SHELBURNE-SHELL.

kinds of gold, silver, and copper shekels are mentioned: the common shekel, the shekel of the sanctuary (probably of double value), and the shekel of royal weight. Besides these, there was a half-shekel (beka), and a fourth-shekel. The sacred shekel was equal to 20 geras (beans), and 3000 sacred shekels made a talent. The gold shekel is reckoned approximatively to contain 161 Troy grains, the silver shekel 275. During the Babylonian exile, the Persian money (dariks) was used by the captives; nor do they seem to have afterwards used any but the coin of their foreign rulers. It was first under the Maccabæans that national money began to be struck, adorned with sacred emblems, and with inscriptions in the native language and characters. De Sauley alone assumes, without much show of reason, Jewish coins to have existed from the time of Alexander the Great. Simon, the prince and highpriest,' received, according to 1 Macc. xv. 16, the permission from Antiochus VII. to strike coin in 138 B. C. The emblems are sacred branches, sheaves, flowers, vases, &c., and the legend (in a peculiarly archaic ['Samaritan'] alphabet) contains the date, the name of the Jewish ruler, and the inscriptions Shekel of Israel,'Jerusalem the Holy,' 'Redemption of Israel.' The latest coins with Hebrew inscriptions date from the revolution of Bar Cochba under Hadrian. The value of the silver shekel is reckoned to be something over two shillings.

of his time, as well as a series of MSS., which were sold to the British Museum for £5000. He was a discerning patron of genius. It was while he resided in Lansdowne House as the librarian and friend of S. that Priestley made the discovery of oxygen. Jeremy Bentham was one of his most intimate friends. S. was the patron and friend of Sir S. Romilly, and twice offered him a seat in parliament. He was also on terms of intimacy with Mirabeau, Dumont, and other foreigners of literary and political distinction. He died at his house in Berkeley Square in May 1805.

SHE'LIF, the chief river of Algeria (q. v.).

SHELL. This term is employed to designate the hard outer coverings of a large number of invertebrate animals. Shells are met with in the Echinodermata, in the great majority of the Mollusca (excluding the Molluscoids), in a few of the Annelida, as Serpula, Spirorbis, &c., in the Cirropoda, and in the Crustacea. The forms of the different varieties of shells are sufficiently noticed in the articles on the classes of animals to which they respectively belong; and we shall confine our remarks to the intimate structure of shell, which, until the publications of Carpenter, Rainey, and others, during the last quarter of a century, was altogether misunderstood. The doctrine formerly held, and still maintained in many popular handbooks of conchology, was, that shell is not only extravascular (or devoid of vessels), but completely inorganic, being composed of an exudation of calcareous particles (chiefly carbonate of lime) cemented together by a kind of animal glue. It is now known that shell always possesses a more or less distinct organic structure, which in some cases resembles that of the epidermis of the higher animals, while in others it approximates to that of the derma, or true skin. The nature of the organic structure is so different in the Echinodermata, Mollusca, and Crustacea, that a separate description is required for each, and as Dr Carpenter remarks: Even in the subordinate divisions of these groups, very characteristic diversities are frequently observ. able, so that, as in the case of the teeth, it is often possible to determine the family, sometimes the genus, and occasionally even the species, from the inspection of a minute fragment of a shell, as well fossil as recent.'

In the Echinodermata, the elementary structure of the skeleton exhibits the appearance of a network composed of calcareous and animal matter intimately united. The diameter of these apertures or meshes of network varies to a certain degree in

