CAIRO 



1046 



CAISSON 



a forwarding center for European manufac- 

 tured goods. Cairo was formerly an impor- 

 tant slave market, but this traffic was finally 

 suppressed in 1877. From 1798 to 1801 the 

 city was held by the French. It was handed 

 over to the Turks by the British, in 1801, 

 and Mehemet AH seized the reins of govern- 

 ment and established a dynasty. In 1915, with 

 the rest of Egypt., Cairo was declared a British 

 possession. Population, 654,500. F.ST.A. 



CAIRO, kay'ro, ILL., a city in the extreme 

 southern part of the state, situated on an arm 

 of land just above the confluence of the Missis- 

 sippi and the Ohio rivers. It is the county 

 seat of Alexander County. Chicago is 364 

 miles northeast, Saint Louis, 148 miles north- 

 west, and Memphis, 170 miles southwest. The 

 population in 1910 was 14,548; in 1914 it was 

 15,392. The area of the city exceeds two square 

 miles. 



Cairo is on the Illinois Central, the Mobile 

 & Ohio, the Saint Louis Southwestern, the 

 Saint Louis, Iron Mountain & Southern and the 

 Cleveland, Cincinnati, Chicago & Saint Louis 

 railroads, and has an an extensive river com- 

 merce. The Illinois Central Railway crosses 

 the Ohio River near the city on a fine steel 

 bridge two miles long and fifty feet above high 

 water. It was built in 1888 at a' cost of nearly 

 $3,000,000. 



Cairo is so situated at the head of all-year 

 navigation of an important river system that 

 it is the natural distributing center and ship- 

 ping point for a large territory. Six large grain 

 elevators, the Singer Manufacturing Company, 

 creameries, wagon and buggy factories, flour 

 mills, wood-working plants and packing houses 

 are among the important industrial establish- 

 ments. Quantities of hardwood and cotton- 

 wood from the surrounding country are 

 shipped. 



Cairo's great problem of recurring river floods 

 has been solved. Levees begun in 1857, many 

 times reconstructed and reinforced, have, since 

 a great flood in 1913, been strengthened suffi- 

 ciently to withstand any probable height to 

 which the water will rise (see LEVEE). The 

 land is drained and protected from seepage. 

 Among the important buildings are the Fed- 

 eral building, erected in 1871 at a cost of 

 $275,000, the Safford Memorial Library, a gov- 

 ernment customhouse, a United States marine 

 hospital and the Saint Louis, Iron Mountain & 

 Southern depot. Five miles from Cairo, at 

 Mound City, is. a national cemetery. 



In Charles Dickens' story, Martin Chuzzle- 



wit, Cairo is the city called Eden. Dickens 

 was a losing stockholder in an early financial 

 attempt to create a city on the site of Cairo, 

 and the town was long an unpromising place. 

 Its settlement was a commercial experiment 

 on the part of those foreseeing the great trade 

 possibilities of the location. Three attempts 

 were made, the first in 1818, the second in 1835 

 and the last in 1851-1854. Cairo was chartered 

 as a city in 1857. The city adopted the com- 

 mission form of government in 1913. W.F.V. 



CAISSON, kay's'n, in civil engineering, a 

 water-tight box or casing, used for several 

 different purposes. It is usually constructed 

 of sheet-iron, and so made that it can either 

 be floated or sunk in the water, as desired. 



ONE FORM OF CAISSON 



Its most general use is for building founda- 

 tions for bridges, dams, or walls in the water. 

 For this purpose the caisson is sometimes built 

 so that it can be floated to the position where 

 it is desired, and there sunk. A caisson to be 

 used in this way is sometimes made with a 

 wooden bottom which can be separated from 

 the sides. Then when the concrete for the 

 structure is placed inside, the sides can be 

 removed. In other cases the caisson is made 

 without a bottom, and the bottom edges are 

 made so that they will cut into the earth. 

 When the casing is thus sunk into the earth 

 below the water, the water is pumped or 

 forced out, and the earth is taken out by in- 

 genious hoisting devices, the caisson sinking 

 deeper as the work progresses. 



For this kind of work it is sometimes neces- 



