98 PREPARATION AND MOUNTING 
easy matter to obtain interesting specimens of Foraminifera. 
Scrape a small quantity of chalk from the mass and shake 
it in water; leave this a few minutes, pour the water away 
and add a fresh quantity, shake up as before, and repeat 
two or three times. Take a litile of the residue, and spread 
it upon the slide, and when quite dry, add a little turpentine. 
When viewed with a power of two hundred and fifty dia- 
meters, this will generally show the organisms very well. 
If it is desired to preserve the slides, they may then be. 
mounted in Canada balsam. Mr. Guyon, in “ Recreative 
Science,” observes that the accumulation of the powder, by 
the action of the rain or exposure to the atmospheric action, 
at the foot or any projection of the chalk cliffs, will afford 
us better specimens than that which is scraped, as the 
organisms are less broken in the former. 
Take a piece of chalk, and with a soft tooth or nail brush, 
brush it under water, and then wash the sediment well till 
the water is not coloured, when the residue will be nearly 
all Foraminifera. 
The above is the most simple method of obtaining Fora- 
minifera from chalk, but is not so satisfactory when any 
number of perfect slides is wanted for the cabinet. I shall, 
therefore, give additional particulars from the experience of 
good men. But some specimens of chalk seem to have 
undergone such powerful action that no perfect forms are 
found in them. This accounts for that disappointment 
which I have now and then heard expressed. One student 
says,—Take about one ounce of chalk, place it in a 
quart bottle with about a pint of water, shake it, and after 
a few moments pour off the milky fluid to about one fourth. 
Add more fresh water, shake and pour off, waiting longer 
each time for it to settle. Continue ten or twelve times in 
one day, and repeat two or three times a day for a few days, 
and the result will be a sediment entirely composed of 
Foraminifera. If fragments of chalk remain, the bottle has 
not been sufficiently shaken. 
Mr. Robertson uses a somewhat different method. Break 
