The Hawaiian gazette., 1899-07-18
REGISTER, IL London BarIlQaaiss
ii Japan.
A MOST DELICATE INSTRUMENT
Loca, Experiments Under Profess
sov Aisxaodss's Direction Win
This Marvellous Machine.

department mas Hnally received the
seisnograph. sometimes termed seis
mome:er. forwarded by Professor John
Milne OF London Ia British Commits
sioner Kenny, which has been lying in
the local custom house for months.
Mr.. Kenny left for japan In January
and the letters announcing the send
ing of the seismograph had to be for
warded to him. He wrote 10 Professor
MAXWELL about the matter and the lat
ter after more correspondence finally
turned the instrument over to the Sur
vey Department OF the Hawaiian gov
eminent. s.'
The seismograph, derived from two
Greek words meaning earthquake
writer" is one Of the most delicate
machines ever invented. II consists of
an iron bed plate and stand carried on
three leveling screws. Resting against
a needle point or pivot projecting from
the base of the stand, and held in a
nearly horizontal position by tie, is
a light aluminium boom. Attached to
the outer end of this boom there is a
small rectangular plate in which there
are two Sits, one OF which is large and
the other small. Partly for the pur.
pose of balancing the weight of the
outer end of the .bosm, and partly for
obtaining the steady poin'" Of a SETS
mograph between the attachment Of a
tie to the pivot, weighted crOss-bar
is pivo.ed When the boom swings to
the right or left, the rectangular plate
with its Sits passes to the right and
left across a fixed slit in the lid OF a
box, inside of which a two-inch strip
Of bromide paper is being driven by
clockwork. Light from a lamp is re-
fected downwards by mirror TO cover
the whole of the latter slit. 1t how
ever, only enters the box to the right
and left of the floating plate and
through the Sits in the same. When
the boom Is steady, the resulting pho
togram on the moving bromide paper
will be, when developed, that of a white
band equal in width to that OF the
moving plate, down the center Of which
band are two very clearly defined
lines, one of which is thick and the
other thin. To the right and left Of
this white band the parer will have
been blackened by the light which en-
tered at,the two ends of the fixed slit.
On one edge of, one of these black
bands! at intervals of about two inches,
there will be seen q series of white
marks which have been produced by
the minute hand of a watch, the broad
ened extremity of which has hourly
at the half hour passed over the end
OF the fixed slit, and for a period of
about one minute eclipsed the light.
Should the clock az any time have fail
ed to drive the bromide strip with re-
gularity this will at once be seen by
differences in the distances between
successive time marks.
any solid pier in Al observatory, or on
a specially constructed pier in the
ground floor OF an ordinary dwelling
or in a hut or shed in the open. The
room should be dry and amply ventilat-
ed with shutters, through one Of which
red light can be admitted.
This marvellous little instrument"
said Professor w. d. Alexander yes
terday, costs fifty pounds in England.
1t is loaned to the Hawaiian Govern
ment Oh the recommendation of Pro-
fessor Davidson of San Francisco by
Professor John Milne, the great Lon
don scientist, who, with Professor
Gray, invented it. All the expenses
connected with sending the instrument
to Honolulu have been paid by Profess
sor Milne.
THE British Association for the
Advancement of Science has a special
committee of scientists, composed of
such eminent men as Lord Kelvin, Sir
F. J. Bramwell, Professor Knott and
others, whose object is to determine
the velocity with which motion is
propagated around, or, possibly,
through, the earth. To attain this the
committee desire records from given
stations of the times at which various
phases of motion are recorded. BY this
means the IOcl OF submarine disturb
ances, such, for example, as those
which from time to time have inter-
fered with telegraph cables, may pos
sibly be determined, and new light
thrown upon changes taking place in
ocean beds.
This committee aims, among other
things, To solve question that is puz-
cling biologists all over the world. and
that Is: DO the vibrations produced
by earthquakes go around or through
the earth? Professor Mines theory Is
that earthquakes originate under the
sea from great submarine landslides.
You know that II has been clearly
proven that the bottom OF the sea Is
composed Of mountain ranges, valleys
and depressi0ns ~ more or less mag
nitude, Well, IL In hoped from the ex-
periments now being conducted In all
uarts az the world IN find our the dan