admit. In other words, it was thought desirable to impart to the work so far as seemed feasible a direct educational value, to the end that the reader might through its pages easily trace the evolution of the electrical science and arts and form at least a passing acquaintance with the monuments of electrical literature. The character of the notes was fixed by this consideration, and in accordance with it a large number of engravings have been introduced, consisting of reproductions of significant pages of text, title pages of rare books, portraits of authors, plates illustrating epochal discoveries, etc. The admirable Introduction by Brother Potamian (Dr. M. F. O'Reilly of Manhattan College, New York City) adds in a high degree to this feature of the work, which is also furthered by an Appendix on that curious fiction of the sixteenth century, the sympathetic telegraph.

The chronological order of entries and the division into sections adopted were naturally suggested by the historical character of the collection and the special nature of some of its parts. A systematic subject classification was not found. practicable for the reason that most of the books antedate any specialization in the electrical science or art. Moreover, for historical research, and especially in the early periods, a chronological arrangement has a distinct advantage where the nature of the subject matter is indicated, as in the present case, by notes accompanying the title entries. Any advantage incident to an alphabetical arrangement according to authors finds compensation in an author index, which also includes all names occurring in the titles as editor, party to a controversy or otherwise, together with all names mentioned in the annotations. Owing to the great richness of the collection in books and pamphlets relating to the telegraph, and especially to the early period of the ocean telegraph, a subject index. has been provided for entries of this class.

In making additions to his library, Mr. Latimer Clark evidently considered nothing obtainable in print should be excluded that has any relation, however slight, to the historical or technical side of electrical science or the electrical arts. This inclusiveness, which greatly enhances the value of the collection, rendered desirable some system of classification that would insure due prominence to its extensive miscellaneous portions, and also avoid what, under a strict chronological arrangement, might be the entry of an important historical work sandwiched between entries of, say, a trade catalogue and a parliamentary report. It was therefore decided to distribute the entries into sections according to certain criteria which, though far from satisfactory from a bibliographical standpoint, nevertheless appeared defensible if judged with reference to the needs of those who will make practical use of the Catalogue. Since circumstances rendered it necessary to carry out the work of classification with reference to a card transcript of titles and annotations and not from examination of the contents of each book, close scrutiny will doubtless show that some items have been misplaced. In particular, the latter method of selection might have placed in Section I. some of the entries now in Section II.

Section I., which occupies Vol. I., comprises the more notable items of the collection. Section II. consists largely of excerpts or reprints from the Transactions of learned societies, from periodicals, etc., the total of entries for this class of items being not far from two thousand. It may be added that these items, together with the pamphlets of the collection, are to be found in the Library gathered in bound volumes numbering about 200. In this section are also included a considerable number of pamphlets and some miscellaneous items, such as engravings, collections of clippings, etc. Sections III., IV. and V. comprise miscellaneous publications relating specific

ally to telegraphy, principally in pamphlet or circular form, and including numerous prospectuses, reports, etc., dating in the early period of cable telegraphy. Section VI. consists of reports of early electric light, telephone and electrical manufacturing companies. Section VII. relates to patent specifications and litigation. Section VIII. contains a considerable collection of parliamentary papers having an electrical bearing, and also covers legislative and legal subjects of a like nature. Section IX. comprises pamphlets, etc., relating to expositions, electrical congresses and societies. Section X. consists of entries of early electrical trade catalogues, circulars and price lists.

Much care has been bestowed on the compilation of Section XI., which is a bibliography of the sets, or partial sets, of periodicals in the collection, in number more than one hundred. The first drafts of entries in these sections were prepared from examination of the volumes and by reference to various available bibliographical sources. The drafts relating to the journals throughout the world now in existence. were then submitted for revision to the present editors of these journals. The secretaries of the English, French and German electrical societies very kindly acted upon a request to have the drafts of the entries of former electrical journals printed in their languages revised by the respective librarians of such societies. In the case of British journals no longer published, the entries for those not strictly electrical in character were revised by Mr. H. M. Mayhew of the periodical department of the British Museum.

Mr. Clark took a special interest in the subject of so-called sympathetic or telepathic telegraphy, and spared no pains to make this section of his Library inclusive of the subject. In view of the completeness of this interesting department, an historical account of the idea of the sympathetic telegraph

is given as an appendix to the Catalogue proper, together with a list of references to the more notable writings in which the subject receives notice, including some works not in the Library.

With the exception of the periodical section, in which the arrangement is alphabetical, the entries in each of the sections are, except as below noted, in chronological order according to the dates of publication. If, however, a work is represented by more than one edition, or by a translation, the chronological order is disregarded in placing such entries, which follow that of the original publication, but with the date of printing set back from the marginal date line. In the case of Peregrinus (No. 46), and of Gilbert (No. 72), and owing to the extensive collections in the Library relating to these great pioneers of electrical literature, all entries connected directly with their names are grouped under the entry earliest in date.

A very complete system of cross-references has been supplied as follows: When an author is represented in Section I. by more than one publication, the first entry under his name is accompanied by a note referring by number to all other entries of his work in the Catalogue. The later entries, however, are accompanied by only a single reference, this being to the earliest entry which, as noted above, is inclusive in its reference indications. Sections II.-X. have cross-references in common according to the above system, but where an author entered in any of these sections is represented in Section I., there are added the necessary cross-references. In addition to the above class of references, cross-references are included in the body of the annotations wherever by this means further light may be afforded on a work or a particular subject of interest. In brackets following the names of authors no longer living are recorded the dates of birth and

death, except in a few cases where this information was not obtainable.

After the purchase of the Latimer Clark collection, Dr. Wheeler made a number of additions to his Gift, which are entered in the Catalogue and distinguished by an asterisk (*) following the entry number. As the Library possessed aside from the Wheeler Gift a small number of books of an historical character, these were also entered, and are distinguished by the addition of a dagger (†) to the entry number. After the text was in type some entries were added, and a few found misplaced were transferred to their proper locations, thereby necessitating the duplication of their entry numbers, as indicated by the addition of the word bis to such numbers. Most of the new entries are of books and pamphlets obtained-principally by gift-in order to render more complete the representation in the Catalogue of certain authors, either by their own writings or by works related thereto. To complete the record of the history of several journals, a few sets of periodicals in the Library, but not in the collection, were entered in Section XI., and are also distinguished by a dagger mark.

Owing to the duplication of entry numbers above referred to, and especially to translations and works represented in more than one edition being assigned merely the entry number of the original edition with a distinguishing affix, as well as to the exceptions noted in the cases of Peregrinus and Gilbert, the number of the final entry of the Catalogue (5966) falls short of representing the total of publications entered in the work.

It is difficult to find terms in which to express adequately the debt of gratitude that the members of the Institute owe to Brother Potamian for his devoted labor in their behalf, as represented by the descriptive and critical notes accom