58 THE AMERICAN MONTHLY [March, 



five minutes after the capture of the fly. Try this method for small 

 soft-bodied insects. — C. M. Vorce. 



Carbolic Acid, liquefied by alcohol (or even benzole), will color 

 but comparatively little on exposure to light. Some so treated in Dec, 

 1888, is now (May, 1S90) only turned a little, being a light, clear 

 amber tint and well fitted for preparing insect specimens. — F. T. 

 Chapman. 



Water-washed Diatoms. — About 1882 Dr. Henry Froeling ad- 

 vised me to try water washing for diatoms, as he had found very clean 

 ones in his still after he had used it many days in making distilled water 

 for his laboratory. I have used it for eight years with perfect success. 

 When I first used it I was corresponding with W. S. McNeill, of 

 Mobile, and advised him to try it, and gave him eight pages of direc- 

 tions ; and he turned out the first water-washed Mobile diatoms. Sev- 

 eral years afterwards Dr. Taylor came forward with his washings, of 

 which I have never yet seen any that could be called perfectly washed. 

 Mr. Michels says that Dr. T. takes ten hours of continuous work. I 

 can show him clean washings that took thirty days ; and I think it 

 doing fast work if I finish a deposit in six days. I shall be pleased to 

 hear from any one interested in diatoms, as I have a very large collec- 

 tion, including vials of really clean water-washed collections from 

 various localities. — Thomas Christiatt^ Richmotid., Va. 



Cardboard Slides. — I send this slide upon its travels that the mem- 

 bers of the Club may see an easy, quick, and inexpensive mode of 

 using portions of leaves, samples of silk, cloth, or other materials that 

 can be examined on both sides. Cardboard slips, 3x1 inch, are 

 punched through the centres, and two of them fastened together with 

 the flat object between them so as to close the central opening of the 

 slides. 



One has only to reverse this slide to quickly look on both sides of the 

 leaf. These pasteboards are procurable at the stationers, and can be 

 thicker or thinner or of different colors than this one. Also one can 

 glue these pieces together so as to form a deep well ; then cover-glasses 

 can be glued over each side of this well after you have put in sand, 

 flower seeds, or any object requiring a deep setting. Also one may use 

 these slips for mounts for polariscope, as a cover-glass on each side will 

 keep in the balsam used in the mounting. For use in classes when 

 slides are passed from hand to hand these are useful, being easily and 

 quickly made ; not breakable, not costly. I see no reason why these 

 slides should spoil by mould, mildew, or moisture if they are properly 

 cared for. — y. Fratik Brown, 



Polished Graphic Granite. — I ground one side of the piece on a 

 lead plate with No. 150 Wellington Mills emery. Smoothed on a 

 Craigleith stone, using water, and powdered Hindostan oil-stone to pre- 

 vent the Craigleith stone glazing. Afterward used the whetstone 

 without the powered oil-stone. This surface was washed with oil of 

 turpentine and cemented with hardened balsam to this slide. A thin 

 slice about g\y of an inch thick was cut, which remained attached to the 

 slide. This last surface was ground and smoothed in the same manner 

 as the first; washed with oil of turpentine and mounted in Canada 

 balsam. The oil-stone is easily powdered, cuts sharp, and does not 

 scratch even if the stone is not reduced to a perfectly even, fine powder. 



