Lesson35
Many strange new means of transport have been developed in our century, the strangest of them being perhaps the hovercraft. In 1953, a former electronics engineer in his fifties, Christopher Cockerell, who had turned to boat-building on the Norfolk Broads, suggested an idea on which he had been working for many years to the British Government and industrial circles. It was the idea of supporting a craft on a' pad ', or cushion, of low-pressure air, ringed with a curtain of higher pressure air. Ever since, people have had difficulty in deciding whether the craft should be ranged among ships, planes, or land vehicles--for it is something in between a boat and an aircraft. As a shipbuilder, Cockerell was trying to find a solution to the problem of the wave resistance which wastes a good deal of a surface ship's power and limits its speed. His answer was to lift the vessel out of the water by making it ride on a cushion of air, no more than one or two feet thick. This is done by a great number of ring-shaped air jets on the bottom of the craft. It 'flies', therefore, but it cannot fly higher--its action de- pends on the surface, water or ground, over which it rides.
The first tests on the Solent in 1959 caused a sensation. The hovercraft travelled first over the water, then mounted the beach, climbed up the dunes, and sat down on a road. Later it crossed the Channel, riding smoothly over the waves, which presented no problem.
Since that time, various types of hovercraft have appeared and taken up regular service--cruises on the Thames in London, for instance, have become an annual attraction. But we are only at the beginning of a development that may transport net-sea and land transport. Christopher Cockerell's craft can establish transport works in large areas with poor communications such as Africa or Australia; it can become a 'flying fruit-bowl', carrying bananas from the plantations to the ports, giant hovercraft liners could span the Atlantic; and the railway of the future may well be the 'hovertrain', riding on its air cushion over a single rail, which it never touches, at speeds up to 300 m.p.h.--the possibilities appear unlimited.
Lesson36
Our knowledge of the oceans a hundred years ago was confined to the two-dimensional shape of the sea-surface and the hazards of navigation presented by the irregularities in depth of the shallow water close to the land. The open sea was deep and mysterious, and anyone who gave more than a passing thought to the bottom confines of the oceans probably assumed that the sea-bed was flat. Sir James Clark Ross had obtained a sounding of over 2,400 fathoms in 1836 but it was not until 1800, when H.M.S. Porcupine was put at the disposal of the Royal Society for several cruises, that a series of deep soundings was obtained in the Atlantic and the first samples were collected by dredging the bottom. Shortly after this the famous H.M.S. Challenger expedition established the study of the sea-floor as a subject worthy of the most qualified physicists and geologists. A burst of activity associated with the laying of submarine cables soon confirmed the Challenger's observation that many parts of the ocean were two to three miles deep, and the existence of underwater features of considerable magnitude.
Today enough soundings are available to enable a relief map of the Atlantic to be drawn and we know something of the great variety of the sea-bed's topography. Since the sea covers the greater part of the earth's surface it is quite reasonable to regard the sea-floor as the basic form of the crust of the earth, with superimposed upon it the continents, together with the islands and other features of the oceans. The continents form rugged tablelands which stand nearly three miles above the floor of the open ocean. From the shore-line out to a distance which may be anywhere from a few miles to a few hundred miles runs the gentle slope of the continental shelf, geologically part of the continents. The real dividing-line between continents and oceans occurs at the foot of a steeper slope.
This continental slope usually starts at a place somewhere near the ice-fathom mark and in the course of a few hundred miles reaches the true ocean-floor at 2,500-3,000 fathoms. The slope averages about 1 in 30, but contains steep, probably vertical, cliffs, and gentle sediment-covered terraces, and near its lower reaches there is a long tailing-off which is almost certainly the result of material transported out to deep water after being eroded from the continental masses.
Lesson37
The Victorians, realizing that the greatest happiness accorded to man is that provided by a happy marriage, endeavoured to pretend that all their marriages were happy. We, for our part, admitting the fact that no feat of intelligence and character is so exacting as that required of two people who desire to live permanently together on a basis of amity, are obsessed by the problem of how to render the basic facts of cohabitation simpler and more reasonable, in order that unhappy marriages may less frequently result. The Victorians would have considered it 'painful' or 'unpleasant' were one to point out that only four marriages out of every ten are anything but forced servitudes. We ourselves start from this very assumption and try to build from it a theory of more sensible relations between the sexes. Of all forms of arrant untruthfulness Victorian optimism appears to me to have been the most cowardly and the most damaging.
Truth, therefore, is an attitude of the mind. It is important, if one does not wish to inconvenience and to bore one's friends, not to tell lies. But it is more important not to think lies, or to slide into those mechanical and untruthful habits of thought which are so pleasant and so easy as descents to mental ineptitude. The victorian habit of mind (which I consider to have been a bad habit of mind) was unduly preoccupied by what was socially and morally convenient. Convenience is, however, in all affairs of life, an execrable test of value. One should have the courage to think uncomfortably, since it is only by rejecting the convenient that one can come to think the truth.
Not, after all, that there is any such thing as truth. At best we can approach to some relative approximation. On the other hand, there is surely such a thing as untruth. One is generally aware when one has said something, or acted in some way which has left on other people an impression not strictly in accordance with the facts. One is generally aware, also. when one has thrust aside an inconvenient thought and slid into its place another thought which is convenient. One's awareness in the former case is in general more acute than in the latter, since we are more on the look-out for the lies we utter than for those we merely think. In fact, however, it is the untruthful thought which is the more vicious of the two. Spoken lies are invariably tiresome and may actually be dishonest. But continuous lying in the mind, a disease to which the Anglo-Saxon is peculiarly exposed, spells the destruction of human thought and character.