146 



SCIENCE, 



[Vol. V., No. 107. 



1877, and held the office of high sheriff of 

 Hertfordshire and other important public trusts 

 at various times. He was treasurer of the 

 Geological society for many years, and honor- 

 ary or corresponding member of many foreign 

 societies. 



In scientific matters, Dr. Jeffreys had some- 

 thing of the conservatism natural to a person 

 of his years ; but his opinions, however firmly 

 held, were never expressed with bitterness, and 

 his genialit} r and hospitality bound to him in 

 friendly ties not only scientific men, young and 

 old, but the intelligent and cultured throughout 

 his wide circle of acquaintance. He leaves a 

 son, Mr. Howel Jeffreys, and five daughters, 

 one the wife of Prof. H. N. Moseley of the 

 Challenger expedition. His collection, which 

 for British seas is absolutely unrivalled, pos- 

 sessing many of the actual types of Turton, 

 Alder, and other early British naturalists, and 

 an extremely rich and largely unique North 

 Atlantic and North European series will form 

 one of the treasures of the National museum 

 at Washington, where a portion of it has al- 

 ready been received. W. H. Dall. 



THE WASHINGTON NATIONAL MONU- 

 MENT. 



The history of the undertaking which has 

 resulted in the completion of the AVashington 

 monument presents a number of interesting 

 and curious facts ; and the construction of the 

 monument itself, by reason of the magnitude 

 of the structure, has involved some problems 

 of considerable engineering importance. 



The early history of the monument may be 

 said to date from 1783, when congress resolved 

 to erect, wherever the residence of congress 

 should be established, an equestrian statue of 

 Washington; and in 1795, when it was pro- 

 posed to build a monument commemorating 

 the American revolution, Major L' Enfant, the 

 designer of the plan by which the city of Wash- 

 ington is laid out, selected, and Gen. Washing- 

 ton himself approved, the site where the finished 

 monument of which we write now stands. 



After the failure of these and other similar 

 plans, the next step was taken in 1833, when, 

 under the auspices of the Washington national 

 monument society, the aid of the people of the 

 United States was invoked to raise the sum 



required to erect a great national monument, 

 no one to contribute more than one dollar, — a 

 restriction which was removed in 1845. Money 

 came in slowly ; but by 1847, $87,000 had been 

 raised, and it was determined to make a be- 

 ginning ; and, by authority from congress, 

 President Polk deeded the present site to the 

 society. Building was at once commenced, 

 but proceeded slowly ; and in 1854 the society 

 had spent $230,000, and raised the monument 

 to a height of 152 feet above the base. 



The original design by Robert Mills included 

 an obelisk faced with white marble, 600 feet 

 high, 55 feet square at the base, and 30 feet 

 square at the top, surrounded at its base by a 

 circular rotunda or colonnade 250 feet in 

 diameter and 100 feet high, in which were to 

 be placed statues of the nation's illustrious 

 dead, with vaults beneath for the reception of 

 their remains. 



The base or foundation masonry was about 

 80 feet square at the bottom, laid at a depth 

 of but eight feet below the surface of the 

 ground, and carried up, in steps of about three 

 feet rise, to a height of 25 feet, where it is 58 

 feet square. The slight depth to which the 

 foundation was carried was due to the anxiety 

 of the building committee to have something 

 to show for the money expended. It was 

 built of rubble masonry of blue gneiss, the 

 blocks large and of somewhat irregular shapes 

 (nearly as they came from the quarry), laid 

 in a mortar of hydraulic cement and stone 

 lime, the joints and crevices filled and grouted. 

 The shaft of the obelisk was built hollow, with 

 walls 15 feet thick at the base ; the well, or 

 hollow interior, being 25 feet square for the 

 whole height then built. The exterior face, 

 to an average depth of sixteen or seventeen 

 inches, was of Maryland marble, usually called 

 alum-stone. The remaining thickness of the 

 walls was of blue-stone rubble backing, not 

 the best construction for a building of such 

 enormous weight. 



To ascertain the kind of earth that would be 

 under the monument, a well was dug, some 

 25 feet deep, in the immediate vicinity of the 

 site, and the earth particularly examined. 

 The material was found very compact, requir- 

 ing a pick to break it up, and was pronounced 

 suitable for a structure of the kind. At a 

 depth of twenty feet a solid bed of gravel was 

 reached, and, six feet lower, water was struck. 

 Before the first course of marble was laid, 

 bench-marks were located from which to test 

 the settlement of the monument. After build- 

 ing to 126 feet in height above the ground, 

 the chairman of the building committee writes, 



