tors for the service of the topmost floors. It is estimated that when the building is fully occupied it will accommodate about 6,000 people.

From an engineering point of view, the most interesting feature of this extraordinary structure is the means adopted in framing the skeleton,

so that it will resist the enormous wind pressure, when the thunder squalls of the summer and the heavy gales of the winter sweep over Manhattan. Decidedly interesting also is the method of treatment which has given this tower an architectural character usually absent from our modern skyscraper. The plan adopted, both in designing the steel skeleton and in the treatment of the exterior, has harmonized both the engineering and architectural requirements of the case. It was realized that, in order to obtain sufficient strength to resist the enormous bending stresses due to wind pressure, it would be necessary to have wind bracing.

The engineers have decided to construct

floors. The corner towers are twelve feet square. This provides an open space of thirty-six feet in width, down the center of each face of the building, which is entirely free from bracing. These spaces are to be occupied by large bays filled in with glass. The lighting of the

the building something like a bridge, the steel work between the massive supporting columns being in the form of lattice work, but the designers have taken no chances and have provided framework, as already stated, heavy enough it is believed to not only sustain the immense weight of the building, but the air pressure as well. It was determined, therefore, to consider the structure as being built up of four square corner towers and a central tower consisting of the elevator well, with "wind braces" running through each wall of each tower continuously, from base to summit, the five towers literally tied together with steel beams at the various

corner towers is by single windows, which are so disposed as to permit the diagonal wind bracing to be carried continuously throughout the whole height of the tower, without interfering with the light. The wind pressure is calculated at thirty pounds to each square foot, uniformly distributed over the whole face of the building, and the total overturning force of the wind reaches the enormous amount of 128,000 foot-tons. The total weight of the tower alone is about 23,000 tons; and yet so great is the wind pressure that on the windward side of the building, should a storm ever blow upon it with sufficient velocity to produce an average pressure of thirty pounds to each

three miles away a second structure is rapidly rising which will make another hole in the sky as large as that caused by the Singer tower. Like the former, while it will be an addition to an office building already completed, it will serve two purposes-not only for business, but for a mighty monument to its erectors. It has a history worth telling. Years ago the Metropolitan Life Insurance Company bought an entire city block fronting on Madison Square, with the exception of a little corner which was occupied by the band of Presbyterians to whom the famous Dr. Parkhurst preaches. They were so satisfied with their location that the insurance company could not buy them out, and thus have all the block for the great structure it had determined to erect. Finally weary of waiting, the company put up a pile of steel and marble that covered every foot of ground except the church site. Then its directors went to Dr. Parkhurst and his trustees and offered to buy a lot on the opposite corner and build a church if the Presbyterians would abandon their present house of worship. The offer was accepted and a beautiful temple was erected on the other corner-one of the most ornate churches in the country. Before the last of the furniture had been moved from the old church, wreckers were tearing down its tower. In a few months a big hole in the ground marked the place where it had stood, but this hole was filled with men and machinery literally making a foundation for the mammoth pile which was to rest upon it -a pile which is to rise so far above the ground that the stream of humanity on the streets about it will look like a swarm of tiny black dots when viewed from its top windows. The lofty tower on Madi

The figures for the weight on a single one of the columns will be of interest: The total dead load on the column will be 289.2 tons, this amount representing the weight of the steel work and masonry. To this must be added sixty per cent of the live load, under which is included furniture, fittings, and the occupants. This reaches a total of 131.6 tons, making a total dead and live load of 420.8 tons. The downward pressure on the leeward side of the building, due to the wind pressure, is estimated at 758.8 tons, which, added to 420.8 tons, gives a total load on the column of 1,179.6 tons. The greatest combined load on a single column is 1,585 tons.

Really the figures are such that their magnitude cannot be appreciated. Yet

-ONE OF THE

son Square garden, which is now such a conspicuous monument in this part of New York, will be dwarfed to insignificance by this new creation of steel and stone which will also excel in height the monument by the Potomac.

It is not how much ground you have, but how you build, that determines the safe construction of sky scrapers or sky piercers. If the frame work is sufficiently strong and sufficiently tenacious to hold up the weight, also to resist the wind which may blow against it, the problem of the building itself is solved. This is why these massive towers rising over 600 feet heavenward are as safe as if they were only a hundred feet high-so say the architects and engineers. But they must have an absolutely firm foundation. Now, much of Manhattan Island is composed of rock so firm that explosives only will rend it apart. Yet strange as it may seem, the building creators often have to go down many feet through what seems to be solid rock, and is solid rock, before the foundation is firm enough to support the mass of steel and stone and brick without "giving." It is cheaper sometimes to make a foundation than to dig one. Then it is literally cast just as melted iron is formed in pigs for the metal worker. Caissons -big steel cylindersare sunk into the ground and form moulds into which is poured a mixture of what is in reality liquid stone. As this solidifies it is squeezed together by enormous pressure exerted usually

by compressed air. Thus is formed a base on which to set the great steel columns which hold the framework. Sometimes the foundation men go down nearly a hundred feet below the surface before putting in the caissons or finding a natural base to suit them. The Times building, which is illustrated in these photographs, rises from a hole seventyfive feet deep, but in this hole are placed

SINGER TOWER BUILDING, NEW YORK.

the big newspaper presses, and it is alive with humanity, hundreds of people working night and day in the basement and sub-basement.

