16. More copies of the earliest printed books were impressed on vellum than on paper; but very soon paper was used for a principal part of the edition, while a few only were printed on vellum, as curiosities, to be ornamented by the illuminators, whose ingenious art, though in vogue before and at that time, did not long survive the rapid improvements in printing. 17. We are informed, that the Mentz printers observed the utmost secrecy in their operations; and, that the art might not be divulged by the persons whom they employed, they administered to them an oath of fidelity. This appears to have been strictly adhered to, until the year 1462, when the city was taken and plundered by Archbishop Adolphus. Amid the consternation which had arisen from this event, the workmen spread themselves in different directions; and, considering their oath no longer obligatory, they soon divulged the secret, which was rapidly diffused throughout Europe. 18. Some idea may be formed of the celerity with which a knowledge of printing was extended, from the fact that the art was received in two hundred and three places, prior to the year 1500. It was brought to England, in 1471, by William Caxton, a mercer of the city of London, who had spent many years in Germany and Holland. The place of the first location of his press was Westminster Abbey. The first press in North America was established at Cambridge, Massachusetts, in 1639. 19. Printed newspapers had their origin in Germany. They first appeared in Augsburg and Vienna, in 1524. They were originally without date or place of impression; nor were they published at regular periods. The first German paper with numbered sheets was printed, in 1612; and, from this time, must be dated periodical publications in that part of Europe. 20. In England, the first newspaper appeared during the reign of Elizabeth. It originated in a desire to communicate information in regard to the expected invasion by the Spanish armada, and was entitled the "English Mercury," which, by authority, was printed at London by Christopher Barker, her highness's printer, in 1588. 21. These, however, were extraordinary gazettes, not regularly published. Periodicals seem to have been first extensively used by the English, during the civil wars in the time of the Commonwealth. The number of newspapers in Great Britain and Ireland amounted, in 1829, to 325, and the sums paid to the government for stamps and duties on advertisements, amounted to about £678,000 sterling. 22. No newspaper appeared in the British colonies of America until 1704, when the "News Letter" was issued at Boston. The first paper published in Philadelphia, was issued in 1719; the first in New-York, in 1733. In 1775, there were 37; and in 1801, there were, in the whole United States, 203; in 1810, 358; at the present time, there are about 1500, and the number is annually increasing.