NICCOLIXI-NICHOLSON. 



double track ; the old cables were replaced with larger 

 ones ; iron trusses took the place of wood and the 

 towers of heavy-framed timbers gave way to towers of 

 steel. All these changes were made without interfer- 

 ing with the traffic. 



The still more remarkable cantilever bridge was com- 

 menced on April 5, 1883, and opened for travel on 

 December 20 of that year. This was the earliest 

 bridge completed upon the cantilever plan in the 

 United States ; the new bridge over the Hudson River 

 at Poughkeepsie, the bridge over the Firth of Forth 

 in Scotland, with a clear span of 10(X) feet, and the 

 bridge over the Fraser River, in Canada, are later ex- 

 amples of the same design. The bridge at Niagara 

 Falls has a double-track railroad, and can carry upon 

 each track at the same time a freight train of the 

 heaviest kind, extending the entire length of the bridge, 

 headed by two " consolidation " engines, and can with- 

 stand a side pressure of 3(1 pounds per square foot, 

 which pressure is produced by wind having a velocity 

 of 75 miles per hour. Under the above loads the 

 structure is strained to only one-fifth of its ultimate 

 strength. The total length of the bridge proper is 895 

 t:it. divided into 2 cantilevers of 375 feet on the Cana- 

 dian side and 3'.5 on the American side, supported on 

 steel towers rising from the water's edge. A fixed 

 span of 125 feet is suspended from and connects the 

 nver arms of cantilevers ; the clear span across the 

 river is 500 feet, being the longest double-track truss 

 span ever built. The excavations were carried down 

 until solid rock was reached, when blocks of ''beton 

 coignet" (q. r.) 20 feet wide, 45 feet long, and H> tret 

 thick, were put in. These form one solid mass that 

 will withstand a pressure almost equal to the best 

 Quincy granite, and will so distribute the load of Itioo 

 tons that comes upon each pair of steel columns that 

 it will produce a pressure of but 25 pounds per square 

 inch on the natural formation. Upon the be'ton 

 blocks, 4 in number, was built masonry of the most 

 substantial character, carried up 50 feet above the 

 surface of the water. On these foundations the steel 

 towers rest, rising 130 feet above the masonry, and 

 upon these are set the steel superstructures. The ma- 

 terial was subjected to the most rigid inspection and 

 testa from the ore until it entered the completed struc- 

 ture. For erection at the bridge site temporary scaf- 

 foldings, which used some 600,000 feet of timber, were 

 built from the bluff on either side out to the edge of 

 the water, on a level with the top of the bluff. Upon 

 these the shore arms of the cantilever were erected, 

 one end resting on the steel towers and the other upon 

 masonry on the bluff. The shore ends are anchored to 

 tins masonry, so that it will take an uplifting force of 

 400 tons at each end to displace it. This constitutes 

 the counterweight to balance the unequal loading on 

 the river arm, and as this load, under the most unfa- 

 vorable conditions, can never equal 200 tons, the provis- 

 ion is ample. After the structure was completed from 

 the shore to the steel towers came the difficult portion 

 of the work to span the 500 feet across and 245 feet 

 above a roaring river whose forces no earthly power can 

 stay, and no temporary structure can survive a moment. 

 Here the skill of the engineer came in to baffle nature. 

 The design of the cantilever was such that, after the 

 shore arm was completed and anchored, the river arm 

 was built out, one panel or section at a time, by means 

 of great travelling derricks, being self-sustaining as it 

 progressed. After one panel of 25 feet wan built and 

 bad its bracing adjusted, the travelling derricks were 

 moved forward and another panel erected. Thus the 

 work progressed, section by section, until the ends of 



utilcver wore reached, when there still remained 

 a L':ip of 125 feet to close. Into this was swung and 

 liumnded from the cantilever arms an ordinary truss 

 bridge, forming the connecting link and completing the 

 M picture. Compensation for expansion and contrac- 

 tion was provided lor by an ingenious iirranircment be- 

 tween tin: ends of tlie cantilever and fixed span, 



Vol.. IV. u. 



allowing the ends to move freely as the temperature 

 changed, while yet preserving perfect rigidity against 

 the side pressure from the wind. There were no guys 

 for this purpose, as in the Suspension Bridge, but the 

 structure was completed within itself. Neither was 

 there any of that wave motion noticed on a suspension 

 bridge as a train moves over. (p. G. M.) 



