108 On the High-Fower Definition of Organic Particles. 



I here, however, wish to record an ohservation made lately in 

 the presence of Mr. Beaumont, F.R.S., 33, Norland-square, and 

 copied by Mr. HolUck, Plate XXVII., upper portion, (for whom I 

 had sent) on the spot. Exhibiting the appearance (described by 

 a little girl, who had never looked down a microscope before, as 

 like " strings of seed pearls"), I accidentally came upon a heap of 

 what appeared to be a crushed Podura scale (of the coarse kind). 

 Mr. Beaumont expressed his astonishment in no measured terms. 

 A large portion appeared distinctly studded over with closely-packed 

 spherules resembling the finest conceivable definition of the 

 Angulatum. 



The covering glass is very strong and thick, and had undergone 

 some kind of pressure, as often happens (when the glass is too 

 "thick) in the endeavour to focus down.* 



I had got the finest definition of the black edging of the sides 

 of the ribs I had ever seen, with orange beads between, when on 

 moving the slide about I could hardly believe my own eyes. 

 Two layers of beading had apparently been compressed into one in 

 the manner of two layers of small shot, arranged with the same 

 regularity, as shot kept in contact. These beads when seen at 

 their best were dark blue, and some of them appeared golden- 

 orange. All the crushed structures had sharp black outlines. 

 Apparently, as Mr. Beaumont pointed out and Mr. Hollick copied, 

 some long tubular-looking bodies scattered about, with extremely 

 jet-black outlines, contained several beads. 



I have found a good efiect from using Kangoon oil ; also the 

 chloride of gold, dissolved in glycerine, 2 grains to the drachm. 



But the strong fact was this : the usual correction for seeing 

 the " tadpoles " at their best failed to exhibit distinctly those beads, 

 and the other beautiful effectg. Therefore to see the minute 

 structure at its best, required, as I am prepared to prove, a 

 difierent correction— a diminution of the spherical over-correction 

 before established. 



* A Dalmeyer twelfth penetrated easily through this glass cover; but a 

 twelfth, marked a Ross, would not at all. 



