OT eee Fy ET a Ae a Le ee er oe ae me en A Ne ee em Fe 
REPORTS FROM THE SECTIONS. 275 
y P 
contained, but the following will answer very well for any of the 
ordinary fresh or salt water gatherings obtainable in this vicinity. 
The apparatus required will be a couple of Florence flasks, a 
spirit lamp, a small quantity of chlorate of potash, and some nitric 
and sulphuric acid. Place the gathering in one of the Florence 
flasks, half-fill with water, and shake well for a couple of minutes; 
this will detatch the diatoms from the vegetable and pees 
i i the 
might be repeated with advantage once or twice, when one 
troublesome element, that is the sand, will have been pretty well 
giving everything plenty of time to settle, carefully pour off 
the water without disturbing the sediment, and add nitric acid 
until the flask is about one-third full; this must now be boiled 
over the spirit lamp for ten minutes or so, then allowing the 
d 
potass ; the liquid will gradually turn lighter and eventually quite 
clear, the diatoms being suspended in it in the form of white 
it 
keeps them suspended for a longer time than water alone n 
they have at last settled pour off and add more water, repeating 
process until th oms are washed clean from t id, 
e il the di 
which will be when the liquid poured off gives no acid taste when 
diat 
e 
applied to the tongue. 
