ONE:A gravity wheel must have a diameter equal to the fall of water, or, to use the technical name, the height of the head. The speed at the periphery of the wheel cannot well exceed sixteen feet per second without losing a part of the effect by the wheel anticipating or overrunning the water. This, from the large diameter of the wheels, produces a very slow axial speed, and a train of multiplying gearing becomes necessary in order to reach the speed required in most operations where power is applied. This train of gearing, besides being liable to wear [38]and accident, and costing usually a large amount as an investment, consumes a considerable part of the power by frictional resistance, especially when such gearing consists of tooth wheels. Gravity wheels, from their large size and their necessarily exposed situation, are subject to be frozen up in cold climates; and as the parts are liable to be first wet and then dry, or warm and cold by exposure to the air and the water alternately, the tendency to corrosion if constructed of iron, or to decay if of wood, is much greater than in submerged wheels. Gravity wheels, to realise the highest measure of effect from the water, require a diameter so great that they must drag in the water at the bottom or delivering side, and are for this reason especially affected by back-water, to which all wheels are more or less liable from the reflux of tides or by freshets. These disadvantages are among the most notable pertaining to gravity wheels, and have, with other reasonssuch as the inconvenience of construction, greater cost, and so ondriven such wheels out of use by the force of circumstances, rather than by actual tests or theoretical deductions.Against these we have to set the confident expressions of belief in a future life employed by all the Platonists and Pythagoreans, and by some of the Stoic school. But their doctrines on the subject will be most advantageously explained when we come to deal with the religious philosophy of the age as a whole. What we have now to examine is the general condition of popular belief as evinced by the character of the funereal monuments erected in the time of the empire. Our authorities are agreed in stating that the majority of these bear witness to a wide-spread and ever-growing faith in immortality, sometimes conveyed under the form of inscriptions, sometimes under that of figured reliefs, sometimes more na?vely signified by articles placed in the tomb for use in another world. I am waiting for my husband, is the inscription placed over his dead wife by one who was, like her, an enfranchised slave. Elsewhere a widow commends her departed husband to the gods of the underworld, and prays that they will allow his spirit to revisit her in the hours of the night.366 In death thou art not dead, are the words deciphered on one mouldering stone. No, says a father to a son whom he had lost in Numidia,236 thou hast not gone down to the abode of the Manes but risen to the stars of heaven. At Doxato, near Philippi in Macedonia, a mother has graven on the tomb of her child: We are crushed by a cruel blow, but thou hast renewed thy being and art dwelling in the Elysian fields.367 This conception of the future world as a heavenly and happy abode where human souls are received into the society of the gods, recurs with especial frequency in the Greek epitaphs, but is also met with in Latin-speaking countries. And, considering how great a part the worship of departed spirits plays in all primitive religions, just such a tendency might be expected to show itself at such a time, if, as we have contended, the conditions of society under the empire were calculated to set free the original forces by which popular faith is created. It seems, therefore, rather arbitrary to assume, as Friedl?nder does,368 that the movement in question was entirely due to Platonic influence,especially considering that there are distinct traces of it to be found in Pindar;although at the same time we may grant that it was powerfully fostered by Platos teaching, and received a fresh impulse from the reconstitution of his philosophy in the third century of our era.
TWO:74But we cant set down or do anythingand we cant see much for the fog, objected Dick. I think we ought to go back and drop a note onto the yacht, telling the people to come here in a boat.