SHELBURNE, WILLIAM PETTY, Earl of, son of the first earl, and descendant of Sir W. Petty, founder of the science of political arithmetic, was born May 1737, and commenced his political career in 1761 by entering the House of Commons as member for Wycombe, but only sat for a few weeks, the death of his father having called him to the House of Lords. When Mr G. Grenville succeeded Bute in 1763, S., whose talents had made him remarked, although only 26, was placed at the head of the Board of Trade. When Chatham formed his second administration in 1766, he made S. one of the Secretaries of State, although not yet thirty. Upon the fall of Lord North's ministry in 1782, George III. sent for S., and proposed to him to form a government. He declined, not being the head of a party, and was sent by the king to the Marquis of Rockingham with an offer of the Treasury, himself to be one of the Secretaries of State. According to Earl Russell, in his Life of C. J. Fox, it soon appeared that S. was not so much the colleague as the rival of Lord Rockingham, the chosen minister of the court, and the head of a separate party in the cabinet. Upon the death of Rockingham in 1782, the king sent at once for S., and offered him the Treasury, which he accepted without consulting his colleagues. Fox thereupon resigned, and S. introduced William Pitt, then only 23, into office as his Chancellor of the Exchequer. S.'s ministry, on the occasion of the king's announcement of his determination to concede the independence of the American colonies, found itself out voted by the coalition between Fox and Lord North. He resigned, and the coalition ministry took his place, but soon broke up. The nation expected that the king on this event would have sent for S., but William Pitt received the splendid prize, and S. was consoled by the coronet of a marquis (of Lansdowne). During the later years of his life, his health was delicate, and he withdrew from public life; but he came forward as a strong supporter of the union with Ireland. Fig. 1.-Thin Lamina of Shell of Echinus, shewing its He indulged his tastes in the adornment of Lans- a, a, portions of subjacent layer; b, b, fractured bases of co umns downe House. Here he collected a splendid gallery of ancient and modern pictures, together with a library of 10,000 volumes, comprising the largest collection of pamphlets and memoirs on English history and politics possessed by any man

Areolar Structure:

connecting the superposed lamina. Magnified 164 diameters.

different parts of the same shell, the openings 1 eing larger in the inner than the outer layers, the extremes being th and roth of an inh. The

SHELL-SHELLDRAKE.

entire shell is made up of an immense number of such plates, which lie parallel to one another, separated by minute vertical pillars.

In the Mollusca, the shell is formed upon the surface of the mantle, which corresponds to the true skin of other animals. Hence it must be regarded as epidermic. It consists of cells consolidated by a deposit of calcareous salts in their interior, but, as in the case of many other tissues, the original cellular organisation often becomes so hidden by subsequent changes, as to cease to be recognisable. The typical condition of the shell in this sub-kingdom is

Fig. 2.-Section of the Shell of Pinna parallel to the surface, shewing Prismatic Cellular Structure, cut transversely, magnified 185 diameters.

best seen in certain bivalves-the genus Pinna, for example. On breaking off a small portion of the projecting margin of one of these shells, and examining it under the microscope, it is found to be made up of a vast number of prisms, hexagonal in form, and nearly uniform in size, which are arranged perpendicular to the surface of the lamina of the shell, so that the thickness of the lanina is formed by their length, and its surfaces by their extremities. On submitting such a lamina to the action of a dilute acid, the calcareous salts are dissolved, and a membrane is left which shews the prismatic structure as perfectly as it was seen in the original shell, the hexagonal divisions being evidently the walls of cells resembling those occurring in the pith or bark of a plant. It sometimes happens in recent, but more commonly in fossil shells, that the animal matter

Fig. 3.-Calcareous Prisms of the Shell of Pinna, from
Chalk.

Fig. 4. Portion of transverse section from Claw of
Crab, magnified 400 diameters.

shell consists of three layers, viz. (1) an external
horny epidermic membrane covering the exterior;
(2) a cellular or pigmentary structure; and (3) an
internal calcareous or tubular substance. The
horny layer is easily detached after the shell has
been for some time immersed in dilute acid; it is
thin and tenacious, and presents no trace of struc-
ture.
crab and lobster, but is much thicker in some other
The pigmentary layer is very thin in the
Decapods. The internal layer is that which con-
stitutes the chief part of the shell; it is in this layer
that the calcareous matter is chiefly deposited; but
even after this has been removed, a very distinct
animal basis remains, which closely resembles that
which is left after the dentine of the teeth has been
deprived of its inorganic constituents, as may be
seen in the accompanying figure, representing a
transverse section from the claw of the crab; the
dark lines representing minute tubules.

For further information on this subject, the reader is referred to Dr Carpenter's various articles on the Microscopic Structure of Shells, and especially to his article Shell' in the Cyclopædia of Anatomy and Physiology (from which the materials of the present article have been almost entirely drawn), and to his Microscope and its Revelations.

