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at whidi the gas is supposed to stand as
if retained collected in a gas-holder, say
60** Fahr. But while the gas is flowing,
its temperature will almost always be
much lower, on account of the expansion
which accompanies the flow. For in-
stance, in the shunt verifying experiment
of the air issuing from the receiver at
initial 17 lbs. apparent pressure, the
density of the stream of air just outside
the plane of the orifice was 0.0937, in-
stead of 0.0749 of the surrounding air
into which the receiver was discharged,
and the volume av calculated by using
the velocity t;=1083 would require to be
increased about 25 per cent, to obtain
the volume of the discharged air on the

supposition of being collected and re-
tained in a gas-holder at atmospheric
pressure, and temperature of 60' Fahr.

The temperature of the air in the same
zero Fahr., which low temperature is to
account for the high density in the jet

Taking V for the volume discharged
pet second, then]

where A^area of the stream of gas be-
ing measured, as for instance, that at the
gas well mouth, or of the well mouth
itself, r, the absolute temperature of the
gas when stored, and r ^at of the gas
in the stream. But

r 273+« ^273+<

=1 + -^— Fahr." (15)
^461 +< ^ -*

Henee

=Av + Av-^^^FBhx.' (16)

The volume discharged per day of 24
hours for dimensions in feet will be

Vol. per day=86400 V. (17)

THS ENCASED THEBMOMSTEB ; OB TEIIPEIU.-
TUBE OF STREAM.

In the impact of the gas against the
open end of a tube, it is just as true,
from theoretical grounds, at least, that
the temperature will be restored as well
as the pressure. That is referring to
the case of the air issuing from the re-
ceiver through the orifice, the pressure in
the Pitot's tube by impact has been
shown to be up just to that in the re-
ceiver. Consequently, the air was com-
pressed back to its original conditions as
to temperature and volume very nearly,
since the time for acquiring heat by a
particle in the act of passing out against
the tube mouth could not much exceed
the 50 thousandth part of a second. The
same is true of the density.

to test tiie question as to restoration of
temperature in the cup mouth by means
of an encased thermometer arrangement
shown in Fig. 6. A glass tube, BC,

Digitized by

100

VAK N08TBAND'8 ENGINEERING MAGAZINE.

about f inch diameter was drawn down
at A to about ^ inch diameter, for the
mouth to present to the J orifice, O, in
the Westinghouse apparatus. Inside of
AC is shown the encased thermometer
supported in the center of the tube, and
with its bulb, B, as near as practicable to
A. In the plug at C is a small hole to
allow a current to flow past the ther-
mometer, so that the air in AC will not
have time to be modified in temperature
after being compressed at A, before it
surrounds the thermometer bulb at B for
determination of temperature.

There was no thermometer in the re-
ceiver to show its temperature. In ex-
perimenting, the pressure would fall, in
each experiment, from between 30 and
40 lbs. per square inch to about 8 or 10,
owing to which, the temperature would,
of course, fall in the receiver. But at
the same time, air was being pumped in

p
I

pact of air upon the thermometer bulb,
and friction of the flowing aii" passing it,
would give such a tendency to elevation
of temperature as to utterly defeat the
effort to determine definite knowledge as
to the actual temperature of the jet by
means of a naked thermometer.

But in presenting the mouth of the
encased thermometer to the jet, the mer-
cury would stand very nearly steady at
about 16^ to 22^ C, sometimes not falling
a single degree. As this temperature
was not far from that within the receiver,
together with the fact that the naked
thermometer would fall frpm 20^ to 25°
lower and yet not reach the limit, it ap-
pears that the encased thermometer is to
be relied upon for indicating the tem-

Hence, from all the facts of experi-
ment, and considerations above noted,
we are prepared to state the following

^ -.iniiiii444-miiiiiiiiiiiiiia

ing.

as fast as the pump would work. Under
these conditions, it is difficult to tell
what the temperature in the receiver at
any time was, but as the room was at
about 26° C, it is probable that the inte-
rior of the receiver ranged from 16° to
20° C.

Exposing the naked thermometer btdb
to the jet, while pressure fell from 36 to
10 lbs., the mercury fell to from 3 to 6
degrees below zero C. ; but the real tem-
perature of the jet must have been very
much lower, from the fact that ice would
form on the bulb and not melt nor even
become moist for several minutes after
removal of thermometer from jet and ex-
posure to the air of the room, thus prov-
ing a great fall of temperature in the act
of expansion at the orifice O. The actual
temperature of jet could not be expected
to be indicated by a naked thermometer
in this way, for the reason that the im-

more general principle ; for nonviscous,
elastic or nonelastic fluids, viz. :

Whsn any fluid flows jfrom a higher
to lower pressure through a frictiordess
passage^ the portion caught direct in a
cup mouth toiU be restored to its original
conditions as to pressure^ temperature and
density.

