,the ,,early ,,history of the ,,airplane
    ,the ,,dayton-,,wright ,,airplane   
,,co4   ,,dayton ,,ohio     ,the ,wright
 ,brothers' ,aeroplane  ,by ,orville and
 ,wilbur ,wright   ,though the subject  
of aerial navigation is generally       
considered new1 it has occupied the     
minds of men more or less from the      
earliest ages4 ,our personal interest in
 it dates from our childhood days4 ,late
 in the autumn of #ahgh our father came 
into the house one evening with some    
object partly concealed in his hands1   
and before we could see what it was1 he 
tossed it into the air4 ,instead of     
falling to the floor1 as we expected1 it
 flew across the room1 till it struck   
the ceiling1 where it fluttered awhile1 
and finally sank to the floor4 ,it was a
 little toy1 known to scientists as a   
helicoptere1 but which we1 with sublime 
disregard for science1 at once dubbed a 
bat4 ,it was a light frame of cork and  
bamboo1 covered with paper1 which formed
 two screws1 driven in opposite         

directions by rubber bands under        
torsion4 ,a toy so delicate lasted only 
a short time in the hands of small boys1
 but its memory was abiding4  ,several  
years later we began building these     
helicopteres for ourselves1 making each 
one larger than that preceding4 ,but1 to
 our astonishment1 we found that the    
larger the bat the less it flew4 ,we did
 not know that a machine having only    
twice the linear dimensions of another  
would require eight times the power4 ,we
 finally became discouraged1 and        
returned to kite-flying1 a sport to     
which we had devoted so much attention  
that we were regarded as experts4 ,but  
as we became older we had to give up    
this fascinating sport as unbecoming to 
boys of our ages4  ,it was not till the 
news of the sad death of ,lilienthal    
reached ,america in the summer of #ahif 
that we again gave more than passing    
attention to the subject of flying4 ,we 
then studied with great interest        
,chanute's ,progress in ,flying         

,machines1 ,langley's ,experiments in   
,aerodynamics1 the ,aeronautical        
,annuals of #aije1 #aijf1 and #aijg1 and
 several pamphlets published by the     
,smithsonian ,institution1 especially   
articles by ,lilienthal and extracts    
from ,mouillard's ,empire of the ,air4  
,the larger works gave us a good        
understanding of the nature of the      
flying problem1 and the difficulties in 
past attempts to solve it1 while        
,mouillard and ,lilienthal1 the great   
missionaries of the flying cause1       
infected us with their own unquenchable 
enthusiasm1 and transformed idle        
curiosity into the active zeal of       
workers4  ,in the field of aviation     
there were two schools4 ,the first1     
represented by such men as ,professor   
,langley and ,sir ,hiram ,maxim1 gave   
chief attention to power flight2 the    
second1 represented by ,lilienthal1     
,mouillard1 and ,chanute1 to soaring    
flight4 ,our sympathies were with the   
latter school1 partly from impatience at

 the wasteful extravagance of mounting  
delicate and costly machinery on wings  
which no one knew how to manage1 and    
partly1 no doubt1 from the extraordinary
 charm and enthusiasm with which the    
apostles of soaring flight set forth the
 beauties of sailing through the air on 
fixed wings1 deriving the motive power  
from the wind itself4  ,the balancing of
 a flyer may seem1 at first thought1 to 
be a very simple matter1 yet almost     
every experimenter had found in this one
 point which he could not satisfactorily
 master4 ,many different methods were   
tried4 ,some experimenters placed the   
center of gravity far below the wings1  
in the belief that the weight would     
naturally seek to remain at the lowest  
point4 ,it is true1 that1 like the      
pendulum1 it tended to seek the lowest  
point2 but also1 like the pendulum1 it  
tended to oscillate in a manner         
destructive of all stability4 ,a more   
satisfactory system1 especially for     
lateral balance1 was that of arranging  

the wings in the shape of a broad ,v1 to
 form a dihedral angle1 with the center 
low and the wing-tips elevated4 ,in     
theory this was an automatic system1 but
 in practice it had two serious defects3
 first1 it tended to keep the machine   
oscillating2 and second1 its usefulness 
was restricted to calm air4  ,in a      
slightly modified form the same system  
was applied to the fore-and-aft balance4
 ,the main aeroplane was set at a       
positive angle1 and a horizontal tail at
 a negative angle1 while the center of  
gravity was placed far forward4 ,as in  
the case of lateral control1 there was a
 tendency to constant undulation1 and   
the very forces which caused a          
restoration of balance in calms caused a
 disturbance of the balance in winds4   
,notwithstanding the known limitations  
of this principle1 it had been embodied 
in almost every prominent flying machine
 which had been built4  ,after          
considering the practical effect of the 
dihedral principle1 we reached the      

conclusion that a flyer founded upon it 
might be of interest from a scientific  
point of view1 but could be of no value 
in a practical way4 ,we therefore       
resolved to try a fundamentally         
different principle4 ,we would arrange  
the machine so that it would not tend to
 right itself4 ,we would make it as     
inert as possible to the effects of     
change of direction or speed1 and thus  
reduce the effects of wind-gusts to a   
minimum4 ,we would do this in the       
fore-and-aft stability by giving the    
aeroplanes a peculiar shape2 and in the 
lateral balance by arching the surfaces 
from tip to tip1 just the reverse of    
what our predecessors had done4 ,then by
 some suitable contrivance1 actuated by 
the operator1 forces should be brought  
into play to regulate the balance4      
,lilienthal and ,chanute had guided and 
balanced their machines1 by shifting the
 weight of the operator's body4 ,but    
this method seemed to us incapable of   
expansion to meet large conditions1     

because the weight to be moved and the  
distance of possible motion were        
limited1 while the disturbing forces    
steadily increased1 both with wing area 
and with wind velocity4 ,in order to    
meet the needs of large machines1 we    
wished to employ some system whereby the
 operator could vary at will the        
inclination of different parts of the   
wings1 and thus obtain from the wind    
forces to restore the balance which the 
wind itself had disturbed4 ,this could  
easily be done by using wings capable of
 being warped1 and by supplementary     
adjustable surfaces in the shape of     
rudders4 ,as the forces obtainable for  
control would necessarily increase in   
the same ratio as the disturbing forces1
 the method seemed capable of expansion 
to an almost unlimited extent4 ,a happy 
device was discovered whereby the       
apparently rigid system of superposed   
surfaces1 invented by ,wenham1 and      
improved by ,stringfellow and ,chanute1 
could be warped in a most unexpected    

way1 so that the aeroplanes could be    
presented on the right and left sides at
 different angles to the wind4 ,this1   
with an adjustable1 horizontal front    
rudder1 formed the main feature of our  
first glider4  ,the period from #ahhe to
 #aijj was one of unexampled activity in
 aeronautics1 and for a time there was  
high hope that the age of flying was at 
hand4 ,but ,maxim1 after spending       
#ajj1jjj1 abandoned the work2 the ,ader 
machine1 built at the expense of the    
,french ,government1 was a failure2     
,lilienthal and ,pilcher were killed in 
experiments2 and ,chanute and many      
others1 from one cause or another1 had  
relaxed their efforts1 though it        
subsequently became known that          
,professor ,langley was still secretly  
at work on a machine for the ,united    
,states ,government4 ,the public1       
discouraged by the failures and         
tragedies just witnessed1 considered    
flight beyond the reach of man1 and     
classed its adherents with the inventors

 of perpetual motion4  ,we began our    
active experiments at the close of this 
period1 in ,october1 #aijj1 at ,kitty   
,hawk1 ,north ,carolina4 ,our machine   
was designed to be flown as a kite1 with
 a man on board1 in winds from #ae to   
#bj miles an hour4 ,but1 upon trial1 it 
was found that much stronger winds were 
required to lift it4 ,suitable winds not
 being plentiful1 we found it necessary1
 in order to test the new balancing     
system1 to fly the machine as a kite    
without a man on board1 operating the   
levers through cords from the ground4   
,this did not give the practice         
anticipated1 but it inspired confidence 
in the new system of balance4  ,in the  
summer of #aija we became personally    
acquainted with ,mr4 ,chanute4 ,when he 
learned that we were interested in      
flying as a sport1 and not with any     
expectation of recovering the money we  
were expending on it1 he gave us much   
encouragement4 ,at our invitation1 he   
spent several weeks with us at our camp 

at ,kill ,devil ,hill1 four miles south 
of ,kitty ,hawk1 during our experiments 
of that and the two succeeding years4   
,he also witnessed one flight of the    
power machine near ,dayton1 ,ohio1 in   
,october1 #aijd4  ,the machine of #aija 
was built with the shape of surface used
 by ,lilienthal1 curved from front to   
rear like the segment of a parabola1    
with a curvature #a_/ab the depth of its
 cord2 but to make doubly sure that it  
would have sufficient lifting capacity  
when flown as a kite in #ae or #bj-mile 
winds1 we increased the area from #afe  
square feet1 used in #aijj1 to #cjh     
square feet--a size much larger than    
,lilienthal1 ,pilcher1 or ,chanute had  
deemed safe4 ,upon trial1 however1 the  
lifting capacity again fell very far    
short of calculation1 so that the idea  
of securing practice while flying as a  
kite had to be abandoned4 ,mr4 ,chanute1
 who witnessed the experiments1 told us 
that the trouble was not due to poor    
construction of the machine4 ,we saw    

