52 Mr. William Ingrams. 
distance from the flame, and the process watched. Fumes 
will soon rise, and the operator will have to retreat unless he 
has some contrivance over the glass to allow them to escape. 
When satisfied by testing that the skeletons are clean, pour 
off the acid after a proper time has elapsed, and-wash with 
distilled water, if you can, four or five times, taking care not 
to be in too much of a hurry in pouring off the liquid. 
The next step is the separation of the flinty particles from the 
diatoms. This is rather a tedious business, but the end is 
near. Have five or six glasses, each about four times the 
size of the small glass, in which the diatoms have been boiled. 
Have about four washings, at intervals of half-an-hour, 
pouring off into one of your vessels each washing. This gets 
rid of a multitude of the smaller particles. Repeat the process 
at different intervals till all the glasses are filled, testing as you 
goon. It is quite possible to have diatoms ready for mounting 
before all the glasses are full. When quite ready, a small 
quantity should be placed on a slide with the tube. The slide 
should be put away for a time out of the dust, to allow the 
water to evaporate. Do not dry it too quickly. The thin film 
on the surface should then be mounted, either dry or in balsam. 
This is a brief sketch of the process for skeletons; that 
for the parasitic form is simpler. The chief difficulty being 
getting the plant, the object, into position. The lesson 
should be learnt at the riverside. All I can say now 
is that a small portion of the conferva, which is known 
to have the diatom, should be placed on the slide, and retained 
in position with the thumb nail. A small quantity of 
water should be allowed to run from a tap to the first joint of 
the thumb. It will diffuse itself over the slide, and the fibres 
of the confer will separate. The water should then be 
turned off, and the slide examined. If the fibres be well 
separated and the specimen worth preserving, it should be 
kept free from dust till the water has evaporated, and then 
mounted either in the dry state or in some preservative 
liquid. Both methods are very easy. I shall therefore say 
nothing more about them, but will answer questions that may 
be put respecting either. 
I thank you very sincerely for your attention, and the next 
time I hear the uncharitable observation respecting patience, 
I shall invite the individual who makes it to attend a meeting 
of the Croydon Microscopical and Natural History Club. 
