The Sun.
London, England, 1845-06-24 00:00:00

GROUP L.

PORTSMOUTH ATMOSPHERIC LINE.

The Committee resumed their inquiry on this line this morning,
Mr. E. B. Denison in the chair, with Lord Clive, Mr. Oswald, Mr.
Vy•ian, and Mr. Monckton Milnes present.
In the course of his examination by Mr. GL;IINEY, Q.C., Mr.
Bidder, surveyor, stated that he objected to the means for pro-
viding for the crossings at the level, inasmuch as they were to be
effected by a mechanical contrivance which everybody knew was
likely to get out of order, instead of by the agency of persons living
' on the spot. The difficulty would, of course, he increased by the
great traffic to Epsom on particular occasions. The ruling gradient
was that at New-cross, which was 1 in 100, where about 600
people an hour were all that could be carried, unless they doubled
the line. At the present, they could only take about 410 per
train, with three trains per hour—that was, 1,200 an hour, when
they ought to run trains at least every ten minutes, each carrying
1,000 passengers. He was decidedly of opinion that the Directors
would have to double their line between London and Epsom.
With regard to the expenses, he calculated the permanent way at
4,8401. per mile ; engines, 2,330/. ; tanks, 2001. ; patent right,
5001. ; points, crossings, and valves, 3501.; wells, 500 ; contingent
expenses, 600/., making a total for the permanent way of 9,3201.
The working expenses would be 6001., exclusive of interest, while
on the locomotive line the cost would be no more than 547/., inclu-
sive of interest.
To Mr. RAWLINSON Mr. Bidder replied that he had arrived at
his conclusions respecting the 600/. a year from the Blackwell
Railway, while Mr. Stephenson got to his conclusions by the work-
ing of the Camden Town engine. The Blackwell Railway Com-
pany paid 3001. a year for water, and had been at an expense of
6,0001. or 7,0001. for forming tanks. No one could fail being
gratified with the first sight of the atmospheric principle, but it was
exceedingly ad captondum, and for a long line he thought it was
unsuited. He had indeed been anxious to apply Mr. Samuda's
principle to a line of his of 21 miles in length, leading to the
Thames, but Mr. Samuda had not acceded to his proposition, al-
though the Blackwell engines might hare been used in the project.
The largest engines could carry on a locomotive line about 600 or
700 people by one train, and he thought that the trains might
be started as fast as they could be filled. On the Greenwich line
they had carried more than 39,000 persons in one day. But he
did not believe that the atmospheric line could start a train every
ten minutes, so that the accommodation could not be yielded by it
which the publie required.
To the re-examination of Mr. Guaisev, Mr. Bidder stated that
he had started without any prejudice against the atmospheric prin-
ciple—o❑ the contrary he greatly admired it; but he feared that
its application could not be so general as he desired.
Mr. Hawkesley, engineer to the Nottingham gas and water_
works, stated that he had been under the necessity of paying great
artention to the passage of fluids through tubes. His experiments
had been applied to gas, water, and air, and they had been ap-
plied particularly at Birmingham. His formula had been applied
by Mr. Low, who bad written to him to ask what quantity
would be delivered from Peter-street at Charing-cross,
through a tube of 18 inches in diameter, and he had stated that the
quantity would be 60,000 feet in an hour. The result perfectly
coincided with the supposition. He had tried the same principle
a tVersailles, and several places in England, among others at Not-
tingham, through a tube two miles in length, fifteen inches in dia-
meter ; and at Edinburgh, through a tube of one mile in length,
fifteen inches in diameter. There was, in fact, no such thing as
suction. That had been known ever since the Tollichlian expe-
riment, which took place 200 years ago. In fact, what was called
suction was neither more nor less than the impulse put upon an
intermediate body, having a proportionably ratified atmosphere
before it, from the impulse put upon it by the denser substance
behind. There was certainly friction in the passing of air through
a tube, partly arising from impact, which was as the square of the
velocity, and partly from the rumbling of the particles among them-
selves, which was simple. Thus, supposing the pressure to be in-
creased tenfold, the friction woull be increased one hundred-fold,
and the rumbling tenfold. The train could consequently move no
faster than the air, and the greatest weight proposed by the pro_
moters could not be carried up a plane of 1 in 100 faster than
thirty miles an hour ; or up a plane of 1 in 80 faster than twenty_
three miles an hour. His formula had been put in by Mr. "Udder.
In the cross-examination cf Mr. AUSTIN, Mr. Hawkesley re-
plied that his formulas were almost absolutely correct with respect
to large tubes, although he had omitted the rolling friction, be_
cause as effects were so minute that it hat no presentable effect on
the result. He had made more than two hundred experiments
through tubes 4of an inch, it of an inch, and of an inch. There
was no difference detween blowing air through a tube and drawing
it away by an air-pump. The rates which he had drawn
the gases through were immaterial, and he thought the instance
he had given in the case of the pipe of eighteen inches sufficient for
a rule for all the cases which could be supposed. He had tried

