TOSCANELLA
786
TOSCANELLI
Observatort of the Ebho, at Roquetas, Cata-
lonia, Spain. The founder and present director is
Father Ricardo Cirera, S.J. The construction of the
buildings was commenced in March, 1903; they were
completed in Sept., 1904, and by 30 Aug., 1905, the
date of a total eclipse of the sun, it was possible to
make all the observations in the observatory. See
"Instrucciones para la observaci6n del eclipse de sol
del 30 de Agosto de 1905" and Cirera, "Noticia del
Observatorio y de algunas observaciones del eclipse
de 30 de Agosto de 1905", issued by the observatory.
The observatory comprises branches in astrophysics,
meteorology, and geophysics.
With the exception of some of the meteorological apparatus, which is installed in the open air, the appa- ratus is distributed in six buildings, a seventh being devoted to the library and general offices, and a small building apart for the mechanician. AU these build- ings are separate, so as to obtain the greatest possible accuracy in the results. In the building for the mag- netic observations, all iron or any other substance which could exert a contrary magnetic influence is carefully excluded. The observatory is at some dis- tance from the nearest town, on an elevation which dominates the valley of the Ebro. There is no electric car line or other factor in this valley which could act as a disturbing influence. (See " Boletln Mensual del Observatorio del Ebro", vol. I, no. 1, with introduc- tion, an observatory publication.)
The Government declared this institution a public utility on 18 Oct., 1904.
The observatory publishes a monthly bulletin, in which the observations, reduced to their absolute values, are given in tables. Other scientific treatises published by the observatory are: "Discurso relativo al Establecimiento de la nueva Secci6n de Astrono- mla y Fisica del Globo", by Father Cirera; "La Secci6n de Astronomia y Fisica del Globo y la Meteo- rologla espanola"; "Los Eclipses de S de Mayo de 1910 y 26 de Abril de 1911"; and "Recientes pro- gresos de las Ciencias Astron6micas en Espaiia".
La Fdentk. // ' ' ' A 1 '"'I 'le Espuila (Madrid, 1873); Gams, Series ., ' ■ ' ilholicx (Ratisbon, 1873);
Cortes, His("" .-M/rfe Torfosa (1747, authen-
tic copy, Coh-in" Ml I' -I!-. !'iri.^.:tl; Martorell, Historia de la Hibera (Tortos:i. 1621;; reprinlfd, Tortosa, 1905); O'Calla- GHAN, Episcopologio de la Santa Iglesia de Tortosa (Tortosa, 1896); Idem, La Cathedral de Tortosa (Tortosa, 1890); Risco, Espatia Sagrada, XLII (Madrid, 1801); Villanueva, Viaje Literario, V (Madrid. 1806); FernAndez, Historia de Tortosa (Barcelona, 1867); Miralles Mesequer. Guia del Obispado de Tortosa (Tortosa, 1902); Direclorium (Tortosa, 1911); for observ- atory of Ebro see Boletln menstml (Jano. 1910), Spanish and French; Nature (London, 23 March, 1911); Scientific American (New York, 1.5 Oct., 1910); Physikalische Zeilschrift (Gottingen, 1 Julv. 1911); Le Radium (Paris, July, 1911); Ciel et Terre (Brussels 1916), 438: Atti delta Pontificia Accademia Romana dei Nuovi Lincei (Rome, 1910-11), Sess. VI«, 21 May. 1911.
Charles J. Mullaly.
Toscanella. See Viterbo and Toscanella, Diocese of.
Toscanelli, Paolo dal Pozzo, mathematician, astronomer, and cosmographer, b. at Florence in 1397; d. there, 10 May, 1482. ToscaneUi, who was one of the most distinguished scientists of the fifteenth cen- tury, was the son of the Florentine physician Dom- inic Toscanelli. He began his mathematical studies at Florence under Giovanni dell'Abacco. At the age of eighteen he entered the University of Padua where he studied mathematics, philosophy, and med- icine. In this period he formed his life-long friend- ship with Nicholas of Cusa who studied law and mathematics at the same university. The two i^rob- ably met at the college Prosdocimos de'Beldomandi. Both left the university in 1424, Nicholas with the title of doctor decrctorum and Paolo as a doctor of medicine. In consequence of this Toscanelli after- wards was frequently called Paolo fisico. While Nicholas of Cusa went back to (icrniany Toscanelli returned to Florence, where he spent the remainder of
Paolo dal Pozzo Toscanelli
>m a painting by Giorgio Vasari in
Signoria, Florence
his life with the exception of short journeys in Tuscany
and brief sojourns at Todi and Rome. At Florence
Toscanelh took up scientific studies in various direc-
tions which brought him into connexion not only with
distinguished artists, as Brunelleschi, but also with
the greatest scholars of Italy and other countries. He
may indeed be said to have been the centre of the
learned world of that era. His contemporaries pro-
nounced him one of the most distinguished mathema-
ticians of his time. Regiomontanus and Cusa sought
his opinion in the most abstruse questions of theoreti-
cal mathematics, or supported their assertions by his
authority. Thus
Nichol.as of Cusa,
even at the height
of his fame, ad-
mired in his friend
the thorough
mathematician,
as is shown by
his treatise "De
transformationi-
bus geometricis"
which was dedi-
cated "Ad Pau-
lum magistri do-
minici Physicum
Florentinum"
The same admi-
ration is evident
when Cusa wrote
as a dialogue
between himself
and Toscanelli the
latter's adverse
criticism of Cu-
sa's "Mathemat-
ica complementa".- In this dialogue Toscanelli says
that like Regiomontanus he found the "Mathematica
complementa", which investigated the squaring of
the circle, obscure and lacking in positiveness.
Toscanelli's services to astronomy are shown by the painstaking and exact observations and calculations, preserved in manuscript, of the orbits of the comets of 1433, 1449-50, of Halley's comet of 1456, of the com- ets of May, 1457, of June-July-August, 1457, and that of 1472. According to his own testimony these observations cost him immense labours and long vigils. He could not entirely throw off the influence of astrology, although two of his contemporaries, Mar- silio Ficino and Giovanni Pico, disbelieved in it. A monument- to his astronomical skill still exists at the Cathedral of Santa Maria del Fiore at Florence in the well-known gnomon, which he constructed about 1468 and which was later improved by Cardinal Ximenes. A marble slab having a small opening in it was placed at a height of 277 feet in the dome over the middle of the left tr;tnsept ; by the shadow he could determine midday to a half-second, and could also settle with much precision the altitudes of the solstices. Toscanelli also gave much attention to cosmography. It seems indeed that he was the most distinguished scholar of the fifteenth century in this branch of science, the aim of which was to gain knowl- edge of the world in its widest extent. The estima- tion in which he was held as a cosmographer is shown by the generally accepted belief, resting on traditions respecting Columbus, that Columbus before under- taking his dangerous western voyage asked Tosca- nelli's advice. Toscanelli had a thorough knowledge of the writings of Ptolemy, he had studied the travels of Marco Polo, and h:id gained personal information from merchants and seamen, above all from the Itiil- ian traveller Xicolo Conti. All that he had thus learned had brought liim to tlie conviction that the transverse extent of Europe and .Vsia covered nearly two-thirds of the earth, that is 230° of latitude, so