NICCOL1NI, GIOVANNI BATTISTA (1782-1 861), an 

 Italian poet, was born at the Bagni di S. Giuliano, 

 Oct. 31 , 1 782. He was educated at the University of 

 Pisa, and enjoyed the friendship of Ugo Foscolo. 

 Several of Niccolini's tragedies were founded in Greek 

 themes, as 1'olissena, Medea, Edipo, and he also trans- 

 lated from jEschylus the Seven, against Thebes and 

 the Ar/amemnon. His Matilda was an imitation of 

 Home s Dmiglas. Under the government of Elisa 

 Bonaparte he was made professor of history and my- 

 thology. His lectures and prose writings were notable 

 contributions to Italian literature. On the downfall 

 of Napoleon he published an allegorical tragedy, 

 Nabnccn. Still greater success had his Antrmin Fos- 

 ciirini (1827), and his revolutionary drama, Giovanni 

 di Procida (1830). I/iidurJco il Afnro, written about 

 the same time, was not allowed to appear until 1847, 

 but his Arnnldo dn Hresciii, in which he gave expres- 

 sion to the ardent desire of the people of Italy for re- 

 ligious and intellectual liberty, was printed secretly at 

 Marseilles, in 1843. Fillppo Strom (1847) contained 

 a representation of the fallen yet not hopeless state of 

 Italy. Among the works of his later years is the lyri- 

 cal drama, Mario e i Cimbri. He died at Florence, 

 Sept. 20. IStil. 



NICHOL, JOHN PRINOI.E (1804-1859), a Scotch 

 astronomer, was born at Brechin, Jan. 13, 1804. He 

 was the son of a bookseller, and studied for the min- 

 istry, but alter being licensed to preach became n 

 popular lecturer on a&tronomy, and was professor of 

 practical astronomy in the University of Glasgow. He 

 died at Rothcsay, Sept. 19, 1859. Among nis works 

 are T'te Architecture of the Heavens (1838J; Coiitim- 

 plaftoiix of (lie &Jnr System (1844); The Stellar 

 Uttioerte (1848); The Irlanetary System (1851); 

 Cydiipcrdia nft/tf. Physical Sciences (1857). 



His son, JOHN NICHOL, was born at Montrone, 

 Sept. 8, 1833. He graduated at the University of 

 Glasgow in 1855, and at Oxford in 1859. He was 

 made professor of English literature in the University 

 of Glasgow in 1861. Helms been a popular lecturer 

 on literature, and has contributed to the leading 

 Britishre views and to the Encyclopaedia Britminicn. 

 Some of his essays were collected under the title 

 Frnflmextx <if Criticism (I860). He has also pub- 

 lished Hannibal, a drama (1^72), Byron in the "Kng- 

 glish Men of Letters" series (1880); Rol>ert Knn<t 

 (1882). His article on American Literature in the 

 Ena/dopcedia Britannica has been published sepa- 

 rately. 



NICHOLSON, ALFRED OSBORN PopE(1808-1870), 

 Senator, was born in Williamson co., Term., Aug. 31, 

 1808. He graduated at the University of North 

 Carolina in 1827, and after studying medicine for two 

 years turned to law. He was admitted to the bar 

 at Columbia, Tenn., in 1833, and was elected to Con- 

 gress, where he served three terms. In 1840 he was 

 appointed U. S. Senator on the death of Felix 

 Grundy, and in 1843 was elected to the State Senate. 

 In 1845 he removed to Nashville, where he edited the 

 Union. In 1850 he was appointed a chancellor but 

 held the office only one year. In 1853 he became 

 editor of the Union at Washington, D. C., and soon 

 after was chosen public printer. Returning to Colum- 

 bia, in 1857 he was elected to the U. S. Senate, but 

 retired on the secession of Tennessee in June, 1861. 

 On account of his sympathy with the Southern Con- 

 federacy he was sent south of the Union lines, and on 

 his return was imprisoned at Nashville. In 1870 he 

 was a member of the State Constitutional Convention, 

 and was also elected to the State Supreme Court, of 



