In like manner, you should know that it is useless to search for two classes of names in the "Dictionary of National Biography," the most copious biographical dictionary of British personages ever published, begun in 1885, under Leslie Stephen, and reaching its sixty-first volume, and letter W in 1899, under the editorship of Sidney Lee. These two classes of names are first, all persons not British, that is, not either English, Scottish or Irish; and secondly, names of British persons now living. This is because this great work, like the Britannica, purposely confines itself to the names of notables deceased; and, unlike the Britannica, it further limits its biographies to persons connected by birth or long residence with the British kingdom. Knowing this fact before-hand, will save any time wasted in searching the Dictionary of National Biography for any persons now living, or for any American or European names. Another caveat may properly be interposed as regards searches for information in that most widely advertised and circulated of all works of reference,--the Encyclopaedia Britannica. The plan of that work was to furnish the reading public with the very best treatises upon leading topics in science, history, and literature, by eminent scholars and specialists in various fields. Pursuant to this general scheme, each great subject has a most elaborate, and sometimes almost exhaustive article--as, for example, chemistry, geology, etc., while the minor divisions of each topic do not appear in the alphabet at all, or appear only by cross-reference to the generic name under which they are treated. It results, that while you find, for example, a most extensive article upon "Anatomy", filling a large part of a volume of the Britannica, you look in vain in the alphabet for such subjects as "blood, brain, cartilage, sinew, tissue," etc., which are described only in the article "Anatomy." This method has to be well comprehended in order for any reader to make use of this great Cyclopaedia understandingly. Even by the aid of the English index to the work, issued by its foreign publishers, the reader who is in hasty quest of information in the Britannica, will most frequently be baffled by not finding any minor subject in the index. The English nation, judged by most of the productions of its literary and scientific men in that field, has small genius for indexing. It was reserved to an American to prepare and print a thorough index, at once alphabetical and analytical, to this great English thesaurus of information--an index ten times more copious, and therefore more useful to the student, than the meagre one issued in England. This index fills 3,900 closely printed columns, forming the whole of volume 25 of the Philadelphia edition of the work. By its aid, every name and every topic, treated anywhere in this vast repository of human knowledge can be traced out and appropriated; while without it, the Encyclopaedia Britannica,