THE BERLIN IRON BRIDGE COMPANY,
THE RELATIVE ECONOMY OF IRON AND WOODEN BRIDGES.
The high price and scarcity of good bridge timber at the present time prevents the building of wooden bridges to any very large
extent, as it costs but little more to build a first-class Iron Bridge, than it does a first-class wooden bridge. To parties who
contemplate building wooden bridges in preference to iron bridges on the score of economy, we have one word to say, as we think we
can prove that in time the iron bridge is much more economical. Suppose, for example, that you can build two wooden bridges for the
same amount of money that it will cost to build one iron bridge, or, that the iron bridge costs twice as much as the wooden bridge.
Suppose two towns wstetj|g a large number of bridges both start in at the same time, one building iron bridges and the other wooden
bridges. Suppose the tomi building iron bridges builds one iron bridge each year, and the town building wooden bridges builds two
wooden bridges each year, thus each town spending the same amount of money each year for bridges. The following table gives the
progress from year to year, and shows where each town will land at the end of each year up to 20 years :
At the end of 10 years, the town building wooden bridges will have to commence to renew those built the first year, as this table is made on the supposition that
the wooden bridges will last for 10 years—this is the life of an ordinary wooden
bridge. Therefore, the town building wooden bridges, at the end of 10 years will
have 20 bridges on hand, all of wood, while the town building one iron bridge each
year will have 10 iron bridges on hand. From this time forward the matter changes,
as the town building two wooden bridges each year, must commence to renew the
two wooden bridges built the first year, so that they will never have more than 20
wooden bridges, if they only build two each year, all their money going for renewals.
The town building iron bridges, however, will keep increasing one bridge each year,
so that at the end of 20 years each town will have the same number of bridges, but
the town building wooden bridges having 20 wooden bridges on hand, part of them
having been in use 10 years, and the town building iron bridges will have 20 iron
bridges on hand. In both cases each town has spent the same amount of money in
the 20 years, and one has 20 iron bridges on hand, and the other 20 wooden bridges,
proving conclusively that in the long run iron bridges are much cheaper than wooden bridges.
6 EAST BERLIN, CONNECTICUT, U. S. A.
TERMS OF YEARS.
At end of 1 year
« « << 2 years
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