258 UTILIZATION OP MINUTE LIFE. 



quantity of infusorial earth than that prescribed be 

 taken, the soluble glass obtained is too alkaline and 

 very deliquescent. 



Soluble glass, first discovered by the ingenious 

 chemist, Fuchs, of Munich, is an alkaline silicate of 

 potash or soda. It has been utilized in various 

 ways, principally for protecting wood, linen, the 

 scenery of theatres, panoramas, etc., from fire. 

 Tissues steeped in it lose their faculty of burning 

 with flame ; if held in the fire they will consume 

 slowly and without flaming, so that any such tissue 

 being set on fire cannot communicate its combusti- 

 bility to other substances near, and in nine cases 

 out of ten it will not take fire at all. 



These infusorial deposits, moreover, furnish 

 very good material for the manufacture of window- 

 glass, plate-glass, etc. ; besides which they make 

 an excellent mortar, and can be converted into 

 filters, into moulds for casting iron, brass, or other 

 metals. Add to this the use made of them as food 

 and their polishing quality, and we shall see at a 

 glance how much the remains of these invisible 

 animalcules have been turned to account by man. 



Chalk, also, which has innumerable uses which 

 is employed, for instance, to prepare mortar, cement, 

 as a manure, as a polishing material for silver and 

 gold, etc., for whitewashing, to prepare lime, etc.; 

 chalk also appears to owe its origin to the remains 



