OF THE FREE DIATOMACE^ Z( 



the bottom, the otliers being about eight inches apart. 

 Each hole is provided with a short tube, of glass or gutta 

 percha, and a stopcock, or spring tap, so that water may 

 be drawn into vessels placed below, through either of the 

 holes, and in any quantity required. At the apex of the 

 cylinder a funnel, g, is placed, and to it is attached a narrow 

 glass tube, h, of sufficient length to reach almost to the bottom 

 of the cylinder. To the lower extremity of the tube, h, a 

 kind of mouthpiece of glass is joined (a short piece of 

 india-rubber tubing will effect the junction), drawn out 

 into a very fine opening. Above the funnel, g, either 

 placed on a stand or fixed against the wall, is a tin vessel, 



with a short pipe, k, leading into the funnel. This vessel 

 is for the reception of water. 



The method of using this little apparatus is as follows : 

 — The Diatomacea 1 , roughly freed from mud and sand, are 

 poured into the cylinder, a, b, and immediately sink to the 

 bottom . The funnel, g, being replaced, the tap, &, is 

 opened, and water begins to flow down the inner tube, h. 

 The effect of this is to cause a grand disturbance among 

 the imprisoned Diatomaceas, which are forced up the sides 

 of the cylinder, a, b, the lightest of course being the 

 highest. On opening the uppermost, c, of the four side 

 sluices, the water, loaded with Diatomacese, issues into a 

 wineglass, or some similar vessel, and this should be 

 continued as long as the fluid remains thick. As soon as 

 it appears clear and bright, let the next tap, d, be opened 

 (the upper one still being allowed to discharge its contents), 

 and the water caught in a second glass. This second glass 

 will then contain all those Diatomacese which were too 

 heavy to rise to the level of the uppermost tap, c, but at 

 the same time too light to sink below the level of the 

 third tap, e. And so the process is continued until each 

 of the taps has been opened. 



It will be well to bear in mind, that the flow of water 

 from the reservoir, j, can be regulated very nicely, and the 

 quantity discharged lessened or increased, by means of the 



