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APPENDIX A. 



CELLS IN CARDBOARD FOR MICROSCOPIC MOUNTING. 



" The first mounting that I had seen of opaque objects was 

 one that I had in 1862 from the Rev. A. M. Norman, an ostra- 

 code, Notodromus monachus, mounted on a hard wood slide, 

 three inches by one, with a round cell in the middle. Finding 

 these cells difficult to get well made, and the price high, I 

 thought that a substitute could be made from cardboard, which 

 I got cut into proper sizes, three inches by one. I procured a 

 round cutter at a gunmaker's shop, with which I punched out 

 the round cell in the slide. I then had black hot-pressed paper 

 pasted on thin cardboard or pasteboard. This was cut the same 

 size as that of the cell-slip, three inches by one, and was cemented 

 to it with thin glue, which hardened sooner, and was less liable 

 to mildew than flour-paste. Thus I had an excellent slide, that 

 did not cost me more than two shillings a gross. I may mention 

 that my greatest difficulty at first was to get the black slip and 

 the cell-slip properly pressed together, till I got a little screw- 

 press made that just took in a slide in breadth, but more than 

 three dozen in length, which answered my purpose well. This 

 was the first cardboard slide, so far as I know, that had been 

 made at the time." 



Diagram of screw-press, reduced. 



