1893. | NEW YORK ACADEMY OF SCIENCES. 91 
I will leave the further consideration of the subject to some 
future occasion. I will add, however, that Prof. Langley 
‘(already quoted) has in the same publication tabulated the 
speed at which planes of varing angles of inclination must be 
driven against the air to rise and “soar,” as he expresses it. 
But in his experiments a rigid arm stretched out to keep his 
Aeroplane constant in its field of action, and if we imagine that 
this support is instantly severed, just as the proper speed to 
cause the plane to “soar’’-is attained, the result is disastrous 
to a continuous flight. Unless the plane is whirling, atmospheric 
resistance immediately upsets it, and it falls in fantastic curves, 
lifeless and inert, like a kite with a suddenly severed string. I 
have stated that my boomerang is a whirling aeroplane, pure 
and simple. And now that we have ascertained a definite 
speed to cause it to soar, it is obvious that it cannot do other- 
wise than return in a backward flight, after it progressive force 
is spent. 
It happened that in explaining the principles involved to an 
enquiring friend, I used the term a “Gyrostatic domination.’’ 
He seemed to be quite satisfied for the time, but after a 
moment’s thoughtfulness he said: ‘‘ Doubtless you are right— 
but Ill be hanged if I can see what makes it come back.”’ 
I offered once a little prize for the best answer as to what 
makes it come back, and | was favored with a large amount of 
of correspondence from all sorts of people, but the most of 
them rehearsed that abominable description in the cyclopedias, 
about the oblique bars of the wind-mill, but the most remark- 
able one of all, in fact the one which truly solved the problem 
in the fewest words was from a mere child, and it was original. 
It was a follows : 
** Dear Mr. Emerson : 
*T am a little boy nine years old. God makes the boomerang 
come back.” 
So to soar a little in amplification of this dear little fellow’s 
answer, it may be said that the same invisible arm which 
stretches out with subtle power to hold the ponderous worlds 
in their awful flight, gently upbears in open palm this simple 
piece of whirling wood till its orbit is complete. 
But to descend to more definite and solid English, I prefer 
the term “‘ gyrostatic domination’’ to ‘‘ parallelism of axis” in 
expressing this sustaining force. ‘ Fixity of the plane of rota- 
tion ’’ may be equally expressive. If, then, we give to our 
whirling Aeroplane the definite speed required to cause it to 
