New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1899-07-04

round hole. and the piston rod is tapered go that
rage the hole is gradually closed the whole being
almost exactly upon the principle Of the hydraulic
Water around the piston when it starts from rest.
to avoid sudden acceerations from the whole mass
Of water in the cylinder
MEASURING RESISTANCE.
The dynamometric apparatus is designed 10 avoid
entirely the use Of multiplying levers or other
devices involving the possibility Of friction and
here again electricity is enlisted. The recording
drum is fitted with apparatus for recording the
measured directly by spring The forward end 81
the spring is attached 70 bracket' when ~
screwed forward or back by an eltclIIc IHytoi aN
a rigid arm runs up from the bracket. with pen
ell recording its position on the STTm brac IKE The
after end Of the spring takes hold Of small cross
a towing rod which takes hold Of the model. This
crOsshead has very slight play between STOPS ~
stop closes an electrical contact, which again
throws electrical clutch. by means OF wmlen 'i,
hack the forward bracket, thus increasing or de-
creasng the tension Of the spring until the CONTACT
There are many rehnements which cannot be
Indicate in this brief description. throw either
clutch at will or them TO work autonatlcaIy'
In practice, when about to make run me opera
Vicinity OF the position which ne knows II WI ~
which ne knows The carrage j. then started; ana
after uniform speed has been oDtaheG, ~ %t ft
speeds up twelve knots Is done WIlhiii ny
he throws in by single motion OF one handle tnS
automatic appliances wficn s,aT In this way
the resistance pen has 70 move put snal az dl-e
10 DoedIatav Incomes steady II will be that
with this device friction is eliminated The accu-
which the automatic stops at the after end OF the
spring be set In practice II IS iouhd ma
an inch. and the springs VIII extend Ten lhcns s9
the results obtained are prGGtcay exact dS "u'-
r. now remains TO describe the method by which
the amount OF this pull can be determined in any
ba sin a kind Of weighing machine. with one Nert!-
cal and one horizontal arm. This is deicatey pal
anced and when the model has been connected up
and is ready for towing. certain sIrlns De lg
in use the vertical arm. or ratfer knIe egg
which bears upon the vertical arm Is connected 20
the model known weight Is t-e. pun mo me rhe
scale pan attached 10 the horizital am. IN -
automatic attachment in connection with the dyna-
momeeT spring Is ToT4 or n9 gear ar backw@rG until
II is In perfect balance and the record pen RECORDING
the position the OF p 5ha s d the spring exactly equal
to the weight in the scale pan. There are number
ing pen and set I'm a definite position TO record
upon the drum one of these pens is set 10 CORE
another weight is put into the scale pan second
pen set 20 record the resistance. and so on II Is
evident then that when the run IL made these hXed
pens mark of upon the paper scale Tor resistance
avoiding all complications OF corrections Ior YEN,
IneasvriDS resistance from one pound up 70 800
pounds and for special work additional special
springs will be obtained.
In connection with the question Of temperature. II
Is Impossible to avoid a certain variation OF the
,en1neraflre Of the water, but ample heating Ia
clItes are provided indicated in the pictures OF
the building where the heater pipes are shown II
is not expected that the variation OF temperature
during the year VIII be suinclent 70 conlpei coIae;
ton In the results OF experiments on this account
The basin Is allied from the water system OF Wash
inRton and will hold million gallons. Two cleo
trical centrfugei pumps are provided, the larger
Of which will empty the tank In about -FOUR hours.
The smaller pump Is 4-nch pump. used for drain
ing the last water from the basin and also FOR
pumping the water from outside the basin, 20
avoid the possibility OF undue pressure II IN case
n IS left empty for some time This If necessary,
since the basin j. only a short distance from the
Potomac River and extends eight or nine feet below
mean tide level gauge indicates the level OF the
outside water which is found be. a rule. abou,
six feet below the water In the basin
The leakage from the basin wnich II slsht, ana
tho eva Doration are made up with Uttered water,
An animai-bone filter being installed with ca
pacity OF from fifty to a hundred gallons minute
deDendine on the turbidty OF the water. In prac-
,Ics a small stream OF fresh filtered water Is kept
running into the basin all the time. and the levsl
Is maintained wherever desired by an adjustable
overflow. - 4,
The building and tank. OF basin proper. were de-
s,gnsd Inv the Bureau OF Construction and Re
nair as well as the machinery for making models
eral Electric Company, many OF the electrical de-
tails OF design being also due 10 them Ihe car
rtage proper was built by the William Sellers Com
many the dynamOmeter apparatus partly by the
Sellers company and partly by SaegmuHer or
Washington who also built the large telegraph;
All Of these are on the designs OF the Bureau OF
CONSTRUCTION and Repair The rnodel-cutung ma
h,nerv was built by DERRICK Harvey. OF Balt-
more 10 the designs OF the Bureau OF CohsTuc-
ton and Repair. J., - -, .,orL y, nv
periments to determine frictionA co-eincieHs Va