The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1899-12-05
AN ABLE LECTURE
On Wireless Telegraphy
by F. ]. Cross.
wave Thee DRY Illustrated HertIzan
Waves Marconi's
System.

A large number of persons intereste,
IN the movement TO introduce Marco
mis- system OF wireless telegranbv i,
the Islands was present at Mr.. F. 7
cross lecture at the Y. VI. c.. a. las
evening. The main features have al
ready been described in the columns n
the Advertiser by Mr.. Cross, who last
night Illustrated them by a series OF
blackboard drawings. Mr.. Cross nref.
aced this portion of his lecture as fol-
lows:
In order 10 fully understand and an
preciate this new branch of science
viz, wireless telegraphy," it will be
necessary for me TO take you back this
evening to the year 1879, when the
hrst phenomenon was discovered rela-
tive to what is now known as ether or
4 hertiZan waves.
First, IL will be well for each of lis
| TO fully understand what is meant nv
the word ether in the sense we are
about TO use il. Webster defines if as
a medium OF extreme tenuity assumed
to exist all through space. 1t is be-
| lieyed TO be invisible, imponderable
exceedingly elastic, and capable of I'M
| dulations as it is being acted upon by
| light and heat. From being the medi-
um through which heat is transmitted
| 1t is sometimes called luminiferous
ether.
The Wave Theory.-It has been as
sumed that this subtle medium. termed
ether, pervades all space; that it is so
attenuated that it can insinuate itself
between the grosser molecules of ma
terial bodies, so that solids of the fin
est and closest texture, as we'll as
liquids and gases, are pervaded by it,
and that light, and probably electrici-
ty, are due to waves or undulations of
this ether
1t has been stated that energy is a
universal property of matter. and the
converse may be accepted, that energy
cannot exist without matter. And,
since light, coming from the sun, must
traverse the interplanetary spaces, |
there must be matter there; else we
shall be compelled TO admit that ener- |
gy can exist without matter, which is |
contrary TO all our teaching and expe- |
rience.
The earth is surrounded by an at
moSphere TO the limit of which we can
not penetrate. In 1922 Dr. Wollaston
made a careful mathematical calcula-
ton as the result of which he claimed |
TO have demonstrated that the earth's
must have limits beyond
which IL cannot exist. And this ap-
parent demonstration was accepted as
and remained unchallenged
for half century. Meantime the wave
theory of light became prominent. and
a medium being one of its fundamental
the existence of the ether
was assumed. and is now generally ac-
cepted.
The assumption is that an atmo-
sphere the same as that of our earth |
pervades all space; that in the inter-
planetary spaces it becomes exceed
Ingly attenuated, and that each of the
heavenly bodies attracts and surrounds
itself with a portion of it, the extent
and density of which is in proportion
TO the mass of the body
The high degree of vacuum which
AN now be attained by improvements
n the air-pump, seems to demonstrate, |
hat while electricity will pass more !
RELY through rarified air, on account r
II the reduced resistance, than through T
Iir of ordinary density, it must have a
Medium in which TO travel; and that
Is passage through an absolute vacu- a
I'M, or space devoid of any known ma
erial substance, is highly improbable c
'ut as the best obtainable vacuum is
till only an approximation TO an alb
olute vacuum, the full demonstration ;
this point has not yet been reached. II
The existence, then, of some elastic la
ledium by which the two forms of IA n
liant energy, known as light and heat |
an traverse the interplanetary spaces
J not questioned. Nor does the theory q
the unlimited expansion of our at Il
losphere conflict at all with the theo- "
Y of the universal existence of ether, n,
nce the theory of ether is that it per- r
leates all material substances.
The wave theory assumes that ra- o'
liant energy is transmitted by the un- al
ulations of some medium; that an
npulse originating at any center of en- nj
'gy, as the sun, produces a wave
hich traverseS this medium with in ~
velocity till it reaches some 81
Stant point, as the earth; and that Nv
lie constancy of such impulses at ev- fo
v point on the sun gives rise to the ~
lenomena of solar light, heat and :.
ectricity. vi
In like manner we may assume any IT
her center of energy, as q red-hot in
etal ball radiating light and heat, a OF
lex Of ebonite, excited by friction, ra- oh
ating electricity. 1t is also assumed
at the impulses radiate in straight LII
les, while the undulationS occur at tn
sht angles to those lines. sp
IL a long rope, stretched lengthwise. tn
tn plenty Of slack. be held at one =;
d, and jerked rapidly up and down, ol-
will De thrown into the waves,
lich will run along its entire length. -
ere it is evident that while the i'm Z
lseS given at one end travel in
ives TO the other, the rope. as a
lole, remains stationary; successiblel
rtions acting as yielding levers TO
Insmit the impulse along its length.
Let number of elastic balls be sus-
nded in a straight line in contact
IN each other. Draw back the outer