I'.Y \. Ml'\D EDWABDS. 21 



ported from abroad, will yield foreign bo the collector. 



There is a plant known in England afl "Dutch rushes," which 

 is imported into that country from Holland, and which is 

 for chair bottoms. These plants grow in the brackish water ol 

 the marshes, and hence upon tlieni are to be found the delicate 



',,<><//.«•>/.< subtilis, Eupodiscus argus, and TriceratiumJ 

 Both of these two last named forms occur commonly on our 

 Atlantic coast, and muds from Charleston, S. C, and Wilming- 

 ton, Ga., have provided me with them in plenty. Cargoes of 

 bones, w T hich present green incrustations from having lain in 

 the water for some time, are said to yield diatoms, some of 

 which may be rare, as coming from foreign ports. The State 

 of New Hampshire has not yet been sufficiently gone over for 

 it to be said what the characteristic forms of • diatoniaceai grow- 

 ing w T ithin its boundaries are, but yet we may safely predict 

 that the lakes, ponds, streams, and sea-coast of that State will 

 yield to the searcher ample material of beautiful forms. 



If the microscopist wishes to mount a few slides of recent 

 diatoms, just to show what diatoms are, nothing is easier. It 

 is only necessary to boil a small mass of them in strong nitric 

 acid in a test tube over a spirit lamp, and, when the acid has 

 ceased to emit red or yellowish fumes, wash them thoroughly 

 with clean water, allowing them to settle completely. Then a 

 little of the clean sediment, consisting almost entirely of the 

 shells of the diatoms, is taken up by means of a "dip-tube, "and 

 placed upon the central portion of a glass slide. Here it is 

 dried, and the slide warmed over a lamp; then a drop of Can- 

 ada balsam is permitted to fall upon the diatoms. As soon as 

 all bubbles have cleared oil' from the balsam, a warm C 

 of thin glass is carefully laid upon it and permitted to settle 

 into place. When cool, it is ready for examination by means 

 of the microscope, any balsam which has exuded around the 

 cover being washed oil" with alcohol. In this way rough and 

 tolerably clean specimens may be obtained; but such would 

 not, or, at all ihonld not. Batisfy the student of the 



diatomaceSB. Tor him more elaborate methods are I 



and these we will now prooeed to consider. 

 Apparatus and Ch /. A chemist's retort-stand, 



which is a heavy iron plate with an upright roil projecting from 



