The San Francisco call., 1898-04-02
BUILDING AN
 ARMY BRIDGE
National Guardsnen Erect a Structure Without Ham
 rner or Nails.
This Will Be One of the Features of the Military Display of the
 First Infantry.

One of the features of the military dis play to be given by the companies of the First Infantry Regiment at the Mechan- ics' Pavilion on the evening of the 22d inst, will be the building of a bridge by Company B, Captain George Filmer. At a practice drill held in the old First armory on Market street, Thursday night, by the members of the company named, there was a demonstration how soldiers can build bridge inside of half an hour without using nail or hammer, and making it strong enough for an army to pass over.
 The particular bridge has a fifteen foot approach on each side of the imaginary ravine, the bridge proper is twenty-four feet long and eight feet wide, and is sup ported in the center from the apex beam of a truss formed by four by six beams the ends of which rest on each side of the ravine. The whole structure Is of beams, blanks and three-quarter inch ropes used for lashings.
 Heavy chalk marks on the floor desig- nate the two sides of the ravine or gully over which none of the builders are per mitted to step during the building. At each side close to this line stand a team of men each having two pieces of rope over their shoulders, and by the side of each team are three pieces of ten-foot timber partly rounded. At the word of command each team goes to work to lash the ends of the three pieces of timber together in such a manner that when placed upright on the free ends they form a tripod. These four tripods are placed at indicated spots, and at a point three feet from the bottom the teams lash three by three inch pieces of wood so as to form a triangle. These triangles form the base of support for the cross timbers on which to rest the floor beams. and the greater the weight the firmer is the flashing and the more solid the tripods. While the teams of three men each are doing this. two other teams are busy flashing heavy cross timber to each end of long beams, one foot from the end. Like work is done on each side of the ravine. When these are properly lashed. the pieces held by guy ropes at the top each guided by one man, are brought to a vertical position and carried forward by strong force of men until the foot of each timber rests against one of the tripods. Then the beams are lowered slowly, simultaneously, until they meet over the center of the ravine, when one cross beam rests on the other and there is a perfect truss. Two men climb up the sides of the truss and by means of ropes haul to the apex a four by four piece ten feet long which they place in the crotch formed by the timbers dashed that firmly, and from the ends fixed guy ropes, the loose ends of which are swung to the edges.
 These being caught are formed into a loop and In this is placed a heavy square timber that is allowed to swing toward the center and in time become the center support of the bridge. The two end cross beams being lashed to the tri- angle of the tripods a twenty-four foot four by six beam is launched from one side of the ravine toward the other side. There is the struggle of the work, for the men who push the beam have but little purchase. but by clever maneuver- ing on the other side and little gym no cfi ica he fran nyod ic 1tcy1,t ht, one of the men and held until it was showed over far enough to allow that end to rest on the other cross beam. The side pieces being in place they are firmly lashed, piece of ash wood is placed in each of the slings, the ropes are twisted and by that means the heavy timber at the bottom of the slings is brought to its proper level, the ends secured, and the ends of the ash sticks are also se- cured. Then it is easy and quick work to place in position the timbers for the approaches, the floor beams, lash them
 -'-- CT tH" flooring after which the bridge Is ready for use. The boys have been practicing twice a week for several weeks and they expect on ex- hibition night to be able to put the bridge together in twenty minutes, and have it ready in that time for the en- tire regiment to walk over it. The prac- tice reflects great credit on the men, nearly all of whom are clerks in stores.