Thayer.] 302 [Nov. 16, 
An investigation of the methods heretofore devised to accomplish this 
object, viz., wheels, propellers, wings, etc., convinced me that all plans 
so far suggested are quite impracticable ; and my experiments led me to 
the following discovery, based on the well-known law of mechanics that 
“action and re-action are always equal, contrary and simultaneous.’’ 
My invention is simply to make use of the reactive force of a powerful 
jet of air, gas or vapor, acting rearwards under pressure ; thus producing* 
a re-action forward equal in every respect to the pressure backwards. 
Under these circumstances the aerial ship will be forced forward at rates 
of speed depending upon the amount of pressure applied, and it is surpris- 
ing to note the small pressure required to send a structure of considerable 
size through the atmosphere at rates of speed varying from ten to fifty 
miles an hour, without the assistance of the wind, which, under some 
circumstances, could be most beneficially employed in generating very 
high rates of motion. 
For the following formule and values of co-efficients below mentioned, 
Iam indebted to Mr. Pole’s paper above referred to; and I have con- 
densed my ideas on the subject in the following memorandum of notes, 
giving all the salient points of the problem : 
Shape. 
d = diameter midship section. 
e = length of axis. 
Shape, cylindrical, pointed at both ends (fore and aft), the best form 
wherein e = 34d. 
Ascending Force of Gas. 
Ad’l, in which A is a co-efficient, depending on the shape of the vessel 
and on the specific quantity of the gas compared with that of the surround- 
ing air, may be taken = .08. 3 
The levity of 1 cu. ft. of hydrogen = .0761 Ib. 
Resistance to Motion through the Air. 
x == .000193 d? v?, in which v = velocity in feet per second. The re- 
sistance varies as the square of v. 
Propeliing Horce. 
The propelling force should act in a horizontal line with all the resist- 
ances, which would be a little below the line of the axis (Pole). This 
force would be produced by air, gas or vapor, acting sternwards under 
pressure ; preferably compressed air, forced through a nozzle suitably 
connected with a high speed air-compressor. 
Machinery Required. 
Boiler, steam-engine, air-compressor (receiver), outlet-pipe with nozzle 
steam-condenser, with chemical refrigerating mixture. 
*Genl, Thayer has taken out patents for this invention, 
