470 ARCHITECTURE AND MECHANICAL SCIENCES. 



supplies the amphitheatre and city of Nimens. The bridge of 

 Alcantara, upon the Taj^us, is still a work fit to raise in us a great 

 idea of the Roman magnificence : it is six hundred and seventy 

 feet long, and contains six arches, each of which measure above a 

 hundred fe-t from one pier to the other; and its height from the 

 surface of the water is two hundred fret. The broken remains of 

 Trajan's bridge over the Danube, are still to be seen ; which had 

 twenty piers of free stone, some of which are still standing, a hun- 

 dred and fifty feet high, sixty in circumference, and distant one 

 from another an hundred and seventy. I should never end, were 

 I to enumerate all the admirable monuments left us by the anci- 

 ents ; the slight sketch here given of them, will more than suffice 

 to answer my purpose. As to the ornaments and convrniencies of 

 their buildings, among many I shall mention but one, that of their 

 usins glass in their windows, and in the inside of their aparlments, 

 just in the same manner as we do. Seneca and Pliny inform us, 

 that they decorated their rooms with glasses ; and do not we the 

 same in the use of mirrors and pier glasses ? But what will more 

 shock the general prejudices is, that they should know how to 

 glaze their windows, so as to enjoy the benefit of lij>ht, without 

 being injured by the air ; yet this they did very early. Before 

 they discovered this manner of applying glass, which is so delight- 

 ful and so commodious, the rich made use of transparent stones in 

 their windows such as the agat, the alabaster, the phengites, the 

 talcum, Sec. whilst the poor were under a necessity of being ex- 

 posed to all the severities of wind and weather. 



If we admire the ancients in those monuments which remain to 

 us of the greatness of their undertakings, we shall have no less 

 reason for wonder in contemplating the dexterity and skill of their 

 artists, in works of a quite different kind. Their works in minia. 

 ture are well deserving of notice. Archytas, who was contempo. 

 rary with Plato, is famous in antiquity, for the artful structure of 

 his wooden pidgeon, which imitated the Qight and motions of a 

 living one. Cicero, according to Pliny's report, saw the whole 

 Iliad of Homer, written in so fine a character that it could be con- 

 tained in a nut-shell : and ./Elian speaks of one'Myrmecides a Mile, 

 tian, and of Callicrales a Lacedemonian, the first of whom made 

 an ivory chariot, so small and so delicately framed, that a fly with 

 its wiing could at the same time cover it, and a little ivory ship of 

 the same dimensions; the second formed ants aud other little ani- 



