228 HENRY F. HAILES ON A FORM OF DEEP CELL. 



unpolished state, but this is only an apparent disadvantage. 

 The refractive index of the balsam is so nearly that of glass, that 

 it causes the granulation entirely to disappear. For mounting in 

 fluids of less density than balsam, it is necessary to run a little 

 balsam into the cell, and dry it off before putting in the fluid. 

 For dry or opaque objects, no preparation is necessary, the ground- 

 glass bottom of the cell making a soft and agreeable background 

 for the object. 



For mounting insects, or parts of insects, either as opaque or 

 transparent objects, I venture to think that the use of these cells 

 Avill be found far preferable to the flattening process usually adopted, 

 and which is less necessary now that we have such good binocular 

 microscopes than it was formerly. I suppose there are no ento- 

 mologists who would entertain the idea of putting a large insect, 

 such as a stag beetle, through a rolling mill, in order to preserve it, 

 and I can see no reason why a flea or an acarus should be subjected 

 to a similar process. It is clear that that which would render the 

 larger insect unrecognizable must equally distort and smash out of 

 recognition the smaller one. 



Mr. C. Baker, of High Holborn, has undertaken to supply the 

 slides at a reasonable price. 



On Some Photographs of Microscopic Writing. 

 The following letter has been received from Dr. Woodward : — 



War Department, Surgeon General's Office, 



Washington, D.C., December 29th, 1873. 



Mr. John E. Ingpen, F.R.M.S. 

 Dear Sir, 



Two samples of Mr. Webb's fine writing on glass 

 have been received at the Museum since my communication of 

 August 18th. Each consists of the Lord's Prayer, written with a 

 diamond, according to the label, in a space ^^ x 44T ^^ ^^ "^^^* 

 In one of the slides the writing is blackened and mounted in 

 Canada balsam ; in the other it is not blackened, and is mounted 

 dry. I send photographs of both herewith — the one magnified 

 650 diameters, the other 825. I find Mr. Webb's statement of the 

 dimensions in which this writing is executed to be substantially 

 correct, and he has certainly produced a most curious and in- 

 teresting object for microscopical study. To compare his work 



