102 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 27 



at various times, but were, of course, made as they suggested themselves with- 

 out any reference to time or season. But while it was customary to make, from 

 time to time, a resume of the progress of the work, yet at the closing of the cal- 

 endar year it was the custom to make a more complete digest of just what had 

 been accomplished during the year. 



Upon thus reviewing the progress of the work during 1894, it was felt that 

 the results which had been accomplished for such a large expenditure of time 

 seemed small, since no real flight had been made by any of the aerodromes, and 

 no definite assurance that a successful flight would be obtained within the imme- 

 diate future seemed warranted by what had already been accomplished. But 

 now that the principal difficulties connected with the launching apparatus had 

 been overcome, thus permitting the aerodromes themselves to be given a fair 

 trial, the belief was encouraged that the continuance of the actual tests of the 

 machines, with slight changes which previous tests had shown advisable, would 

 finally result in a successful flight. 



The early weeks of 1895 were spent in a series of pendulum tests on No. 5, 

 and in making such slight changes as these tests indicated would be advisable. 

 As a result of small improvements introduced in the boilers, No. 5 had by the 

 middle of March shown a repeated lift of considerably over 50 per cent, and in 

 some lests as much as 62 per cent of its flying weight. Certain radical changes 

 previously described in Chapter VII were also made in Aerodrome No. 4, and 

 in the pendulum tests of it a lift of 44 per cent of its flying weight had been 

 obtained. 



Encouraged by the better results which the aerodromes had shown in the 

 above tests, it was decided to test them again in free flight, and they were ac- 

 cordingly sent down to Quant ico in charge of the two mechanics, R and M, Mr. 

 Langley, accompanied by Dr. Graham Bell, whom he had invited to witness the 

 tests, following on May 8. On the evening of May 8 No. 5 was moulded on the 

 launching apparatus in order to drill the mechanics so that when favorable 

 weather presented itself the aerodrome could be got ready for launching with the 

 minimum delay. 



On May 9 Mr. Langley and Dr. Bell reached the house-boat at 5 a. m., but 

 even with the drill of the previous evening the mechanics were not able to have 

 No. 5 ready for trial until 6.15 a. m. The principal conditions of No. 5 at this 

 time were: 



Total weight 11,200 grammes (24.6 pounds), including 800 grammes of 

 fuel and water. Previous lift on the pendulum 54 per cent, with a steam pres- 

 sure of 150 pounds. Wilh this steam pressure the engine made about 600 

 R.P.M. when driving the 95 cm. propellers, which through their reduction 

 gearing made about 500 R. P. M. 