the experiments from the very slowest to the very quickest velo-
cities, and through tubes of from one inch long to 160,000 inches.
He had tried it with a pressure of 41 inches of water, which was
equal to one inch of mercury. The speed of fifteen tidies an hour
would be equal to five inches from the barometer through a three-
mile tube, and everything remains the same through a tube half
the length ; the pressure remaining the same the speed would be
44 miles an hour. The leakage would account for the diffe•
rence, and the train would stop at the point where the
leakage would balance the pressure of the atmosphere, but
at that distance he could not exactly say, but could calculate if the
plane, tube, and pressure were given to him. His results had been
formed by equation, and were confirmed by ascertaining that the
constants given by theory had been confirmed by more than a
thousand experiments, and among others, upon many of Yr.
Samuda's own premises. He had no doubt whatever that increasing
the tube from one and a half mile to three miles in length would
greatly reduce the mean velocity. In fact, the friction would be
increased, and that which was called suction was neither more nor
less than the ab.traction of a quantity of air near the engine, the
space being occupied by a more rarified atmosphere, that which
was nearest the engine being driven forward by the denser medium
behind. In fact, it was nothing more than blowing.
To Mr. OSWALD—The witness replied that, in the event of the
disabling of one pair of engines, those at six miles' distance, the
next engines, would be useless, for he found by experiment that at
the end of seven miles the initial force would be only two and a
half miles, so that at a little further distance, the engines would
only be able to pump out the leakage, and they might go on for
everlasting, just neutralising the rorce of the air one way or the
other, without moving the train a single inch.
Mr. Harrison, engineer, was examined by Mr. SAIITIS, and ex-
pressed his opinion that the atmospheric principle could not be
efficiently worked. He had himself been delayed twenty minutes
the other day at the Euston-square station in consequence of some
derangement of the stationary engine. Some third-class trains
might take 500 passengers at once, and he did not think that that
number in third-class carriages would exceed fifty tons. In all
his assumptions of the third-class passengers, he thought that the
tube might be 18 inches. He had been engineer to the Newcastle
and Darlington, and two other railways, and was decidedly of opi-
nion that the gradients could not be surmounted as represented,
and if there were a delay in the early hours of the day it would
affect every other train during the day.
This concluded the evidence against the atmospheric principle.

After some discussion it was decided that the counsel for the
atmospl.eric line should call evidence as to the new matter which
had been adduced by the opponents of the line, when
Mr. Joseph Cubitt was called by Mr. ALEXANDER, and produced
a table, showing the comparative cost of single works and single
line, which would be 1,279,9301.; for double earthwork, with
double bridges and tunnels, with single line, the cost would be
1,393,583/. ; while for the whole of the doubleline,everything double,
1,431,1984 ; and f 4* a double locomotive line it would be 1,312,7981.
This was all exclusive of the Chichester branch ; for the expense
of this latter there would be a cost of 122,2801., making a total
for this cutting of 1,435,1791. Accordiog to his calculations the
Guildford and Portsmouth line would be 877,2321., making an
average of 19,174/. per mile, and the whole value of the wages of
the gate.kcepers would be 34,5001., making a total of 19,228/. per
mile. By the atmospheric line the whole cost would be 15,582/. per
mile, and inclusive of the gatekeepers, tube, and electric telegraph,
the cost would be 24,9151, a mile. ♦ccording to Mr. Locke's
prises, Ore sort would be
Kent, and the pride of the neighbourhood. He knew that the
proposed line passed by the southern side of the park, but did not
think it interfered with any part of it.

Mr. WILMORE then said that he had a number of witnesses to
examine as to the same part of the line that had been spoken of
by those
but he would not call them unless the
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tec jusysti3rlo4.3_thiti.7ed;