The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1891-01-11

uos > edI anu uIScofeIeu Tile same virtue in
that"
Then he rubs pieces of silk ribbon and
bits of linen, paper and wood shaving and
leather,
AND GoLD-BEATER's SKIN.
And finds that all these, too. become eler-
trlcal, and that paper crackles and gives
light in the dark.
The device which lie employed to fest
the electrical condition of these bodies was
q feather suspended by piece of raw silk !:
but why he uses silk, or that he even
thought that the silk had anything to do
win preventing the electrical charge COM
municated to the feather from running
away from it, does not appear. Eight wears
elapsed before he found out the why and
wherefore of it.
Probably the world does not know more
than small fraction OF the experiments
made and results obtained by Gray in this
interval; nor how much knowledge after
ward discovered, or perhaps never since dis
covered, died with him. He published a
rec I'd of some of his experiments and die
tated an account of the rest of them on his
death-bed. Although il was perfectly we'll
known that an electrified body would attract
another dy, it was not at all known
whether or not one body could communicate
its own electrical condition to another and
this Gray undertook TO find out
He says, in referring to his experiments OF
1928, that long prior 70 that time he had
noticed that glass tube, if rubbed in the
dark, communicated light to bodies Just
how he does not explain, nor have we any
know ledge what this experiment was But,
at all events, touching, as it were, accident
ally the very uttermost boundary of electri-
cal science as 1t is now (the curious relation
and probable identity of light and cleo
tricity) he wonders why, as the tube when
rubbed In the dark communicated light to
bodies, it might not at the same time COM
municate electricity to them"
Sn ha M q do rha Of oil
half feet long by little over an inch in
diameter, and, in order to keep it clean in
side, put cOrks in the extremites. Being
CAUTIOUS INVESTIGATOR,
And not wishing to disturb his experiments
by overlooked conditions, he thought it
would be advisable 10 try whether the rubbed
tube acted any differently when the corks
were inserted to the ends. Not that he sup
posed that the corks would have any effect,
but lie thought it was just as we'll to see that
they did not. So he rubbed his tube before
the corks were put in, and rubbed it after
ward, applying it both times to a suspended
leather, and tile tube attracted the feather
at one time just as we'll as it did the other.
But, whether by accident or design is not
known, on one occasion, instead of present.
ing the glass tube to his feather he pre-
scented the surface of the cork. And then,
10 his surprise, lie saw the feather
behave Just the same as If the glass itself
had been approached 10 it. Here was an
answer TO his question at once; for the cleo
tIical virtue OF the tube had certainly been
communicated to the cork, despite the total
dissimilarity of the two substances.
1t Is easy to imagine the flood of questions
which must have pressed upon him at once
for solut on. If the electricity will go from
the tube to the cork, Will it go from the
cork to anything else? Over how long a
piece of cork would it travel? win it travel
over anything else but cork? Fortunately
for Gray the answers were all within the
reach of his scant income.
His first experiment was to insert wooden
rod four inches long into the cork and fasten
an ivory ball on the end of the ROT. And he
saw that This ball, even at ;hat distance, at
tracted and repealed the feather as well as
the tube Itself did. He then increased the
length OF the rod, and found the result the
same.
And then for the rod he substituted iron
wire and brass wire in lengths of two or
three feet, and still the same result. And
then he hung the ball by piece of
pack-thread from the tube. Still the same
happening. Then he asked himself, Can
this virtue be communicated only to an
ivory ballP And II not, to what else? The
things
HE HUNG ON THAT PACK THREAD
Were extraordinary in their variety. Here
Is list of them: A guinea, a shilling.
a halfpenny, piece of block lin, piece OF
lead, fire shovel tOngs, an iron poker, a
copper tea-kettle (Which, he says, "suc-
ceeded just the same whether empty or full
of hot or cold water y, a silver pint-pot, a
brick, tile. piece of chalk, various stones,
including the lodestone, and sundry vege-
tables, all of which worked perfectly well.
Then came the question, How far would
the electricity travel? SO for the wire. two
or three feet long, he substituted his fishing
rod, added joint after joint, and still the
electricity apparently ran to the end of it..
And then he substituted other rods still
longer, and finally he got 10 long pieces Of
pack thread, forty or fifty feet in length.
But when the thread became as long AS
this it was troublesome TO support; so he
fastened the line by loops here and there to
the beams of his room. Now he got into
trouble, for the electric virtue, as he called
1t, no longer appeared at the end of the line.
Nothing daunted he searched for the diff
Guilty and found it; the electric charge ran
OFF the line through the loops to the beams
and so 1t did not travel the path which was
intended for it. But finding difficulty is
one thing and overcoming it is another. so
codged the obstacle by continuing his ex-
periments with vertical lines ONLY. getting
the desired length by dropping them from
The tops of buildings
- One fine June day of 1929 Gray goes to
Otterden place 10 give his friend Mr.
Wheeler specimen of the experiment. and
he shows Wheeler how electricity will RIM
down wire thirty-four feet high Wheeler
Is astonishrd, but not satisfied. He does
not see why the electricity cannot be made
| line. '''
But the question OF supporting the thread
comes up again, and finally GRAY reachas
the conclusion that if he uses Something
when IS quite strong and very thin. the
eiectricity' OF al least some OF it, will not be
ABLE TO GET THROUGH
The thin loon, and will stav and travail
along the thicker thread So he
try, supports of silk. And then. Wheeler
and his servants assisting, they put mn a line
sixty feet in length in n long gallery and
the electric charge goes easily from end TO
end of it. N "
Then Wheeler boldly proposes to donh1e
the line. carrying it back to its STARING
point. And again the result was snccessf mi
The investigators become enthusiastic. they
go outdoors and put up line nearly 400
feet long; and the ball at the end of the
thread attracts the feather as strongly no
before when the tube connected to the oiheT
end of the line is rubbed.
The discovery and electrical eonduction is
not only complete. not only is it proved thai
electricity will trace over long lines from
place to place, but Gray has reached tbe
border oil another great discovery ennallv
important. NaU"i''
Wheler, always wanting longer line. pro-
posed returning the longest cord thew had
yet used back on itself. This was done. Int
the weight Of the line being considerable.
| when it was shaken by the rubbing of fhs
tube the little silk threads which held lit If
up broke. Thereupon they got some
pieces OF brass wire of the same thickness
as the SIX loops and supported the line an
| them. -0 i'he vi
lie wire held the line up all right. bn,
| the electric virtue no longer ran over its
path. And now, says the record, "they were