only one other explanation--that the    
tables of air-pressures in general use  
were incorrect4  ,illustration  ,we then
 turned to gliding--coasting downhill on
 the air--as the only method of getting 
the desired practice in balancing a     
machine4 ,after a few minutes' practice 
we were able to make glides of over #cjj
 feet1 and in a few days were safely    
operating in #bg-mile winds4 ,in these  
experiments we met with several         
unexpected phenomena4 ,we found that1   
contrary to the teachings of the books1 
the center of pressure on a curved      
surface traveled backward when the      
surface was inclined1 at small angles1  
more and more edgewise to the wind4 ,we 
also discovered that in free flight1    
when the wing on one side of the machine
 was presented to the wind at a greater 
angle than the one on the other side1   
the wing with the greater angle         
descended1 and the machine turned in a  
direction just the reverse of what we   
were led to expect when flying the      

machine as a kite4 ,the larger angle    
gave more resistance to forward motion1 
and reduced the speed of the wing on    
that side4 ,the decrease in speed more  
than counterbalanced the effect of the  
larger angle4 ,the addition of a fixed  
vertical vane in the rear increased the 
trouble1 and made the machine absolutely
 dangerous4 ,it was some time before a  
remedy was discovered4 ,this consisted  
of movable rudders working in           
conjunction with the twisting of the    
wings4 ,the details of this arrangement 
are given in specifications published   
several years ago4  ,the experiments of 
#aija were far from encouraging4        
,although ,mr4 ,chanute assured us that1
 both in control and in weight carried  
per horse-power1 the results obtained   
were better than those of any of our    
predecessors1 yet we saw that the       
calculations upon which all flying      
machines had been based were unreliable1
 and that all were simply groping in the
 dark4 ,having set out with absolute    

faith in the existing scientific data1  
we were driven to doubt one thing after 
another1 till finally1 after two years  
of experiment1 we cast it all aside1 and
 decided to rely entirely upon our own  
investigations4 ,truth and error were   
everywhere so intimately mixed as to be 
undistinguishable4 ,nevertheless1 the   
time expended in preliminary study of   
books was not misspent1 for they gave us
 a good general understanding of the    
subject1 and enabled us at the outset to
 avoid effort in many directions in     
which results would have been hopeless4 
,the standard measurements of           
wind-pressures is the force produced by 
a current of air of one mile per hour   
velocity striking square against a plane
 of one square foot area4 ,the practical
 difficulties of obtaining an exact     
measurement of this force have been     
great4 ,the measurements by different   
recognized authorities vary #ej per     
cent4 ,when this simplest of            
measurements presents so great          

difficulties1 what shall be said of the 
troubles encountered by those who       
attempt to find the pressure at each    
angle as the plane is inclined more and 
more edgewise to the wind8 ,in the      
eighteenth century the ,french ,academy 
prepared tables giving such information1
 and at a later date the ,aeronautical  
,society of ,great ,britain made similar
 experiments4 ,many persons likewise    
published measurements and formulas2 but
 the results were so discordant that    
,professor ,langley undertook a new     
series of measurements1 the results of  
which form the basis of his celebrated  
work1 ,experiments in ,aerodynamics4    
,yet a critical examination of the data 
upon which he based his conclusions as  
to the pressures at small angles shows  
results so various as to make many of   
his conclusions little better than      
guesswork4  ,to work intelligently1 one 
needs to know the effects of a multitude
 of variations that could be            
incorporated in the surfaces of flying  

machines4 ,the pressures on squares are 
different from those on rectangles1     
circles1 triangles1 or ellipses2 arched 
surfaces differ from planes1 and vary   
among themselves according to the depth 
of curvature2 true arcs differ from     
parabolas1 and the latter differ among  
themselves2 thick surfaces differ from  
thin1 and surfaces thicker in one place 
than another vary in pressure when the  
positions of maximum thickness are      
different2 some surfaces are most       
efficient at one angle1 others at other 
angles4 ,the shape of the edge also     
makes a difference1 so that thousands of
 combinations are possible in so simple 
a thing as a wing4  ,we had taken up    
aeronautics merely as a sport4 ,we      
reluctantly entered upon the scientific 
side of it4 ,but we soon found the work 
so fascinating that we were drawn into  
it deeper and deeper4 ,two testing      
machines were built1 which we believed  
would avoid the errors to which the     
measurements of others had been subject4

 ,after making preliminary measurements 
on a great number of different-shaped   
surfaces1 to secure a general           
understanding of the subject1 we began  
systematic measurements of standard     
surfaces1 so varied in design as to     
bring out the underlying causes of      
differences noted in their pressures4   
,measurements were tabulated on nearly  
#ej of these at all angles from zero to 
#de degrees at intervals of #b-a_/b     
degrees4 ,measurements were also secured
 showing the effects on each other when 
surfaces are superposed1 or when they   
follow one another4  ,some strange      
results were obtained4 ,one surface1    
with a heavy roll at the front edge1    
showed the same lift for all angles from
 #g-a_/b to #de degrees4 ,a square      
plane1 contrary to the measurements of  
all our predecessors1 gave a greater    
pressure at #cj degrees than at #de     
degrees4 ,this seemed so anomalous that 
we were almost ready to doubt our own   
measurements1 when a simple test was    

suggested4 ,a weather-vane1 with two    
planes attached to the pointer at an    
angle of #hj degrees with each other1   
was made4 ,according to our tables1 such
 a vane would be in unstable equilibrium
 when pointing directly into the wind2  
for if by chance the wind should happen 
to strike one plane at #ci degrees and  
the other at #da degrees1 the plane with
 the smaller angle would have the       
greater pressure1 and the pointer would 
be turned still farther out of the      
course of the wind until the two vanes  
again secured equal pressures1 which    
would be at approximately #cj and #ej   
degrees4 ,but the vane performed in this
 very manner4 ,further corroboration of 
the tables was obtained in experiments  
with the new glider at ,kill ,devil     
,hill the next season4  ,in ,september  
and ,october1 #aijb1 nearly #a1jjj      
gliding flights were made1 several of   
which covered distances of over #fjj    
feet4 ,some1 made against a wind of #cf 
miles an hour1 gave proof of the        

effectiveness of the devices for        
control4 ,with this machine1 in the     
autumn of #aijc1 we made a number of    
flights in which we remained in the air 
for over a minute1 often soaring for a  
considerable time in one spot1 without  
any descent at all4 ,little wonder that 
our unscientific assistant should think 
the only thing needed to keep it        
indefinitely in the air would be a coat 
of feathers to make it light6  ,with    
accurate data for making calculations1  
and a system of balance effective in    
winds as well as in calms1 we were now  
in a position1 we thought1 to build a   
successful power-flyer4 ,the first      
designs provided for a total weight of  
#fjj lbs41 including the operator and an
 eight horse-power motor4 ,but1 upon    
completion1 the motor gave more power   
than had been estimated1 and this       
allowed #aej lbs4 to be added for       
strengthening the wings and other parts4
  ,our tables made the designing of the 
wings an easy matter1 and as            

screw-propellers are simply wings       
traveling in a spiral course1 we        
anticipated no trouble from this source4
 ,we had thought of getting the theory  
of the screw-propeller from the marine  
engineers1 and then1 by applying our    
tables of air-pressures to their        
formulas1 of designing air-propellers   
suitable for our purpose4 ,but so far as
 we could learn1 the marine engineers   
possessed only empirical formulas1 and  
the exact action of the screw-propeller1
 after a century of use1 was still very 
obscure4 ,as we were not in a position  
to undertake a long series of practical 
experiments to discover a propeller     
suitable for our machine1 it seemed     
necessary to obtain such a thorough     
understanding of the theory of its      
reactions as would enable us to design  
them from calculations alone4 ,what at  
first seemed a problem became more      
complex the longer we studied it4 ,with 
the machine moving forward1 the air     
flying backward1 the propellers turning 

sidewise1 and nothing standing still1 it
 seemed impossible to find a            
starting-point from which to trace the  
various simultaneous reactions4         
,contemplation of it was confusing4     
,after long arguments we often found    
ourselves in the ludicrous position of  
each having been converted to the       
other's side1 with no more agreement    
than when the discussion began4         
,illustration  ,it was not till several 
months had passed1 and every phase of   
the problem had been thrashed over and  
over1 that the various reactions began  
to untangle themselves4 ,when once a    
clear understanding had been obtained   
there was no difficulty in designing    
suitable propellers1 with proper        
diameter1 pitch1 and area of blade1 to  
meet the requirements of the flyer4     
,high efficiency in a screw-propeller is
 not dependent upon any particular or   
peculiar shape2 and there is no such    
thing as a best screw4 ,a propeller     
giving a high dynamic efficiency when   

used upon one machine may be almost     
worthless when used upon another4 ,the  
propeller should in every case be       
designed to meet the particular         
conditions of the machine to which it is
 to be applied4 ,our first propellers1  
built entirely from calculation1 gave in
 useful work #ff per cent4 of the power 
expended4 ,this was about one-third more
 than had been secured by ,maxim or     
,langley4  ,the first flights with the  
power machine were made on ,december    
#ag1 #aijc4 ,only five persons besides  
ourselves were present4 ,these were     
,messrs4 ,john ,t4 ,daniels1 ,w4 ,s4    
,dough1 and ,a4 ,d4 ,etheridge1 of the  
,kill ,devil ,life-,saving ,station2    
,mr4 ,w4 ,c4 ,brinkley1 of ,manteo2 and 
,mr4 ,john ,ward1 of ,naghead4 ,although
 a general invitation had been extended 
to the people living within five or six 
miles1 not many were willing to face the
 rigors of a cold ,december wind in     
order to see1 as they no doubt thought1 
another flying machine not fly4 ,the    

