The New York herald., 1870-05-22
TEE CUMULATIVE EFFECT OF FORCE on
IRON FOUNDATIONS.

WASHINGTON, May 49, 1870
To THE EDITOR OF THE HERALD:-
The railroad acccldent In Greenwich street, OF
which read the account In your paper, Is worthy
Of the special consideration OF engineers as to the
effect OF accumulated pressure on iron girders
With your permission will state case In point for
your use, which occurred under my Immediate OBJ
servatlon more than thirty years ago on OF the
old-fashioned "Adams printing presses" The pres.
sure Of the power rested the centre Of cast iron
bar Immediately under the press. In course Of the
first three hours OF operation the bar parted at the
centre and broke down. A thicker bar was forth
with substituted, which, in like manner broke down
In few days. third bar. OF twice the thickness
OF the first. was next supplied, and the pressmen
were directed to watch the under surface OF the
bar. After working two weeks small transverse
fssure was noticed In the middle OF the under sur
face 81 s par wc aS &c aa oe 70
susation 81 it was then determined to apply an
previously used and 1t proved sufficient and
endured for years without further breach. This was
Ssy Rst the tendency to break
Is progressive, however efflcienr 1t may appear on
The i melancholy accident on the United States
ship Princeton, wnen the celebrated Stockton gun
burst, with such deadly enecG near TINS CITY, IN
stantly killing SIX distinguished persons inciua,ng
This happened to be wrought iron gun, OF tne
largest then existing calibre 1t had OF course un-
dergone the usual rigid tests OF the largest charges
and thus proved and approved. 1t had been dis
charged many times and was deemed perfectly sale.
But on this impressive occasion, In presence OF
President Tyler and his Cabinet many members OF
both houses OF Congress ana large assemblage OF
ladies and gentlemen. invited to witness the range
OF this powerful missile, and after many sale dis
charges mad been made II exploded foul, with such
disastrous effects 1t was sad surprise and shock
to the gallant and distinguished naval ofiicer who
had projected the gun and who stood very near It
OF the tlme and who had invited the distinguished
social party to witness the experiment.
The theory Is that at each consecutive discharge,
with such ponderous ball, the internal surface OF
the gun began to yield gradually, and continued to
expand and to deDiitate the gun UNTIL after OFT re-
peated discharges the vast force or the powder and
the resisting ball caused the explosion at the breach
AS this gun had repeatedly been discharged with
sion than that the weakening effect progressive.
On such principles we may account for the consecu-
tive breaks In the printing press above referred TO-
On these simple principles, suppose that the IRON
glrder In Greenwich street had proved suficent,
and the tram had gone safely with the ten tons OF
pig iron, what security would have been LETT Tor
subsequent passages with the same weight2 one,
two or twenty OF such burdens might pass safe, ana
the twenty first might break down. Nor Is this all
After oft repeated strains light train OF passengers
might become the victims. 1t Is the last feather
which breaks the camels back.
/ respectfully submit these views and facts for the
consideration or engineers, railroad adventurers
and more Intelligent readers generally, on subject
Of much interest to the whole community.
Yours, very respectfully,
JOSEPH THORNTON ADAMS.