56 THE NORTHERN MICROSCOPIST. 
balsam is taken out each time, and having been exposed for a long 
time to the air it has lost the whole of its turpentine. 
If any reader adopts this process I am sure he will be satisfied 
with it, but if any difficulties occur, I hope we shall hear of them 
in the “Notes and Queries” department. 
DIATOMS: HOW TO FIND AND HOW iG 
PREPARE THEM. 
From the American Fournal of Microscopy, April, 1880. 
LITTLE experience will enable any one to find and to gather 
all he may desire. Those living in this city can easily procure 
many beautiful varieties by simply fastening a muslin bag like an 
umbrella cover to the hydrant. After securing a quantity of the 
sediment, empty it into a large fruit jar or other receptacle nearly 
filled with water, and let it settle. 
The green, brown, or fawn-coloured scum on the surface of 
pools, bogs and marshes, is mostly diatoms, and it may be taken 
up by means of a spoon or bottle and preserved, always in alcohol 
and water, or dried upon paper. The living weeds should be 
taken carefully from their location without much compressing or 
washing. ‘The finer water plants yield the richest harvest. Fresh 
water forms are sometimes found hanging in green-coloured masses 
from drains, sluices and water-pipes. ‘To gather from the lake, a 
net of fine muslin, having an opening in the bottom in wuicha 
wide-mouthed vial is tied, may be towed at the stern of a steamer. 
The sediment left in the bottom of pails, barrels and other vessels, 
contain a good supply. To obtain varieties not found at home, 
open a correspondence with gatherers in other localities, who will 
gladly exchange. Lake Michigan alone contains probably several 
hundred kinds. 
The process of cleaning diatoms requires time, skill, patience, 
and personal experience, in addition to what may be learned from 
others. After trying for a long time to dispose of sand and mud 
the novice will be more careful in collecting. After an explosion 
or two, involving the loss of valuable material, and possibly the 
destruction of clothing, he will learn that strong acids and other 
chemicals are not to be handled like water. Experience makes 
the process safe and comparatively easy, requiring but a few 
minutes’ attention ata time. No one method will apply in all 
cases, for some gatherings are imbedded in stone, some cemented 
with lime, which require special attention, while many gatherings 
require nothing more than a strong heat to destroy the organic 
matter and leave them ready for mounting., 
