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562 been made in the interpretation of the stellar lines through experi- ments in the laboratory. In particular, the use of stronger dis- charges than had previously been employed has led to the discovery of new lines of several elements, which have been identified with the lines occurring in the hotter stars. Certain lines of the Wolf-Rayet stars, for example, have thus been traced to carbon by Merton, 1 and others to oxygen by Fowler and Brooksbank. 2 The general outcome of the experimental reproduction of stellar lines is to sup- port the view that the order in which the different classes of stars had been arranged is a true temperature sequence. This order, pre- viously indicated by Secchi and Vogel, is now generally expressed by the classification introduced at Harvard by E. C. Pickering, in which the most important classes, passing from the white to the redder stars, are designated by the letters B, A, F, G, K, M. s On passing from the relatively cool M stars to the hot B stars, it is necessary, in accordance with the work of Lockyer, to employ a gradually increasing stimulus in order to excite the spectra which appear at successive stages of the stellar sequence.

There are certain peculiarities of the successive stellar spectra which call for explanation, if it be assumed that all stars are of essen- tially the same composition. Thus, at every stage of the stellar sequence there are many elements which are not represented at all, and different selections of the elements appear at the various stages. The earlier attempts to deal with such questions are incompatible with modern views as to the origin of spectra. The new theory of spectra, however, supplemented by a theory of the temperature radiation of gases, has been shown by Dr. M. N. Saha * to provide a very probable explanation of most of the phenomena. According to this theory, a gas or vapour may emit radiations, or become ionized, by subjecting it to appropriate thermal stimulus, depending in part upon the density, and the emissions produced mechanically by the spark may thus also be generated by the action of a sufficiently high temperature. Dr. Saha concludes that, under the temperature stimu- lus prevailing in the atmosphere of any particular star, certain ele- ments are excited to radiation of their characteristic lines, in accord- ance with their resonance and' ionization potentials, while other elements are either ionized, or the stimulus is too weak to excite the lines by which their presence could be recognized. When an ele- ment is completely ionized in this way, it will often happen that the most characteristic lines of the modified atoms will he far in the ultra-violet, outside the range of possible observation, so that the element will escape detection. Again, under the action of the highest temperatures, a second step in ionization may set in, producing still more refrangible chief lines as a rule, so that even the elements which yield enhanced lines in the ordinary range of spectrum at some stages will eventually cease to be represented. The simplification of_the spectra of the hotter stars thus receives an acceptable explanation ; the surviving elements represented in the spectra are those for which the maximum amount of energy is required to produce the succes- sive ionizations, or those for which these conditions yield lines of sufficient intensity within the range of spectrum which is open to observation. Preliminary calculations of the probable temperatures at which such changes of spiectrum would occur are in substantial agreement with the temperatures of the various classes of stars deduced from spectro-photometric observations^ by Wilsing and Scheiner. It therefore seems probable that temperature is the con- trolling factor in determining the character of the spectrum given by a star, and, as Dr. Saha remarks: " The stellar spectra may be regarded as unfolding to us, in an unbroken sequence, the physical processes succeeding each other as the temperature is continually varied from 3000 to 40,000."

BIBLIOGRAPHY. To the works mentioned in the earlier article the following should be added: Eder and Valenta, Atlas typischer Spektren (1911); P. 'Zeeman, Researches in Magneto-Optics (1913); J. Stark, Die Atomionen chemischer Elemente und ihre Kanalstrahlen- spectren (1913) ; T. Lyman, The Spectroscopy of the Extreme Ultra- violet (1914); A. Sommerfeld, Atombau und Spektrallinien (1921); L. Silberstein, Report on the Quantum Theory of Spectra (1920); A. L. Hughes, " Report on Photo-Electricity, including Ionising and Radiating Potentials and Related Effects," Bull, of National Research Council, Washington (1921); A. Fowler, Series in Line Spectra, Phys. Soc., London (1921). (A. F.)

SPEE, COUNT MAXIMILIAN VON (1861-1914), German admiral, was born June 23 1861 at Copenhagen. He was first officer of the battleship " Brandenburg " when it was sent to East Asia in 1899 during the Chinese boxer disturbances. In

1 Proc. Roy. Soc., A, xci., 498 (1915).

1 Monthly Notices, R.A.S., Ixxvii., 511 (1917).

1 The work of H. N. Russell, in general agreement with that of Lockyer, renders it probable that the true sequence is from M to B with increasing temperature, and thence from B to M with decreasing temperature, the density increasing throughout. Stars of rising temperature, on account of their great volume, have been called " giants," those of falling temperature " dwarfs." Differences between the spectra of giants and dwarfs of the same spectral class have been found by Adams (see Monthly Notices, R.A.S., Ixxxi., 334).

