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- Жюль Верн
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- Путешествие на Луну
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- Стр. 12/99
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"
3
.
What
will
be
the
period
of
transit
of
the
projectile
when
endowed
with
sufficient
initial
velocity
?
and
,
consequently
,
at
what
moment
ought
it
to
be
discharged
in
order
that
it
may
touch
the
moon
at
a
particular
point
?
"
4
.
At
what
precise
moment
will
the
moon
present
herself
in
the
most
favorable
position
to
be
reached
by
the
projectile
?
"
5
.
What
point
in
the
heavens
ought
the
cannon
to
be
aimed
at
which
is
intended
to
discharge
the
projectile
?
"
6
.
What
place
will
the
moon
occupy
in
the
heavens
at
the
moment
of
the
projectile
's
departure
?
"
Regarding
the
first
question
,
"
Is
it
possible
to
transmit
a
projectile
up
to
the
moon
?
"
Answer
.
--
Yes
;
provided
it
possess
an
initial
velocity
of
1,200
yards
per
second
;
calculations
prove
that
to
be
sufficient
.
In
proportion
as
we
recede
from
the
earth
the
action
of
gravitation
diminishes
in
the
inverse
ratio
of
the
square
of
the
distance
;
that
is
to
say
,
at
three
times
a
given
distance
the
action
is
nine
times
less
.
Consequently
,
the
weight
of
a
shot
will
decrease
,
and
will
become
reduced
to
zero
at
the
instant
that
the
attraction
of
the
moon
exactly
counterpoises
that
of
the
earth
;
that
is
to
say
at
4752
of
its
passage
.
At
that
instant
the
projectile
will
have
no
weight
whatever
;
and
,
if
it
passes
that
point
,
it
will
fall
into
the
moon
by
the
sole
effect
of
the
lunar
attraction
.
The
theoretical
possibility
of
the
experiment
is
therefore
absolutely
demonstrated
;
its
success
must
depend
upon
the
power
of
the
engine
employed
.
As
to
the
second
question
,
"
What
is
the
exact
distance
which
separates
the
earth
from
its
satellite
?
"
Answer
.
--
The
moon
does
not
describe
a
circle
round
the
earth
,
but
rather
an
ellipse
,
of
which
our
earth
occupies
one
of
the
foci
;
the
consequence
,
therefore
,
is
,
that
at
certain
times
it
approaches
nearer
to
,
and
at
others
it
recedes
farther
from
,
the
earth
;
in
astronomical
language
,
it
is
at
one
time
in
apogee
,
at
another
in
perigee
.
Now
the
difference
between
its
greatest
and
its
least
distance
is
too
considerable
to
be
left
out
of
consideration
.
In
point
of
fact
,
in
its
apogee
the
moon
is
247,552
miles
,
and
in
its
perigee
,
218,657
miles
only
distant
;
a
fact
which
makes
a
difference
of
28,895
miles
,
or
more
than
one-ninth
of
the
entire
distance
.
The
perigee
distance
,
therefore
,
is
that
which
ought
to
serve
as
the
basis
of
all
calculations
.
To
the
third
question
.