first flight lasted only #ab seconds1 a 
flight very modest compared with that of
 birds1 but it was1 nevertheless1 the   
first in the history of the world in    
which a machine carrying a man had      
raised itself by its own power into the 
air in free flight1 had sailed forward  
on a level course without reduction of  
speed1 and had finally landed without   
being wrecked4 ,the second and third    
flights were a little longer1 and the   
fourth lasted #ei seconds1 covering a   
distance of #heb feet over the ground   
against a #bj-mile wind4  ,after the    
last flight the machine was carried back
 to camp and set down in what was       
thought to be a safe place4 ,but a few  
minutes later1 while we were engaged in 
conversation about the flights1 a sudden
 gust of wind struck the machine1 and   
started to turn it over4 ,all made a    
rush to stop it1 but we were too late4  
,mr4 ,daniels1 a giant in stature and   
strength1 was lifted off his feet1 and  
falling inside1 between the surfaces1   

was shaken about like a rattle in a box 
as the machine rolled over and over4 ,he
 finally fell out upon the sand with    
nothing worse than painful bruises1 but 
the damage to the machine caused a      
discontinuance of experiments4  ,in the 
spring of #aijd1 through the kindness of
 ,mr4 ,torrence ,huffman1 of ,dayton1   
,ohio1 we were permitted to erect a     
shed1 and to continue experiments1 on   
what is known as the ,huffman ,prairie1 
at ,simms ,station1 eight miles east of 
,dayton4 ,the new machine was heavier   
and stronger1 but similar to the one    
flown at ,kill ,devil ,hill4 ,when it   
was ready for its first trial every     
newspaper in ,dayton was notified1 and  
about a dozen representatives of the    
,press were present4 ,our only request  
was that no pictures be taken1 and that 
the reports be unsensational1 so as not 
to attract crowds to our experiment     
grounds4 ,there were probably #ej       
persons altogether on the ground4 ,when 
preparations had been completed a wind  

of only three or four miles was         
blowing--insufficient for starting on so
 short a track--but since many had come 
a long way to see the machine in action1
 an attempt was made4 ,to add to the    
other difficulty1 the engine refused to 
work properly4 ,the machine1 after      
running the length of the track1 slid   
off the end without rising into the air 
at all4 ,several of the newspaper men   
returned the next day1 but were again   
disappointed4 ,the engine performed     
badly1 and after a glide of only #fj    
feet1 the machine came to the ground4   
,further trial was postponed till the   
motor could be put in better running    
condition4 ,the reporters had now1 no   
doubt1 lost confidence in the machine1  
though their reports1 in kindness1      
concealed it4 ,later1 when they heard   
that we were making flights of several  
minutes' duration1 knowing that longer  
flights had been made with airships1 and
 not knowing any essential difference   
between airships and flying machines1   

they were but little interested4  ,we   
had not been flying long in #aijd before
 we found that the problem of           
equilibrium had not as yet been entirely
 solved4 ,sometimes1 in making a circle1
 the machine would turn over sidewise   
despite anything the operator could do1 
although1 under the same conditions in  
ordinary straight flight1 it could have 
been righted in an instant4 ,in one     
flight1 in #aije1 while circling around 
a honey locust tree at a height of about
 #ej feet1 the machine suddenly began to
 turn up on one wing1 and took a course 
toward the tree4 ,the operator1 not     
relishing the idea of landing in a      
thorn-tree1 attempted to reach the      
ground4 ,the left wing1 however1 struck 
the tree at a height of #aj or #ab feet 
from the ground and carried away several
 branches2 but the flight1 which had    
already covered a distance of six miles1
 was continued to the starting-point4   
,the causes of these troubles--too      
technical for explanation here--were not

 entirely overcome till the end of      
,september1 #aije4 ,the flights then    
rapidly increased in length1 till       
experiments were discontinued after     
,october #e1 on account of the number of
 people attracted to the field4         
,although made on a ground open on every
 side1 and bordered on two sides by     
much-traveled thoroughfares1 with       
electric cars passing every hour1 and   
seen by all the people living in the    
neighborhood for miles around1 and by   
several hundred others1 yet these       
flights have been made by some          
newspapers the subject of a great       
mystery4  ,a practical flyer having been
 finally realized1 we spent the years   
#aijf and #aijg in constructing new     
machines and in business negotiations4  
,it was not till ,may of this year that 
experiments 7discontinued in ,october1  
#aije7 were resumed at ,kill ,devil     
,hill1 ,north ,carolina4 ,the recent    
flights were made to test the ability of
 our machine to meet the requirements of

 a contract with the ,united ,states    
,government to furnish a flyer capable  
of carrying two men and sufficient fuel 
supplies for a flight of #abe miles1    
with a speed of #dj miles an hour4 ,the 
machine used in these tests was the same
 one with which the flights were made at
 ,simms ,station in #aije1 though       
several changes had been made to meet   
present requirements4 ,the operator     
assumed a sitting position1 instead of  
lying prone1 as in #aije1 and a seat was
 added for a passenger4 ,a larger motor 
was installed1 and radiators and        
gasoline reservoirs of larger capacity  
replaced those previously used4 ,no     
attempt was made to make high or long   
flights4  ,in order to show the general 
reader the way in which the machine     
operates1 let us fancy ourselves ready  
for the start4 ,the machine is placed   
upon a single-rail track facing the     
wind1 and is securely fastened with a   
cable4 ,the engine is put in motion1 and
 the propellers in the rear whir4 ,you  

take your seat at the center of the     
machine beside the operator4 ,he slips  
the cable1 and you shoot forward4 ,an   
assistant who has been holding the      
machine in balance on the rail starts   
forward with you1 but before you have   
gone #ej feet the speed is too great for
 him1 and he lets go4 ,before reaching  
the end of the track the operator moves 
the front rudder1 and the machine lifts 
from the rail like a kite supported by  
the pressure of the air underneath it4  
,the ground under you is at first a     
perfect blur1 but as you rise the       
objects become clearer4 ,at a height of 
#ajj feet you feel hardly any motion at 
all1 except for the wind which strikes  
your face4 ,if you did not take the     
precaution to fasten your hat before    
starting1 you have probably lost it by  
this time4 ,the operator moves a lever3 
the right wing rises1 and the machine   
swings about to the left4 ,you make a   
very short turn1 yet you do not feel the
 sensation of being thrown from your    

seat1 so often experienced in automobile
 and railway travel4 ,you find yourself 
facing toward the point from which you  
started4 ,the objects on the ground now 
seem to be moving at much higher speed1 
though you perceive no change in the    
pressure of the wind on your face4 ,you 
know then that you are traveling with   
the wind4 ,when you near the            
starting-point the operator stops the   
motor while still high in the air4 ,the 
machine coasts down at an oblique angle 
to the ground1 and after sliding #ej or 
#ajj feet1 comes to rest4 ,although the 
machine often lands when traveling at a 
speed of a mile a minute1 you feel no   
shock whatever1 and cannot1 in fact1    
tell the exact moment at which it first 
touched the ground4 ,the motor close    
beside you kept up an almost deafening  
roar during the whole flight1 yet in    
your excitement you did not notice it   
till it stopped6  ,our experiments have 
been conducted entirely at our own      
expense4 ,in the beginning we had no    

thought of recovering what we were      
expending1 which was not great1 and was 
limited to what we could afford in      
recreation4 ,later1 when a successful   
flight had been made with a motor1 we   
gave up the business in which we were   
engaged1 to devote our entire time and  
capital to the development of a machine 
for practical uses4 ,as soon as our     
condition is such that constant         
attention to business is not required1  
we expect to prepare for publication the
 results of our laboratory experiments1 
which alone made an early solution of   
the flying problem possible4     ,how   
,we ,made the ,first ,flight  ,by       
,orville ,wright   ,the flights of the  
#aijb glider had demonstrated the       
efficiency of our system of maintaining 
equilibrium1 and also the accuracy of   
the laboratory work upon which the      
design of the glider was based4 ,we then
 felt that we were prepared to calculate
 in advance the performance of machines 
with a degree of accuracy that had never

 been possible with the data and tables 
possessed by our predecessors4 ,before  
leaving camp in #aijb we were already at
 work on the general design of a new    
machine which we proposed to propel with
 a motor4  ,immediately upon our return 
to ,dayton1 we wrote to a number of     
automobile and motor builders1 stating  
the purpose for which we desired a      
motor1 and asking whether they could    
furnish one that would develop eight    
brake-horsepower1 with a weight complete
 not exceeding #bjj pounds4 ,most of the
 companies answered that they were too  
busy with their regular business to     
undertake the building of such a motor  
for us2 but one company replied that    
they had motors rated at #h horse-power1
 according to the ,french system of     
ratings1 which weighed only #ace pounds1
 and that if we thought this motor would
 develop enough power for our purpose   
they would be glad to sell us one4      
,after an examination of the particulars
 of this motor1 from which we learned   

that it had but a single cylinder of    
#d-;inch bore and #e-;inch stroke1 we   
were afraid it was much over-rated4     
,unless the motor would develop a full  
#h brake-horsepower1 it would be useless
 for our purpose4  ,finally we decided  
to undertake the building of the motor  
ourselves4 ,we estimated that we could  
make one of four cylinders with #d-;inch
 bore and #d-;inch stroke1 weighing not 
over two hundred pounds1 including all  
accessories4 ,our only experience up to 
that time in the building of gasoline   
motors had been in the construction of  
an air-cooled motor1 #e-;inch bore and  
#g-;inch stroke1 which was used to run  
the machinery of our small workshop4 ,to
 be certain that four cylinders of the  
size we had adopted 7#d x #d7 would     
develop the necessary #h horse-power1 we
 first fitted them in a temporary frame 
of simple and cheap construction4 ,in   
just six weeks from the time the design 
was started1 we had the motor on the    
block testing its power4 ,the ability to

