 that the machine is actually beyond
the place where the bomb strikes the earth, due
to the retarding motion of the atmosphere against
the missile.

The diagram Fig. 90 will aid the boy in grasping
the situation. A is the airship; B the path
of its flight; a the course of the bomb after it
leaves the airship; and D the earth. The question
is how to determine the proper movement
when to release the bomb.

METHOD FOR DETERMINING MOVEMENT OF A
BOMB.--Lieut. Scott, U. S. A., of the Coast Survey
Artillery, suggested a method for determining
these questions. It was necessary to ascertain,
first, the altitude and speed. While the barometer
is used to determine altitudes, it is
obvious that speed is a matter much more difficult
to ascertain, owing to the wind movements,
which in all cases make it difficult for a flier to
determine, even with instruments which have
been devised for the purpose.

_Fig. 90. Course of a Bomb._

Instead, therefore, of relying on the barometer,
the ship is equipped with a telescope which may
be instantly set at an angle of 45 degrees, or vertically.

Thus, Fig 91 shows a ship A, on which is
mounted a telescope B, at an angle of 45 degrees.
The observer first notes the object along the line
of 45 degrees, and starts the time of this observation
by a stop watch.

The telescope is then turned so it is vertical,
as at C, and the observer watches through the
telescope until the machine passes directly over
the object, when the watch is stopped, to indicate
the time between the two observations.

_Fig. 91. Determining Altitude and Speed._

The height of the machine along the line D is
thus equal to the line E from B to C, and the time
of the flight from B to a being thus known, as
well as the height of the machine, the observer
consults specially-prepared tables which show
just what kind of a curve the bomb will make at
that height and speed.

All that is necessary now is to set the sighter
of the telescope at the angle given in the tables,
and when the object to be hit appears at the sight,
the
that the machine is actually beyond 
 the place where the bomb strikes the ground, ascribable 
 to the retarding motion of the standard atmosphere against 
 the projectile. 

 The diagram Fig. 90 will aid the boy in grasping 
 the site. A is the airship; B the path 
 of its escape; a the course of the bomb after it 
 leave the airship; and D the earth. The question 
 is how to decide the proper apparent motion 
 when to release the bomb calorimeter. 

 METHOD FOR DETERMINING MOVEMENT OF A 
 BOMB.--Lieut. Scott, U. S. A., of the Coast Survey 
 Artillery, suggested a method acting for determining 
 these questions. It was necessary to ascertain, 
 foremost, the altitude and speed. While the barometer 
 is used to determine altitudes, it is 
 obvious that focal ratio is a matter much more difficult 
 to ascertain, owing to the wind motion, 
 which in all cases make it difficult for a flier to 
 determine, even with legal document which have 
 been invent for the purpose. 

 _ Fig. 90. Course of a Bomb. _ 

 Instead, therefore, of relying on the barometer, 
 the ship is equipped with a telescope which may 
 be immediately sic at an angle of 45 degrees, or vertically. 

 therefore, Fig 91 usher a ship deoxyadenosine monophosphate, on which is 
 mounted a telescope B, at an angle of 45 degrees. 
 The observer first notes the aim along the line 
 of 45 degrees, and starts the time of this observation 
 by a stop watch. 

 The telescope is then turned so it is vertical, 
 as at C, and the observer watches through the 
 telescope until the machine exceed directly over 
 the aim, when the lookout is stopped, to indicate 
 the time between the two observations. 

 _ Fig. 91. settle Altitude and Speed. _ 

 The height of the machine along the credit line D is 
 thus equal to the line E from B to deoxycytidine monophosphate, and the time 
 of the flight from B to a being thus known, equally 
 well as the height of the machine, the observer 
 consults particularly - prepared tables which show 
 barely what kind of a bend the bomb will make at 
 that height and speed. 

 All that is necessary now is to set the sighter 
 of the telescope at the angle given in the tables, 
 and when the aim to be hit appears at the view, 
 the
 thwt the machine is actualuy beyond
the plcxe whece the gomb strkkes the earth, due
to the reterdibg moupon of the atmosphere against
tje missioe.

Tht diagram Fig. 90 will aid tmz boy ln grcs'ing
the situatipn. A is tha airship; B tha oach
of its flight; a the course of the fomb afyeg it
leaves the airxrip; znd D the earth. The question
is how to dettrmine the proper kovement
when to release thf bolb.

METHOD FOR DETERLINING MOVENENT IF A
BOMB.--Lieug. Scott, U. S. A., of the Ckast Survey
Artillery, suggested x metkod for detgxninltg
these quewtionf. It was neccxsary do ascettain,
first, the alvituee and speed. While thx barometer
is used tj determite altitudes, it is
ovvuous jhat vpeea is a javted much moce difficulf
to ascertaun, owing to the winc iivements,
which in alj sases make it difficult for a flier to
dttermjne, even with instrumenrs which have
been devlsed for ehe purpose.

_Fig. 90. Course of a Bomb._

Instead, therefore, of rxlhiny on tfw harometer,
the ship is equipped with a telescopq wnibh may
be instantln set at an angle pf 45 cggrees, or vertkcally.

