SIDEREAL MAGNETISMSIDNEY. 



249 



before an audience which melted into tears on the 

 occasion. She, however, performed, in 1816, for 

 the benefit of her brother, Mr Charles Kemhle, 

 and a few nights in Edinburgh, to assist her daugh- 

 ter-in-law. Her greatest characters are well known 

 to have been Catharine, in Henry VIII., and lady 

 Macbeth, in which she manifested a dignity and 

 sensibility rarely equalled. She died June 8th, 

 1831 See Campbell's Life of Mrs Siddons. 



SIDEREAL MAGNETISM, with the believers 

 in animal magnetism, denotes the beneficial influ- 

 ence of the stars upon patients. 



SIDEREAL TIME. A sidereal day is the 

 time during which the whole body of fixed stars 

 appears to revolve round the earth. It is found by 

 observing two successive passages of the same star 

 over the meridian. The time from one passage to 

 the other consists of twenty-four hours, each of 

 sixty minutes, each of sixty seconds, &c. Sidereal 

 time is not adapted to the purposes of common life 

 (see Solar Time}, but is particularly suitable for 

 astronomical observations, on account of its perfect 

 uniformity. Astronomers have sidereal clocks. 

 The sidereal day, and of course each subdivision, 

 is shorter than the solar day, because the sidereal 

 day is determined simply by the rotation of the 

 earth on its axis, and is completed as soon as this 

 rotation is performed ; but in the case of the solar 

 day, the earth's revolution round the sun is also to 

 be taken into the account. The earth advances in 

 its orbit nearly a degree each day ; and to bring 

 the sun to any particular meridian, it has to make 

 so much more than a complete rotation on its axis 

 as will counterbalance its advance in its orbit. 

 The average amount of this daily advance is 59' 

 8'. So much, therefore, must the earth turn on 

 its axis beyond one rotation in order to complete 

 the solar day, which is therefore three minutes 

 fifty-six seconds longer than a sidereal day. Hence 

 the mean solar day is twenty-four hours three mi- 

 nutes fifty-six seconds sidereal time ; or the sidereal 

 day is twenty-three hours fifty-six minutes four 

 seconds mean solar time. See Lalande's Abrege d' 

 Astronomic (Paris, 1795); see, also, the article 

 Day. 



SIDER1SMUS (from <r/S^, iron); the name 

 given by the believers in animal magnetism to the 

 effects produced by bringing metals and other inor- 

 ganic bodies into a magnetic connexion with the 

 human body. Hence we hear of sideric bodies 

 and sideric power. The former are inorganic 

 bodies, in contradistinction to the animated bodies, 

 which produce somnambulism. 



SIDEROGRAPHY; the art of engraving on 

 steel. (See Engraving. ) The word comes from 

 fibn^n', iron. 



SIDNEY, ALGERNON, a celebrated English re- 

 publican and martyr to liberty, was the second son 

 of the earl of Leicester, by the daughter of the 

 earl of Northumberland. He was born, according 

 to some accounts, in 1617, and to others, in 1622, 

 and educated under the inspection of his father, 

 whom he accompanied in his embassies to Denmark 

 and France. He was also early trained to a mili- 

 tary life, and served with some distinction under 

 his brother, lord Lisle, during the Irish rebellion. In 

 1643, both brothers returned to England, and joined 

 the parliament. In 1645, Algernon was promoted 

 by Fairfax to the colonelcy of a regiment of horse, 

 and, after being present in several actions, was in- 

 trusted with the government of Chichester. He 

 was then stationed in Ireland (1646), but soon after 



returned to England, where he was thanked by 

 parliament for his services, and made governor of 

 Dover. When the high court of justice was formed 

 for the trial of the king (see Charles /.), he was 

 nominated a member, but was neither present when 

 sentence was pronounced, nor signed the warrant 

 for the execution. It appears, however, that he 

 vindicated that measure, which has led to a suppo- 

 sition that, in withholding his signature, he only 

 yielded to the influence of his father. A politician 

 so inimical to the encroachments of authority was 

 not likely to acquiesce in a usurpation ; and he 

 warmly opposed the designs of Cromwell. During 

 the government both of the protector and his son 

 Richard, he lived In retirement at Penshurst, where 

 he is supposed to have composed his celebrated 

 Discourses on Government. When the return of 

 the long parliament gave expectations of the estab- 

 lishment of a republic, he assumed a public charac- 

 ter, and was nominated one of the council of state. 

 He was soon after appointed a commissioner to 

 mediate a peace between Denmark and Sweden, 

 and while engaged in this embassy, the restoration 

 took place. Conscious of the offence he had given 

 the royal party, he refused to return, and remained 

 an exile for seventeen years ; and, although occa- 

 sionally assisted by his family, he found it difficult 

 to support himself in conformity to his birth and 

 rank. At length, in 1677, the influence of his 

 father obtained leave for him to return, with a 

 pardon for all offences. At the time of his return, 

 parliament was urging the king to a war with 

 France ; and it was feared by the opposition that 

 Charles II. would agree to it until he obtained the 

 supplies, and would then squander them on his 

 pleasures, or devote them to arbitrary purposes. 

 The English patriots were therefore opposed to 

 this war, and some of the leaders intrigued with 

 the French ambassador, Barillon, to defeat the 

 measure. (See Russel, Lord William.} It even 

 appears, according to the Barillon papers, as given 

 by Sir John Dalrymple, that the name of Sidney 

 was among those who received pecuniary aid from 

 France. The testimony thus afforded against a 

 man of high character, and whose sacrifices to prin- 

 ciple were notorious, has led to the suspicion of 

 fabrication and interpolation. The death of his 

 father, soon after his return, led him openly to join 

 in the opposition, and he consorted much with the 

 duke of Monmouth and others who held views 

 kindred or similar to his own. In the Rye-house 

 plot he is named as one of a council of six, who 

 were to organize an insurrection in conjunction with 

 the Scottish malcontents. It was, however, for 

 his supposed share in the subordinate conspiracy for 

 assassinating the king, that he was arrested, with 

 lord William Russel and others. After the sacrifice 

 of the latter, he was tried, as the next most obnoxi- 

 ous person, for high treason, before the hardened 

 tool, chief-justice Jeffreys, November 21, 1683. 

 There was no direct evidence against him, except 

 that of the disgrace to nobility, lord Howard, while 

 the law for high treason required two witnesses. 

 To help this defect, the attorney-general had re- 

 course to the expedient of producing passages from 

 some discourses on government, found in manuscript 

 in his closet, which maintained the lawfulness of 

 resisting tyrants, and the preference of a free to an 

 arbitrary government. Although there was no 

 proof that these papers were in his own hand-writ- 

 ing, in defiance both of law and common sense, they 

 were deemed equivalent to a second witness; and, 