 do this so quickly was largely due to  
the enthusiastic and efficient services 
of ,mr4 ,c4 ,e4 ,taylor1 who did all the
 machine work in our shop for the first 
as well as the succeeding experimental  
machines4 ,there was no provision for   
lubricating either cylinders or bearings
 while this motor was running4 ,for that
 reason it was not possible to run it   
more than a minute or two at a time4 ,in
 these short tests the motor developed  
about nine horse-power4 ,we were then   
satisfied that1 with proper lubrication 
and better adjustments1 a little more   
power could be expected4 ,the completion
 of the motor according to drawing was1 
therefore1 proceeded with at once4      
,illustration  ,while ,mr4 ,taylor was  
engaged with this work1 ,wilbur and ,i  
were busy in completing the design of   
the machine itself4 ,the preliminary    
tests of the motor having convinced us  
that more than #h horse-power would be  
secured1 we felt free to add enough     
weight to build a more substantial      

machine than we had originally          
contemplated4         99       99       
99       99       99  ,for two reasons  
we decided to use two propellers4 ,in   
the first place we could1 by the use of 
two propellers1 secure a reaction       
against a greater quantity of air1 and  
at the same time use a larger pitch     
angle than was possible with one        
propeller2 and in the second place by   
having the propellers turn in opposite  
directions1 the gyroscopic action of one
 would neutralize that of the other4    
,the method we adopted of driving the   
propellers in opposite directions by    
means of chains is now too well known to
 need description here4 ,we decided to  
place the motor to one side of the man1 
so that in case of a plunge headfirst1  
the motor could not fall upon him4 ,in  
our gliding experiments we had had a    
number of experiences in which we had   
landed upon one wing1 but the crushing  
of the wing had absorbed the shock1 so  
that we were not uneasy about the motor 

in case of a landing of that kind4 ,to  
provide against the machine rolling over
 forward in landing1 we designed skids  
like sled runners1 extending out in     
front of the main surfaces4 ,otherwise  
the general construction and operation  
of the machine was to be similar to that
 of the #aijb glider4  ,when the motor  
was completed and tested1 we found that 
it would develop #af horse-power for a  
few seconds1 but that the power rapidly 
dropped till1 at the end of a minute1 it
 was only #ab horse-power4 ,ignorant of 
what a motor of this size ought to      
develop1 we were greatly pleased with   
its performance4 ,more experience showed
 us that we did not get one-half of the 
power we should have had4  ,with #ab    
horse-power at our command1 we          
considered that we could permit the     
weight of the machine with operator to  
rise to #gej or #hjj pounds1 and still  
have as much surplus power as we had    
originally allowed for in the first     
estimate of #eej pounds4  ,before       

leaving for our camp at ,kitty ,hawk we 
tested the chain drive for the          
propellers in our shop at ,dayton1 and  
found it satisfactory4 ,we found1       
however1 that our first propeller       
shafts1 which were constructed of heavy 
gauge steel tubing1 were not strong     
enough to stand the shocks received from
 a gasoline motor with light fly wheel1 
although they would have been able to   
transmit three or four times the power  
uniformly applied4 ,we therefore built a
 new set of shafts of heavier tubing1   
which we tested and thought to be       
abundantly strong4  ,we left ,dayton1   
,september #bc1 and arrived at our camp 
at ,kill ,devil ,hill on ,friday1 the   
#beth4 ,we found there provisions and   
tools1 which had been shipped by freight
 several weeks in advance4 ,the         
building1 erected in #aija and enlarged 
in #aijb1 was found to have been blown  
by a storm from its foundation posts a  
few months previously4 ,while we were   
awaiting the arrival of the shipment of 

machinery and parts from ,dayton1 we    
were busy putting the old building in   
repair1 and erecting a new building to  
serve as a workshop for assembling and  
housing the new machine4  ,just as the  
building was being completed1 the parts 
and material for the machines arrived   
simultaneously with one of the worst    
storms that had visited ,kitty ,hawk in 
years4 ,the storm came on suddenly1     
blowing #cj to #dj miles an hour4 ,it   
increased during the night1 and the next
 day was blowing over #ge miles an hour4
 ,in order to save the tar-paper roof1  
we decided it would be necessary to get 
out in this wind and nail down more     
securely certain parts that were        
especially exposed4 ,when ,i ascended   
the ladder and reached the edge of the  
roof1 the wind caught under my large    
coat1 blew it up around my head and     
bound my arms till ,i was perfectly     
helpless4 ,wilbur came to my assistance 
and held down my coat while ,i tried to 
drive the nails4 ,but the wind was so   

strong ,i could not guide the hammer and
 succeeded in striking my fingers as    
often as the nails4  ,the next three    
weeks were spent in setting the         
motor-machine together4 ,on days with   
more favorable winds we gained          
additional experience in handling a     
flyer by gliding with the #aijb machine1
 which we had found in pretty fair      
condition in the old building1 where we 
had left it the year before4  ,mr4      
,chanute and ,dr4 ,spratt1 who had been 
guests in our camp in #aija and #aijb1  
spent some time with us1 but neither one
 was able to remain to see the test of  
the motor-machine1 on account of the    
delays caused by trouble which developed
 in the propeller shafts4  ,while ,mr4  
,chanute was with us1 a good deal of    
time was spent in discussion of the     
mathematical calculations upon which we 
had based our machine4 ,he informed us  
that1 in designing machinery1 about #bj 
per cent4 was usually allowed for the   
loss in the transmission of power4 ,as  

we had allowed only #e per cent41 a     
figure we had arrived at by some crude  
measurements of the friction of one of  
the chains when carrying only a very    
light load1 we were much alarmed4 ,more 
than the whole surplus in power allowed 
in our calculations would1 according to 
,mr4 ,chanute's estimate1 be consumed in
 friction in the driving chains4 ,after 
,mr4 ,chanute's departure1 we suspended 
one of the drive chains over a sprocket1
 hanging bags of sand on either side of 
the sprocket of a weight approximately  
equal to the pull that would be exerted 
on the chains when driving the          
propellers4 ,by measuring the extra     
amount of weight needed on one side to  
lift the weight on the other1 we        
calculated the loss in transmission4    
,this indicated that the loss of power  
from this source would be only #e per   
cent41 as we originally estimated4 ,but 
while we could see no serious error in  
this method of determining the loss1 we 
were very uneasy until we had a chance  

to run the propellers with the motor to 
see whether we could get the estimated  
number of turns4  ,the first run of the 
motor on the machine developed a flaw in
 one of the propeller shafts which had  
not been discovered in the test at      
,dayton4 ,the shafts were sent at once  
to ,dayton for repair1 and were not     
received again until ,november #bj1     
having been gone two weeks4 ,we         
immediately put them in the machine and 
made another test4 ,a new trouble       
developed4 ,the sprockets which were    
screwed on the shafts1 and locked with  
nuts of opposite thread1 persisted in   
coming loose4 ,after many futile        
attempts to get them fast1 we had to    
give it up for that day1 and went to bed
 much discouraged4 ,however1 after a    
night's rest1 we got up the next morning
 in better spirits and resolved to try  
again4  ,while in the bicycle business  
we had become well acquainted with the  
use of hard tire cement for fastening   
tires on the rims4 ,we had once used it 

successfully in repairing a stop watch  
after several watchsmiths had told us it
 could not be repaired4 ,if tire cement 
was good for fastening the hands on a   
stop watch1 why should it not be good   
for fastening the sprockets on the      
propeller shaft of a flying machine8 ,we
 decided to try it4 ,we heated the      
shafts and sprockets1 melted cement into
 the threads1 and screwed them together 
again4 ,this trouble was over4 ,the     
sprockets stayed fast4  ,just as the    
machine was ready for test bad weather  
set in4 ,it had been disagreeably cold  
for several weeks1 so cold that we could
 scarcely work on the machine for some  
days4 ,but now we began to have rain and
 snow1 and a wind of #be to #cj miles   
blew for several days from the north4   
,while we were being delayed by the     
weather we arranged a mechanism to      
measure automatically the duration of a 
flight from the time the machine started
 to move forward to the time it stopped1
 the distance traveled through the air  

in that time1 and the number of         
revolutions made by the motor and       
propeller4 ,a stop watch took the time2 
an anemometer measured the air traveled 
through2 and a counter took the number  
of revolutions made by the propellers4  
,the watch1 anemometer and revolution   
counter were all automatically started  
and stopped simultaneously4 ,from data  
thus obtained we expected to prove or   
disprove the accuracy of our propeller  
calculations4  ,on ,november #bh1 while 
giving the motor a run indoors1 we      
thought we again saw something wrong    
with one of the propeller shafts4 ,on   
stopping the motor we discovered that   
one of the tubular shafts had cracked6  
,illustration  ,immediate preparation   
was made for returning to ,dayton to    
build another set of shafts4 ,we decided
 to abandon the use of tubes1 as they   
did not afford enough spring to take up 
the shocks of premature or missed       
explosions of the motor4 ,solid         
tool-steel shafts of smaller diameter   

than the tubes previously used were     
decided upon4 ,these would allow a      
certain amount of spring4 ,the tubular  
shafts were many times stronger than    
would have been necessary to transmit   
the power of our motor if the strains   
upon them had been uniform4 ,but the    
large hollow shafts had no spring in    
them to absorb the unequal strains4     
,wilbur remained in camp while ,i went  
to get the new shafts4 ,i did not get   
back to camp again till ,friday1 the    
#aath of ,december4 ,saturday afternoon 
the machine was again ready for trial1  
but the wind was so light a start could 
not have been made from level ground    
with the run of only sixty feet         
permitted by our monorail track4 ,nor   
was there enough time before dark to    
take the machine to one of the hills1   
where1 by placing the track on a steep  
incline1 sufficient speed could be      
secured for starting in calm air4       
,monday1 ,december #ad1 was a beautiful 
day1 but there was not enough wind to   

