free hypochlorous acid, and is a valuable bleaching solution. In the application of this solution to actual bleaching, I found on immersing pieces of unbleached cotton cloth in the solution, that it worked admirably as a bleaching agent. But it must be understood that these results are only in the experimental stage. I am, however, very confident that we have a process in this, which, if properly worked out, will be of great value to the bleaching industry.

THE KANSAS CITY BRIDGE.

BY ISAAC LEWIS WINCKLER, 1887, NEW BRUNSWICK.

The movement which led to the bridging of the turbulent and unstable Missouri by the Kansas City bridge, dates from the incorporation of the Kansas City, Galveston and Lake Superior railroad by the State of Missouri, in 1857. In 1865 a charter was obtained from the Legislature of Missouri for a carriage and railroad bridge at Kansas City; but the company was never organized under it, owing to the failure to obtain the necessary capital. In the following year, 1866, the Kansas City, Galveston and Lake Superior Railroad Company, which had been revived, and whose name had been changed to the Kansas City and Cameron railroad, had its charter amended, so that they obtained the privilege of bridging the Missouri. A preliminary survey of the bridge site was made in 1866 by M. Hjortsberg, Chief Engineer of the Chicago, Burlington and Quincy railroad. On the 7th of the following February, Mr. Chanute took charge as Chief Engineer, and acted as such until the completion of the work.

The corner-stone of the south abutment was laid August 21st, 1867. The last stone was laid May 5th, 1869. This completed the masonry of the bridge. The contract for the superstructure was given to the Keystone Bridge Company, of Pittsburgh, on November 22d, 1867, and was carried to completion under the direction of that company. The draw was swung June 15th, 1869, and the first engine crossed the bridge ten days after. On July 3d it was publicly opened to travel.

46

The fact that gives interest to the construction of this bridge is that it was the pioneer bridge over the Missouri, and it is owing to the character of that river that the chief difficulties were due. Rising in the eastern part of the Rocky Mountains and flowing with a rapid descent down the westerly slope of the great basin, the Missouri unites within itself all elements of unstableness and irregularity, combining the impetuosity of a mountain torrent with the volume of a lowland river." Its navigable length is about 3,150 miles and area of drainage 518,000 square miles. Its course is through a low alluvial deposit inclosed on each side by high bluffs. Its fall is ten inches to the mile. It is subject to sudden rises, when the current becomes very violent, heaping sand bars in some places and cutting

new channels in others. Observations of the speed of the current showed the minimum velocity to be two miles per hour and the maximum velocity about eight and one-half miles per hour.

The bridge is situated below a long curve in the river, at a point where the main channel is close to the Kansas City shore. The southern bank is a rocky bluff, while the northern bank is low bottom land. The width of the river at this place, measuring from the bluff to the wooded shore on the north, is almost exactly one-quarter of a mile.

Owing to the unstable character of the Missouri, and the continual wash and scour of the river, the chief difficulties lay in the matter of the foundations. A particular method of founding was necessary for almost every pier. Piers Nos. 1, 2, 3 and 4 were founded on the solid bed-rock; while Nos. 5, 6 and 7 were founded on piles. The piles under pier 5 were driven to solid rock. All foundations were put in for a double-track bridge. The form of pier adopted was such that it combines strength with beauty of outline. The stone used in the piers was limestone, the most of which was obtained near the city. The piers are of two sizes, called the "seven-foot pier" and "eightfoot pier;" these dimensions referring to the width at the "neck." They are all of the same length, 47.4 feet. (The other dimensions we have given in the drawings.)

Careful observations of the direction of the current were made. This direction was found to make an angle of 72° with the bridge line. The piers were built parallel to the current. Hence it was necessary to build the bridge on a skew of 18°.

The superstructure was designed for railroad and common travel. It is a single-track bridge, but, as the foundations were put in for a double-track bridge, it can at any time be widened. Both the railroad and the common travel are admitted to the same floor. This, with proper regulations, has been found to work well. For foot passengers a foot-walk is built on one side, supported by brackets fastened to the floor beams.

The superstructure consists of five fixed spans and one pivot draw. The lengths of each span, beginning at the south side of the bridge, are as follows: A fixed span of 132 feet, extending from the south shore to pier No. 1; a pivot draw 363 feet long, each arm having a clear span of over 160 feet; a fixed span 200 feet; a span of 250 feet; another of 200 feet, and the last of 177 feet, extending from pier 6 to pier 7 on the north side of the river. Adding to the sum of these lengths a shore span of 68 feet, we have for the total length of the structure, from outside to outside of masonry, 1,400 feet. The approach to the bridge on the north is an open trestle-work, built of oak and 2,380 feet long. It has an ascent of one in one hundred till within 618 feet of the bridge, the remaining 618 feet being level, to allow trains to come to a stop before crossing.

