It is the object of such an index to point out, and make readily accessible to the reader, all the important items of knowledge contained in the work. This is attained:

1. By exhibiting, in alphabetical order, everything treated of in the work, whether professedly as the subject of a leading article, or incidentally in connection with it, and whatever is casually alluded to in such a manner as to convey useful intelligence by the connection or otherwise.

2. By inserting in the index subjects not treated of by name, on which information may be found under other names.

The plan of the index is as follows:

All names of persons or objects in connection with which any information is given, and would naturally be sought in that connection, are entered alphabetically, the titles of leading articles distinguished by small capitals.

Of articles of great length the leading divisions are entered to facilitate reference.

On many subjects the information sought is scattered through different articles, to which reference is made in the index.

When there are two or more names, or more than one mode of spelling the name, of the same person or object, each is entered in its alphabetical order.

Names formed with an originally separate prefix are entered as they are commonly written; as De Kalb, De la Beche, Le Clerc, Delacroix, Descartes. Surnames and titles, by which some personages are about equally known, are both inserted.

All pictorial representations of objects described, with which this edition is profusely illustrated in the best style of engraving, are entered by name in their proper connection, with the abbreviation (illustr.) annexed. They are also entered separately, where this is deemed necessary, or convenient for ready reference. For example: Torsion balance (Coulomb's), partially described under Balance (vol. ii., p. 234, 1st col.), is fully explained under Electricity (vol. vi., p. 503, 2d col.), and is represented to the eye as clearly as by the instrument itself in the illustration on p. 504. The illustration is referred to in the index under Coulomb, and also under Torsion balance. Objects thus represented to the eye, without being named in the text, are also entered by name in the index; as, the Aryballos (Egyptian), represented on p. 779 of vol. xiii., Phoenician vase, ibid. Much that can be communicated only by pictorial illustration is thus brought to the reader's notice.

The index is to be first consulted, when information is sought on any subject. Time is thus saved by directing attention to the volume, page, and part of the page, where what is sought may be found. It will thus be seen whether the subject is treated of by name in a leading article so entitled, or in connection with some other subject; saving the trouble of first seeking it in the CyclopAedia, and then by the aid of the index. It often happens, moreover, that important light is thrown on the subject of one leading article by the views presented in others, to which attention is directed by the index.

In the references to the CyclopAedia, the first numeral (Roman) refers to the volume, the second and third (Arabic) respectively to the page and column, and the letters, a, b, c, to the first, second, or third part of the column. E. g., "Titanotherium, vi., 673, 1, c," means that what is said of it may be found in the sixth volume, page 673, 1st column, lower third of the column. - References to the index itself are followed by that word in parentheses; as, Licks (Salt), see Salt-licks (Index).

A few examples will indicate the use and value of an index to the general reader.

Vulcanized Rubber

This substance and its uses are fully described in the article Caoutchouc, vol. iii., 737, 1, b - 738, 1, c, and the article Goodyear, vol. viii., 103, 1, c.

Imprisonment For Debt

There is no leading article on this subject. But its legal introduction into England, with details of the harsh treatment of the debtor, are described in the article Acton Burnell, and the measures for its abolition in the articles Debt, Debtor, and Bankruptcy, as referred to in the index.

Juries

Their right to judge of evidence independently of the dictation of the court. The first establishment of this great principle of English law, not mentioned under the title Jury, is inoidentally referred to in the article William Penn, vol. xiii., p. 251, b.

Mississippi Scheme

Described in the article Law, John, of Lauriston, vol. x., 217, 2, b-c. Physical porosity, not defined in the article Porosity, is fully explained in the article Compressibility.

Rhodian Law (Of Commerce)

Mentioned in the article Law Merchant, vol. x., 219, 1, c.

Bed Of Justice (Holding Of)

See Parliament, vol. xiii., 117, 1, c.

Prince Rupert's Drops

This curious philosophical toy, and the Bologna phial, are fully described in the article Annealing, vol. i., 532 1, b and c.

St. Cuthbert's Beads

Scott's "Marmion " has the following allusion to them, in Canto II., xvi,:

".... On a rock, by Lindisfarne, St. Cuthbert sits, and toils to frame The sea-born beads that bear his name".

The index directs the reader to the article Encrinite, where they are mentioned by name, with a description of their origin, and an engraved illustration of the fossil marine animal of which they were the articulating joints.

Eeliotype

See Albertype, another name for the process, vol. xiii., 472, 2, a.

Great Salt Lake, VIII. 183

See also the article Salt, vol. xiv., 577, 2, b. •

Smallpox, XV. 109

First mention of, see Aaron II., vol. i., 4, 1, c.

Rialto, a bridge in Venice, with an open square at each end; vol. xvi., 296, 2, b and c.

Leaning Tower (Of Pisa)

See Campanile, vol. iii., 661, 2, a; illustration, Pisa, vol. xiii., 340.

For further illustration we may take a single article; for example, Pottery and Porcelain (14½ pages), vol. xiii., pp. 777-792. In this are explained, among others, the following objects, on which the information there given would naturally be sought under the names they bear: Sèvres china, 785, 2, a, and 791, 1, c-2, a; Sèvres vase (illustration), 785, 2; old Sèvres china, 786, 2, b; composition of, 792, 1, a. - Stanniferous, 778, 1, c - Bat printing, 786, 1, b. - Crackle, 784, 1, a; Crackle vase (illustration), ibid. - Raffaelle (ware), 781, 2, b. - Frit, 790, 2, b and a - Pug mill, 787, 1, b, c; illustration, ibid - Samian (ware), 780, 2, b; illustration, i, c. - Henri Deux (ware), 782, 1, a; Henri Deux Faince vase (illustration) ibid. - Seggar, 789, 2, c-790, 2, a; illustration, ibid. - Mezza, majolica (ware), 781, 1, c; Majolica vase (illustration) ibid. - Potter's wheel (Egyptian use of), 778, 2, c - Potter's lathe, 787, 2, b; illustration, ibid. - Porzellana, 781, 2, a. - Delft (ware), 782, 2, a-c - Blunger, 788, 2, K - Muffle (illustration), 792 1, c - Slip, 788, 2, c, 791, 1, a. - Queen's ware, 783, 1, a. - Jasper ware, 783, 1, b. - Petuntse, 783, 2, a - Parian biscuit, 783, 2, a, 786, 2, c - Wedgwood, 783, 1, a; Wedgwood ware, b, c.

Subjects on which interesting and valuable information is given are far more numerous than the titles of the leading articles. But, if entered as such in the alphabetical arrangement of the work, they would generally be taken out of the connection in which they are best understood and appreciated, and would swell the number of leading articles beyond reasonable limits. The reader, consulting these only, may often be disappointed, failing to obtain the information which he seeks, and cannot find without an index.