enable a start to be made from the level
 ground about camp4 ,we therefore       
decided to attempt a flight from the    
side of the big ,kill ,devil ,hill4 ,we 
had arranged with the members of the    
,kill ,devil ,hill ,life ,saving        
,station1 which was located a little    
over a mile from our camp1 to inform    
them when we were ready to make the     
first trial of the machine4 ,we were    
soon joined by ,j4 ,t4 ,daniels1 ,robert
 ,westcott1 ,thomas ,beachem1 ,w4 ,s4   
,dough and ,uncle ,benny ,o',neal1 of   
the station1 who helped us get the      
machine to the hill1 a quarter mile     
away4 ,we laid the track #aej feet up   
the side of the hill on a #i-;degree    
slope4 ,with the slope of the track1 the
 thrust of the propellers and the       
machine starting directly into the wind1
 we did not anticipate any trouble in   
getting up flying speed on the #fj-;foot
 monorail track4 ,but we did not feel   
certain the operator could keep the     
machine balanced on the track4  ,when   

the machine had been fastened with a    
wire to the track1 so that it could not 
start until released by the operator1   
and the motor had been run to make sure 
that it was in condition1 we tossed up a
 coin to decide who should have the     
first trial4 ,wilbur won4 ,i took a     
position at one of the wings1 intending 
to help balance the machine as it ran   
down the track4 ,but when the           
restraining wire was slipped1 the       
machine started off so quickly ,i could 
stay with it only a few feet4 ,after a  
#ce to #dj-;foot run it lifted from the 
rail4 ,but it was allowed to turn up too
 much4 ,it climbed a few feet1 stalled1 
and then settled to the ground near the 
foot of the hill1 #aje feet below4 ,my  
stop watch showed that it had been in   
the air just #c-a_/b seconds4 ,in       
landing the left wing touched first4    
,the machine swung around1 dug the skids
 into the sand and broke one of them4   
,several other parts were also broken1  
but the damage to the machine was not   

serious4 ,while the test had shown      
nothing as to whether the power of the  
motor was sufficient to keep the machine
 up1 since the landing was made many    
feet below the starting point1 the      
experiment had demonstrated that the    
method adopted for launching the machine
 was a safe and practical one4 ,on the  
whole1 we were much pleased4  ,two days 
were consumed in making repairs1 and the
 machine was not ready again till late  
in the afternoon of the #afth4 ,while we
 had it out on the track in front of the
 building1 making the final adjustments1
 a stranger came along4 ,after looking  
at the machine a few seconds he inquired
 what it was4 ,when we told him it was a
 flying machine he asked whether we     
intended to fly it4 ,we said we did1 as 
soon as we had a suitable wind4 ,he     
looked at it several minutes longer and 
then1 wishing to be courteous1 remarked 
that it looked as if it would fly1 if it
 had a suitable wind4 ,we were much     
amused1 for1 no doubt1 he had in mind   

the recent #ge-mile gale when he        
repeated our words1 a suitable wind6    
,during the night of ,december #af1     
#aijc1 a strong cold wind blew from the 
north4 ,when we arose on the morning of 
the #agth1 the puddles of water1 which  
had been standing about camp since the  
recent rains1 were covered with ice4    
,the wind had a velocity of #aj to #ab  
meters per second 7#bb to #bg miles an  
hour74 ,we thought it would die down    
before long1 and so remained indoors the
 early part of the morning4 ,but when   
ten o'clock arrived1 and the wind was as
 brisk as ever1 we decided that we had  
better get the machine out and attempt a
 flight4 ,we hung out the signal for the
 men of the life saving station4 ,we    
thought that by facing the flyer into a 
strong wind1 there ought to be no       
trouble in launching it from the level  
ground about camp4 ,we realized the     
difficulties of flying in so high a     
wind1 but estimated that the added      
dangers in flight would be partly       

compensated for by the slower speed in  
landing4  ,we laid the track on a smooth
 stretch of ground about one hundred    
feet north of the new building4 ,the    
biting cold wind made work difficult1   
and we had to warm up frequently in our 
living room1 where we had a good fire in
 an improvised stove made of a large    
carbide can4 ,by the time all was ready1
 ,j4 ,t4 ,daniels1 ,w4 ,s4 ,dough and   
,a4 ,d4 ,etheridge1 members of the ,kill
 ,devil ,life ,saving ,station2 ,w4 ,c4 
,brinkley1 of ,manteo1 and ,johnny      
,moore1 a boy from ,nag's ,head1 had    
arrived4  ,we had a ,richards hand      
anemometer with which we measured the   
velocity of the wind4 ,measurements made
 just before starting the first flight  
showed velocities of #aa to #ab meters  
per second1 or #bd to #bg miles per     
hour4 ,measurements made just before the
 last flight gave between #i and #aj    
meters per second4 ,one made just after 
showed a little over #h meters4 ,the    
records of the ,government ,weather     

,bureau at ,kitty ,hawk gave the        
velocity of the wind between the hours  
of #aj3cj and #ab o'clock1 the time     
during which the four flights were made1
 as averaging #bg miles at the time of  
the first flight and #bd miles at the   
time of the last4         99       99   
99       99       99  ,wilbur1 having   
used his turn in the unsuccessful       
attempt on the #adth1 the right to the  
first trial now belonged to me4 ,after  
running the motor a few minutes to heat 
it up1 ,i released the wire that held   
the machine to the track1 and the       
machine started forward into the wind4  
,wilbur ran at the side of the machine1 
holding the wing to balance it on the   
track4 ,unlike the start on the #adth1  
made in a calm1 the machine1 facing a   
#bg-mile wind1 started very slowly4     
,wilbur was able to stay with it till it
 lifted from the track after a          
forty-foot run4 ,one of the life saving 
men snapped the camera for us1 taking a 
picture just as the machine had reached 

the end of the track and had risen to a 
height of about two feet4 ,the slow     
forward speed of the machine over the   
ground is clearly shown in the picture  
by ,wilbur's attitude4 ,he stayed along 
beside the machine without any effort4  
,the course of the flight up and down   
was exceedingly erratic1 partly due to  
the irregularity of the air1 and partly 
to lack of experience in handling this  
machine4 ,the control of the front      
rudder was difficult on account of its  
being balanced too near the center4     
,this gave it a tendency to turn itself 
when started2 so that it turned too far 
on one side and then too far on the     
other4 ,as a result the machine would   
rise suddenly to about ten feet1 and    
then as suddenly dart for the ground4 ,a
 sudden dart when a little over a       
hundred feet from the end of the track1 
or a little over #abj feet from the     
point at which it rose into the air1    
ended the flight4 ,as the velocity of   
the wind was over #ce feet per second   

and the speed of the machine against    
this wind ten feet per second1 the speed
 of the machine relative to the air was 
over #de feet per second1 and the length
 of the flight was equivalent to a      
flight of #edj feet made in calm air4   
,this flight lasted only #ab seconds1   
but it was nevertheless the first in the
 history of the world in which a machine
 carrying a man had raised itself by its
 own power into the air in full flight1 
had sailed forward without reduction of 
speed1 and had finally landed at a point
 as high as that from which it started4 
99       99       99       99       99  
,at twenty minutes after eleven ,wilbur 
started on the second flight4 ,the      
course of this flight was much like that
 of the first1 very much up and down4   
,the speed over the ground was somewhat 
faster than that of the first flight1   
due to the lesser wind4 ,the duration of
 the flight was less than a second      
longer than the first1 but the distance 
covered was about seventy-five feet     

greater4  ,twenty minutes later the     
third flight started4 ,this one was     
steadier than the first one an hour     
before4 ,i was proceeding along pretty  
well when a sudden gust from the right  
lifted the machine up twelve to fifteen 
feet and turned it up sidewise in an    
alarming manner4 ,it began sliding off  
to the left4 ,i warped the wings to try 
to recover the lateral balance and at   
the same time pointed the machine down  
to reach the ground as quickly as       
possible4 ,the lateral control was more 
effective than ,i had imagined and      
before ,i reached the ground the right  
wing was lower than the left and struck 
first4 ,the time of this flight was     
fifteen seconds and the distance over   
the ground a little over #bjj feet4     
,wilbur started the fourth and last     
flight at just #ab o'clock4 ,the first  
few hundred feet were up and down as    
before1 but by the time three hundred   
feet had been covered1 the machine was  
under much better control4 ,the course  

for the next four or five hundred feet  
had but little undulation4 ,however1    
when out about eight hundred feet the   
machine began pitching again1 and1 in   
one of its starts downward1 struck the  
ground4 ,the distance over the ground   
was measured and found to be #heb feet2 
the time of the flight #ei seconds4 ,the
 frame supporting the front rudder was  
badly broken1 but the main part of the  
machine was not injured at all4 ,we     
estimated that the machine could be put 
in condition for flight again in a day  
or two4  ,while we were standing about  
discussing this last flight1 a sudden   
strong gust of wind struck the machine  
and began to turn it over4 ,everybody   
made a rush for it4 ,wilbur1 who was at 
one end1 seized it in front1 ,mr4       
,daniels and ,i1 who were behind1 tried 
to stop it by holding to the rear       
uprights4 ,all our efforts were vain4   
,the machine rolled over and over4      
,daniels1 who had retained his grip1 was
 carried along with it1 and was thrown  