SHE'LLDRAKE, or SHIELDRAKE (Tadorna), a genus of ducks of the section having the hind-toe without any pendent membrane. The shelldrakes

decays and leaves the prisms ununited, and easily separable from one another. It is only in a few families of bivalves that the cellular structure is seen in this very distinct form, or that it makes up a large portion of the shell; and these families are closely allied to Pinna. In many shells, the external layer is formed on the above plan, while the internal layer is nacreous; in many, again, the nacre, or 'mother of pearl,' and in others sub-nacreous structure, constitutes nearly the whole thickness of the shell. The nacre, according to Sir D. Brewster, consists of a multitude of layers of carbonate of lime, alteruating with animal membrane; and the grooved lines on which iridescent lustre depends, are due to the wearing away of the edges of the animal laminæ, while those composed of carbonate of lime stand out; it is, however. more probable, from Dr Car- are a connecting link between geese and ducks, havpenter's researches, that the peculiar lineation of ing much resemblance to the former. The species the surface of nacre is due to the disposition of are mostly natives of the southern hemisphere,

SHELLEY.

out the COMMON 8. (T. vulpanser, or Bellonii) is common on the sandy sea-shores of Britain; many coming from the north for the winter, and some remaining all the year, and breeding, making their nests in rabbit-burrows or other holes in soft soil, whence in some places the S. receives the name of Burrow Duck. It is a beautiful bird, the sexes nearly alike in plumage; the head and upper part of the neck green, with a collar of white, and a lower collar of rich chestnut, extending over part of the back, the rest of the back white. The whole length is fully two feet. The S. is very capable of being tamed, and breeds in domestication. Its note is a shrill whistle. Its flesh is coarse and unpalatable.—The RUDDY S. (T. rutila), the only other European species, is rare as a British bird, although common in many parts of Europe and Asia.

