edina, in 1557. From
that time, enormous quantities of mercury have been continually
required for the mining operations in the silver-producing districts
of Spanish America. Efforts were occasionally made by the Mexican
viceroys to procure it in China; but "the Chinese mercury obtained
from Canton and Manilla was impure, and contained a great deal of
lead; and its price [1782] amounted to 80 piastres the quintal." See
Humboldt's account, descriptive and historical, of this use of mercury,
in his _New Spain_ (Black's trans.), iii, pp. 250-288.

In this connection, see the interesting statement by Santiago de Vera
(_Vol_. VI, p. 68) that as early as 1585 the Japanese (who then had but
little communication with the Spaniards) were using Chinese quicksilver
in the silver mines of Japan. Some of the Chinese mercury had been
brought to Manila in 1573 (_Vol_. III, p. 245), and Sande mentions
(_Vol_. IV. p. 54) the mines of silver and quicksilver in China.

[69] This document is simply an abridgment or summary made by Ventura
del Arco from the letter of Ledesma.

[70] Cf. this statement with the royal decree of May 26, 1609, which
is presented in this volume, p. 79, _ante_.

[71] Valerio de Ledesma was born at Alaejos. March 23, 1556, and
became a novitiate in the Jesuit order in 1571-1572. He was sent
to the Philippines, where he served as rector of Cebu, associate of
the provincial, rector of Manila, provincial, rector and master of
novitiates at San Pedro Macati, and again rector at Manila, where he
died, May 15, 1639. See Sommervogel, Barrantes (_Guerros piraticas_),
and Pardo de Tavera (_Biblioteca Filipina_, Washington, 1903) as
to his authorship. See also Murillo Velarde's _Historia_ (Manila,
1749), book ii, ch. vii, pp. 260-266, for a notice regarding him. In
the Ventura del Arco MSS., at the end of this summary of Ledesma's
letter appears a tracing of his autograph signature.

[72] According to Sommervogel, Juan de Ribera was born at Puebla
de los Angeles in 1565, and entered upon his novitiate at Rome in
1582. He was sent to the Philippines in 1595, and taught theology
and was rector at Manila, where he died June 5, 1622. Besides the
present letter, Father Ribera was the author of the _Lettera annua_
from the Philippines for 1602-1603, which was printed at Venice and
Paris, in Italian and French respectively, in 1605.

[73] In regard to the correction of Manila time, see _Vol_. I, p. 22,
note 2.

[74] That is