W.B. — 3 
would have an advancing effect. Then alternations in 
the density of the air, and in its velocity, may he 
utilized hy variations of muscular pressure not observ¬ 
able as such. That advantage is taken of everything 
we may be quite sure,-and the factors are many, beside 
the admitted one of favorable lift. 
In the gliders I am experimenting with, and 
which are an invention or discovery of my own, one 
plane is placed behind another and on the same level 
but both inclined downward slightly towards each other , 
like this in fore and aft section: '**======== =lt ^ 
There is a reaction from the first which has 
an upward trend so that the second seemingly glides 
upon it as bird on a rising current, and receives support 
and forward propulsion. They are very suggestive, and 
give promise of practical results in the future. 
Perhaps we may have an opportunity to discuss 
these things at some time more directly, if Kennard 
arranges the meeting he spoke of to me. 
Thanking you once more, I am 
Cordially yours, 
