82 HIDDEN BEAUTIES OF NATURE 



the world, or from some geologist. As a rule, geolo- 

 gists have specimens in the natural and in the 

 prepared conditions, and are always delighted to 

 facilitate the study of their favourite science. Take 

 a piece of the stone about the size of a pea and place 

 it in a glass test-tube ; pour in some acid, either 

 nitric or sulphuric, and some water; cover the opening, 

 and shake the tube well. The acid will dissolve the 

 carbonate of lime, i.e. the chalky matter, and the 

 contents will appear milky. Pour out the liquid, 

 taking care to keep back the sediment. Do this once 

 or twice a day for three or four days, when the 

 milky appearance will have passed away. The resi- 

 duum is composed of the flinty shells you are 

 seeking. Dry them. They will now look like a 

 powder, so much so, that some people will tell you 

 that you are showing them a sample of snuff. Place 

 the so-called snuff on a glass slip, and bring the 

 microscope to bear upon it. 



You will then have a view before you which it 

 will be very difficult to excel. To add to the effect, 

 some slide-mounters heat the shells on a hot plate 

 before mounting them. 



This gives a pearly white appearance, and when 

 viewed with a light thrown on them, the effect is 

 most pleasing. To view them in this manner it is best 

 to place a black disc of paper on the underneath side 

 of the glass slip, thus shutting out any light below. 



Some mounters prefer to arrange them without 

 any disc underneath, and to treat them as transparent 



