Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

Dr. E. Halley, F.R.S. But to Dr. Edmund Halley, secretary of the Royal Society, undoubtedly the honour is due of having invented the first really practical diving bell. This is described in the Fig. 90. Philosophical Transactions, 1717, in a paper on “ The Art of Living Under Water by means of furnishing air at the bottom of the Sea in any ordinary depth.” Halley's bell was constructed of wood, covered with lead to give it the necessary sinking weight, and so distributed as to ensure the bell keep- ing a perpendicular position when in the water. It was in the form of a truncated cone, three feet in diameter at the top, five feet at the bottom, and eight feet high. In the roof a lens was introduced for admitting- light, and also a tap to let out the vitiated air. Fresh air was sup- plied to the bell by means of two lead-lined barrels, each having a bung-hole in the top and bottom. To the hole in the top was fixed a leathern tube, weighted in such man- ner that it always fell below the lever of the bottom of the barrel so that no air could escape. When, however, the tube Debrell's Submarine Boat. was turned up by the attendant in the bell, the pressure of the water rising through the hole in the bottom of the barrel, forced the air through the tube at the top and into the diving bell. These barrels were raised and lowered alternately with such success that Halley says that he, with four others, remained at the bottom of the sea, at a depth of nine toten fathoms, for an hour and a half at a time without inconvenience of any sort. Robert Boyle, in his Experiments Physico-Mechanical (1647), describes a sub- marine vessel, contrived by one Cornelius Debrell about the year 1620, which was to be rowed and used under water and was actually tried in the river Thames by order of James I. It is said to have succeeded well, carrying twelve rowers besides passengers. Boyle says : “ Debrell conceived that it is not the whole body of the air but a certain spirituous part of it that fits for respiration, so that besides the mechanical contri- vances of his boat he had a chemical liquor, the fumes of which, when the vessel con- taining it was unstopped, would speedily restore to the air, fouled by the respiration, such a portion of vital parts as would make it again fit for that office.'" Boyle assures us that the liquid which was used for restoring the air was discovered by a physician who married Debrell’s daughter, and the secret of which Debrell disclosed to only one person, who imparted it to Boyle. The statement seems incredible, but, if true, the secret of the preparation of this wonderful elixir vitce has passed away with Boyle. kO