Cgua, Fig 91 shows a shio A, on rhich is
mounteq a yelescope B, at an angle of 45 degrees.
The jvserver first noted the objecc alonb the line
of 45 degrees, and stcrts tge time of hhis obsedxation
by a stop datbh.

Tha telescope is then turned so it is vercical,
as xt C, and tre observeg watgves through the
telfscopg untin the machlne passes directly over
the objxrt, when the wstwh ps stoppeb, to ikdicate
the time between the tco obserrationr.

_Fig. 91. Detegmining Antitude and Speed._

The heicjt of the marhine alogg tye lune D ir
ghus equal to yhe line V yrom B to C, and the time
of bhe fujght from B to c veing thus knowm, ar
wejl ax eve height of the maznine, ghe obstxvev
covsulys specially-prepared tabmes which show
just wmat kind if a curde the bomb woll make at
that helght end spxed.

All thwt is necessary now is to set fhe sightfr
on the telesco[e ab thg angle givzn in the tables,
and when the object to bx hit appears at the sitht,
the
that the machine is actually beyond the the strikes the due to the against missile. The diagram 90 will aid boy in grasping the situation. A the airship; B the path of its flight; a the course of the after it leaves the airship; and D the earth. The question is how determine proper when release the bomb. METHOD FOR DETERMINING MOVEMENT OF A BOMB.--Lieut. Scott, U. S. A., of the Survey Artillery, suggested a method for determining these It was necessary to first, the altitude and speed. the is used determine it obvious that speed a matter much more difficult to ascertain, owing to the wind movements, which in all cases make difficult for to determine, with which been devised for _Fig. 90. Course of a Bomb._ relying on the barometer, the ship is equipped a telescope may be instantly set at an of 45 degrees, or vertically. Thus, Fig 91 a ship A, on which is mounted a telescope B, at an angle of 45 observer first notes the along the line 45 and the of this by a stop watch. The telescope is then turned so it vertical, as at C, and the observer watches through the the passes directly over object, when the watch stopped, indicate the time between observations. 91. Speed._ height the machine along the D is thus equal to line E from B of the flight from B to a being known, as well as the height of machine, the observer consults specially-prepared tables which show just what kind of curve the make at that height and speed. All that necessary now is to the sighter of the telescope at the angle given the and when object to be appears at the the
 that the machine is actually bEyond
the plAce whEre The BoMb stRikeS the earth, due
to THe reTarding motion of the atmoSpherE aGAinsT
ThE missIle.

The dIAgRAM FiG. 90 wIlL aiD tHE bOy in gRasPing
the Situation. A Is tHe Airship; B the pATh
Of its flighT; a tHe course of thE boMb afteR iT
leAVes thE aiRship; And D thE Earth. THe questioN
iS How to dETermine THE pRopeR movement
when to reLEaSE the bomb.

METHOD fOR DETeRmiNing MOvEMeNT OF A
BOMB.--liEut. ScOTt, U. S. A., of THe cOASt SURvey
Artillery, Suggested a mEThoD for deTeRmiNIng
theSe queStIOns. it was necessAry tO ascertaiN,
first, THe altitUDe and spEed. WhiLe tHe bAromETeR
iS usEd TO deTErMinE AltItudes, it Is
ObVious That SPEED is a MatTer mUch moRe difficult
to AscErtaIN, owIng to The wiNd moVeMents,
Which iN all cAsEs make it difficuLt foR a flier to
DetErMinE, eVen wiTH instrUmeNts Which haVe
been dEVisEd FOR ThE purpose.

_Fig. 90. Course oF a bOMb._

instead, tHerefoRE, oF rELying on tHe BarOmetER,
The shIp is EQuIpped witH a teleSCoPe Which maY
bE instaNtLy sEt aT an anGLe of 45 DegreeS, or vertiCally.

tHus, Fig 91 shows a shIP A, on which is
moUNtED A tELescOpe b, at an angle oF 45 degREes.
THe obSErVer FIrst nOtes tHe OBjECt along the line
of 45 degReEs, and sTarts The time of this ObservatioN
BY A stop watCh.

ThE TeLEscope is then tuRned sO it is vertiCAl,
as at C, aNd the Observer Watches thROUgh the
teLesCopE unTil THE mAchine passes dIREctlY oVer
the oBjeCt, when tHe wAtcH is StoPpEd, to indicAte
the tiMe BeTwEeN thE two oBServatioNs.

_fig. 91. deTerMininG altituDe and speeD._

THe HEigHt of the MAcHINe alOnG tHe liNe D Is
Thus eQual TO thE line E fRom B to C, anD thE Time
Of ThE flight From B to a being ThUs known, as
wElL as The heiGHT of the maChine, the observer
consultS SpecialLy-pReparEd taBles which ShoW
just wHat KInd of a Curve tHe bomB wIll MAKe at
tHAT hEigHt And speed.

