ASTRONOMY. 70 
(Pope Sylvester If.), the Emperor Frederic IL, King Alphonso of Castile, 
and some others, make the only honorable exceptions by their active 
participation in the study. Alphonso the Tenth held at Toledo, in 1240, 
an astronomical convention, whose fruit was the Alphonsine tables. 
At a later period appeared the first European astronomers, properly so 
called, Vitello, Bonatus, Purbach, John of Gamundia (first rectifier of the 
calendar), and Regiomontanus (calculator of ephemerides). At the end of 
the fifteenth century, Savonarola and Picus of Mirandola earnestly contended 
against Astrology. All were, however, eclipsed by Copernicus, who, in 
1508, presented to the world his theory, and its proofs, of the true arrange- 
ment of the planets in our system. Nevertheless he found many opponents, 
particularly Tycho Brahe, one of the greatest of practical astronomers. 
This latter individual defended the immobility of the earth, and presented 
another system of the planets, known under his name, which was, however, 
very soon overthrown by the celebrated laws of Kepler (1571-1630), who 
constructed the first tables (the Rudolphian), calculated according to the 
Copernican system. A contemporary of Kepler, Galileo, was in a measure 
the martyr of the Copernican theory, for he was obliged to renounce at 
Rome his belief in the double motion of the earth; this, however, could not 
hinder the spread of truth, since at this time the telescope was invented, by 
means of which an entirely new view of the universe was gained. The 
mountains of the moon were discovered, the phases of Venus, the moons of 
Jupiter, the spots of the sun, &c., all of which testified to the truth of the 
Copernican theory. Huyghens, the inventor of the pendulum, discovered a 
moon, and the true shape of the ring of Saturn. In the seventeenth century, 
Halley, Flamsteed, Hevel, and others, examined the heavens incessantly and 
accurately, and Newton was the immortal creator of Physical Astronomy. 
by his discovery of the law of gravitation. The delusion of Astrology 
now vanished, and there remained alone the fear of great comets. In the 
eighteenth century, Kuler, Clairaut, and D’Alembert, worked out still further 
Newton’s Mechanics of the Heavens. Dollond invented the achromatic 
telescope, and, somewhat later, Herschel brought the Newtonian reflecting 
telescope to a wonderful degree of perfection : the discovery of the planet 
Uranus and his six moons was the result. A little before this, Mayer con- 
structed his accurate tables of the moon. Bradley discovered aberration 
and mutation, and Lacaille, at the Cape of Good Hope, mapped out the 
southern hemisphere. Maupertuis, in Lapland, and La Condamine, in Peru, 
carried on measurements of a degree, in order to a more accurate determina- 
tion of the size and figure of the earth; this end was, however, first obtained 
during the end of the last and the beginning of the present century, by the 
well known great French measurement of a degree. After Laplace and 
Lagrange had worked out in a masterly manner the theory of planetary 
perturbations, Birg, Burckhardt, Zach, Carlini, Lindenau, Bouvard, Damoi- 
seau, and others, were enabled to construct their sun, moon, and planetary 
tables, which agree within a few seconds with the actual positions of those 
bodies. At the commencement of the present century, not a few comets 
were discovered by Olbers, Pons, Mechain, Huth, and others, as also the 
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