By using a tube of some nonconduct-
ing material, like pasteboard, or papier
mach&, for the casing Fig. 6, extending
from A to some distance past the ther-
mometer bulb, and then glass, better re-
sults would doubtless be obtained than
for all glass, though glass wotdd be much
better than metal.

The temperature of the encased ther-
mometer, as well as the pressure by the
Pitot tube, for any stream of gas ob-
served, should be regarded as that of the
from which the same gas would flow to

Digitized by

MEASUREMENT OF GA8 WELLS AND STREAMS.

101

produce the same jet as that obserred
for which the temperature and pressure
would be that of the encased thermome-
ter and Pitot tube.

This fact is to be taken advantage of
for securing the temperature of the flow-
ing jet by calculation from the tempera-
ture as observed from a thermometer
placed in the non-conductor tube.

Then the temperature of the stream of
gas can be calculated from the well-

y-i

t^-t

Cent.''

whence

^= 1 .^« Cent^= ' , Fahr.*^

where t^ is the temperature observed
from the encased thermometer, m the
value found from the table given above,
and t the temperature of the stream.
When the result for t comes out negative,
it is to be read " below zero."

This value of ^ is to be used in (6), (7)
or (10).

DENSITY, OB SPEOIFIO OBAVITY.

As the formulas for calculating the ve-
locity of flow contain the specific gravity
of the gas, some convenient way of find-
ing it is desirable. Where the analysis
of the gas in question is not known. Bun-
sen's Effusion Principle, as already stated,
may be applied. A simple way of doing
this is to draw a f -inch glass tube down
blunt to a fine orifice, put this into a
cork, orifice up, and the cork into a bot-
tle with the bottom knocked out. Then
fill the bottle with water set it into a
common plate filled with water. Now,
let the water flow out over the edge of
the plate and draw air in through the
effusion orifice at the top of the tube in
the cork and note the time. Then fill
the bottle again, and similarly allow the
gas in question to flow through the effu-
sion orifice and empty the bottle, noting
the time of flow. Then Bunsen's princi-
ple makes the densities proportional to
the squares of the times, and the specific
gravity equal to the ratio of the squares
of the times.

A mark may be placed on the neck and
near the bottom of the bottle to start and
stop at ; and a piece of rubber hose may
be stuck upon the effusion tube and grip-
ped to prevent flow till ready.

The gas may be caught from the gas
well by a shunt in a Hght bag for the
effusion tube to draw from in observing
for time of effusion of gas, care being
taken to get all air from uie connections.

APPLICATIONS.

Primarily in this investigation, the ob-
ject was to measure gas wells, but the
appliances are applicable to other streams
or currents of gas, even where the fluid
is of indefinite extent, as in high winds.
Several instances are known of failures
of wind anemometers at the critical time
of a most valuable record, because of
delicacy, compleidty, etc., of instrument.
In the Pitot tube, we find an instrument
of the greatest possible simplicity and
stability, one not having a single moving
part exposed to the wind.

Thus, to find a reliably wind velocity
or pressure of the tornado, put up on
strong iron frame-work, several Pitot
tube points radiating in different direc-
tions, including up and down, each with
double mouth, one direct and one lateral,
connected properly with a gauge as above
explained, with a maximum indicator.
This contrivance could be left to stand
by itself year after year, observed or
not. Finally, the maximum wind pressure
with direction could be read off. These
could be located at various points about
the country, any one of which struck by
^ cyclone, could make known the various
interesting facts so much desired, as to
pressure, velocity, variety of direction,
lifting power, etc.

A double mouth tube placed inside a
conducting pipe would show by gauge'
located at any convenient situation, the
velocity in the pipe.

OAS WELLS.

The following results of application to
gas wells can be given :

Karg Well, Findlay, Ohio.

At well mouth, Pitot tube pressure,
15 lbs. per square inch.

p^ 14.6
m= 0.4876
v=1513 ft. per sec.
A =.0873 square ft.
Cubic ft. per day =12, 080,000

Digitized by

102

VAN N08TRAND'8 ENGINEERING MAGAZINE.

