ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



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filter-paper. A drop of the solution and a drop of milk are placed on a 

 slide and thoroughly mixed. A cover-glass is put on and squeezed down, 

 and then the gelatin is set by putting the slide on ice. This method, 

 which is quite suitable for other liquids containing particles in suspension, 

 gives very satisfactory results. 



Cover-glass Cleaner.* — S. E. Dowdy describes an appliance for 

 cleaning cover-glasses as follows. Procure a 1 oz. wooden pill-box, a 

 small piece of thick felt and a strip of chamois leather. Cut or punch 

 out a sufficient number of circular discs of the felt to fill up the bottom 

 part of the box, which should be first smeared inside with seccotine to 

 hold the discs in position. Xow line the inner part of the box-lid with 

 a piece of chamois leather in the same way, taking care to get it tightly 

 stretched across, free from creases. The thickness of felt and leather 

 must be so arranged that when the lid is fitted on the box their surfaces 

 just touch. In use, place the cover-glass flat on the felt surface, put 

 on the box-lid, and, holding the box sidewise, rotate its two portions in 

 opposite directions. In this way the thinnest cover-glass may be cleaned 

 without risk of breaking. As a rule, fresh cover-glasses are easily freed 

 from the thin film of adherent grease by soaking them in a little dilute 

 ammonia, afterwards rinsing in distilled water, and either drying at 

 once on a piece of silk or placing them in absolute alcohol, which 

 removes the water and is itself got rid of by evaporation. 



Metallography, etc. 



Watson and Sons' Metallurgical Auxiliaries.! — 1. Universal 

 Metal-holder (fig. 43). — This combines in itself a metal-holder with the 

 means of levelling the specimen. Two clamps with rotating jaws grip 



Fig. 43. 



Fig. 44., 



the specimen C, and if its plane is not at right angles to the objective, 

 it can be tilted exactly to the desired position by means of the adjusting 

 screws A and B, B'. This fitting is usually made to interchange with 

 the levelling stage plate on the main stage of the Microscope, and for 

 rapid and precise work is of great importance and convenience. 



* English Mechanic. Ixxix. (1904) p. 14. 



t W. Watson & Sons' Catalogue of Micro-Outfits for Metallurgy, pp. 8, 9, 11. 