about head over heels inside of the     
machine4 ,fortunately he was not        
seriously injured1 though badly bruised 
in falling about against the motor1     
chain guides1 etc4 ,the ribs in the     
surfaces of the machine were broken1 the
 motor injured and the chain guides     
badly bent1 so that all possibility of  
further flights with it for that year   
were at an end4  ,illustration     ,some
 ,aeronautical ,experiments  ,by ,wilbur
 ,wright   ,the difficulties which      
obstruct the pathway to success in      
flying machine construction are of three
 general classes3 7#a7 ,those which     
relate to the construction of the       
sustaining wings4 7#b7 ,those which     
relate to the generation and application
 of the power required to drive the     
machine through the air4 7#c7 ,those    
relating to the balancing and steering  
of the machine after it is actually in  
flight4 ,of these difficulties two are  
already to a certain extent solved4 ,men
 already know how to construct wings or 

aeroplanes which1 when driven through   
air at sufficient speed1 will not only  
sustain the weight of the wings         
themselves1 but also that of the engine1
 and of the engineer as well4 ,men also 
know how to build engines and screws of 
sufficient lightness and power to drive 
these planes at sustaining speed4 ,as   
long ago as #ahic a machine weighing    
#h1jjj lbs4 demonstrated its power both 
to lift itself from the ground and to   
maintain a speed of from #cj to #dj     
miles per hour2 but it came to grief in 
an accidental free flight1 owing to the 
inability of the operators to balance   
and steer it properly4 ,this inability  
to balance and steer still confronts    
students of the flying problem1 although
 nearly ten years have passed4 ,when    
this one feature has been worked out the
 age of flying machines will have       
arrived1 for all other difficulties are 
of minor importance4  ,the person who   
merely watches the flight of a bird     
gathers the impression that the bird has

 nothing to think of but the flapping of
 its wings4 ,as a matter of fact1 this  
is a very small part of its mental      
labour4 ,even to mention all the things 
the bird must constantly keep in mind in
 order to fly securely through the air  
would take a very considerable treatise4
 ,if ,i take a piece of paper1 and after
 placing it parallel with the ground1   
quickly let it fall1 it will not settle 
steadily down as a staid1 sensible piece
 of paper ought to do1 but it insists on
 contravening every recognized rule of  
decorum1 turning over and darting hither
 and thither in the most erratic manner1
 much after the style of an untrained   
horse4 ,yet this is the style of steed  
that men must learn to manage before    
flying can become an everyday sport4    
,the bird has learned this art of       
equilibrium1 and learned it so          
thoroughly that its skill is not        
apparent to our sight4 ,we only learn to
 appreciate it when we try to imitate   
it4 ,now1 there are two ways of learning

 how to ride a fractious horse3 one is  
to get on him and learn by actual       
practice how each motion and trick may  
be best met2 the other is to sit on a   
fence and watch the beast awhile1 and   
then retire to the house and at leisure 
figure out the best way of overcoming   
his jumps and kicks4 ,the latter system 
is the safest2 but the former1 on the   
whole1 turns out the larger proportion  
of good riders4 ,it is very much the    
same in learning to ride a flying       
machine2 if you are looking for perfect 
safety you will do well to sit on a     
fence and watch the birds2 but if you   
really wish to learn you must mount a   
machine and become acquainted with its  
tricks by actual trial4         99      
99       99       99       99  ,my own  
active interest in aeronautical problems
 dates back to the death of ,lilienthal 
in #ahif4 ,the brief notice of his death
 which appeared in the telegraphic news 
at that time aroused a passive interest 
which had existed from my childhood1 and

 led me to take down from the shelves of
 our home library a book on ,animal     
,mechanism1 by ,prof4 ,marey1 which ,i  
had already read several times4 ,from   
this ,i was led to read more modern     
works1 and as my brother soon became    
equally interested with myself1 we soon 
passed from the reading to the thinking1
 and finally to the working stage4 ,it  
seemed to us that the main reason why   
the problem had remained so long        
unsolved was that no one had been able  
to obtain any adequate practice4 ,we    
figured that ,lilienthal in five years  
of time had spent only about five hours 
in actual gliding through the air4 ,the 
wonder was not that he had done so      
little1 but that he had accomplished so 
much4 ,it would not be considered at all
 safe for a bicycle rider to attempt to 
ride through a crowded city street after
 only five hours' practice1 spread out  
in bits of ten seconds each over a      
period of five years2 yet ,lilienthal   
with this brief practice was remarkably 

successful in meeting the fluctuations  
and eddies of wind gusts4 ,we thought   
that if some method could be found by   
which it would be possible to practice  
by the hour instead of by the second    
there would be hope of advancing the    
solution of a very difficult problem4   
,it seemed feasible to do this by       
building a machine which would be       
sustained at a speed of #ah miles per   
hour1 and then finding a locality where 
winds of this velocity were common4     
,with these conditions a rope attached  
to the machine to keep it from floating 
backward would answer very nearly the   
same purpose as a propeller driven by a 
motor1 and it would be possible to      
practice by the hour1 and without any   
serious danger1 as it would not be      
necessary to rise far from the ground1  
and the machine would not have any      
forward motion at all4 ,we found1       
according to the accepted tables of air 
pressures on curved surfaces1 that a    
machine spreading #bjj square feet of   

wing surface would be sufficient for our
 purpose1 and that places could easily  
be found along the ,atlantic coast where
 winds of #af to #be miles were not at  
all uncommon4 ,when the winds were low  
it was our plan to glide from the tops  
of sand hills1 and when they were       
sufficiently strong to use a rope for   
our motor and fly over one spot4 ,our   
next work was to draw up the plan for a 
suitable machine4 ,after much study we  
finally concluded that tails were a     
source of trouble rather than of        
assistance1 and therefore we decided to 
dispense with them altogether4 ,it      
seemed reasonable that if the body of   
the operator could be placed in a       
horizontal position instead of the      
upright1 as in the machines of          
,lilienthal1 ,pilcher and ,chanute1 the 
wind resistance could be very materially
 reduced1 since only one square foot    
instead of five would be exposed4 ,as a 
full half-horse-power could be saved by 
this change1 we arranged to try at least

 the horizontal position4 ,then the     
method of control used by ,lilienthal1  
which consisted in shifting the body1   
did not seem quite as quick or effective
 as the case required2 so1 after long   
study1 we contrived a system consisting 
of two large surfaces on the ,chanute   
double-deck plan1 and a smaller surface 
placed a short distance in front of the 
main surfaces in such a position that   
the action of the wind upon it would    
counterbalance the effect of the travel 
of the center of pressure on the main   
surfaces4 ,thus changes in the direction
 and velocity of the wind would have    
little disturbing effect1 and the       
operator would be required to attend    
only to the steering of the machine1    
which was to be effected by curving the 
forward surface up or down4 ,the lateral
 equilibrium and the steering to right  
or left was to be attained by a peculiar
 torsion of the main surfaces1 which was
 equivalent to presenting one end of the
 wings at a greater angle than the      

other4 ,in the main frame a few changes 
were also made in the details of        
construction and trussing employed by   
,mr4 ,chanute4 ,the most important of   
these were3 7#a7 ,the moving of the     
forward main cross-piece of the frame to
 the extreme front edge2 7#b7 the       
encasing in the cloth of all            
cross-pieces and ribs of the surfaces2  
7#c7 a rearrangement of the wires used  
in trussing the two surfaces together1  
which rendered it possible to tighten   
all the wires by simply shortening two  
of them4  ,illustration  ,with these    
plans we proceeded in the summer of     
#aijj to ,kitty ,hawk1 ,north ,carolina1
 a little settlement located on the     
strip of land that separates ,albemarle 
,sound from the ,atlantic ,ocean4 ,owing
 to the impossibility of obtaining      
suitable material for a #bjj-square-foot
 machine1 we were compelled to make it  
only #afe square feet in area1 which1   
according to the ,lilienthal tables1    
would be supported at an angle of three 

degrees in a wind of about #ba miles per
 hour4 ,on the very day that the machine
 was completed the wind blew from #be to
 #cj miles per hour1 and we took it out 
for a trial as a kite4 ,we found that   
while it was supported with a man on it 
in a wind of about #be miles1 its angle 
was much nearer #bj degrees than three  
degrees4 ,even in gusts of #cj miles the
 angle of incidence did not get as low  
as three degrees1 although the wind at  
this speed has more than twice the      
lifting power of a #ba-mile wind4 ,as   
winds of #cj miles per hour are not     
plentiful on clear days1 it was at once 
evident that our plan of practicing by  
the hour1 day after day1 would have to  
be postponed4 ,our system of twisting   
the surfaces to regulate the lateral    
balance was tried and found to be much  
more effective than shifting the        
operator's body4 ,on subsequent days1   
when the wind was too light to support  
the machine with a man on it1 we tested 
it as a kite1 working the rudders by    

cords reaching to the ground4 ,the      
results were very satisfactory1 yet we  
were well aware that this method of     
testing is never wholly convincing until
 the results are confirmed by actual    
gliding experience4  ,we then turned our
 attention to making a series of actual 
measurements of the lift and drift of   
the machine under various loads4 ,so far
 as we were aware1 this had never       
previously been done with any full-size 
machine4 ,the results obtained were most
 astonishing1 for it appeared that the  
total horizontal pull of the machine1   
while sustaining a weight of #eb lbs41  
was only #h4e lbs41 which was less than 
had previously been estimated for head  
resistance of the framing alone4 ,making
 allowance for the weight carried1 it   
appeared that the head resistance of the
 framing was but little more than #ej   
per cent4 of the amount which ,mr4      
,chanute had estimated as the head      
resistance of the framing of his        
machine4 ,on the other hand1 it appeared