Cory Well, Findlay, Ohio.
End of 2" pipe, 21 ft from well mouth.
Pilot tube pressure, 9.25 lbs.

Pt 1^-6

m=0.3797
v=1178 ft. per sec.
A=.0308 square ft.
Cubic ft. per day =3,318,000.

By shunt at this well, the velocity was
1111. feet per second, by three observa-
tions giving 48.3, 45.2 and 44.6 cubic
inches per second, respectively.

Briggi Welly Findlay, Ohio.

Apiil 17th, 1886.
End of 2" pipe, 91 ft. from well mouth.
Pitot tube pressure=6.6 lbs.

e^=^J=1.445

tw=.3274

t;=1016 feet per second.
A =.0276 square feet
Cubic ft per day=2,565,000

From a second stratum above the firsts
water gauge.

h.
Inches.

0.48

0.5625
29.0

Diameter.

Inches.

2}

Cubic feet

per day.

206,100

184,400

186,200

Velocity.

Feet.

67.7

62.61

449.5

By Anemometer 186,400

These four measurements are for the
same stream of gas.

Jones Welly Findlay, Ohio.
April 17th, 1886.
Pressure by water gauge,

Diameter. Velocity. Cubic feet

Inches. Feet. per day.

7H 46.45 1.444.000

8f 161.7 918.600

Inches.
0.8125
8.79

Mean 1.181.800

By Anemometer 1,159,200

The jet was here yery irregular, the
gas being forced out at right angles
through a valve, from the main well tub-
ing ; the first result being got from the
end of a flaring funnel, and the second,
from the valve mouth direct The sev-
eral anemometer results also differed
greatly among themselves.

STEEL SLEEPEES FOE PEBMANENT WAY.

Bt J. W. POST.
Translated from Sohwelzerisoher Bauzeltimg, for Abstracts of the Institution of Ciyll Bnffineers.

Fbom a railway point of view the intro-
duction of steel sleepers is good, because
the average life of a sleeper is increased,
the price of wood sleepers is lowered by
the competition, and in industrial coun-
tries the making of a ton of steel sleepers
brings over the railways a traffic of about
ten tons of raw material.

The first trials of hard steel-sleepers
were not encouraging, and some railway
companies gave them up at once. Other
companies laid test lengths on different
systems, inspected them carefully and
kept statistics of the cost of maintenance.
and German railways, and with some
success, and to these trials are due the
results and experience now available.

Since the Bessemer, Thomas and Sie-
mens processes have rivaled each other in
producing mild steel, steel sleepers have
come much more into competition.

It is generally agreed that :

1. The average life of good steel sleep-
ers is considerably longer than that of
the best wooden ones.

2. The width of gauge is better main-
tained with steel sleepers.

3. The cost of maintenance of perma-
nent way on steel sleepers remains almost
constant after the second year, but on
wood sleepers increases constantly with
age, so that the average cost of the latter
is greater.

4. There are systems of fastenings on
steel sleepers wluch are at once safer and

Digitized by

STEEL SLEEPEBS FOB PERMANENT WAT.

103

more easily maintained than those for
wood sleepers.

5. A good steel sleeper should not
cost more than from 125 to 160 per ceni
of the cost of a wood sleeper.

6. The "old material " value of a steel
sleeper is greater ihsu that of a wood
sleeper.

If, for comparison of the relative cost
per mile of steel and wood, account is
taken of the manufacture, transport, lay-
ing, maintenance, interest (lately the low
rate of interest has told in favor of the
lasting material), and value as scrap, it is
seen that there are few countries in the
world where the exclusive use of wood
sleepers is really economical. For coun-
tries where climate and insects destrov
wood sleepers in a few years, this is evi-
dent; but it speaks better for steel
sleepers that in Holland, which produces
no steel and gets wood sleepers very
cheaply by sea, all the railway companies
have introduced metal sleepers without
any pressure from the Government.

The first metal sleepers were too weak ;
owing to a mistaken idea that they must
be as cheap as those of wood, they were
made only from 56 to 66 lbs. weight, and
it was not clearly seen that they were
weakest where the rails rested on them,
because (1) the holes of the fastenins^ re-
duce the cross section ; (2) the punching
of the holes makes the metal round them
more or less brittle ; (3) the foot of the
rail and the fastenings eat in time into
the top of the sleeper ; (4) with rational
beating up of the ballast the moment of
reaction of the ballast is a maximum at
the cross-section where the wheel load is
applied; (5) the impulse of the moving
is transferred directly to the sleepers at
these places ; and (6) in the various sys-
tems the material suffers most at these
places during the forming of the 1 in 20
slope, to give the cant to the rail, whether
that is done in the hot or cold.

