22 
OF THE FREE DIATOMACEJ2. 
suspended, or fixed, in an upright position. To the lower 
part is attached a short piece of india-rubber tubing,, 
ending in a glass mouthpiece with a fine opening, and 
provided with a kind of tap, known in Germany as a 
‘ Quetsclihahn,’ which may be freely interpreted ‘ spring- 
tap.’* The Algse having been partially cleansed from 
sand and dirt, the mass is poured into the upper opening 
of the tube, and a short time being allowed for settle- 
ment, the tap is opened, and a portion drawn off into a 
glass. The tap being again closed, and a few minutes 
allowed to pass, some more of the water is run into a 
second glass ; and so on, a longer period being allowed 
between each opening of the tap, until the whole of the 
* As this peculiar and most useful form of tap is, I believe, 
known, or nearly so, 
Fig. 35. 
Tig. 36. 
to English Diatomologists^ I append a short 
'description. It con- 
sists, as shown in 
the accompanying 
figures, of an elastic 
wire bent round to 
form two parallel 
sides, which are 
again bent at right 
angles to its axis, so as to cross one another, 
and each ending in a flat button A, B. Its 
elasticity, when made to grasp the india-rubber 
tubing, completely prevents the passage of a 
fluid. If it is desired that the fluid should 
escape from the tube, it is only necessary to 
press the buttons A, B, upon which the two 
sides separate to any required extent. On re- 
leasing the buttons, they immediately fall back 
to their former position, and the flow of liquid 
is arrested. 
This instrument (which may be procured at 
Mr. Baker’s, 243, High Holborn) is greatly to 
be preferred to the ordinary stop-cock for use 
in washing Diatomaceae ; being cheaper, more 
easily cleaned, and far less liable to get out 
of order, or to be choked by sand or mud. — E d* 