 sadly deficient in lifting power as    
compared with the calculated lift of    
curved surfaces of its size4 ,this      
deficiency we supposed might be due to  
one or more of the following            
causes3--7#a7 ,that the depth of the    
curvature of our surfaces was           
insufficient1 being only about one in   
#bb1 instead of one in #ab4 7#b7 ,that  
the cloth used in our wings was not     
sufficiently air-tight4 7#c7 ,that the  
,lilienthal tables might themselves be  
somewhat in error4 ,we decided to       
arrange our machine for the following   
year so that the depth of the curvature 
of its surfaces could be varied at will 
and its covering air-proofed4  ,our     
attention was next turned to gliding1   
but no hill suitable for the purpose    
could be found near our camp at ,kitty  
,hawk4 ,this compelled us to take the   
machine to a point four miles south1    
where the ,kill ,devil sand hill rises  
from the flat sand to a height of more  
than #ajj feet4 ,its main slope is      

toward the northeast1 and has an        
inclination of #aj degrees4 ,on the day 
of our arrival the wind blew about #be  
miles an hour1 and as we had had no     
experience at all in gliding1 we deemed 
it unsafe to attempt to leave the       
ground4 ,but on the day following1 the  
wind having subsided to #ad miles per   
hour1 we made about a dozen glides4 ,it 
had been the original intention that the
 operator should run with the machine to
 obtain initial velocity1 and assume the
 horizontal position only after the     
machine was in free flight4 ,when it    
came time to land he was to resume the  
upright position and alight on his feet1
 after the style of previous gliding    
experiments4 ,but in actual trial we    
found it much better to employ the help 
of two assistants in starting1 which the
 peculiar form of our machine enabled us
 readily to do2 and in landing we found 
that it was entirely practicable to land
 while still reclining in a horizontal  
position upon the machine4 ,although the

 landings were made while moving at     
speeds of more than #bj miles an hour1  
neither machine nor operator suffered   
any injury4 ,the slope of the hill was  
#i4e deg41 or a drop of one foot in six4
 ,we found that after attaining a speed 
of about #be to #cj miles with reference
 to the wind1 or #aj to #ae miles over  
the ground1 the machine not only glided 
parallel to the slope of the hill1 but  
greatly increased its speed1 thus       
indicating its ability to glide on a    
somewhat less angle than #i4e deg41 when
 we should feel it safe to rise higher  
from the surface4 ,the control of the   
machine proved even better than we had  
dared to expect1 responding quickly to  
the slightest motion of the rudder4     
,with these glides our experiments for  
the year #aijj closed4 ,although the    
hours and hours of practice we had hoped
 to obtain finally dwindled down to     
about two minutes1 we were very much    
pleased with the general results of the 
trip1 for1 setting out as we did with   

almost revolutionary theories on many   
points and an entirely untried form of  
machine1 we considered it quite a point 
to be able to return without having our 
pet theories completely knocked on the  
head by the hard logic of experience1   
and our own brains dashed out in the    
bargain4 ,everything seemed to us to    
confirm the correctness of our original 
opinions--7#a7 that practice is the key 
to the secret of flying2 7#b7 that it is
 practicable to assume the horizontal   
position2 7#c7 that a smaller surface   
set at a negative angle in front of the 
main bearing surfaces1 or wings1 will   
largely counteract the effect of the    
fore-and-aft travel of the center of    
pressure2 7#d7 that steering up and down
 can be attained with a rudder without  
moving the position of the operator's   
body2 7#e7 that twisting the wings so as
 to present their ends to the wind at   
different angles is a more prompt and   
efficient way of maintaining lateral    
equilibrium than that employed in       

shifting the body of the operator of the
 machine4  ,when the time came to design
 our new machine for #aija we decided to
 make it exactly like the previous      
machine in theory and method of         
operation4 ,but as the former machine   
was not able to support the weight of   
the operator when flown as a kite1      
except in very high winds and at very   
large angles of incidence1 we decided to
 increase its lifting power4            
,accordingly1 the curvature of the      
surfaces was increased to one in #ab1 to
 conform to the shape on which          
,lilienthal's table was based1 and to be
 on the safe side we decided also to    
increase the area of the machine from   
#afe square feet to #cjh square feet1   
although so large a machine had never   
before been deemed controllable4 ,the   
,lilienthal machine had an area of #aea 
square feet2 that of ,pilcher1 #afe     
square feet2 and the ,chanute           
double-decker1 #acd square feet4 ,as our
 system of control consisted in a       

manipulation of the surfaces themselves 
instead of shifting the operator's body1
 we hoped that the new machine would be 
controllable1 notwithstanding its great 
size4 ,according to calculations1 it    
would obtain support in a wind of #ag   
miles per hour with an angle of         
incidence of only three degrees4        
,illustration  ,our experience of the   
previous year having shown the necessity
 of a suitable building for housing the 
machine1 we erected a cheap frame       
building1 #af feet wide1 #be feet long1 
and #g feet high at the eaves4 ,as our  
machine was #bb feet wide1 #ad feet long
 7including the rudder71 and about #f   
feet high1 it was not necessary to take 
the machine apart in any way in order to
 house it4 ,both ends of the building1  
except the gable parts1 were made into  
doors which hinged above1 so that when  
opened they formed an awning at each end
 and left an entrance the full width of 
the building4 ,we went into camp about  
the middle of ,july1 and were soon      

joined by ,mr4 ,e4 ,c4 ,huffaker1 of    
,tennessee1 an experienced aeronautical 
investigator in the employ of ,mr4      
,chanute1 by whom his services were     
kindly loaned1 and by ,dr4 ,a4 ,g4      
,spratt1 of ,pennsylvania1 a young man  
who has made some valuable              
investigations of the properties of     
variously curved surfaces and the travel
 of the center of pressure thereon4     
,early in ,august ,mr4 ,chanute came    
down from ,chicago to witness our       
experiments1 and spent a week in camp   
with us4 ,these gentlemen1 with my      
brother and myself1 formed our camping  
party1 but in addition we had in many of
 our experiments the valuable assistance
 of ,mr4 ,w4 ,j4 ,tate and ,mr4 ,dan    
,tate1 of ,kitty ,hawk4         99      
99       99       99       99  ,it had  
been our intention when building the    
machine to do most of the experimenting 
in the following manner3--,when the wind
 blew #ag miles an hour1 or more1 we    
would attach a rope to the machine and  

let it rise as a kite with the operator 
upon it4 ,when it should reach a proper 
height the operator would cast off the  
rope and glide down to the ground just  
as from the top of a hill4 ,in this way 
we would be saved the trouble of        
carrying the machine uphill after each  
glide1 and could make at least #aj      
glides in the time required for one in  
the other way4 ,but when we came to try 
it we found that a wind of #ag miles1 as
 measured by ,richards' anemometer1     
instead of sustaining the machine with  
its operator1 a total weight of #bdj    
lbs41 at an angle of incidence of three 
degrees1 in reality would not sustain   
the machine alone--#ajj lbs4--at this   
angle4 ,its lifting capacity seemed     
scarcely one-third of the calculated    
amount4 ,in order to make sure that this
 was not due to the porosity of the     
cloth1 we constructed two small         
experimental surfaces of equal size1 one
 of which was air-proofed and the other 
left in its natural state2 but we could 

detect no difference in their lifting   
powers4 ,for a time we were led to      
suspect that the lift of curved surfaces
 little exceeded that of planes of the  
same size1 but further investigation and
 experiment led to the opinion that 7#a7
 the anemometer used by us over-recorded
 the true velocity of the wind by nearly
 #ae per cent42 7#b7 that the well-known
 ,smeaton coefficient of 4#jje ,v#b for 
the wind pressure at #ij degrees is     
probably too great by at least #bj per  
cent42 7#c7 that ,lilienthal's estimate 
that the pressure on a curved surface   
having an angle of incidence of three   
degrees equals 4#ede of the pressure at 
#ij degrees is too large1 being nearly  
#ej per cent4 greater than very recent  
experiments of our own with a special   
pressure testing machine indicate2 7#d7 
that the superposition of the surfaces  
somewhat reduced the lift per square    
foot1 as compared with a single surface 
of equal area4  ,illustration  ,in      
gliding experiments1 however1 the amount

 of lift is of less relative importance 
than the ratio of lift to drift1 as this
 alone decides the angle of gliding     
descent4 ,in a plane the pressure is    
always perpendicular to the surface1 and
 the ratio of lift to drift is therefore
 the same as that of the cosine to the  
sine of the angle of incidence4 ,but in 
curved surfaces a very remarkable       
situation is found4 ,the pressure1      
instead of being uniformly normal to the
 chord of the arc1 is usually inclined  
considerably in front of the            
perpendicular4 ,the result is that the  
lift is greater and the drift less than 
if the pressure were normal4 ,while our 
measurements differ considerably from   
those of ,lilienthal1 ,lilienthal was   
the first to discover this exceedingly  
important fact1 which is fully set forth
 in his book1 ,bird ,flight the ,basis  
of the ,flying ,art1 but owing to some  
errors in the methods he used in making 
measurements1 question was raised by    
other investigators not only as to the  

accuracy of his figures1 but even as to 
the existence of any tangential force at
 all4 ,our experiments confirm the      
existence of this force4 ,at ,kitty     
,hawk we spent much time in measuring   
the horizontal pressure on our unloaded 
machine at various angles of incidence4 
,we found that at #ac degrees the       
horizontal pressure was about #bc lbs4  
,this included not only the drift       
proper1 or horizontal component of the  
pressure on the side of the surface1 but
 also the head resistance of the framing
 as well4 ,the weight of the machine at 
the time of this test was about #ajh    
lbs4 ,now1 if the pressure had been     
normal to the chord of the surface1 the 
drift proper would have been to the lift
 7#ajh lbs47 as the sine of #ac degrees 
is to the cosine of #ac degrees1 or     
74#bb x #ajh7 _/ 4#ig  #bd lbs42 but    
this slightly exceeds the total pull of 
#bc lbs4 on our scales4 ,therefore1 it  
is evident that the average pressure on 
the surface1 instead of being normal to 

