ittle seems to be known, is credited with
having invented in 1680 a submarine boat, whose descent and ascent
were regulated by a series of leather bottles placed in the hull of
the boat with their mouths open to the surrounding water. The
English magazine, _Graphic_, published a picture which is considered
the oldest known illustration of any submarine boat. This picture
matches in all details the description of Borelli's boat, but it is
credited to a man called Symons.

Twenty-seven years later, in 1774, another Englishman, J. Day, built
a small submarine boat, and after fairly extensive experiments,
descended in his boat in Plymouth harbour. This descent is of
special interest because we have a more detailed record of it than
of any previous submarine exploit, and because Day is the first
submarine inventor who lost his life in the attempt to prove the
feasibility of his invention. The _Annual Register_ of 1774 gives a
narration in detail of Day's experiments and death and inasmuch as
this is the first ungarbled report of a submarine descent, it may be
quoted at length.

_Authentic account of a late unfortunate transaction, with
respect to a diving machine at Plymouth._

Mr. Day (the sole projector of the scheme, and, as matters have
turned out, the unhappy sacrifice to his own ingenuity) employed
his thoughts for some years past in planning a method of sinking
a vessel under water, with a man in it, who should live therein
for a certain time, and then by his own means only, bring himself
up to the surface. After much study he conceived that his plan
could be reduced into practice. He communicated his idea in the
part of the country where he lived, and had the most sanguine
hopes of success. He went so far as to try his project in the
Broads near Yarmouth. He fitted a Norwich market-boat for his
purpose, sunk himself thirty feet under water, where he continued
during the space of twenty-four hours, and executed his design to
his own entire satisfaction. Elated with this success, he then
wanted to avail himself of his invention. He conversed with his
friends, convinced them that he had brought his undertaking to a
certainty; but how to reap the advantage of it was the difficulty
that remained. The person in whom he confided suggested to him,
that, if he acquainted the sporting Gentlemen with the discovery,
and