THE POLK SYSTEM 



I I 



character has been so notably maintained, we must see that there 

 is a material on whose merits we can form a definite and certain 

 judgment, and the judgment thus formed impels us irresistibly to 

 the conclusion that we have no building construction which, viewed 

 from any standpoint, measures up to the incomparable standard 

 established by concrete." 



Other evidences of the constructive uses of cement are found in 

 various parts of the old world. In Ireland are old lookout towers, 

 supposed to have been built by the Druid priests more than one 

 thousand years ago. They are made of hydraulic cement concrete, 



and are cylindrical in form, 

 about six feet in diameter, 

 and 100 feet high. Some 

 years ago one of these tow- 

 ers was undermined and fell 

 over. The shock was so 

 great that the shaft was bur- 

 ied one-half in the ground 

 for its entire length, yet 

 there was not the slightest 

 fracture in the monolithic 

 structure. Any natural 

 rock would have been shat- 

 tered to bits. In Spain and 

 other countries with a flour- 

 ishing early history all signs 

 point to an early and exten- 

 sive use of a rude sort of ce- 

 ment and concrete. The 

 pre-historic people of the 

 New World also knew some- 

 thing of the value of an artificial stone. The Mound Builders who 

 inhabited the Ohio Valley some 12,000 years ago cooked and boiled 

 in vessels that appear to have been made of a rock conglomerate 

 held together by a cement. The Peruvian Incas built themselves 

 houses of a crude concrete to prevent loss from earthquakes and 

 volcanic tremors. 



So the Ancients worked in concrete. Of course they had noth- 



Ed John's Concrete Silo, 16x40 feet, La Fox, III. 

 by Polk System. W. H. Warford Contractor. 



"They are not built of pieces* and they 

 cannot go to pieces. 



