Evening star. [volume] (Washington, D.C.) 1854-1972, 1916-11-19


and instruments employed in the meas
| urement of record flights
Airn1ane of aeroplanes and bal
| looms. 1t is somewhat anus
| 0ecoAoS ing to read that one avi-
ator has just broken the record of
1880 feet by fifty feet. for the reason
that 1t is an impossibility. SO say ex
| perts of the bureau of standards. to
measure such heights with the means
| at the disposal of the aviator to any
thing like fifty feet for such eleva-
ton with any degree of certainty. Of
\ ficials of the bureau have recently car
ried on a large number of tests with
the measuring instruments, and it is
as result of these tests that they
say the instruments cannot be abso
| lutely relied upon for accurate read
| ings
| The means by which the height of
moving objects can be measured, it is
said, are. first. the method of triangu-
lation, which is only possible when a
| measured base and the necessary sur
| the aviator attains his highest altitude
| near the selected base. The restric-
| tons and expense attendant upon this
| method render its use impracticable
|
| monty used on account of its great
| convenience. depends upon the use of
| the barometer, which really measures
| the decrease in pressure or height, but
are subject to numerous and large err
| rors, experts of the bureau say. due
| to temperature effects, the imperfect
| elasticity of the spring which measures
the pressure and the mechanism which
| records it, etc, depending upon the
! type of barometer.
1t is said that very good results may
| he obtained for measuring the nelshts
! of mountains with the mercury barom-
! eter by taking certain preca utions, but
| such instruments are not suitable for
| the aviator account of their frag1l-
ity. the pumping effect OF the mercury
| In the tube. the necessity of constantly
adjusting the zero of the instrument
the impossibility of securing con-
| tinuous record of the readings. etc.
! The aviator is compelled to use an
| instrument that is light durable. tree
| from the need of adjustment after he
| has started his flight. and which can
be read at glance. 1t is said that the
anerofd barometer satisfies his REQUIRE
ments in all the respects enumerated,
but its readings are subject to numer-
| Gus errors it has been found by the
| bureaus EXPERTS. and they cannot ordl-
| narily be depended upon to a degree
| of accuracy that would warrant the
conclusion that one aviator had flown
| higher than another because his baroh-
eter showed great height.
| Investigations of aneroid harometers
| and Paragraphs conducted at the bu-
| reau of standards show that the read
| ings of such instruments purchased in
| the open market may differ by 10 per
! cent or more. y group of eight baro-
| graphs taken up simultaneously. on
| the occasion of the acceptance test OF
| an aeroplane for the government, reg
| istered maximum figures varying all
| the way from 1890 to 1850 feet. The
average came below the required fight
| of 1000 feet in ten minutes. and the
| aeroplane was not accepted. 1t is
| highly proba BILE. however, the officials
| say, that suitable laboratory test
| would have proved the Paragraph which
| indicated 1850 feet to be the most ac-
. curate of the group. since it was one
| of a type which has usually been found
to be more accurate than the other
| seven in that group.
r
| Thorough tests of devices to prevent
| fish from entering irrigation bitches
| are to be made by forest
Irrigation service officers who say
| that thousands Of the
OltcAeS. trout placed in western
| streams by the government are killed
through being carried into the bitches
| and washed out on the fields. There
!
| projects on or near the national for
ests. and in many places the loss OF
| trout is very heavy. The amount Of
! water used in irrigation, it is SAID,
often determines the advisability OF
{ artiflcially stocking the streams
| The government annually plants large
| quantities of fish fry in the streams
| Of the national forests. Last year
more than 100000 were planted in
| Y aiy,o al
| was done to render the forests more
attractive to the public by affording
good fishing.
| Most of the states of the west have
! laws requiring that the d1tches be
| screened, but these laws are seldom
enforced The farmers are said 10 dls-
, like the screens, because they coliect
| driftwood and trash, which prevents
| the free flow of water Very often.
| too IL is stated, the farmers can sup
ply their families with a mess OF hsh
! by collecting the trout which are round
/ in the fields.
t the bitches are in use. and, while two
| or three have been found to be larry
effective, most of them are said TO be
unsa tisfactory 1t Is asserted that thls
tunity for inventors, since success
| full screen will be sure to be widely
used. Under present conditions o.
| fcials are slow to recommend that the
|
are apt to be led off into the irrigation
bitches.
| This is the time Of the year, accord
! ing to plant specialists of the Depart
| ment of Agriculture, when
Diseases rose gardeners s"on'u
free their plants. as far
| OF Roses. as possible, from dis
/ eases by methods that cannot be
| followed during the growing season.
This is also the time. they say, when
| roses can best be cut and propagated.
| At this season of the year diseased
narts of the rose bushes should be cut
away and the plant sprayed. according
/ to the experts making a special STUDY
| of plant diseases.
| one of the common and very in1uri-
| ous rose diseases to which department
| officiais have called attention is the
| leaf blotch also known as black spot
| The first symptoms are the appearance
I of irregular bIa ckish spots on the upper
surface of nearly full-grown leaves: In
| this stage the trouble may be controlled
! Lv several sprayings with ammoniacal
| conner carbonate or Bordeaux mixture,
| hui il these precautions are not