The times dispatch. [volume] (Richmond, Va.) 1903-1914, 1904-05-29

! m ton OF the other tho Under block was
the heavier. for the rcasot, that CRAWL
| tntion decreases as objects recede from
thr centre Of tho earth. That process
,nrreserted n delicany In Weighing of
ono pnrt In 1o0,Wo,0oo and In order to
! show The difference represented by NOV
Inc the blocks as Indicated 1t would De
necessary to weigh to about oile-ton-tllou-
sandtl Of n grain. @
ut Is possible to Ineastlre temperature
to n mllionth Of a degree. One OF tho
! recent determinations IN measuring ra
| of heat thrown off by a candle SIX miles
I distant. The instrument Used to record
| those ,adintions is an exceedingly slim
pie affair." consisting usually of n very
| light mica disk deicately suspended ~
n. bulb from which most of the mir has
been exhausted. When the rndiutions
from the candle fall on this DISK they
hea IL sufficiently to force 1t back.
GAS a rule light lends itself very nicely
to extremely fine measurements IT is
no trick to calculate accurately to Il
thousanlth part Of the width Of a rnlntte
substance that Is almost Invisible to tho
naked eye, this being possible through
the interference OF waves OF light. II
we have two systems Of waves which
come together so that tho crests Of ono
system coincide with the crests Of the
other, the two systems arc then In step,
as we say. and help each other. On the
other hand, II for any reason one of them
is trlfle behind, they come In out Of
step and neutralize each other. If the
movement Of watch were to expand
twenty-five thousandths Of an inch In
temperature of 10 degrees above the
normal, the expansion would be equiva-
lent to about two OF these waves OF light.
Suppose you are buying or are manu-
Featuring for sale some dncnndescent
lamps which should be, for example, 10
candle power on 11O-volt circuit. You
can send one Of these lamps to the bureau
and receive in return an official certifi-
cate stating whether 1t is or Is not up
to the standard The laws define the
unit of+electrical strength and resistance
and also the resistance Of given column
of mercury. The strength OF oil electrl-
cal current is determined by ascertalning
the amount OF silver which q specific
current will deposit in a given length Of
time, as in silver plating. All we have to
do Is to weigh the silver deposited. and
NO have the standard OF current imme-
diately.
From time to time ] have asked the
bureau to test for this laboratory DIFF
ferent pieces of electrical appara tus, such
as cells dynamos, ratio coils, resistance
boxes and transformers Other labora-
tories, as we'll as manufacturers, have
gas engines microscopes, telescopes, pho-
tograph lenses, etc. The weights used re-
Gently by the assay commission were all
standardized by tho bureau Of standards.
If you are about to purchase some cop
per for electrical purposes. and have
shown to you q quantity of that metal
and are told that it is Of a certain con-
ductlvity, all you need to do Is to send
it to Washington and find out II 1t mas
hoen corrective represented. The same
thing Is true as to tho purity Of gold and
silver and all other metals In course Of
time the bureau doubtless will be able
to test radium, thorium actinium. polo
mum and other radlo-a ctive substances
with tho same degree Of skill that has
characterized It's other experiments In
fact In this field alone, the bureau prom
ises to be Of immense value to our citi-
zens. since 1t Is commonly bei,eVea tiat
radi,,m and like properties will soon be
found In abundance in the United states
New York Times.