4 Proc. Roy. Soc., A, xcix., 135 (1921).

1908 he was chief of the staff of the North Sea command, and in 1913 he was appointed chief in command of the Cruiser Squadron. When the World War broke out he was on a voyage with this squadron from Tsing-tau to the South Sea Islands. He was hard pressed by British and Japanese naval forces, but was at an advantage when he was engaged on Nov. i 1914 off Coronel on the Chilean coast by Adml. Cradock with a British squadron which was inferior to his own in numbers and speed, as well as in range and weight of fire. Adml. Cradock went down with his ship, the " Cape of Good Hope," and the " Monmouth " was also sunk. On the following Dec. 8 Count Spec's squadron was drawn into action off the Falkland Is. by the powerful cruiser squadron of Adml. Sturdee which had been sent out to look for him. Count Spec's own ship, the " Scharnhorst, " was sunk, he himself and his two sons going down with all hands. The " Gneisenau " was also sunk, as were the " Leipzig " and the " Nurnberg." The light cruiser " Dresden " escaped, but was afterwards sunk off Juan Fernandez in the Pacific.

SPIELHAGEN, FRIEDRICH VON (1829-1911), German novelist (see 25.667), published during his later years Freigeboren (1900); Die schonen Amerikanerinnen (1902); Ultimo (1903); and Am Wege (1903). He died at Charlottenburg, Berlin, Feb. 25 1911.

SPIERS, RICHARD PHENÉ (1838-1916), English architect and author. Phene Spiers occupied a unique position amongst the English architects of the latter half of the igth century, his long mastership of the architectural school at the Royal Academy having given him the opportunity of moulding and shaping the minds of more than a generation of students. He was educated in the engineering department of King's College, London, and proceeded thence to the atelier Questel of the Ecole dcs Beaux- Arts, Paris, for upwards of three years, a method of study rare for an architectural student in those days. On his return he won the gold medal and travelling scholarship of the Royal Academy, and in 1865 the Soane medal of the R.I.B.A. In 1871, after he had worked in the offices of Sir Digby Wyatt and William Bur- ges, he gained second premium with a spirited design (showing a good deal of the Neo-Grec feeling consequent on his French train- ing) for the new Criterion building, London. His work of about this period included Lord Monkswell's house, Chelsea. Pheng Spiers travelled in France, Spain, Egypt, Syria and the East, and besides his record of more purely architectural data, he made many water-colour sketches showing much talent and facility. He was a frequent exhibitor at various galleries, and a good specimen of his art the loggia at Hampton Court is in the Victoria and Albert museum. His works and publications were many, and covered a wide ground. Amongst them are his new edition of James Fergusson's History of Architecture and the further volumes on Indian and Eastern art; Architectural Draw- ing; The Architecture of Greece and Rome (conjointly with the late W. J. Anderson) ; The Mosque at Damascus; and the articles on Persian and Roman Architecture in Dr. Russell Sturgis's Dic- tionary of Architecture, besides an edition of Pugin's Normandy. For the E.B. Spiers wrote most of the articles dealing with ar- chitecture. The position to which his erudition and ability en- titled him was fully recognized in other countries as well as his own,"as is shown by his election to membership of many foreign societies in France, Spain and America. He died in London Oct. 3 1916.

SPIRITUALISM: see 1922 Encyclopædia Britannica/Psychical Research.

 SPITSBERGEN (see 25.708). The highest peaks in Spitsbergen are believed to be Mount Newton, 5,676 ft., and Mount Poincaré, 5,446 ft., both in the eastern part known as New Friesland. Mount Eidsvoll in King James Land is 4,770 ft. and Mount Monaco on Prince Charles Foreland is 3,543 ft.

Geology.—Considerable exploration has not greatly modified the main conception of the geological structure. The old rocks of the W., generally described as the Hekla Hook series, seem to be of Silurian age to which may also be ascribed the so-called Archaean rocks of the N.W. There are no Permo-Carboniferous rocks in King James Land and the strips of rocks on the N.E. side of Prince Charle Foreland and the opposite shores of the mainland, formerly attrib-