ARBORICULTURE 



189 



accomplished by any ordinary labor, in 

 a simple and inexpensive machine. 



While the enormous skyscrapers of 

 ten to thirty stories high must of necessity 

 have the framework of steel, thorougly 

 tied together with a network of steel, yet 

 the exposed portions have a casing of 

 brick, tile, stone or concrete, the founda- 

 tion being of concrete. 



This, by the way, is but man's improve- 

 ment upon nature's methods in the matter 

 of time. Nature taking thousands of 

 years to complete the manufacture of 

 limestone, sandstone or granite, while 

 man, by using practically the same 

 materials, makes as solid stone of cement, 

 sand and water in a few days' tim.e. 



There are evidences of some of the 

 Egyptian structures, erected thirty centu- 

 ries ago, which were in part made of 

 concrete- So it is not exclusively the 

 invention of the twentieth century, 

 although many of the processes are quite 

 modern. 



CONCRETE PILING FOR FOUNDATIONS 



We were greatly interested recently in 

 observing the method of placing the 

 concrete foundations under a large busi- 

 ness block at Louisville, Ky. 



Wooden piles, as is well known, do 

 not decay after being driven deep below 

 the action of the atmosphere, air being 

 essential for the propagation of fungi or 

 rot. But wooden piles are becoming 

 very scare, and with long distances for 

 transportion, hence concrete is taking 

 the place of wood for this purpose. 



The hardest of granite gives way under 

 the blows of the chisel and mallet of the 

 stone mason. The best natural stone is 

 fractured by concussion also; while arti- 

 ficial stone made of concrete will support 

 an enormous weight of superstructure in 

 a quiet load, it may easily be crushed 

 by concussion. 



PLACING CONCRETE PILES 



These piles are thirty or more feet in 

 length or depth, and eight inches diameter 

 • at bottom, increasing in size to about 

 eighteen inches at surface of the ground. 

 A steel pile, or core, as it is termed, just 

 the shape of an ordinary pile, is encased 

 in a sheet steel casing, having a rounded 

 cap at bottom of the core. 



These are driven together by huge 

 steam pile drivers until a solid foundation 

 is reached The core, which is collapsa- 

 ble, is then withdrawn, leaving the steel 

 casing in the ground. 



Machine-mixed concrete, in a semi- 

 fluid condition, is then dumped into the 

 cavity from wheelbarrows made for this 

 purpose, one man after another pouring 

 his load into this form until it is filled, 

 it being tamped all the while. 



After the material has set and become 

 sufficiently hardened, concrete walls are 

 built in the ordinary forms or frames, 

 which retain the mass while being 

 hardened. 



Metal stays, twisted strips of steel, are 

 placed in the forms and encased in the 

 concrete for reinforcement and to prevent 

 its cradiing. Thus no concussion occurs 

 in placing the piles or in any subsequent 

 operations. 



CONCRETE FENCE POSTS 



"Near the editor's home there lives a 

 farmer upon whose land are some excel- 

 lent ledges of limestone which by careful 

 manipulation may be quarried into long 

 rectangular blocks. This farmer has 

 used these limestone blocks for fence- 

 posts, thus enclosing his property. 



Imitating this method, there are being 

 made concrete fence posts, reinforced 

 with metal, binding the material and 

 giving added strength. 



But sometimes both the stones and 

 concrete posts are broken, besides being 

 quite expensive, especially so when com- 

 pared with wooden posts, so long as 

 these are obtainable. 



CONCRETE TELEGRAPH POLES 



The Pennsylvania Railway Company, 

 by their Engineer Maintenance of Way 

 at Ft. Wayne, Indiana, Mr. F. M. 

 Graham, has constructed and erected a 

 mile of reinforced concrete telegraph 

 poles, ten miles east of Ft. Wayne. 



The poles are octagonal, and are 

 placed one hundred feet apart in the 

 line, to better sustain the increasing 

 number of wires and prevent the frequent 

 breakage of wires from ice and sleet. 



A remarkable feature in theseconcrete 

 poles is their flexibility. They bend 18 



