water. Significant improvements came only with the de-
velopment of the steam engine and better road-building
methods long after the Renaissance had ended.
Further reading: Carlo M. Cipolla, Guns and Sails in
the Early Phase of European Expansion, 1400–1700 (New
York: Pantheon Books, 1965); Denis Cosgrove et al, Water,
Engineering and Landscape (Chichester, U.K.: John Wiley
& Sons, 1994); Richard Leslie Hill, Power From the Wind:
A History of Windmill Technology (Cambridge, U.K.: Cam-
bridge University Press, 1994; repr. 1996); William B. Par-
sons, Engineers and Engineering in the Renaissance
(Cambridge, Mass.: MIT Press, 1968); Terry S. Reynolds,
Stronger Than a Hundred Men: A History of the Vertical
Water Wheel (Baltimore, Md.: Johns Hopkins University
Press, 1999; repr. 2003); Paolo Rossi, Philosophy, Technol-
ogy and the Arts in the Early Modern Era (New York and
London: Harper & Row, 1970).
Teixeira, Pedro (fl. 1587–1610) Portuguese traveler and
historian of Persia
Texeira, who may have been a doctor by profession, prob-
ably sailed for Goa in 1586. He traveled extensively in
Portuguese India, then moved to Hormuz (c. 1593–97),
where he became proficient in Persian. From Malacca
(1597–1600) he returned home (1600–01) by a route via
Acapulco, across Mexico on horseback, then by ship to
Cuba, and eventually Seville. Discovering that money he
had sent home via the Cape had not arrived, he sailed
again for Goa (1602), returning by land through Me-
sopotamia (1604–05). On his return he settled in Ant-
werp. His account of his travels was published with his
Persian history: Relaciones ... d’el Origen, Descendencia y
Succession de los Reyes de Persia, ...y de un Viage hecho por
el mismo Autor dende la India Oriental hasta Italia por tierra
(1610).
telescopes Optical instruments for making distant ob-
jects appear larger. The first undisputed description of a
telescope, in the official Hague records for 1608, attributes
the invention to Hans Lippershey (died c. 1619), a spec-
tacle maker of Middelburg, Holland. Details are scarce and
the precise nature of the instrument is unknown. The
claim was challenged immediately by James Metius of
Alkmaar and Zacharias Janssen of Middelburg. It is now
known that all three had in fact been anticipated by
Thomas HARRIOT. All such instruments were refractive
telescopes and operated with a biconvex object lens and
biconcave eyepiece. Word of the new invention spread
quickly, for in 1609 in Padua a similar refractor capable of
magnifying 33 times had been made by GALILEO. Such in-
struments, known as Dutch telescopes, produced an erect
image (which fitted them well for military and naval ap-
plications) but presented an unacceptably small field of
view. The latter defect was overcome by Johannes KEPLER
in 1611, by using two biconvex lenses, though at the price
of producing an inverted image. This was not a serious
drawback for astronomers, and Kepler’s arrangement be-
came known as the “celestial” telescope—as opposed to
the “terrestrial” or Galilean instrument.
More serious faults remained. The images produced
were distorted and often surrounded by colored rings. The
defects, known respectively as spherical and chromatic
aberration, were in fact inherent properties of refracted
light. At best they could be minimized by constructing
telescopes, the so-called aerials, with very long focal
lengths. Instruments 150 feet long were in fact con-
structed, but proved too impractical. The solution—to
construct reflective rather than refractive telescopes—
came much later (1672) with Isaac Newton.
See also: OPTICS
Further reading: Richard Parek, Seeing and Believing:
How the Telescope Opened Our Eyes to the Heavens (New
York: Penguin Viking, 1998).Telesio, Bernardino (1509–1588) Italian natural
philosopher
Telesio was born at Cosenza and was educated by his
uncle who taught him Greek, thus enabling him to make
direct contact with Greek scientific writings. He studied at
Padua where he became disillusioned with contemporary
ARISTOTELIANISM, influenced as it was by Arabic interpre-
tations. After he left Padua he spent some years develop-
ing his own views, which amount to a return to the
authentic opinions of Aristotle. In 1565 he published his
first book, De rerum natura iuxta propria principia, a work
that he continued to expand and that reached its final
form in 1586. In 1566 he founded the Academia Telesiana,
a scientific society. He died at Cosenza.44660 0 TTeeiixxeeiirraa,, PPeeddrrooGalilean telescopeeye objecteye objectKeplerian telescopeTelescopesThe operation of the two kinds of refractive
telescope produced by the early pioneers in the field, Galileo
and Kepler.