the chord1 was so far inclined toward   
the front that all the head resistance  
of framing and wires used in the        
construction was more than overcome4 ,in
 a wind of #ad miles per hour resistance
 is by no means a negligible factor1 so 
that tangential is evidently a force of 
considerable value4 ,in a higher wind1  
which sustained the machine at an angle 
of #aj degrees1 the pull on the scales  
was #ah lbs4 ,with the pressure normal  
to the chord the drift proper would have
 been 74#ag x #ih7 _/ 4#ih  #ag lbs41 so
 that1 although the higher wind velocity
 must have caused an increase in the    
head resistance1 the tangential force   
still came within one pound of          
overcoming it4 ,after our return from   
,kitty ,hawk we began a series of       
experiments to accurately determine the 
amount and direction of the pressure    
produced on curved surfaces when acted  
upon by winds at the various angles from
 zero to #ij degrees4 ,these experiments
 are not yet concluded1 but in general  

they support ,lilienthal in the claim   
that the curves give pressures more     
favorable in amount and direction than  
planes2 but we find marked differences  
in the exact values1 especially at      
angles below #aj degrees4 ,we were      
unable to obtain direct measurements of 
the horizontal pressures of the machine 
with the operator on board1 but by      
comparing the distance traveled in      
gliding with the vertical fall1 it was  
easily calculated that at a speed of #bd
 miles per hour the total horizontal    
resistance of our machine when bearing  
the operator1 amounted to #dj lbs41     
which is equivalent to about #b-a_/c    
horse-power4 ,it must not be supposed1  
however1 that a motor developing this   
power would be sufficient to drive a    
man-bearing machine4 ,the extra weight  
of the motor would require either a     
larger machine1 higher speed1 or a      
greater angle of incidence in order to  
support it1 and therefore more power4   
,it is probable1 however1 that an engine

 of six horse-power1 weighing #ajj lbs41
 would answer the purpose4 ,such an     
engine is entirely practicable4 ,indeed1
 working motors of one-half this weight 
per horse-power 7#i lbs4 per            
horse-power7 have been constructed by   
several different builders4 ,increasing 
the speed of our machine from #bd to #cc
 miles per hour reduced the total       
horizontal pressure from #dj to about   
#ce lbs4 ,this was quite an advantage in
 gliding1 as it made it possible to sail
 about #ae per cent4 further with a     
given drop4 ,however1 it would be of    
little or no advantage in reducing the  
size of the motor in a power-driven     
machine1 because the lessened thrust    
would be counterbalanced by the         
increased speed per minute4 ,some years 
ago ,professor ,langley called attention
 to the great economy of thrust which   
might be obtained by using very high    
speeds1 and from this many were led to  
suppose that high speed was essential to
 success in a motor-driven machine4 ,but

 the economy to which ,professor        
,langley called attention was in        
foot-pounds per mile of travel1 not in  
foot-pounds per minute4 ,it is the      
foot-pounds per minute that fixes the   
size of the motor4 ,the probability is  
that the first flying machines will have
 a relatively low speed1 perhaps not    
much exceeding #bj miles per hour1 but  
the problem of increasing the speed will
 be much simpler in some respects than  
that of increasing the speed of a       
steamboat2 for1 whereas in the latter   
case the size of the engine must        
increase as the cube of the speed1 in   
the flying machine1 until extremely high
 speeds are reached1 the capacity of the
 motor increases in less than simple    
ratio2 and there is even a decrease in  
the fuel consumption per mile of travel4
 ,in other words1 to double the speed of
 a steamship 7and the same is true of   
the balloon type of airship7 eight times
 the engine and boiler capacity would be
 required1 and four times the fuel      

consumption per mile of travel2 while a 
flying machine would require engines of 
less than double the size1 and there    
would be an actual decrease in the fuel 
consumption per mile of travel4 ,but    
looking at the matter conversely1 the   
great disadvantage of the flying machine
 is apparent2 for in the latter no      
flight at all is possible unless the    
proportion of horse-power to flying     
capacity is very high2 but on the other 
hand a steamship is a mechanical success
 if its ratio of horse-power to tonnage 
is insignificant4 ,a flying machine that
 would fly at a speed of #ej miles an   
hour with engines of #a1jjj horse-power 
would not be upheld by its wings at all 
at a speed of less than #be miles an    
hour1 and nothing less than #ejj        
horse-power could drive it at this      
speed4 ,but a boat which could make #dj 
miles per hour with engines of #a1jjj   
horse-power would still move four miles 
an hour even if the engines were reduced
 to one horse-power4 ,the problems of   

land and water travel were solved in the
 nineteenth century1 because it was     
possible to begin with small            
achievements and gradually work up to   
our present success4 ,the flying problem
 was left over to the twentieth century1
 because in this case the art must be   
highly developed before any flight of   
any considerable duration at all can be 
obtained4  ,illustration  ,however1     
there is another way of flying which    
requires no artificial motor1 and many  
workers believe that success will first 
come by this road4 ,i refer to the      
soaring flight1 by which the machine is 
permanently sustained in the air by the 
same means that are employed by soaring 
birds4 ,they spread their wings to the  
wind1 and sail by the hour1 with no     
perceptible exertion beyond that        
required to balance and steer           
themselves4 ,what sustains them is not  
definitely known1 though it is almost   
certain that it is a rising current of  
air4 ,but whether it be a rising current

 or something else1 it is as well able  
to support a flying machine as a bird1  
if man once learns the art of utilizing 
it4 ,in gliding experiments it has long 
been known that the rate of vertical    
descent is very much retarded1 and the  
duration of the flight greatly          
prolonged1 if a strong wind blows up the
 face of the hill parallel to its       
surface4 ,our machine1 when gliding in  
still air1 has a rate of vertical       
descent of nearly six feet per second1  
while in a wind blowing #bf miles per   
hour up a steep hill we made glides in  
which the rate of descent was less than 
two feet per second4 ,and during the    
larger part of this time1 while the     
machine remained exactly in the rising  
current1 there was no descent at all1   
but even a slight rise4 ,if the operator
 had had sufficient skill to keep       
himself from passing beyond the rising  
current he would have been sustained    
indefinitely at a higher point than that
 from which he started4         99      

99       99       99       99           
,illustration  ,in looking over our     
experiments of the past two years1 with 
models and full-size machines1 the      
following points stand out with         
clearness3--  #a4 ,that the lifting     
power of a large machine1 held          
stationary in a wind at a small distance
 from the earth1 is much less than the  
,lilienthal table and our own laboratory
 experiments would lead us to expect4   
,when the machine is moved through the  
air1 as in gliding1 the discrepancy     
seems much less marked4  #b4 ,that the  
ratio of drift to lift in well-balanced 
surfaces is less at angles of incidence 
of five degrees to #ab degrees than at  
an angle of three degrees4  #c4 ,that in
 arched surfaces the center of pressure 
at #ij degrees is near the center of the
 surface1 but moves slowly forward as   
the angle becomes less1 till a critical 
angle varying with the shape and depth  
of the curve is reached1 after which it 
moves rapidly toward the rear till the  

angle of no lift is found4  #d4 ,that   
with similar conditions large surfaces  
may be controlled with not much greater 
difficulty than small ones1 if the      
control is effected by manipulation of  
the surfaces themselves1 rather than by 
a movement of the body of the operator4 
#e4 ,that the head resistances of the   
framing can be brought to a point much  
below that usually estimated as         
necessary4  #f4 ,that tails1 both       
vertical and horizontal1 may with safety
 be eliminated in gliding and other     
flying experiments4  #g4 ,that a        
horizontal position of the operator's   
body may be assumed without excessive   
danger1 and thus the head resistance    
reduced to about one-fifth that of the  
upright position4  #h4 ,that a pair of  
superposed1 or tandem1 surfaces has less
 lift in proportion to drift than either
 surface separately1 even after making  
allowance for weight and head resistance
 of the connections4  ,illustration     
----------------------------------------

--------------------------              
,transcriber's ,note3                   
,on page #ae3                           
,wilbur1 who was at one end1 seized it  
in front1 ,mr4 ,daniels and ,i1   who   
were behind1 tried to stop it behind1   
tried to stop it by        holding to   
the rear uprights4                      
has been changed to                     
,wilbur1 who was at one end1 seized it  
in front1 ,mr4 ,daniels and ,i1   who   
were behind1 tried to stop it by holding
 to the rear uprights4                  
,on page #ba3                           
,lilienthal was the first to discover   
this exceedingly though our             
measurements differ considerably from   
those of ,lilienthal4 ,while            
important fact1 which is fully set forth
 in his book1 ,bird          ,flight the
 ,basis of the ,flying ,art1 but owing  
to some errors in     the methods he    
used in making measurements1 question   
was raised      by other investigators  
not only as to the accuracy of his      

figures1 but even as to the existence of
 any tangential force at     all4 ,our  
experiments confirm the existence of    
this force1 at ,kitty   ,hawk we spent  
much time in measuring the horizontal   
pressure on      our unloaded machine at
 various angles of incidence4           
has been changed to                     
,while our measurements differ          
considerably from those of              
,lilienthal1 ,lilienthal was the first  
to discover this exceedingly            
important fact1 which is fully set forth
 in his book1 ,bird          ,flight the
 ,basis of the ,flying ,art1 but owing  
to some errors in     the methods he    
used in making measurements1 question   
was raised      by other investigators  
not only as to the accuracy of his      
figures1 but even as to the existence of
 any tangential force at     all4 ,our  
experiments confirm the existence of    
this force4 ,at         ,kitty ,hawk we 
spent much time in measuring the        
horizontal            pressure on our   

unloaded machine at various angles of   
incidence4                              
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