During the interval, in the course of a tour in Switzerland, he had formed the acquaintance of Lord Byron, with whom afterwards in Italy he had much intimate intercourse. In March 1818, he left England finally-as it proved -to proceed to Italy; and during that and the following year, chiefly while a resident in Rome, he produced what may rank as his two finest poems-the grand lyrical drama of Prometheus Unbound and the tragedy of The Cenci. While at Venice with Lord Byron in 1820, he wrote Julian and Maddalo, a record in enduring verse of an interesting conversation of the discussional kind between the noble poet and him. self. His other works of chief importance are: Rosalind and Helen, begun before he left England; The Witch of the Atlas, written in 1819; Epipsy chidion; Adonais (a lament on the death of Keats); and Hellas (a lyrico-dramatic burst of exultation SHELLEY, PERCY BYSSHE, the eldest son of Sir on the outbreak of the Greek war of liberty)—all Timothy Shelley, Bart., the representative of an old three produced in 1821. The winter of 1822, S. Sussex family, was born at Field Place, near Hors- passed at Pisa; and in the April following, he ham, in that county, on August 4, 1792. His earlier established himself near Lerici, in the Gulf of Spezia. education he received at home with his sisters. His fondness for boating had through life amounted About the age of ten, he was sent to a school near to a passion, and here he indulged it to the full. Brentford, and thence, three years after, transferred On July 8, 1823, in the company of an ex-naval to Eton. Shy and sensitive, yet self-willed and friend, Mr Williams, he sailed from Leghorn, whither unsubmissive, he suffered much from the harsh he had gone to welcome his friend, Mr Leigh Hunt, discipline of masters and the tyranny of his ruder to Italy, and was lost in a sudden squall on his associates. In his refusal to fag at Eton, he gave voyage homeward. The bodies were, after some early indication of that passionate impatience of time, washed ashore, and were burned, as the quarevery form of constituted authority not approving antine law of the country required, in presence of itself to his reason which continued through life to Lord Byron, Mr Leigh Hunt, and another intimate distinguish him, and to find expression in his writ- friend, Mr Trelawney. S.'s ashes were carefully ings. In 1808, he left school, and after two years preserved, and lie buried in the Protestant cemetery passed at home, he was sent to University College, at Rome, near the grave of Keats. Oxford. Even thus early, he had become a free- In S.'s opinions, religious, social, and political, thinker of a somewhat advanced kind, and a pam- crude as they often were, and everywhere expressed phlet, entitled A Defence of Atheism, which he with an unwise reckless vehemence, there was much circulated during the second year of his college that might reasonably offend; and they not only on course, led to his expulsion from Oxford. This so their own account roused against him a storm of irritated his father, that for some time he declined obloquy, but made him throughout life the accreto receive him; and on his rash marriage, in August dited mark of the most foul and malicious slanders. 1811, to a Miss Harriet Westbrook, the daughter of To this chiefly it is to be attributed that, whilst he a retired innkeeper, the estrangement between them lived, his genius met with no wide appreciation; but became final and complete, the old gentleman con- since, it has been amply recognised, and perhaps no Benting to allow his son a liberal yearly income, but writer of his time at this day ranks higher on the never after having any intercourse with him. S.'s whole than he. In sustained lyrical impetuosity, marriage was in its issue tragical. In 1813, a separ- S. surpasses every other writer; his diction is not ation took place between him and his wife, who, more remarkable for its opulence than for the with two children, returned to the care of her expressive subtlety and precision with which it father; and three years after, the unhappy woman defines the nicest refinements of feeling and thought; drowned herself. The refinements of intellectual and his page flashes with imagery like a royal robe sympathy which poets desiderate in their spouses, rich with gems. But too often, whilst he dazzles, S. failed to find in his wife, but for a time he seems he also bewilders; he is fond of supersubtle abstrac to have lived with her not unhappily; nor to the tions, unsubstantial as clouds or dreams; and frelast had he any fault to allege against her, except quently in reading him we seem merely to be such negative ones as might be implied in his looking on wreaths of rainbow-coloured mist. This meeting a woman he liked better. This was Mary want of clear and firm outlines is more or less felt Godwin, daughter of the celebrated William Godwin throughout all his larger works, with the single and Mary Wollstonecraft, with whom, in 1814, he exception of The Cenci, in which a terrible story of travelled in France and Switzerland, and who after- real life is dramatised with consummate vigour and wards became his second wife. Such excuse of his directness of treatment. As to the matter of the conduct in the matter as the theory of congenial rest of his poems, they concern themselves, for the souls' may afford in the eye of the moralist must most part, not with the world as it is or has been, but to the full be allowed for Š., whose later union was with a perfected world which is to be. S. is the of almost ideal felicity and completeness. On the rates of the future, as Scott is the poet of the past. death of his first wife, he laid claim to his children; Of the charge of atheism against S., it is enough to but this their grandfather, Mr Westbrook, strange say that it rests mainly on his boyish poem of Queen as it may now seem, successfully resisted at law Mab; that this he did not himself give to the on the ground of his atheism, as exhibited in the world; and that when, in 1821, it was surreptipoem of Queen Mab, which a year or two before he tiously published, he issued an express protest had printed, though only for private circulation. against his being held answerable for any opinions In 1815, while living at Bishopsgate, near Windsor, set forth in it. In his later works, a vague Panhe wrote his Alastor, one of the most finished and theism seems indicated; and one or two passages characteristic of his works; which was followed by occur which fairly admit of a purely theistic interThe Revolt of Islam, composed in 1817 at Marlow.pretation. The only complete edition of S.'s poems

SHELL-GUN-SHELLS.

is that published by Mrs Shelley in 1839. A selection from his letters, with translations and prose-essays appeared in 1840. See Medwin's Life of Shelley (1849); Trelawney's Recollections of the Last Days of Shelley and Byron (Lond. 1858); Thomas Jefferson Hogg's Life of Shelley (Lond., 2 vols., 1858), and the Shelley Memorials, by Lady Shelley (Lond., 1859).

By common testimony of all who knew him, S., who was held up to execration as a perfect monster of iniquity, was one of the purest, gentlest, most lovable of men; of the tenderest private affections, and, beyond the immediate circle of these, of the largest flowing charity. The passion of philanthropy expressed in his writings found as practical an expression in his daily life as if he had never made any very great profession of it. The episode of his first marriage seems more or less awkward for him; but the one passionate frailty of a boy can scarcely be held a serious blemish on a man whose whole subsequent life was exceptional in virtue and beneficence.

