776

the structure, witli the further most important
item, that whilst the latter has to be entirely
rebuilt in so comparatively short a space of
time, the former will stand with no repairs
being needed, (requiring only to be occasion-
ally painted), for a period, at a very moderate
computation, of at least five times the duration-
of any wooden structure whatever. And as
the Rider bridge has received the highest
encomiums from many scientific persons who
have examined into its properties, and the
plan of its construction, there will be little
doubt that it will soon supersede all others
and become the most useful and economical
bridge that can be adopted.

The Rider bridge has been in use on the
Harlem railroad a year and a half, and fully-
tested by the very able chief engineer of the
road, Allen Campbell, Esq, the result of
which haslinduced the company to give fur-
ther orders; the properties and plan of-con-
struction have been examined also by many
other scientific and practical engineers, who
have bestowed on the inventor the highest
encomiums for his skill and ingenuity, and
besides the bridges for the Harlem railroad,
orders have been talrenfrorn the Erie rail
road compiny, T. S. Brown, chiefengineer;
the Louisa railtoal, Va., W. A. Kuper, chief
engineer; the state of New York, by the
Canal commissioners; and the White’s Cor-
ners and Buffalo plank road company, near
Buffalo; all of which‘ will be soon in“ use,
‘and may be referred to,.as-to the great utility
of the Rider bridge over-all others now

Testing Nal/ba7l'l8l Ricle)"s Patient Iron
Truss Briclge.

The committee of the National association
of inventors, charged with the examination
of the plan of an Iron bridge, submitted to
the association by Mr. Nathaniel Rider, re-
spectlully represent that they have inquired
into the plan of said bridge, and have care-
fully examined one which has actually been
constructed in conformity with said plan at
the workshop of the Harlem railroad compa-
ny. They found that said bridge is composed
of an octangular frame, the upper rail of
which, with the queen posts, are composed of
cast iron, while the lower rail iszformed of
wrought iron ; this frame is diagonally braced
by bars of wrought iron. In inquiring into
the principles on which said. bridge is con-
structed, the committee have come to the
conclusion that the two materials are so _,com-
bined as to bring each of them into action to
resist the effects of a force applied to bend or
break the structure, oti the riiode for which
its peculiar nature and strength is obtained,
with a small quantity of either material.——-
i/Vithout entering into a comparison with
other plans of spanning openings by either of
these materials, or by their combinations, the
committee feel warranted in expressing a de-
cided opinion that the plan in question can
be applied with great advantage and economy
in various cases, and that it is particularly
advantageous as a mode of constructing via‘-
dncts on railroads. , In forming this opinion,
the committee, unwilling to trust its theory

known , and in confirmatiori oftlie foregoing
reference is made to the reports and certifi-
cates hereto annexed. , - -

Ewlmct from the Report of lite. .C_ommillee on
Roads and Bridges, made to the Jlfamigcrs
oflhe 19l/I. A7L7Lua:l‘ Fair, ail/Le Castle
Gamrlen, in the city of New York, Oct.
1846.

Of Mr. Rider’s iron railroad bridge, the
committee would say that in their opinion it
is of great importance that railroad bridges
should be constructed of a less destructible
material than wood, and that every effort to
obtain that result is entitled to encourage-
ment. .

Mr. Rider, in his plan, No 262, has aimed
to effect this by a combination of wrought
and cast iron, whereby, with a limited
amount of material, the adequate strength is
to be obtained. The committee think favor-
ably ot the combination, and for bridges of
not too large a span, believe that his plan

alone, required the inventor to submit that
which has been stated to have been actually
constructed to the test of experiment.. In
conformity with their request, the bridge,
which has a spam. 0_ff0'rl_'z/feel, and contains
about two and one half tons of iron, was
loaded with a large locomotive engine, a ten-
der, and a pair of large wheels with their
axle; the latter being placed over oneof the
abutments, was not reckoned in the weight,
which omitting, amounted to Z-u'entg/four
Ions. » L

tUnder the pressure of this weight, the
bridge sprang the forty-four hundredth part
of an inch, and upon the removal of the en
gine, which weighed eighteen tons, it imme-
diately resumed its former figure. The
committee, therefore, concluded that it must
have borne at least four times the weight.
without reaching the limits of its elasticity,
which limits are far short of that at which
danger of fracture is to be apprehended.
The committee have, in conclusion, to

will be found useful, and they, therefore, re-
commend a favorable notice on the part of the
institute.

