KIGID STABLE AEROPLANES. 385 



iicz.Mcrfe/ tf-i X 7f X f 



Fig. 3. 



both longitudinally and transversely under most trying cir- 

 cumstances. You have seen how the exact work of W. R. 

 Turnbull was not of the slightest use to aeronautics till it 

 could be combined with the other essentials of flying. You 

 have observed that all flying machines that have been 

 described previously embody scaffold-like structures for- 

 ward or aft to hold movable surfaces requiring constant 

 attention, and this fact alone indicates that the art as 

 practised to-day is at the stage it was on April 12, 1890, 

 as per our Journal of that date. You also understand, as 

 a matter of pure mechanics, that the air is permeated with 

 gusts and tremors of the most rapid and conflicting nature, 

 and that the weight of a body that has to move through 

 it and preserve a uniform aspect, must have a minimum of 

 inertia so that it can instantly adapt itself readily to ever 

 changing conditions. Common sense steps in here and says : 

 Separate the parts you ivant to be mobile from the parts 

 you want to be inert. You have seen the result, and I 

 know many have the skill to apply it. 



This is the very heart of the invention, and in the present 

 state of the industry cannot fail to be understood. I am 

 advised that it is, or was, patentable before it was exhibited 

 here, but mature thought shows the perfect impossibility 

 of collecting revenue from the consumers who are the 

 Dracticers of the art I wish to advance and not to retard. 



