298 Tyansactions. — Geology. 



invisible organisms give invisible scratches ; hence the vakie of 

 the earth as a pohshing-powder. 



(2.) In the manufacture of sihcate of potash or sihcate of 

 soda — " ivasser glassc " or Hquid glass. This is becoming a 

 most useful article, and may be prepared by treating diatom 

 earth with hydrate of lime and then with potash or soda. 

 Liquid glass is useful for many things, such as making a fire- 

 proof paint for wood, in the manufacture of soap ; and is far 

 better than plaster of Paris or gum and starch for use in stiff 

 bandages for surgical purposes. 



(3.) In the manufacture of porcelain. 



(4.) For making cement. 



(5.) As a filtering medium. 



(6.) For lighting fires. Taking advantage of its highly 

 absorbent properties, it is fitted in convenient sizes to an iron- 

 ware handle, then saturated with kerosene. When it is desired 

 to light a fire put a match to the saturated earth and place it 

 between the bars of the grate. When the fire is lit remove 

 the earth and blow it out, and use again when required. 



(7.) A lost art — one known to the ancients — has been redis- 

 covered — viz., the art of making floating bricks. This is done 

 by the addition of one-twentieth of clay. 



(8.) In the manufacture of dynamite and lithofracteur, the 

 first containing 73 per cent, of nitro-glycerine, the latter 69 per 

 cent. 



(9.) As a surgical dressing for suppurating wounds. I have 

 long used it for this purpose. It is highly absorbent and 

 unirritating. I find that 60 grains of diatom earth, quite dry, 

 will absorb in a couple of hours more than its own weight of 

 water. One piece that I tried weighed 60 grains dry, and 135 

 grains when saturated. I powder it finely and add small 

 quantities of some antiseptic, and dust it over the wound. 



Now as to the methods to be adopted to clean and mount 

 the diatoms in this deposit. The first thing to be done is to 

 disintegrate the earth. This can be done (a very slow process) 

 by soaking the earth a very long time in water and letting it 

 crumble, and then carefully washing put the clay. A much 

 quicker plan has been suggested by M. Parmentier, a pro- 

 fessor of chemistry in Belgium, and was communicated by M. 

 Guimard to the Quekett Club.''' 



It consists in the supersaturation of the earth by some 

 neutral salt, and then recrystallizing it. The crystals penetrate 

 in every direction ; then, when redissolved, the earth breaks 

 up into a fine powder. More exactly, place a few small frag- 

 ments of the earth, the size of peas, in a test-tube, and cover 

 them to about 2 centimetres with acetate of soda, and add a 



" Journ. Quekett Club," Dec, 1887. 