The disadvantages of the sleepers be-
ing too weak soon showed, in the bead-
ing and shaking, the escape of the ballast
and consequent expensive maintenance;
also in the cracking of the sleepers
lengthwise and crosswise where the rails
rest. Some railways then introduced
heavier sleepers (up to 165 lbs. weight),
which lasted well, but were expensive.
Yarious attempts to strengthen the
deeper by riveting or bolting to it plates

for the rail to rest on, with or without
the 1 in 20 slope, were unsuccessful be-
cause of the increased cost, or because
the connection between rail and sleeper
was less secure.

Latterly improvements in roUing ma-
chinery have rendered it possible to make
sleepers of varying thickness, and having
the 1 in 20 slope for the rail, the whole
being done in the process of rolling.
This improvement enables the metal to
be disposed where most required, and ef-
fects a saving in weight of from 12 to 21
per cent, in the sleeper. The minimum
cross-section of the sleeper is kept for
about two-thirds of the length, while it
is thickened under the rail and for a short
distance on each side of it.

After the Netherlands State Eailway
Company had for some years laid test
lengths of their main line on sharp curves
and heavy gradients, with iron and steel
sleepers of various designs, and carefully
compared the cost of maintenance with
that of similar lengths of line laid on
new oak sleepers, they decided in favor
of the mild steel sleepers, 8 feet 6 inches
long, 9.25 inches wide over the extreme
edges at the bottom, 2.52 inches deep for
the greater part of its length but in-
creased to 2.92 inches under the rail, and
3.23 inches at about 4 inches outside the
rail, so as to give the inclination of 1 in
20 for the cant of the fiat-bottomed rail
which rests directly on the sleeper. Ad-
vantage was taken of the low prices of
steel during the past two years to lay
down large quantities of these sleepers
on the Dutch, Belgian and German lines
of the company. One of the district en-
gineers in his annual report for 1884,
states that on a test piece of line 1,144
yards long, on a curve of 820 yards ra-
dius and a gradient of 1 in 83, no beating
up of the sleepers was required for
twenty-two months ending December 31,
1884, and that the only maintenance re-
quired was one man for thirty-four days
inspecting and tightening up the bolts.
He states that the cost of maintenance
of a steel sleeper road, three and a-half
years old, is the same as that of the same
age laid on wooden sleepers, but that
from this point the cost of the latter in-
creases, while the cost of the former
tends to diminish, owing to the consoli-
dation of the bed. The following ad-
vantages are claimed for the sleeper

Digitized by

104

VAN NOSTRAND'S engineering MAGAZINE.

(adopted from the St. Qothafd Bailwaj)
by the Netherlands State Railway Com-
pany:

1. It is easily packed with any kind of
ballast, sand, gravel, ashes or slag.

2. The triangular toe which forms the
bottom edge of the sloping sides of the
sleeper prevents damage to the edge dur-
ing beating up, and by lowering t le
neutral axis of the section gives additional
stiffness. It also makes the section
easier to roll.

3. It gives a broad surface to the foot
of the rail to rest upon.

The weight of this sleeper is 104.7 lbs.,
whereas a sleeper of the same strength,
with a uniform instead of a varying
cross-section, would weigh 16 per cent,
more. The last steel sleepers ordered
(July, 1885) cost at the works, including
a two years' guarantee, not quite 6
francs each, or almost the same as an oak
sleeper.

The author proceeds to show by draw-
ings how by giving them a varying cross-
section the various forms of steel sleepers
now in use may be improved, including
the Yautherin, Elberfeld, Prussian State
Railways, Bhenish Railway and Austrian
Railway patterns. The principle is ap-
plicable not only to sleepers for Vignoles
rails, but the advantage of the local
strengthening is even more apparent
when, as in the case of Webb's sleepers
as used on the London and North- West-
em Railway, a number of holes have to
be made in the sleeper for the attachment
of a chair to carry a bull-head rail ; for
in order that the rivets may hold for a
length of time it is necf^ssary that the
plates should have a certain thickness.

