786 SUMMAEY OF CUEEENT RESEARCHES RELATING TO 



manufacture of silicate of soda or potash, also known as soluble glass. 

 The manufacture of this compound is simplicity itself. Carbonate of 

 soda or potash, as the case may be, is dissolved in boiling water to 

 saturation, in a capacious iron kettle, and fresh hydrate of lime added 

 until all the carbonic acid is precipitated, and the alkali becomes 

 caustic. Diatomaceous earth in a powdered state is then added as long 

 as silica is dissolved, and the whole covered and allowed to cool. 

 When the insoluble matters have settled, the clear liquid is drawn off 

 and evaporated in a clean vessel to the required density. 



Diatomaceous earth is also used in the manufacture of porcelain, 

 and it is a constituent of certain cements and artificial stones. At one 

 time it was claimed to be a fertilizer, but this is thought to be a 

 fallacy, although Ehreuberg states that the fertilizing power of the 

 Xile mud is furnished by fossil Infusoria. 



Slabs of diatomaceous earth absorb liquids with avidity, and are 

 used in laboratories for di-ying crystals and filters. This property 

 might be more generally utilized if better known. 



A convenient contrivance for lighting fires is a lump of diatomace- 

 ous earth with a handle of stout iron wire. It is dipped into a vessel 

 of petroleum, placed in the stove or fireplace, and lighted with a 

 match. It continues to burn safely for some time. It can be used 

 asain and again. Xo person, however, should make use of it who has 

 nut the common sense to carefully set away the vessel containing the 

 coal-oil before lighting the match. 



Bricks that float in water are made of diatomaceous earth mixed 

 with one-twentieth part of clay and well burned. The art of making 

 these floating bricks was well known in the time of Pliny, but was 

 afterwards lost. It has recently been rediscovered. In the Italian 

 department of the Paris Exposition of 1878 these bricks were exhibited, 

 and attracted considerable attention. Floating bricks, made wholly 

 of Califoruian material may be seen in the State Museum. 



Kieselguhr or '' flint froth " of the Germans, from a deposit in 

 Hanover, is extensively used in the manufacture of dynamite, giant 

 powder, lithofractetir, and other explosives. Diatomaceous earth 

 absorbs from three to four times its weight of nitro-glycerine, with the 

 advautaf^e over other absorbents of retaining the uitro-slvcerine under 

 greater pressure. Dynamite contains 27 per cent, and lithofracteur 

 23 per cent, of diatomaceous earth. Before the kieselguhr can be 

 used, it is subjected to treatment to remove water, all organic matter 

 and coarse particles. It is first calcined in a succession of furnaces, 

 crushed between rollers, and sifted. 



Diatomaceous earth is largely used in the manufacture of soap, to 

 mechanically increase its detersive power. The Standard Company 

 receive large quantities of it from the southern counties of the 

 State. 



It is not to be supposed that all the uses of this remarkable sub- 

 stance have been discovered : it remains for the intelligent inventor to 

 search for new applications." 



C. W. G. also says * that on examining some of the powder known 

 * Amer. Mod. Micr. Journ.. ii. (1881) p. 158. 



