The Daboll trumpet was invented by Mr. C.L. Daboll, of
Connecticut, who was experimenting to meet the announced wants of the
United States Lighthouse Board. The largest consists of a huge trumpet
seventeen feet long, with a throat three and one-half inches in diameter,
and a flaring mouth thirty-eight inches across. In the trumpet is a
resounding cavity, and a tongue-like steel reed ten inches long, two and
three-quarter inches wide, one inch thick at its fixed end, and half that
at its free end. Air is condensed in a reservoir and driven through the
trumpet by hot air or steam machinery at a pressure of from fifteen to
twenty pounds, and is capable of making a shriek which can be heard at a
great distance for a certain number of seconds each minute, by about
one-quarter of the power expended in the case of the whistle. In all his
experiments against and at right angles and at other angles to the wind,
the trumpet stood first and the whistle came next in power. In the trial
of the relative power of various instruments made by Gen. Duane in 1874,
the twelve-inch whistle was reported as exceeding the first-class Daboll
trumpet. Beaseley reports that the trumpet has done good work at various
British stations, making itself heard from five to ten miles. The engineer
in charge of the lighthouses of Canada says: "The expense for repairs, and
the frequent stoppages to make these repairs during the four years they
continued in use, made them (trumpets ) expensive and unreliable. The
frequent stoppages during foggy weather made them sources of danger
instead of aids to navigation. The sound of these trumpets has
deteriorated during the last year or so." Gen. Duane, reporting as to his
experiments in 1881, says: "The Daboll trumpet, operated by a caloric
engine, should only be employed in exceptional cases, such as at stations
where no water can be procured, and where from the proximity of other
signals it may be necessary to vary the nature of the sound." Thus it
would seem that the Daboll trumpet is an exceptionally fine instrument,
producing a sound of great penetration and of sufficient power for
ordinary practical use, but that to be kept going it requires skillful
management and constant care.