We are always being told that there are far too many of us on the globe and that soon there will be no room for anyone; not that we need this warning. Our landlords, those who reserve places on planes and hotels, and other well-wishers constantly keep us informed on this score. We long to ''twitch our mantle blue/Tomorrow to fresh fields and pastures new,'' but where are they? In Siberia or Central Asia perhaps, or at the South Pole, but then we would have to find some way round curtains of various materials, frontiers, passports, visas - issues the uncouth swain did not need to face.
Yet, sometimes the world has been able suddenly to enlarge its scope, new horizons have stretched away on either hand, and opportunities arisen for our alter ego, that strange ''man in the street.'' Prince Henry the Navigator, Columbus, Drake, and countless others blazed paths we could follow. We had hoped that space would do that for us today, but except for the odd genius who builds a shuttle in his garden, for most of us it's just television, mathematics, money , machinery - it remains beyond our ken, utterly unfamiliar.
History encourages us, nevertheless. Not very long ago Europe entered a vastly enlarged framework when it fell in love with what it called the East - that is, the Near East and North Africa. This attraction began in a small but distinguished way much earlier, and accelerating in the 19th century as a part of the Romantic movement, was borne on by a variety of reasons, and through brilliant individuals.
Early 19th-century Europe found a certain relief from its chronic boredom (a heritage from the medieval ''acedia'') in looking eastwards to the world of deserts, mirages, ruins, minars, Bedouins. Their ideas of ''the opaque and mysterious empire of the Ottomans over the Arab Levant'' were absorbing, although usually highly subjective and often inaccurate. Susceptibility being an endearing trait, it is rather touching to look back on their enthusiasm and sentiment, which embraced the impressions of scholars, writers, artists, merchants - even the tourists who began to flourish in mid-Victorian times.
Delacroix, who spent six months in North Africa in 1932, coming back to France with a wealth of exciting material, was one of those whose influence in these matters was tremendous and lasting. Colorful individuals like Lady Hester Stanhope, living so grandly alone in the Syrian desert, the exotic Lady Jane Digby, and Richard Burton worked on the imagination of those at home. Most of all, there was Byron.
''Byronism was sweeping England, and Europe too. Don Juan's graceful verses were on every lip. The romantic East suddenly came into focus. Until then, it had been represented, for the most part, as remote and uncomfortable, and smacking disagreeably of commerce, and the East India Company's machinations. Now a nearer East was sensed, the East of odalisques and scented fountains.''
The fact that the Romantic movement coincided with the earlier part of the Industrial Revolution enhanced the importance of the former in many people's view. With all its wonders, the spread of industry dismayed and shocked those who thought it was destroying both the countryside and the rural population. They wanted now something quite different, yet not wholly unfamiliar.
A.W. Kinglake introduces his beloved ''Eothen or Traces of Travel Brought Home from the East'' (published in 1884) with the words ''I had come, as it were , to the end of this wheel-going Europe, and now my eyes would see the splendour and havoc of the East.'' He rejoiced, too, in the new, unconventional outlook he would find across the Jordan, where ''... there reigns the people who will be like to put you to death for not being a vagrant, for not being a robber, for not being armed and houseless. There is comfort in that - health, comfort, and strength to one who is aching from the very weariness of that poor, dear, middle-aged, deserving, accomplished, pedantic, and painstaking governess, Europe.''
Other currents went that way, also. The Bible was being scrutinized in a new fashion, Darwin would write ''On the Origin of Species'' and Renan, ''La Vie de Jesus.'' Clergymen formed the first archaeological societies and went to the Holy Land to discover how much of the scriptural record could be substantiated. Artists went too, somewhat in this spirit. Men like Holman Hunt insisted that the Bible should be illustrated realistically, with Jews and Arabs as its personages, not Dutch peasants or Italian Madonnas.
The camera was just coming into use - had it been developed a little earlier, no doubt we should now have photographic records rather than the oils and watercolors the ''Orientalists'' produced. The public did not demand great art from these people - it wanted to know how things looked, it wanted to be able to recognize Jerusalem, the Pyramids, the Parthenon, the great ruins.
The painter needed to awaken in his viewer a sense of recognition, and often, a religious sentiment. Many then could not look upon Jerusalem without tears. It was an emotional epoch. But among many mediocrities there was also a host of great artists; for instance, Lear, whose beautiful watercolors remain exquisite records of what he himself saw in Egypt, Palestine, Greece, and India. Theodore Frere, a competent and pleasing painter, also traveled extensively in the region , his last journey made in 1869, 30 years after his first picture was exhibited in the Salon. ''Jerusalem from the Environs'' (1881) was exactly what his public liked.
This is still true - a recent exhibition of Orientalist painting in London confirmed this interest in how things looked in the East during those decades - an affection for representational art, dealing with these topics. I went to this show in the company of a niece who had lived for a time, some 15 years ago, in Jordan, when that country still held part of Jerusalem. Her pleasure in recognizing monuments and types was evident. It was like ''meeting a friend unexpectedly in a far country.'' ''That's the way the mothers carry their children still,'' she said, pointing out a picture of a peasant woman whose child lay almost across her head; ''and that's the Dome of the Rock!''
That's what we want - a medley of the strange and the familiar, which can enlarge our present experience.