for the production of artificial
silk or lustra-cellulose; the alkaline solution of the cellulose
derivative being drawn either into concentrated ammonium salt solutions
or into acid baths. This product, known as artificial silk, prepared by
the three competing processes, was in 1908 an established textile with a
total production in Europe of about 5000 tons a year, a quantity which
bids fair to be very largely increased by the advent of the viscose
process, which will effect a very considerable lowering in the cost of
production. The viscose solution of cellulose is also used for a number
of industrial effects in connexion with paper-sizing, paper-coating,
textile finishes, and the production of book cloth and leather cloth,
and, solidified in solid masses, is used in preparing structural solids
which can be moulded, turned and fashioned.

For the special literature of cellulose treated from the general point
of view of this article, the reader may consult the following works by
C.F. Cross and E.J. Bevan: _Cellulose_ (1895, 2nd ed. 1903),
_Researches on Cellulose_, i. (1901), _Researches on Cellulose_, ii.
(1906). (C. F. C.)

FOOTNOTE:

[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. 1