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The Microscope, 



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Editor The Microscope : — 



I enclose a drawing of a useful device for centring slides and 

 covers in mounting. Please print it on an advertisement })age 

 from which it may be cut and pasted on a piece of wood, with 

 the ends and one side enclosed by small strips of wood, against 

 which the slide can be held while mounting. 



Yours truly, 



Highland Fali^, N. Y. Alfred Pell. 



[The illustration of Mr Pell's device will be found inserted in 

 the advertisement pages.] 



Editor The Microscope : — 



I have some phials of Diatoms which were originally in dis- 

 tilled water. The water has evaporated through the cork so that 

 the Diatoms have dried en the sides of the phial as a film which 

 clings persistently and refuses to be loosened. I have filled up 

 with Avater, also with alcohol, but several days' action appears to 

 make no impression. I am afraid to scrape for fear of crushing 

 the valves. What procedure would you advise? 



I have another puzzling case. I possess some insect dissec- 

 tions that have been in phials of turpentine for two or three 

 years, and by evaporation through the cork the turpentine has 

 thickened, grown whitish and resinous, and has finally deposited 

 a whitish substance (probably resinous in its nature) on the in- 

 sect parts so as to spoil them for mounting purposes. I have 

 tried soaking them in turpentine and benzole but do not succeed 

 in cleaning them. Have you ever had a like experience? and 

 what would yoii suggest? Yours very truly, 



Room 5, Central Union Depot, Edwin A. Hill. 



Cincinnati, O. 



