538 8UMiIARY OF CURRENT RESEARCHES RELATING TO 



ensuring immunity from damp, while lie has never kno^n an instance 

 in which any object was in the least affected by contact with the wax 

 itself. 



Wax Cells with White Zinc Cement for Fluid Mounts. — Mr. W. 

 H. Walmsley, of Philadelphia, points out that while much has been 

 written regarding the use of wax cells for dry mounts, their eminent 

 adaptability for fluid mounts has been strangely overlooked. His 

 own use of them for this purpose has extended over a considerable 

 period of time, and has given great satisfaction. In the matter of 

 economy, ease of preparation, and durability he considers the method 

 adopted of considerable value. His chief reliance for the permanency 

 of the cells rests upon the use of white zinc cement for coating the 

 wax, the latter being mainly used for making the cells of various 

 depths. Thirteen years' use of the white zinc cement, during which 

 time he has prepared thousands of slides, has satisfied him of its 

 entire permanence, while it is the most easily used of any cement, 

 and its appearance is elegant on a finished slide. The only defect is 

 that it tui-ns yellow in time. 



A ring of the cement is first made upon the slide with the turn- 

 table. The wax ring is then added, and over the same successive 

 coats of the cement are applied, allowing each to dry before another 

 is added. After the last coat has been applied and the cell allowed 

 to dry for some time, the cement becoming hard in about a day, or 

 even less time, a thin coat of the cement is now applied, after which 

 the cell is filled with the mounting fluid and the object is spread out 

 and arranged properly in the cell. A thin glass cover must then be 

 made to cover the cell in the usual manner, expelling the air, and it 

 will adhere to the fresh cement all around. A spring clip is attached, 

 the slide washed with clean water, using a camel's-hair pencil, then 

 dried with a soft towel, when after a time another ring of the cement 

 may be run around the cell, and the cell ornamented with coloured 

 rings. The fluids used have been glycerine both pure and diluted, 

 carbolic acid water, and Goadby's fluid. 



3Ir. Walmsley recently forwarded to the Society several slides 

 which he had prepared and which appeared to be in every way ex- 

 cellent,* and he has communicated the formula which he now uses 

 for preparing the cement as follows : — 



One part (by weight) of mastic (tears) to 3 parts of gum dammar, 

 dissolved in benzol. To 3 pints of this solution (about the con- 

 sistency of cream) add 1 lb. of pure French oxide of zinc, ground in 

 a small portion of linseed oil, and stir thoroughly. As the zinc will 

 settle by standing it should be stirred every time it is used, and if it 

 becomes too thick to flow readily, add a little benzol. 



How to make Wax Cells.| — The wax cell seems to be in the 

 peculiar position that, while some — even its originator — have discarded 

 it, others declare that it is a valuable means of mounting objects. 

 Dr. F. L. Bardeen, of Rochester, N.Y., writes as follows. 



• See this Journal, aide, p. 147. 



t Araer. Journ. Micr., vi. (1881) p. 48 (4 £g?.). See Engl. Mech., xxxiii. 

 (1881) p. 158. 