MARY WOLLSTONECRAFT GODWIN, wife of the poet, was born in London 1798, married Shelley, as above stated, in 1816; and in the same year produced a remarkable novel, entitled Frankenstein, the hero of which, a profound student of nature, discovers the secret of creating life, and produces a monster whose history, though wild and horrible in its incidents, is invested with a strong human interest. The work had a great success, and may be reckoned the best of Mrs Shelley's literary efforts. Other novels of hers are Valperga, The Last Man, Lodore, and The Fortunes of Perkin Warbeck. She likewise wrote Rambles in Germany and Italy; a series of biographies of foreign artists and poets for the Cabinet Cyclopædia; and carefully edited her husband's poems. She died in London, February 1, 1851.

SHELL-GUN belongs rather to the past than the present, as in modern rifled artillery all guns fire shells. Before their introduction, however, shells were fired from guns of large bore, and proportionately small thickness of metal, not differing materially from howitzers, except that they had greater length.

SHELL-LAC. See LAC.

SHELLS, called in earlier times bombs, consist of hollow vessels of metal, containing gunpowder or other explosive compound, so arranged that it shall explode at a certain point, and spread destruction around by the forcible dispersion of its fragments. The invention of this murderous missile cannot be accurately traced. Shells were employed in 1480 A. D. by the sultan of Gujerat, and by the Turks at the siege of Rhodes, in 1522. The Spaniards and Dutch both used them during the war of Dutch independence; and they appear to have been generally adopted by about 1634. As shells required Mortars (q. v.) for their projection, they were not used in naval warfare until the French constructed special bomb-vessels in 1681; but since that period, shell-guns, being cannon of large bore, have been introduced, and shells are now employed by all ships of war.

of seconds. This fuse might either be kindled by hand the moment before the mortar was fired, or its ignition might be effected by the act of firing itself. The Shrapnell shell, introduced by Colonel Shrapnell of the Royal Artillery about 1808, contained a number of bullets, and being fired at bodies of men, it was timed to explode about 100 yards before reaching them, when the shell burst, and the bullets with the fragments continued their course, diverging continually as they went, until they reached their object in a death-cloud. The Concussion shell, or Percussion shell, is one in which the charge is fired by the detonation of a cap on striking an object. If sufficiently delicate to explode on touching a soft object, and at the same time not to be exploded by the resistance of the air to its rapid flight, this form of shell is the most certain in execution.

Since the introduction of rifled ordnance, the shell has become the commonest form of projectile. It has ceased to be spherical, and is usually in the shape of an elongated bolt. Several rival shells at present divide public favour, and compete for adoption into war service. Without noticing the numerous varieties which are in course of trial on the continent and in America, the following are the principal British competitors. The Armstrong shell is a pointed bolt of iron (usually percussion), containing an inner 'segment shell,' made

up of 49 segments of cast iron. Seven of these segments form a circle, or ring, and seven circles give the necessary length. A coating of lead affords a soft medium for fitting into the grooves of the gun. The shell thus made somewhat resembles a bottle without the neck. The necessary bursting charge having been inserted, the rear-end is plugged with lead, the fuse is screwed into the front, and the shell is ready for action. This projectile has a great and accurate range, and its segments cannot fail, on explosion, to do great damage. The principal drawback has been found in the lead-casing, which is often thrown off in parts soon after the shell leaves the gun, and which thus falls among the foremost ranks of the army using it, sometimes inflicting severe Until within a few years, every shell was a wounds. The Whitworth shell is hollow sphere of cast-iron, varying in thickness an elongated hexagonal bolt of from half an inch to two inches, and in diameter iron or steel, cast in one piece, from five and a half inches to thirteen inches. The and with a bursting charge at sphere had a fuse-hole (like a bung-hole) an inch the rear-end. It explodes on across, through which the charge was inserted, consisting of pieces of metal and powder to burst the shell. The hole was plugged by a fuse, which was a tube of slow-burning powder, timed to communicate fire to the charge after the lapse of a certain number

percussion; but the space allowed Whitworth Shell for the burster is deemed insuffi

cient to produce the full effect which the length and correctness of the weapon's range give cause to expect. The Lancaster shell is oval, to fit the

SHELL-SAND-SHEMITIC LANGUAGES