New-York tribune., 1879-04-12
SCIENCE FOR THE PEOPLE.


cussion recently took place at meeting OF London
ckmakers on compensation penduums. The general
Judgment seemed be in favor OF plain wooden pehdn
ums for all sorts OF tmepiecos One speaker sad tna'
wooden pendulum rods generally in use for turet
ana church clocks and also regulators Another con-
cured IN that statement and he thought that wooden
penduums good for church clocks. they might
usefuy be adopted for bracket clocks He had accord
ingy altered very old family clock Of that description
and OF the best London make by substituting wooden
for "A brass pendulum. with very decided advantage
II might possibly be worth while to make similar
alteration generally; brass, being a cheaper and
prettier material, having probably been used by the
makers OF bracket clocks without consideration
third maker never used anything but wood when he
could help It for railway, church or turret clocks
Another speaker considered that Of the advantages
in the OF wood for pendulums might be that In fa
OF temperature when the rod would be shortened the
bygroseOpio property of the wood would come INTO
play, which would tend TO engthen It, and so cause
natural compensation by the thermometnc and hygro-
scopic properties Of the wood acting in opposite drec
tions In climates that certainly might no the
case though I'm Others they would work together when
the effect would be to increase the error IL was stated
that a wooden pendulum with lcaden bob had been
affixed to regulator CLOCK IN one OF Tue Ieans SUp
ana was keeping excellent titne IL was yeIy sInpS
form OF pendulum. and might be made very economl,
pendulum Dr. Mann had used one in Natal, which was
simply rod of vanished wood supporting cyllndrlcal
diverses of heat but IL worked eXcellenty for many
Sham's best steel pcndulums, and though there was
some Improvement IT was much slighter than might
have been expected In short, 1t was ABOUT as soou
pehdulum as could be conceived.
A REMARKABLE WALKIYG-STICK.-A walk
ingsck for tourists and boanists recently patented
in Germany by Herr Herb. OF Pusntz, Is furnished
with the following articles: One side OF the handle is
asgnal pipe and on the other side can be fixed kie
(Which above the ferrule In the middle OF the hande
a compass The handle itself can be screwed or ana
within f. small microscope with six objectGlasses In
the stick the handle is vessel containing ethcr
chloroorm Outside the stick there IS inserted on one
side n thermometer and on the other sand or minute
glass Above the ferrue IL the knife already referred
TO, and to the ferrule can be screwed a b9tans's
metre measure is adapted to the STICK.
SIGNALLING AT SEA.-An apparatus for sig
Mailing at night which has been IN use for short time
on board German ships, is based on the principle
of forcing petroleum vapOr, by means of violent cur
rent OF air. the interior OF sprit-lamp hame pro-
ducing light OF great brlliancy, which can be inter
rupted will. reservoir in which air can he coIn-
pressed to 10 atmospheres by Of pump ls sur
mounted by a reservoir Of petroleum. communicating
with the through tube at the upper part Two
tubes bring the air and petroleum little under the
cylindrical wick OF the spirit lamp, and valve serves
to close both at The passage OF the petroleum
may be graduated that the fame may be pretty
white. II will readily understood that on opening or
closing the valve the flame Of petroleum will appear or
disappear and very rapid signals be had In this
way. In ships OF the Austrian Navy device OF
the following has been adopted for transmitting
orders to the steersman: Two graduated metallic sec
tors each with two indces are placed before the eyes
Of the commander and the steersman respectively
When the ndices OF the IA turned
by the officer index Of the second sector is, By suit
able mechanism turned 10 the same extent The steers
man then turns the wheel OF the helm in the direction
indicated, and this motion ia transmitted by gearing To
the other index OF his sector he stops when tnese Two
ndices coincide, he has fulhed tue order At
the secOnu index OF the first sector has
passed through tie same angle coincidence with the
first index, indicating the officer that his order
has been obeyed. The rapdlty with which the ohcer
moves his index Will guide the steersman whether To
move the wheel slowly rapidly, The advantages OF
the officer beng able 10 control Immediately, and with
precision all the movements Of the he m, obvious.