The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1897-04-23
MEASURING RAIN.
The New Device in Use at the Weather
Bureau Office.

1t Automatically Measures Each Hun
ed in the Office Down Stairs-How 1t
Is Done.
Do you know how the rain fall Ia
measured? Up on the roof of the First
National Bank building thers is a ma
chine for the purpo Sc which is wonder
full piece Of mechanics seen from the
outside it is not an imp osing object in
appearance but 1t contains delicately
adjusted apparatus which not on1y meas
ures each hundredth of an iuoh of precip.
itation but records it in the office in the
building below. Mr.. u. z. Jones, the
observer of the weather bureau here, fur
nishes thie description of the new gauge !:
L he improved tipping bucket rain
gauge is the result of large number of
careful experiments and tests. The COL
| Iector and inclosing case consists of tire e
sections to facilitate convenience IL
| getting to ali parts. The top section,
called the receiver or collector il made
| of seamless brass tubing turned to a
sharp edge accurately IL inches in diam
| eter, inside, and provided with funnel
| shaped bottom md a small tube orifloe
| at the apex. so that all the water received
therein is carried to point directly over
the center of the tipping bucket bearings.
The middle section is made Of galvanized
iron with hinged door, and the lower
section. or reservoir, is Of galvanized iron
and provided with brass stop cock ut
the bottom, for emptying the gauge OF
water. These parts or sections ct togesh-
er by overlapping seams and the whole
| jE mOuDtRd n 6Qfpah hal hive frq1 a
extending centrally across the top of the
reservoir section. The brass bucket is
divided by central partition into two
equal compartments. This bucket Is
mounted ON suitable bearings placed be-
low the center OF gravity. Two stop
pins are provided, which limit the move
nent of the bucket ON it's axis and per-
NIT it to rest in one of two positions, in
which either one or the other oompart
msnts OF the bucket is presented in such
manner that it will receive and retain
the water delivered through funnel of
the collector. The weight and position
ufsthe cente! of gravity of the bucket has
tesn SO adjusted in relation to its sup
ports that when one of the compartments
mas been charged with the quantity of
water representing one one-hundredth of
an inch OF rain in the l2-ireh gauge, the
| bucket tips over upon lis bearings,
| empty1nR the water from one compart-
ment, and at the same moment res eut-
ing the other compartment to receive the
incoEaing WAFER. The water thus deliv-
cred rom the buckets is retained in the
reservoir section for subsequent measure
ment in bulk. The automatic reqistra-
ton of each bundredth of an inch Of rain
fall, that is. each tip of the nucket is
effected by aid Of the electrical current
closer. A short sector is attached to the
tipping bucket. When the bucket is at
rest In either Of its limiting positions the
| sector stands near TO, hut not in con-
tact with. pin on an insulated contact
spring. In the act of tipping, however.
after the BUCKET has been moved little
| the sector makes contact with the pin
and rubs over 1t the grenter part of the
subsequent motion. This effectually
closes the electric circuit Which is formed
between the whole metallic framework,
| including the bucket and the insulated
spring. Turing the last portion of the
| tip CT the bucket the sector slips off and
| moves q small distance away from the
pin. thus opening the electric circuit,
and also leaving the bucket perfectly free
to begin any subsequent tipping move
| ment.
While the oontact'of the sector with the
pin will, i'll general, suffice to effectually
close the electric circuit. yet in ord or to