434 



BELL 



suspended, for it is my purpose, at the earliest moment that I can 

 possibly spare the time for it, to reequip the aerodrome with proper 

 supporting surfaces and using the same launching apparatus, to give 

 the aerodrome a fair trial, this time over the land instead of over the 

 water, when I feel very certain that it will fully demonstrate the 

 correctness of its design and construction and crown Mr. Langley's 

 researches with the success which they so richly deserve, and I trust 

 that the day that this will be achieved is very near at hand. It was 

 the launching apparatus, all will remember, which in both of the 

 experiments caused the accidents that prevented any test of the aero- 

 drome itself. These accidents were not due to defects in the design or 

 fundamental construction of the launching apparatus, for the smaller 

 apparatus of exactly the same design had been used more than thirty 

 times for launching the smaller machines and without a single failure. 

 Certain minute defects in the releasing mechanism were the sole cause 

 of the trouble. 



It has been very generally supposed that in his experiments Mr. 

 Langley used exclusively what maybe called " single tier " surfaces 

 and that he did not recognize that the superposing of the lifting sur- 

 faces presented certain great advantages not only as regards ease of 

 construction and strength, but also in reducing the size of the machine. 

 This general impression is due to the fact that all of the photographs 

 of the machines in flight which he published officially, and also those 

 published by the newspapers, have shown the machine as equipped 

 with " single tier" surfaces. I may say however that as early as 1S90 

 and constantly from that time until the work was temporarily suspended 

 in 1903, Mr. Langley experimented with superposed surfaces, the first 

 experiments of course being with very small models having their motive 

 power furnished by means of stretched or twisted rubber. The same 

 large steam driven models which flew so successfully in 1S96, the first 

 flight of which Dr. Bell has just spoken of having witnessed, were in 

 1899 equipped with superposed surfaces and were tested in free flight 

 during the months of July and August. 



The quarter-size model of the large aerodrome driven by a gasolene 

 engine which was first tested in 1901 and later in the summer of 1903, 

 was also equipped with superposed surfaces, but in the test of August, 

 1903, which was witnessed by the newspaper representatives, the 

 a single tier " surfaces were used. The prime reason that the large 

 aerodrome was equipped with the " single tier" surfaces was that the 

 best flights of the models were with such surfaces, and although in the 

 beginning it was planned to build superposed surfaces for the large 



