428 BELL 



than-air type, at whatever speed it moves, will be able to make 

 headway against a wind of much greater velocity, provided 

 its momentum is greater than the momentum of the air that op- 

 poses it. 



DISCUSSION OF DR. BELL'S ADDRESS BY CHARLES M. MANLY. 



It is a notable sign of the kind of attention aeronautical work is now 

 attracting , that one who has to his credit the accomplishment of such 

 big things as Dr. Bell has, should become so actively engaged in it. 

 As Dr. Bell has already pointed out, the world owes much to Mr. 

 Langley for taking hold of the subject when it was looked upon as the 

 wild dream of cranks and enthusiasts and by putting it on a scientific 

 basis made it seem worthy of serious attention. It is no less fortunate 

 that we have to-day such men as Dr. Bell actively engaged in the con- 

 struction of large man-carrying machines, for the influence of their 

 example causes the work to be looked on by the public more and more 

 seriously all the time. 



Dr. Bell has pointed out that one of the advantages possessed by 

 such a slow speed aerodrome as he will be able to construct by util- 

 izing his important invention of tetrahedral cells, is the possibility of 

 anchoring such a machine and having it maintained at a height through 

 its ability to fly as a kite. This suggests the superiority which such a 

 machine will possess not only as regards safety in case of a break-down 

 of the machinery, but also as regards its use as a war machine. The 

 ability to anchor and remain steadily over a given point will enable 

 the operator or operators to thoroughly study and map out fortifications 

 and the disposition of field forces, as there is very slight probability of 

 so small an object as an anchor rope being discovered by the enemy, 

 and even if it should be, the ability of the operator to cut the rope 

 would render him comparatively free from capture. 



As a war machine Dr. Bell's tetrahedral plan of cellular construction 

 for the surfaces would also I think present another very great advantage. 

 Such a machine might be badly riddled with shot and yet be able to 

 maintain very good equilibrium, while a machine having large units of 

 surface with large parts in the frame work of its surfaces, would be 

 very seriously crippled should a chance shot disable one of the main 

 supports on one side. 



It may not be amiss to call attention also to the fact that the operator 

 on any aerodrome or balloon when at a considerable height can plainly 

 see submarine boats at any depth in the water. Such machines can 

 therefore be used for determining the number of submarine craft in 



