi'jrometer (metric preferred) and a good turn-table; also Carpenter, or Beale, on 

 the Microscope Will exchangee for above, boolcs on Mineralogy and Chemistry and tceneral 

 liti-rary works. Correspondence solicited. A. F. BARNARD, Box 150. Oberlin, O. 