The sky scraper or sky piercer may be said to be born when its foundation is finished ready for its skeleton. Although the use of concrete has expanded so rapidly that they are beginning to "cast" buildings out of cement and sand and stone, steel is so suited in framing tall structures that it is used almost entirely. If you want to realize how much pressure it will stand in contrast with wood for example, take a piece of steel wire and hang weight upon it until it breaks. You will have to use a very small wire or you cannot tie enough load on it to break it. As compared with a piece of oak or hickory the steel will hold as much as a stick of one of these woods more than a dozen times its diameter. So at the rolling mills they turn out whole skeletons for the sky scrapers-columns to stand upright, girders and beams to be stretched from column to column not

only to help strengthen the structure, but to support the floors. Then there are braces of many sizes and sorts. Perhaps the weight on a column is so great that it is safer to use two or four together. These are fastened by horizontal or diagonal braces so that they will sustain almost as much weight as if they formed one solid mass of steel three times their combined weight. In fact the strength of one of these composite columns is amazing to the novice.

If all of the skeleton is made at orfe plant each piece is finished for the place where it is to be set, being numbered and lettered so that it can be readily found. It is pierced with holes for the rivets or bolts and is of the right length to the fraction of an inch. So

as fast as the columns are set in place the girders to be laid upon them are ready to be put in position and riveted or bolted. Connecting the girders are the smaller floor beams on which is to be laid the concrete or tile which is supposed to make the floor fireproof. But the framework goes up so rapidly that the iron workers and riggers may finish their jobs and stick the Stars and Stripes from the top of the highest column before any of the other labor is performed. It is surprising how many portions of the framework. are independent of support. Thus one corner may be put together so rapidly that it is four or five stories higher than the others. This is because the corner is practically a separate structure supported on its own columns. The framework which connects it with the other parts is merely for the connection and does not strengthen it except to aid in resisting side pressure such as the wind.

It is a fascinating sight to see the riggers at work even on a twelve-story building. Perhaps a score of them will

do all the erecting with the aid of the big boom derricks that, actuated by the rattling little donkey engines, lift the mass of steel as if it were so much wood. If the rigger chances to be on the ground and wants to go aloft, he straddles the girder and is hoisted with it. When a beam is to be set, the workers think nothing of climbing far out on the ends of the girders to which it is to be riveted. Standing on the very edge, they lean over and guide the beam to its place as it swings on the end of the boom cable. They will rivet a beam or girder, standing on a foot wide plank where the slightest misstep means a plunge to the ground a hundred feet below. From the little heater back in the center of the building, a helper grips a red hot rivet with his pincers. Tossing it up to the man on the plank, the latter catches it in his empty keg he had for the purpose, then with his own pincers he pushes it through the girder holes and while his companion hammers the other end, presses it firmly against the steel with his own hammer-not an easy task to keep your balance at this work on the ground, but up here to lose it means sure death.

Yes, the huge skeleton is fastened with remarkable swiftness by the little band of frame setters, so deftly and speedily do they work, but the shell or skin is put on almost as rapidly. Sometimes the brick-layers begin at the bottom, sometimes at the middle story, occasionally at the top if it is most convenient. In New York the curious sight has been witnessed of one gang laying up bricks from the bottom and another upward from the tenth story. It is simply a matter of putting up staging and going to work, dangerous as it may appear, so when the contractor is in a hurry he can rush this

part of the job faster than any other, for delay means loss to the builder.

Really the interior of one of the miniature cities usually requires more time to complete than the walls or framework. Before the flooring is put down and the walls and ceilings decorated, a tangle of wire and tubing must be set for the telephones, the stock tickers, the fire alarm, the janitor and other service calls. Safes are set into the rooms-a very tedious process. The elevators must be finished and tested to make sure they are in perfect running order. Compressed air conduits for cleaning the building are required these days. Then there is the mail chute that must be installed, since it is as much of a necessity as the elevators. But the men who are doing big things of this sort can tell almost to a day when they can put the last touch to the structure and turn it over to the owner, ready for its thousands of ten

THE FINISHING TOUCHES.