DIATOMS. ^3 



6. — In South Carolina, the land in some places is rich in 

 diatoms, which is said to account for its fertility, and we 

 know that the Guano, so much used in this country, owes 

 some of its properties to its diatomaceous character. Mr. 

 Hanks also says that it is used in the manufacture of soap; 

 and last and most curious of all, the well-known " Vege- 

 table Sozodont Tooth-Powder " is composed of diatoma- 

 ceous material, and makes a good microscopic slide. 



All these facts show how important it is that we should know 

 more of diatomaceous formations than we do, and the study of 

 these organisms is recommended to every beginner in microscopic 

 work, as the care, skill, and dexterity requisite to resolve even the 

 simplest form give a steady hand, require much perseverance, and 

 make the worker observant and a neat manipulator. 



To anyone so disposed, this locality (Stroud) affords ample 

 scope for working, as there is not a drain, ditch, or pond where 

 these structures may not be found in quantities. When going my 

 own rounds, I often take a dip with my bottle and generally meet 

 with a good reward, as so many beautiful forms exist without 

 going far away. Amongst a few localities in which I have col- 

 lected are : — 



Stroud Upper Reservoir — Cocconenia and Finindaria. 

 Seven Springs, Bisley — JDiafojna vulgare and GompJwne^na, 

 Salmon's Spring — Synedra radians, S. nobilis, etc. 

 Stratford Mill Pond — SiifHrella and Pleurosigma. 

 Lightpill — Cocconema lanceolatiim. 

 Pond, Bowbridge — Pleurosigma, etc. 

 Heven's Spring — Navicida. 



Some other forms from different parts of the world may be 

 interesting to mention ; for example, the Sozodont Tooth-Powder 

 before alluded to. This diatomaceous deposit comes from Vir- 

 ginia City, near Nevada, California ; and in addition to its use as 

 a dentifrice is applied to the manufacture of what is known as 

 '•''Rock Soap" and the ^^ Electoric Silicon." From Nevada City, 

 Maryland, U.S., we get forms of a similar character to the so- 

 called Bermuda earth (New Nottingham deposit). Coming nearer 

 home, a deposit from the Humber pond-beds, and another from 

 the Thames mud, both show fine forms of diatoms. 



Mr. Kitton has sent me some Bergh Mehl, or " rock-flour," a 

 term applied to diatomaceous deposits, especially of fresh-water 

 origin ; also called Keeselgiirh, a miner's term for wet or sloppy 

 layers. It is also called Essebare Erden^ on account of being 



