n the year 1617, but when
tried it was found to be useless. G. A. Borelli in the year 1679
invented an apparatus which enabled persons to go to a certain depth
under water, and he is credited with being the first to introduce means
of forcing air down to the diver. For this purpose he used a large pair
of bellows. John Lethbridge, a Devonshire man, in the year 1715
contrived "a watertight leather case for enclosing the person." This
leather case held about half a hogshead of air, and was so adapted as to
give free play to arms and legs, so that the wearer could walk on the
sea bottom, examine a sunken vessel and salve her cargo, returning to
the surface when his supply of air was getting exhausted. It is said
that Lethbridge made a considerable fortune by his invention. The next
contrivance worthy of mention, and most nearly resembling the modern
diving-dress, was an apparatus invented by Kleingert, of Breslau, in
1798. This consisted of an egg-ended metallic cylinder enveloping the
head and the body to the hips. The diver was encased first of all in a
leather jacket having tight-fitting arms, and in leather drawers with
tight-fitting legs. To these the cylinder was fastened in such a way as
to render the whole equipment airtight. The air supply was drawn through
a pipe which was connected with the mouth of the diver by an ivory
mouthpiece, the surface end being held above water after the manner
mentioned in Vegetius, viz. by means of a floating bladder attached to
it. The foul air escaped through another pipe held in a similar manner
above the surface of the water, inhalation being performed by the mouth
and exhalation by the nose, the act of inhalation causing the chest to
expand and so to expel the vitiated air through the escape pipe. The
diver was weighted when going under water, and when he wished to ascend
he released one of his weights, and attached it to a rope which he held,
and it was afterwards hauled up.

_Modern Apparatus._--This, or equally cumbersome apparatus, was the
only diving gear in use up till 1819, in which year Augustus Siebe (the
founder of the firm of Siebe, Gorman & Co.), invented his "open" dress,
worked in conjunction with an air force pump. This dress consisted of a
metal helmet and shoulder-plate attached to a watertight jacket, under
which, fitting more closely to the body, were worn trousers, or rather a
combination suit reaching to the armpits. The helmet was fitted with an
air inlet v