Page:The American Cyclopædia (1879) Volume VI.djvu/162

 154 DIVING favorite method was to suspend the ring by a hair within a goblet, when it began to swing, the motion gradually increasing till it struck the vessel once or twice for yes or no, as pre- viously determined. Gyromancy consisted in walking round in a circle, the circumference of which was marked with letters, the pres- age being drawn from the letters on which the inquirers stumbled when they became too dizzy to stand. Hydromancy, or divination by water, consisted in observing the colors and images presented by water in a vase, either when motionless or when disturbed by drop- ping little stones into it. The motions of the agitated waves of the sea were also studied for purposes of divination, especially by the ancient Sicilians and Eubceans. Lampado- mancy furnished presages for the future from the form, color, and fluctuations of the flame of a lamp. Lithomancy was a method of divination by means of precious stones. The sounds of stones striking each other gave pres- ages, and the amethyst was believed to have the virtue of sending prophetic dreams to who- ever possessed it. The ~bwtylia, or animated atones, of which the Greeks learned from the Persians, and which were believed to bear oracles, are celebrated instances. Ornitho- mancy, or divination from the flight and song of birds, was a principal function of the Ro- man augurs. (See ATJGUE.) The flame of fire (pyromancy), the accidental opening of a book (rhapsodomancy), the combination of cards (chartomancy), the drawing of lots, the drop- ping of staffs or observation of cups (especially in use among the old Egyptians), the interpre- tation of dreams, the reflections of mirrors, and the contortions of serpents, are other means. Several of these methods of divina- tion are yet in use among the superstitious. Some of the more remarkable forms of divina- tion are treated in special articles, as ASTROLO- GY, CHIBOMANCY, DIVINING ROD, and MAGIC. DIVING. Though the natural constitution of man entirely unfits him for remaining under water with safety for more than a few mo- ments, the desire of obtaining valuable articles lying at the bottom of the sea, as well as the necessity for the execution of certain manual operations in civil engineering, has led him to devise numerous expedients by which he is enabled to lengthen his continuance at mode- rate depths. It has been said that the pearl divers of Ceylon can remain under water six minutes, but this is hardly credible ; and Admi- ral Hood, who took pains to time their diving, found that they were under water in no in- stance more than a minute. The instance nar- rated by Dr. Halley of a Florida Indian diver at Bermuda, who could remain two minutes under water, is regarded as an extreme case. In Franohfere'fl " Narrative of a Voyage to the N. W. Coast of America," mention is made of the feats of diving of the Hawaiian island- era. Two of them were induced to go down in 14 fathoms of water in search of two sheaves lost overboard. They went down several times, each time bringing up shells as a proof that they had been to the bottom. " We had the curiosity to hold our watches while they dove, and were astonished to find that they remained four minutes under the water. That exertion appeared to me, however, to fatigue them a great deal, to such a degree that the blood streamed from their nostrils and ears. At last one of them brought up the sheaves, and re- ceived the promised recompense, which con- sisted of four yards of cotton." Statements are made by others which render it probable that the time may be somewhat extended be- yond that observed by Admiral Hood, or even by Dr. Halley. The lungs retain at each ordina- ry expiration considerable carbonic acid. By breathing deeply for a short time the quantity is lessened, and the blood becomes more than usually aerated and capable of performing its functions for a longer time than usual without renovation. It is told of Brunei that, wishing to examine a break in the Thames tunnel, he was lowered with another person in a diving bell to the depth of 30 ft., and the brake not permitting the bell to descend further, he dived into the water, holding a rope in his hand. He found no great difficulty in continuing under water fully two minutes, which is explained by the circumstance that the air in his lungs had been condensed in the bell to but little more than half its ordinary bulk, and therefore was capable of supplying much more oxygen. The pressure exerted by the water is not only felt in the lungs but upon all parts of the body to a sensible degree. At a depth of 17 ft. it amounts to about 7 Ibs. to every square inch of surface, and increases about 0*44 of a pound with every additional foot of depth. To en- able the diver to stay a considerable time under water, a dress called a diving armor is now generally em- ployed for the laying of foundations and at- taching apparatus for raising sunken vessels, and also by pearl and coral divers. Such a one is now (1874) in use in the construction of the foundations of the piers at the Bat- tery in New York har- bor. The diving dress or armor consists of a copper helmet, shown in fig. 1, tinned inside, and supplied Avith thick glass windows, and a copper breastplate which has a collar, to which the helmet is readily adjusted. The helmet is large enough for considerable rota- tion and lateral motion of the head, and allows FIG. 1. The Diver.