[1] C.F. Cross and E.J. Bevan, _Jour. Chem. Soc._, 1895, 67, p. 449;
C.R. Darling, _Jour. Faraday Soc._ 1904; A. Campbell, _Trans. Roy.
Soc._ 1906.
CELSIUS, ANDERS (1701-1744), Swedish astronomer, was born at Upsala on
the 27th of November 1701. He occupied the chair of astronomy in the
university of his native town from 1730 to 1744, but travelled during
1732 and some subsequent years in Germany, Italy and France. At
Nuremberg he published in 1733 a collection of 316 observations of the
aurora borealis made by himself and others 1716-1732. In Paris he
advocated the measurement of an arc of the meridian in Lapland, and took
part, in 1736, in the expedition organized for the purpose by the French
Academy. Six years later he described the centigrade thermometer in a
paper read before the Swedish Academy of Sciences (see THERMOMETRY). His
death occurred at Upsala on the 25th of April 1744. He wrote: _Nova
Methodus distantiam solis a terra determinandi_ (1730); _De
observationibus pro figura telluris determinanda_ (1738); besides many
less important works.
See W. Ostwald's _Klassiker der exacten Wissenschaften_, No. 57
(Leipzig, 1904), where Celsius's memoir on the thermometric scale is
given in German with critical and biographical notes (p. 132); Marie,
_Histoire des sciences_, viii. 30; Poggendorff s _Biog.-literarisches
Handworterbuch_.
CELSUS (c. A.D. 178), a 2nd-century opponent of Christianity, known to
us mainly through the reputation of his literary work, _The True Word_
(or _Account_; [Greek: alethes logos]), published by Origen in 248,
seventy years after its composition. In that year, though the Church was
under no direct threat of attack, owing to the inertia of the emperor
Philip the Arabian, the atmosphere was full of conflict. The empire was
celebrating the l000th anniversary of its birth, and imperial
aspirations and ideas were naturally prominent. Over against the state
and the worship of the Caesar stood as usual the Christian ideal of a
rule and a citizenship not of this world, to which a thousand years were
but as a day. A supernatural pride was blended with a natural anxiety,
and it was at this juncture that Origen brought to light again a book
written in the days of Marcus Aurelius, which but for the great
Alexandrian might have been lost for ever. Sometimes quoting, sometimes
paraphrasing, sometimes merely referring, he reproduces and replies to
all Celsus's arguments. His work shows many signs of haste, but he more
than compensates for this by the way in which he thus preserves a
singularly interesting memorial of the 2nd century. When we remember
that only about one-tenth of the _True Word_ is really lost and that
about three-quarters of what we have is verbatim text, it would be
ungracious to carp at the method.