ABROAD IN AMERICA: LITERARY DISCOVERIES OF THE NEW WORLD FROM THE PAST 500 YEARS; edited by Robert Blow; Continuum; 343 pages; $21.95.

Beginning with an account of the westering voyages of the legendary (and real) Irish monk St. Brendan in the sixth century and concluding with the impressions - warm and cool - of recent visitors in the 1980s, this chronologically arranged collection of Old World responses to the New World functions almost as an eyewitness-to-history book."Abroad in America" captures the sense of wonder - sometimes admiration, sometimes shock, even horror - felt by foreigners first encountering America, from the earliest voyagers and explorers who dreamed of finding El Dorado or an earthly paradise to the later generations of immigrants seeking "a land of riches and plenty where all may be happy and free," as editor Robert Blow aptly puts it.

The excerpts are arranged in four sections, each preceded by a brief, informative introduction. The first, and shortest, section is a handful of accounts of explorers who preceded Columbus. The second part opens with selections from Columbus' logbook and concludes with a powerful narrative by Gustavus Vassa, an African sold into slavery who eventually attained his freedom and went on to speak out against the evils of the system in his autobiography, which was published in 1789.

Impressions of "The New Nation," forming the third part of this anthology, range from actress Fanny Kemble's shock at the plight of slaves on her new American husband's Georgia plantation to the Marquis de Lafayette's delight at the spirit of brotherhood he finds among citizens, rich and poor, of the new republic.

Some of the most fascinating entries deal with the Europeans' first impressions of the American Indians, whose language, rites, demeanor and customs are described in poignant detail.

An Englishman himself, Blow gives precedence to English writers, not least because there is no need to lose anything in translating. Unlike everyone else whose words appear in these pages, Blow has never, he confesses, been to America. "This does not seem to me to be a disadvantage in an anthologist," he remarks. Judging by the excellence of this anthology, one would have to agree.