70 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. -I 



The wings and tail constructed for No. 5 were identical with those of No. 4, 

 being slightly curved and containing 2.62 sq. m. (28.2 sq. ft.), equivalent to 1.4 

 sq. ft. to the pound, which with the flimsy construction of the wings gave an en- 

 tirely inadequate support to the aerodrome. 



During the summer a launching apparatus of a new and improved type, 

 which is described in Chapter X, had been perfected, and with it repeated tests 

 were made of both aerodromes in October, November, and December, with the un- 

 satisfactory results recorded in Chapter IX. In the course of these experiments, 

 many slight modifications of the burners and boilers were made, but no important 

 changes were introduced except that the cross-frame of No. 5 was enlarged and 

 strengthened so as to admit of its carrying one metre propellers safely. The 

 results, however, which were obtained, did not compensate for the increased 

 weight of the larger frame. 



Viewing the work of this year from the standpoint of results obtained in 

 the numerous attempts at flight, it would seem that very little progress had been 

 made, and that there was small reason to expect to achieve final success. How- 

 ever, if the work be examined more particularly, it will be seen that two of the 

 most difficult problems had been solved, one completely as far as the models 

 were concerned, and the other to a very satisfactory degree. First, a launching 

 apparatus, with which it was possible to give the aerodrome any desired initial 

 velocity, had been devised, and so far perfected that no trouble was ever expe- 

 rienced with it in testing the models. Second, as a result of the extended and 

 systematic series of experiments, which had been conducted under the direction 

 of Dr. Barus, a steam pressure of 115 pounds could be maintained steadily in 

 the boilers for at least a minute, and the burners could be kept lighted even in 

 a considerable breeze. 



A summary of these experiments, together with some account of the diffi- 

 culties encountered and the results finally obtained with the apparatus in use 

 at the end of the year, is given in the following report, which was prepared by 

 Dr. Barus in December, 1894. 



" If water be sprayed upon a surface kept in a permanent state of ignition, 

 any quantity of steam might be generated per time unit. Similarly advantage- 

 ous conditions would be given if threads of water could be passed through a 

 flame. In practice this method would encounter two serious difficulties, the im- 

 portance of which is accentuated when the boiler apparatus is to be kept within 

 the degree of lightness essential in aerodromics. These difficulties are (1) the 

 danger of chilling the flame below the point of ignition or of combustion of the 

 gases, and (2) the practical impossibility of maintaining threads of water in 

 the flame. For it is clear that the threads must be joined in multiple arc, so 

 as to allow a large bulk of water to circulate through the boiler, whereas even 

 when there are but two independent passages for the water through the furnace, 

 it is hard to keep both supplied with liquid without unduly straining the pump. 

 [f the water he even slightly deficient, circumstances will arise in which one of 