The design of the fixed spans is that of a double triangular truss

or trellis girder. They were built by the Keystone Bridge Company, of Pittsburgh, Pa., after plans drawn up by the Chief Engineer. They are partly of wood and partly of iron. Pieces subjected to compression are of wood, and those subjected to tension are of wroughtiron. The top chord, end posts and the braces are of wood, and the lower chord and ties are of wrought-iron. In the connections of pieces cast-iron is used. The draw is a Pratt truss, entirely of iron. The skew is taken out of the draw by making the end panels of unequal length.

The upper chords in each span are of wood. They are built beams, packed in the usual manner. In the 130-foot span the chord is built of 3 pieces, while in all of the other spans it is formed of 5 pieces and supplemented at the center by a sub-chord of 2 pieces. They are all covered in to protect them from the weather. In the 130 and 176foot spans the chords are straight and parallel, the depth between them being 22 feet. In the other larger spans the upper chords are arched, the depth at the ends being kept at 22 feet, while the central depth is increased to one-eighth of the length of the span.

The lower chords are of wrought-iron, upset links with pin connections, made under the Linville & Piper patent.

The braces are solid, square pieces of wood, probably oak. In place of the ordinary square ends they are cut with two faces, making an obtuse angle with each other, and the angle blocks are cast to correspond. This makes it impossible for a brace to slip from its bearing. In the 130-foot span both the main and counter-braces are single. In all the other spans the main braces are in pairs; the counters are single, passing between the main braces. A counterbrace is placed in every panel and they bear on brackets placed on the sides of the main braces.

The ties are of square iron, with a welded loop at the lower end passing around the chord pin. In the 130 and 176-foot spans both main and counter-ties are in pairs, the main ties passing outside of the main braces and the counter-ties between the main and counter-braces. The arrangement of the ties is the same in the central panels of the 198 and 248-foot spans, but near the ends there are four main ties instead of two; two passing outside the main braces and two between them and the counters.

In this bridge a great deal of attention was given to the form of the angle block. Those in the upper chord were so arranged that the strain on the chord should be distributed through the whole section, and also that the vertical component of the strain in the ties should be thrown directly on the braces.

STRAINS IN 130-FOOT TRUSS.

The assumed live load for this span was 2,800 lbs. per running foot, or 1,400 lbs. per lineal foot for each truss. The length was 128.3

feet. Therefore, the whole live load on each truss was 1,400X128.3= 179,620 lbs. There are 10 panels; ... the live load per panel would be 179,620 10=17,962 lbs. In Appendix F of Mr. Chanute's work, he gives the live load per panel as 16,000 lbs.-a difference of nearly one ton.

The dead load on each truss per panel is 13,150 lbs. Below is the computation of the strains in the ties and braces, and in the chords, taking the live load as 16,000 lbs. per panel.

STRAINS IN DIAGONALS-FIRST METHOD.

p=16,000 lbs.

=

W.= 13,150 lbs.:

8 tons = live load on each joint of lower chord. = = 6.575 tons = 6575 p.822 p = dead load. Height of truss = 22 feet, length of one panel = 12.83 feet. 0 inclination of diagonals to the vertical.

... sec 0h2+12 = 1.1576.

h

Call compressive strains,+; and tensile strains,-.

=

In the figure let A and B be the piers. Let 1, 2, 3, &c., represent the number of a diagonal inclining downward to the right. Consider each weight separately: First, take p, on joint No. 1. A carries, P and B carries p; or, A carries 7.2 tons, and B .8 tons, due to p1. .. the strain on diagonal No. 1 is 7.2 sec 08.335 tons, and is entered in the table below, opposite diagonal 1, under p1. The strain on 9, 7, 5, 3, due to p1, is .8 sec 0.926 tons, entered under p, opposite diagonals 3, 5, 7, 9. In same manner with each weight (see table). The maximum + or-on each brace or tie is found by adding together all the + values for compression, or all-values for tension. These are entered under maximum + p and maximum p. Since w. is .822 p, the strain under w. due to w. is found by taking .822 of the algebraic sum of the compressive and tensile strains opposite each diagonal. The maximum strain due to both live and dead loads is evidently the algebraic sum of the strains due to each. These results are entered in the last two columns: