It is singular to see how this telegraphic agency is measured by the
chemical consumption of zinc and acid. Mr. Jones (who has written a
work upon the Electric Telegraphs of America) estimates that to work
12,000 miles of telegraph about 3000 zinc cups are used to hold the
acid: these weigh about 9000 lbs., and they undergo decomposition by
the galvanic action in about six months, so that 18,000 lbs. of zinc
are consumed in a year. There are also about 3600 porcelain cups to
contain nitric acid; it requires 450 lbs. of acid to charge them once,
and the charge is renewed every fortnight, making about 12,000 lbs. of
nitric acid in a year.