Nelson • Vegetable Jewels at Work 



145 



country during the past sixty or seventy 

 years. 



The uses of diatoms are not con- 

 fined to this one field, however, for 

 modem industrial research engineers 

 have probed deep into their possibil- 

 ities. 



As can be seen from a microscopic 

 view of this tiny vegetable, a single 

 diatom has a very intricate design made 

 up of extremely delicate lines. Micro- 

 scope workers— biologists, chemists, 

 metallurgists, and others— have found 

 that single diatoms are valuable for 

 testing the quality of expensive, high- 

 powered microscope lenses. A good 

 lense will show the lines on a diatom 

 shell sharply and clearly; a poor lens 

 will cause these lines to blur and ap- 

 pear to run together. 



Another use that chemists have 

 found for diatomaceous earth is in the 

 handling of the large glass bottles 

 called "carboys," in which strong acids 

 are shipped. These bottles are packed 

 in crates, surrounded with powdered 

 diatom material. If the glass bottle is 

 broken during shipping, the shell-earth, 

 which is very absorbent, will soak and 

 hold all the acid, thereby preventing 

 the spilled liquid from doing any dam- 

 age. 



If you have the opportunity to ex- 

 amine a diatom under a good micro- 

 scope, you will notice that the shells all 

 have a file-like surface. This fact gave 

 researchers another idea. If you want 

 to remove rust from iron, you can use 

 either a file or sandpaper. But when 

 expensive silverware and silver plate be- 

 come tarnished, it must be polished so 

 that the tarnish and stains will be re- 

 moved, but the silver itself will not be 

 marred. So in most kitchens today 

 there is a jar "full of diatoms"— actu- 

 ally, silver polish made from diatoma- 

 ceous paste. 



In modem sugar refineries, a little 

 diatom earth is added to the sugar 



syrup. When this solution is put 

 through the filter, the microscopic di- 

 atoms pile up on the cloth, and the 

 fine shells catch and hold the dirt. As 

 more of the sugar syrup is poured in, 

 more shells fall to the bottom, and so 

 on during the entire process. Tlicre is 

 no hard cake of dirt forming against 

 the cloth to slow up the filtering. 



Diatoms added to paint make it last 

 longer. The ridges of the shells lock 

 together as the paint dries, forming a 

 hard, thin film that will neither crack 

 nor peel. Added to dr}^ cement powder, 

 diatoms have much the same effect, 

 making the finished concrete materially 

 harder and stronger. 



When shell-earth is mixed with fine 

 asbestos fibers, the resulting material 

 forms an excellent insulating material 

 for modem homes. Stuffed between 

 the walls of a house, the material keeps 

 the interior cool in summer and warm 

 in winter, cutting down street noises. 



Still another important war-time 

 use of diatoms, requiring many hun- 

 dreds of tons of material, was as a 

 "flatting" agent in camouflage paints, 

 enamels, and lacquers, as well as in 

 flat finishes used on all kinds of military^ 

 equipment. A flat finish, incidentally, 

 is one that has little or no gloss. A flat 

 finish is desirable because it does not 

 reflect light and so betray positions to 

 the enemy. Camouflage paints were 

 used in tremendous quantities. 



The uses to which diatoms are now 

 being put run literally into the hun- 

 dreds. They pop up in all sorts of un- 

 expected places. They are used in mak- 

 ing soaps and cosmetics; in the manu- 

 facture of ink; as "filler" materials; to 

 improve the quality of paper, and in 

 many other ways. 



Thus has the trained, disciplined 

 imagination of the industrial engineer 

 taken advantage of the peculiar prop- 

 erries and structure of the diatom. 

 Forty years ago, people knew little 