There has been much discussion as to
the relative merits of the Vignoles and
who have been sent to England to report
upon English permanent way, and its
small cost of maintenance, have some-
times overlooked the fact that it weighs
from 400 to 550 lbs. per yard as against
240 to 320 lbs. per yard, the weight of
the German line. For the same price as
is paid for the English permanent way a
line on the German system could be made
just as solid and capable of resistance.

It has been objected that metal sleep-
ers are not heavy enough to make a good
permanent way. The secret of a good

sleeper is, however, not weight alone, but
depends also on —

(1) Appropriate form.

(2) A section with sufficient moment of
resistance.

(3) A material not easily fractured.

(4) Safficient bearing area and length.
As to form, the closing of the end of

the sleeper deserves special attention.
In the early open-ended sleepers the 1 in
20 slope for the bed of the rail tended
to drive the ballast out from underneath,
while a sloping closed end, as now used
by the Netherlands Railway Company,
tends to drive the ballast in under the
rail.

In order that the punching of the holes
for fastenings may not have an injurious
effect hard steel is now avoided, and the
sleepers are made of mild steel (Bessemer,
Thomas or Siemens) capable of resisting
a tensile strain of 26.4 to 28.6 tons per
square inch, with a minimum contraction
of 30 to 40 per cent

In case of anything leaving the line,
also, mild steel is much to be preferred
to hard steel for sleepers, as it is less li-
able to be broken.

Formerly there was anxiety as to the
rusting of iron sleepers, but it is now
known that this is trifling in the case of
sleepers in use, so few railway companies
use preventives such as galvanizing,
steam oxidation, oxide of lead or tar.
Only for the sleepers kept in reserve by
the side of the line or for parts of the
line where the atmospheric iimuences are
bad (damp tunnels), or for sleepers for
transport by sea is it needful to use tar
or paint.

After many years of trial the Nether-
lands State Riulway has decided to keep
to screw bolts as the means of attach-
ment between the rail and sleeper. In
1865 they had lain ten thousand iron
sleepers of a now antiquated design on
their main line near Deventer. The rails
were fastened by four bolts, 0.42 inch
diameter, to each sleeper. For the iirst
time, in 1883, it was necessary to renew
two thousand of these forty thousand
bolts, and the remaining thirty-eight
thousand are still (August, 1885) in use.
This shows the bolts 0.86 inch in diame-
ter now used will be satisfactory. The
bolt-holes in the sleepers are square
except that the comers are slightly
rounded.

Digitized by

FLOODING THE SAHAEA.

106

The beatiog up of the ballast under It is also very important that during the
steel sleepers must be so done that the i first few months after the sleepers are
middle of the sleeper is filled but not | laid, the road should have great and con-
with compact ballast, while for a distance stant attention until the beds become
of 12 to 15 inches on each side of the consolidated. The cost of this ought to
rail the ballast must be well beaten be considered as part of the cost of lay-

FLOODING THE SAHAEA.

Br GEO. W. PLYMPTON.
• From "Science."

MnoH misinformation has of late been
interior sea of Africa,^ and the public has
been misled by inaccurate statements in
regard to the magnitude of the enter-
prise, which, it is assumed, the French
people are about to undertake. For
these current erroneous impressions the
English and American scientific journals
are largely to blame. An old theory re
garding the Sahara — that it was for the
most part below the level of the ocean —
has been adopted as though modem sur-
veys had not refuted it ; and so the con-
version of a material portion of the Afri-
can continent into a navigable sea is
being popularly considered as not only
possible, but altogether likely to be ac-
complished.

A brief consideration of the published
results of the recent surveys will be suf-
ficient to convince the r^er that the
popular estimate of the magnitude of
this enterprise is absurdly out of propor-
tion to the greatest possible accomplish-
ment.

This overestimate is not surprising
when we consider the character of the
references to the scheme which have been
made by journals of the best standing.
The following paragraph from the fore-
most among engineering journals may be
taken as a sample :

'* With reference to the daring French
project for flooding the desert of Sahara
with what would be virtually a new sea,
it may be well to recall the opinion ex-
pressed by M. Elis6e Eeclus, that at one
period in the world^s history the desert
was covered by a sea very similar to the
Mediterranean, and that this sea exer-
Vol. XXXV.— No. 2—8

cised a very great influence upon the
temperature of France, as comparatively
cold^-or, at any rate, cool — winds blew
over it, while now the winds whidi pre-
vail in the great expanse are of a much
higher temperature, and are, in fact,
sometimes suffocatingly hot. The ap-
pearance of the desert seems to support
the theory of M. Elisee Beclus, that it

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