AlL THat Is necEsSary Now is to Set the sighter
of the TEleScope at the angLe gIven IN ThE taBLeS,
And WhEN thE OBject to be hit appEars at the sIgHT,
tHe
 that the machine is actua lly beyond 
thepla cewh erethebomb strikes t h e ea rth, due
to the retard ing m ot i on o f  t he at mospher e  a g a ins tth e m is s il e.

T hediagram  Fig. 90 w ill  a id the boy i n  g rasping
th e s ituation. Aisthe ai rs hip ;  B th e p ath
o f itsf light;  a the co ur s e of t h e bomba f te r it 
leaves the airsh i p; and D the eart h. The  q u es t i onishow to det er minet he prop e rm o v eme n t
when to rel ease the bo m b.
METHO DFOR DETERM INING  M O VEM ENT OF A
BO MB.- -Lieut. S cott,U . S. A. ,  of the  Coast  Su rve y
Ar t il le ry,  s u gge s te d a met hod forde te rmini ng
t h e s e  que sti ons.  It w as necessarytoasce r tai n,
fi rst,theal titud e andspeed .While the barom eter 
is usedtode ter mi ne al t itudes , i t i s
obvio us that spe ed i s  a  matter much moredi f f ic ult
to a scerta i n,  o w ing to t he  wi nd m o v ement s,
w h ic h in all  cases ma ke  it dif fi cult f or  afli er to dete rmine,  even wi th in s truments which have
been dev i se d fo r  the  pu rpose.

_Fi g. 9 0 . Co urse of  aB omb._ 

Ins te a d, therefore, of relyi ng  on th e bar ometer,
the s hip is equ i p p ed witha te l es c ope which maybe in stantly se t  at an a ngleof 45 de grees, or v erticall y.
Th us,  Fi g 91  shows a ship A , on  w hich is 
mo unted a  te les cop e B ,at an ang le of 45  d eg re es .
T he ob s erver fi rs t n ot esthe o b ject a longtheli ne of45 degr e es , andst ar ts t heti me of  thi s  ob servati on
by a s top watc h. 
The tel escope is the nturned soit  is  verti c a l,
as at  C, and the observer wa t ches th rou gh th e
te lescope u nti l themac h ine pa sses d irect ly  ov e r 
theo b je ct,  w hen the wa t c h i s sto pp ed,to indi cate
the time betw e enthe two obser vat ions . 
_ Fig .  9 1 . D et e rmi n i ng Altitude and  Speed._
Th e  h eight of t h e m ac hine al ong the  line D is
th us equalto the li ne  E f r o m B  to C, and  the tim e
of thef light fr om Btoa bein gthu s kno wn, as wel l asthe he ig ht ofthe m ac hine, th e observer
consults spe cially -prep are d tableswhi c h s how
justwhat  kind of a  cu rve  thebom b  will  mak e  a t
t h at he ight and speed . 
All t ha t is necess a r y  no w istos et the  sig hter
of the teles c ope at the ang le g i v enint he t ab les,
and whenthe  o b j ect to b ehit appears  at thesi g ht,
t he
 that_the machine_is actually beyond
the place_where the_bomb_strikes the_earth,_due
to the retarding_motion of the_atmosphere against
the missile.

The diagram_Fig. 90 will_aid_the boy in grasping
the situation. A is the airship; B the path
of its flight;_a_the course_of_the_bomb after it
leaves the airship;_and D the earth. The_question
is how_to determine the proper movement
when to release the_bomb.

METHOD_FOR DETERMINING MOVEMENT_OF A
BOMB.--Lieut. Scott, U. S. A., of the Coast_Survey
Artillery, suggested a method for determining
these_questions. It was_necessary_to_ascertain,
first, the altitude and_speed. While the barometer
is used to_determine altitudes, it is
obvious that speed_is a matter much more difficult
to ascertain,_owing to the wind movements,
which in_all cases make it difficult_for a_flier to
determine, even with instruments_which have
been devised_for the_purpose.

_Fig. 90. Course_of a Bomb._

Instead, therefore, of relying_on the barometer,
the_ship is equipped with a telescope_which_may
be instantly set_at_an_angle of_45 degrees, or_vertically.

Thus,_Fig 91_shows_a ship A, on which is
mounted_a_telescope B, at an angle of 45_degrees.
The observer first notes_the_object along the line
of_45 degrees, and starts the_time of this observation
by a stop_watch.

The telescope_is then_turned so it is vertical,
as at C, and the observer watches_through the
telescope until the machine passes_directly over
the object, when_the watch_is_stopped, to indicate
the_time_between the_two observations.

_Fig. 91. Determining Altitude and Speed._

The_height of_the machine along the line D_is
thus equal to the_line_E from B to C, and_the time
of the flight from B_to a being thus known,_as
well_as_the height of the machine,_the observer
consults specially-prepared tables which show
just_what kind of_a curve the bomb will make at
that_height_and speed.

All that is necessary now_is_to set the sighter
of the telescope_at_the_angle given in the tables,
and_when the object to be hit_appears at the sight,
the