220

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��to any more of the rnanj valuable aud impor- tant papers contained in tbia handsome volume. The parliament of Roumania, upon the plea of poverty, has deeliDed to extend an invitation to the congress to hold its next session the present year at Bucharest, which the leading members, under the initiative of the Baron de Baye, had selected as the place of meeting. ■ We learn, however, that arrangements have been made for it to take place at Athens in 1886.

��HARTLEBEN'S LIBRARY OF ELECTRI- CAL TECHNOLOGY (ELEKTHOTECH- NISCUE BIBLIOTHEK).

The admirable collection of treatises pub- lished under this title was originally announced to contain ten volumes ; but the number issued has already reached twenty-six, and others are stated to be in preparation. Almost every subject relating to electricity receives atten- tion, inchiding telegraphy, telephony, electric lighting, and electroplating; while certain topics are very minutely discussed, as, for ex- ample, electrical conductors, electrical clocks, the medical uses of electricity, and its appli- cations to military purposes. The various volumes, white necessarily somewhat unequal both in merit and in importance, are yet all of tkcra of substantial value ; and it is much to be desired that they may, in part at least, be translated into English for the benefit of that lat^e class of readers who are desirous of se- curing information at once elementary and accurate. This has, indeed, already' been done in the case of the initial volume of the series, — thaton dynamo-electrical machinery, by Glaser- De Cew, which has been translated by Dr. Pa- get Higgs, and which, notwithstanding some minor slips, is by far the best treatise of its size upon the specific matters which it discusses. The treatise on instruments for electrical meas- urements, by Wilke, contains some interesting descriptionsof special forma of galvanometers and electrometers ; as, for example, the admir- able dead-beat galvanometers with Isell-sbaped magnets made by Hartmanu and other German makers, the special form of Thomson galvanom- eter made by yiemens & Halskc, Kohlrauach's torsion electrometer, and Ziillner's biOlar elec- trometer. Zech's ' Elektrisches formelbucb ' is of very high grade, and contains mucli in- formation that is not easily fouud elsewhere in a collected form. Its topics are arranged al- phabetically ; and it contains, in an appendix, a brief electro- technical dictionary giving the equivalent electrical terms in German, French, and English. Its scope will best be indicated

��by a brief reference to a few litle« almost at random. Under ' Bussole ' we find a general discussion of the effect of a circular current on a magnetic needle, including the tangent, sine, aud Hclmholtz-Gaugain galva- nometers, t«getherwith the cosine galvanometer of Professor Trowbridge ; the latter assigned, however, to Obach and Denzler instead of to its real inventor. The article ' Dampfnng ' gives ft demonstration of the formulae for the dampii of a magnet ; and under ' Schwingung ' there given the derivation of the various formulae ' vibrations, including vibration with damping and ai^eriodic motion. Another valuable worlc is that of Tumltrz on potential. Volume xx. of the library contains a bibliography of electricity from 18110 to 1883, with special reference to tech- nical electricity. Among the more timely of the works relating especially to the industrial appli- cations of electricity are those by Japing electrical transmission of power, and Kramer ' electrical I'ailways. The volume relating to tiple telegraphy not only contains the duplex quadruples systems, but also the multiple a; terns of Meyer. Granfold, and Baudot scribed at length. The American systems Gray and Delany are not noticed, certainly *' most unfortunate omission. The last volume issued, that on cable telegraphy, is the most comprehensive treatise on the subject that we know, and is particularly valuable, as woita relating to it arc so few.

�� ��RECENT GOVERNMENT REPORTS.

��We regret that we are obliged to note decided degeneration in the Bulletin of the fld^ commisfiion. What might and should proper- ly be one of our most important government reports each year becomes less valuable. The present volume, although it contains several important scientific contributions, is in Uw main made up of unimi>ortant letters, of valw to very few people so far as we can judge. The first hundred and fifty pages are entirely occupied by lists and tables by the editor. not one of which is of importance to any class of people. What, for instance, can be the possible use of " A list of the blank forms and circulars of the U.S. fish- commission," which alone takes up twenty-one pages? Judging

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