I-floimrio ALLEN,

JOHN B. Jiaitvis, Committee.

Joinv D. WARD, --
. I hereby certify that the above is a true
copy from the report on file,  Gold Medal
awarded).

H. MEIGS, Recording Sea.
New York, Nov. 10th, 1846.

Copy of Reports made by (L Committee op-
- painted by tile National associattovt of 
- ‘centers, for the purpose-of e:ca.mini7z.g’aml

state, that the plan in question requires the
useof a less weight of materials than any
other, with the exception of suspension
bridges, and is in consequence, capable, if

properly proportioned, of being constructed
of a greater span than any bridge except
those on the principle of snspension,to which

its freedom from oscillation renders it far
superior.

JAMES RENWICK,
GEORGE GIFFORD
CLINTON ROSEVELT,
J. L. KINGSLEY, J
New York, July 27th, 1846.

l

Committee.

AREERICAN RAILROAD JOURNAL.

I certify that the above is it correct copy
frotn the minutes.

JOSEPH P. PIRSSON. Jit., Rec. See.
New Y ark, April 41/1,, 1848.

This is to certify that the Rider Patent
Iron Bridge, now on the New York and
Harlem railroad, crossing 109th street, of 70
feet span, is in as good condition now as
when first built, and of a superiority over all
bridges that I know of now in use. It was
btfilt in April, 1847.

PETER K. Bansrow,
S'll]7e7'2i7Llé’7l(l£’7’Ll N. Y. and II. R. R.
Enginee-rs Ofice, N. Y. and Ifarlcnt R R. g
Crolon Falls July 29th 1848.

An Iron bridge of about '70 feet span, on
“ Riders plan,” was put on this road in
April 1847, between the city of New York
and Harlem, over which part of the road
trains pass very frequently, and many ‘of
them drawn by heavy engines. Alter SIX-
teen months of continued use, the bridge has
answered every expectation ; and so well sat-
isfied am I of its strength and efficiency, that
contracts have been made for several small
spans of about the same length on the ex-
tension of this road, which are now in pro-
cess of erection.

Several road and street bridges over the
railroad, have also been built on this plan on
the island of New York ; these are light,du-
rable and cheap structures.

From my knowledge of Ridei"s bridge,
obtained from experience on the road, I coin-
mend it to the favorable notice of railroad
companies.

ALLAN CAi\iri3i:LL, Chief Engineer‘.

I_ have examined the plan upon which the
Rider bridge is constructed, and fully conctir
with the opinion above expressed by Mr.
Campbell the chief engineer of our road.

A ROBERT SCI-IUYLER,

Presirlcnl N. Y. rmcl II. R. R.

Couvvay 'T!lbl1Ifl—Jl'.flI;Jrii(lgc.

the following statement in relation to the second
tube over the Conway, on the Chester and Holy-
head railway. The first one of the pair has now
been in successful use several months without the
least indication of yielding, and this one completes
the double track at this point. The mail for Ireland
will pass over this line next season, or as soon as
the bridge-—-a similar structure—-is completed over
the Menai Straits. These structures are ubblc evi-
dences of the advance of the engineering science of
the age, and leads us to look forward with confi-
dence to the accomplishment of other equally diffi-
cult and useful works

VCHESTER. AND“ HOLYI-IEAD.-—Oct. 12.-The
second tubular bridge over the Conway
Straits was floated on the pontoons to the
piers. The operation, combined with the
stupendous machinery employed in the pro-
cess, attracted large crowds from Conway,
and other parts of the principalities. At pre-
cisely 9 A. M., or 50 minutes before high
water, Capt. Claxton, R. N., gave the signal,
and almost immediately the tremendous
freight was seen stealing to its destination.——-—
Next to him was Mr. R. Stephenson, M. P.,
attended by several other engineers. The

tube was lifted in about 60 minutes, com

We find in the R. VV. Chronicle of 14th October, '