NO. 3 LANGLEY MEMOIR ON MECHANICAL PLIGHT 93 



The shores of the Potomac on both banks were scrutinized for this pur- 

 pose, from a point about two miles above Washington to below Chopawamsic 



Island, some thirty miles below the city. Several lofty and secluded positions 

 were found, but in all these there was the danger that the aerodrome might be 

 wrecked before reaching the water, or, turning in its course, fly inland; but more 

 than this, it could be launched only on the rare occasions when the exact wind 

 was blowing which the local conditions demanded. 



Finally, the idea, which seems obvious enough when stated, presented it- 

 self of building a kind of house-boat, not to get up initial motion by the boat's 

 own velocity, but to furnish an elevated platform, which could be placed in the 

 midst of a considerable expanse of water, if desired, under conditions which 

 admitted of turning in the direction of the wind, as it need hardly be repeated 

 that it was indispensable to the machine, as it is to the bird, to rise in the face 

 of a wind, if there be any wind at all. 



The house-boat in question was nothing more than a scow about 30 feet long 

 by 12 feet wide, upon which a small house was erected, to be used for the occa- 

 sional storing of the aerodromes. On account of the accidents which were cer 

 tain to occur in the first attempts, it was fitted up with the means of making 

 small repairs. On the roof of the house there was a platform upon which the 

 operator stood when making a launch, and upon which were mounted the launch- 

 ing devices hereafter described. 



This boat, shown in Plate 18, was completed in November, 1892. 



1893 



By the kindness of the Superintendent of the Coast Survey, the house-boat 

 was towed in May, 1893, down to Chopawamsic Island, a small island near the 

 western bank of the Potomac River, not far from the Quantico station of the 

 Washington and Richmond Railroad Company. A map of the island and the ad- 

 jacent land and water is shown in Plate 19. 



The house-boat was at all times moored somewhere on the west side of the 

 island, in the stretch of quiet water between that and the west shore of the river. 

 The waters shown here are, with the exception of a narrow channel, very shallow, 

 and, indeed, partly dry at low tide, so that there was no danger of an aerodrome 

 being lost, unless its flight carried it a long distance away and over the land. 



Field Trials 1 

 Aerodrome No. 4, as shown in Plate 11, had a single midrod, a flying weight 

 of 9 pounds, 2 and supporting surface, consisting of wings and tail, of 18 square 



ir The site of these experiments, which was 30 miles below Washington, has been described. 

 The writer is designated by the initial " L " ; Dr. Barus, who several times assisted, by the letter 

 "B"; Mr. Reed, carpenter, by "R"; Mr. Maltby, machinist, by "M"; and Mr. Gaertner, instru- 

 ment maker, by " G." 



2 Weights and dimensions are here given in approximate pounds and feet. 



