the

In addition to extra cables

and parts, the bridge is so constructed as to become flexible in case of seismic disturbance, it being made in sections of fifty feet, with the sections connected by thirty pivots, eight inches in diameter and twelve feet in length. By this arrangement the structure may sway, expand or contract and still maintain its level

without injury to

any part.

from their foundation, at a distance of 2,280 feet apart.

In constructing the piers in San Francisco channel, the difficulty of pier construction in the greatest depth of water ever before attempted will have to be met, the water pressure at 140 feet reaching almost 9,000 pounds to the square foot. To meet these extraordinary difficulties, Mr. Rush has planned for these piers resting in the waters of the bay, a special caisson, 225 by 325 feet in width and 150 feet

high. The structure will be hexagonal in shape, constructed of steel and reinforced concrete, and will be made with a series of internal shafts and tubes. These will be equipped with air locks, and when the structure is filled with compressed air it will have a buoyancy of approximately 110,000 tons, as against 90,000 tons dead weight; with resisting power to outside water pressure of 16,000 pounds to the

square foot, as against approxi

and at the base of

the bridge with ec

centric bearings, which compels the bridge to lift one or more of its parts or sections before the whole structure can sway, vibrate or move out of a perpendicular line. Thus it becomes self-adjusting in storms, even with a cable stretch between piers of SO great a distance as 3,000 feet.

The bridge will have ten piers, and if the distance to bedrock in both the Oakland and San Francisco channel shall prove to be 150 feet, the piers will be approximately 600 feet high

sure which will have to be met in San Francisco channel. This great caisson will be floated to the location of the piers, steadied by two immense barges, the air allowed to escape from the compartments, and the structure sunk. After this the water and mud will be pumped from the inside and beneath, and then the caisson, by its own weight, will sink to bed rock. The air compartments will be filled with stone and granite, forming the base of the pier, after which the pier proper will be built up the required

height to receive and hold the ten great cables above. These plans for the bridge, the construction of the piers and their sinking have received. the highest commendation from eminent engineers, who have investigated them, though they are entirely new, and some of the principles involved have hardly yet become known to the engineering world at large.

At either terminus of the bridge, on Telegraph Hill and on the Oakland side, it is planned to extend the pier up 1,200 feet high, 200 feet higher than any structure now in existence, forming a tower for marine lights and for observation. Access to these towers will be by spiral railway, or by a system of elevators, thus making it convenient for visitors at all times.

On the Oakland side, the location of the tower is planned to be in a park upon tide lands, in which the arches of the bridge would begin and finally terminate; the design of the whole structure is of such beauty as to add attractiveness to its surroundings, as

The height of the bridge above water level will probably be 180 feet, or great enough to clear all ocean vessels and meet the approval of present and future shipping interests of the bay.

From both San Francisco and Oakland terminals, connections by elevated lines will be made with all surface cars, making it possible for passengers to take a car in either city and land at their destination in the opposite city without change of cars for the bridge. Thus a portion of the city that is now lying dormant will be utilized. In this, as in many other ways, the benefit to the bay cities from this great bridge is beyond computation at the present time, for the future alone can reveal the advantages to be derived from such a mode of transportation.

sitions, she was finally admitted to full membership in the sisterhood of ships.

I say of lowly origin, for the first tugboats were practically old hulks, which after reaching the dead-line in the carrying trade, were fitted with engines and set to towing vessels in and out of Atlantic seaports. It was not until 1849 that a boat built exclusively for towing purposes appeared upon the American seaboard. In that year W. H. Webb constructed at New York two powerful tugs, named the Ajax and Goliah.

Upon her completion the Goliah was sold to California parties, who intended to run her upon the Sacramento River. Her new owners became involved in financial difficulties and the vessel was placed in the hands of a U. S. Marshal. This individual awoke one morning to find himself on the way to the new Eldorado, without his knowledge or consent.

Thomas, where her coal supply was replenished, and after rather an eventful voyage finally steamed into San Francisco Bay. Converted into a passenger steamer under the name of the Defender, she ran on the Sacramento River until bought off by the combination, after which she was placed on one of the ocean routes for a long period.

After being successively shortened and lengthened, until like the Irishman's knife that had been given a new handle and several new blades, there was little of the original material left, in 1864 she re-entered the towing field, operating at the entrance to the Golden Gate. Remember the Goliah, as she will figure further in this article.

Meanwhile, up on Puget Sound several small tugboats had appeared, but these had devoted all their energies to the towing of logs for the various

timber-clad shores of this great inland sea of the Northwest.

The pioneer in this trade was the Resolute, which steamed up from San Francisco in 1858. Feeling that the time was ripe for the operation of a vessel devoted exclusively to the towing of ships, the owners of the Resolute turned their backs upon log-booms and stationed their craft at the entrance to the Strait of Juan de Fuca for the accommodation of shipping.

This maneuver caused surprise as well as indignation on the part of the old sea-dogs frequenting these waters. What, patronize these wood-eating, smoke spitting aquatic threshing machines? They could never countenance such an unholy alliance between steam and sail. The suggestion that time could be saved by towing seemed a reflection upon their seamanship. Had they not been fighting the winds and tides of old Cape Flattery for years, with nothing to depend upon

but their own resources? Then why should they wish to change at this late day?

But the ship-owners were taking a different view of the situation. Although the commerce of the Northwest had been increasing at a tremendous rate, vessels of all nationalities had been heading towards Puget Sound to get a share of the lumber trade and a general reduction in rates had followed this foreign invasion.

There was no question that if vessels were to continue earning their accustomed dividends cargoes would have to be handled with greater despatch. In short, time was to become a factor in the transportation business of the Northwest.

So the ship-owner had been busy figuring. On one side of the ledger he entered the price of a tow in and out of the Sound. It was seemingly a dead expense. But when upon the other side were placed the value of