d of harpsichords called piano-forte, are introduced, etc.
Piano-Forte movements.
A, Bartolomineo Cristofori of Florence, 1711.
B, Mason, London, 1755. C, single action.
The hammer-harpsichord, so called from the substitution of hammers for plectra, was the first piano-forte, and invented by Cristofori of Florence, 1711.
It had a row of leather-topped hammers, which vibrated on a rod and struck the string from below.
A projection on the hammer near its axis was struck by a tongu after the geocentric system, which then obtained, — the earth in the center, and so on.
A planetarium constructed at Florence in the fifteenth century is described in a letter from Angelo Politiano to his friend Francesca Casa.
It illustrated theek book, 1476.
Aldus introduced italics, 1476.
The Pentateuch in Hebrew, 1482.
Homer in folio, by Demetrius of Florence, 1488.
The Complutensian Polyglot of Cardinal Ximenes, in 1517.
The exact conformity of different copies of the bo
had been attained.
A bar of phosphor bronze, under a strain of 10 tons, resisted 862,980 bends, while the best gunmetal broke after 102,650 bends.
Another bar, tested under a strain of 9 tons, has resisted 1,260,000 bends without breaking.
In Austria the following comparative results have been obtained: —
Absolute Resistance.
Phosphor bronze81,798 pounds per square inch.
Krupp cast-steel72,258 pounds per square inch.
Ordnance bronze31,792 pounds per square inch.
The best English m the foregoing and those shown in the next figure, and a comparison of others for which we have no room here, it appears that the ancient Egyptian, Etruscan, Syrian, and Greek plows were equal to the modern plows of the South of France, part of Austria, Poland, Sweden, Spain, Turkey, Persia, Arabia, India, Ceylon, and China.
The last thirty years may have worked a partial change, but not sufficient to invalidate the general truth of the statement.
The ancient Etruscan plow, for instance, wa
