THE EIFFEL TOWER. 737 



huge obelisk stands high ou the list of wonderful strnctnres, the press- 

 ure at its base amounting to 58.35 ])Ounds in the proportion above 

 given. With the excei)tion of the Eifl'el tower, it is easily a bolder 

 undertaking than any other of its kind known in the world, because it 

 stands upon a relatively small base, with no side support, with a weight 

 upon its 'foundations of 45,000 tons. Tliis immense square shaft, about 

 55 feet ou a side, served as an illustration of the danger in attempting 

 to carry masonry to a greater height than before achieved. Fortu- 

 nately, the foundation settled evenly, but to prevent probable demo- 

 lition, part of the base was re-constructed and tilled in with concrete. 

 Meantime the strncture began to lean to an extent that caused great 

 uneasiness, and tinally the suspension of the work. The construction 

 was begun in 184:8, and in 1854, when it reached a height of 152 feet, 

 its dangerous condition became somewhat marked. Its original in- 

 tended altitude of 600 feet was thfu reduced to 500. In 1880, after 

 great difficulties, the base had been widened and the foundation en- 

 larged "and deepened. Work was then recommenced, and the masonry 

 continued upward at the rate of about 100 feet yearly, until the top- 

 most stone was laid December 6, 1884. The inauguration took place 

 February 21, 1885. 



An additional source of peril in the use of masonry, not included in 

 the danger of settling, as in the Washington Monument, is the insnffi- 

 cient adherem^e of modern mortar to great masses of stone, causing 

 serious crumbling, and a reputation for danger much to be dreaded. 

 An attempt to extend stone work to a height of 1,000 leet would cause 

 an expense too great for the end attained, and the danger of fracture 

 would be incessant and unavoidable. It seems that we can excel the 

 ancients very little in the treatment of masonry. There is no easily 

 discovered evidence that they built any such structure higher than the 

 great Pyramid of Cheops, originally 4hO feet in height. Tliey had good 

 reasons for this caution. If the fonndations are solid, the stone may 

 disintegrate, owing to the nne(puil distribution of the enormous weight, 

 due to the limited ])ower of the mortar to act as a cushion to equalize 

 the force. The Egyptian and other ancient budders constructed some 

 masonry without mortar by polishing and closely fitting the stone, but 

 it is not probable that they tried to carry such work to a very great 

 height. In vsome modern buildings it is found that the resistance of 

 very hard stone increases that of the mortar. Stone or brick work 

 might reach a higher point than the Eiffel tower by the invention of 

 cements more efficient than any now known. 



In considering the important question of the foundations for this 

 great tower, elaborate borings were made in the Chami)-de-Mars at 

 Paris. This is a level field or park, about two thirds of a mile long and 

 half as broad, devoted usually to the drilling of troops and to reviews, 

 ui)Oj^ which the Exposition buildings for 1889, are now approaching 

 n^mpletion, in commemoration of the storming of the Bastile one hun- 

 H. Mis. 224 47 



