main object of these remarks is to enable chemists to judge for themselves as to the degree of confidence his conclusions are entitled to. On the density of chlorine and on the vapour density of ferric chloride, by MM. C. Friedel and J. M. Crafts. For chlorine the mean at 21° C. is here determined at 2:471, and at 440° C. 2'448, while between 321° and 442° C. the perchloride of iron is shown to have a somewhat constant density corresponding to the formula Fe,Cl.-On the vapour density of the perchloride of gallium, by MM. C. Friedel and J. M. Crafts. According to Lecoq de Boisbaudran's determinations the perchloride of gallium (Ga,Cl) melts at 75°5 and boils at 215° to 220°. Here the density at 237° and 307° is found to be 1173 and 1061 respectively, or somewhat less than the theoretic density. Above 307° it diminishes considerably, falling to 8°5 at 357°, and 6° 6 at 440°.—On the gigantic dimensions of some fossil mammals, by M. Albert Gaudry. These remarks are made in connection with the accurate measurements of the St. Petersburg mammoth (Elephas primigenius) supplied by Tilesius. The skeleton, a photograph of which has recently been taken by M. Strauch, is 3'42 metres high to the top of the head, as compared with the 4 22 of the Durfort skeleton (Elephas meridionalis) in the new gallery of the Paris Museum. Comparing these with the remains of Dinotherium giganteum and other monsters of the Upper Miocene and later epochs, the author groups the larger extinct mammals according to their dimensions in five classes, as follows: (1) Dinotherium giganteum of the Upper Miocene, Attica ; (2) Elephas antiquus of the Quaternary, neighbourhood of Paris; (3) Elephas meridionalis of the Upper Pliocene, Durfort (Gard); (4) Mastodon americanus, of the Quaternary, United States; (5) Elephas primigenius, of the Quaternary, Siberia, this last being about the same size as the living elephants.--Observations of the comet 1888 a, by M. Cruls.

These observations were made at the Imperial Observatory of Rio Janeiro for the period from February 24 to April 2.-Positions of the comet 1888 I., measured with the 8-inch equatorial of the Observatory of Besançon, by M. Gruey. The positions of the comet and comparison stars are given for the period from June 7 to June 19.--An isochronous regulator, by M. Baudot. The object of this apparatus is to maintain at a uniform velocity the rotation of the distributor employed by the inventor in his multiple printing telegraph system, despite the variations of the motor power and those of the resisting force caused by the action of the several parts of the instrument, or by any other disturbing element. Its action consists in introducing into the motor mechanism a resistance varying automatically whenever necessary, thus maintaining a perfect equilibrium between the total motor and resisting forces.-On a telephone with closed magnetic field, and plaque with equal concentric cylindrical sections, by M. Krebs. With the appliance here described the vibrations preserve a large degree of amplitude, while the section is saturated at no point of the magnetic circuit. These dispositions greatly facilitate the construction of powerful instruments of all sizes.-Magnetic charts of the West Mediterranean basin, by M. Th. Moureaux. The magnetic charts which the author now presents to the Academy have been mainly prepared from the data supplied by the series of observations described in the last number of the Comptes rendus. They comprise, besides the chief islands, the whole of the European seaboard from Cadiz to the Strait of Messina, and the North African coast between Tangier and Tripoli.-The storage of electricity and thermodynamics, by M. Gouy. In this paper the author endeavours to connect the principle of the preservation of electricity with the general laws of thermodynamics, taking as his experimental starting-point the first law of electric actions. On the electric conductibility of mixtures of salts in solution, by MM. E. Bouty and L. Poincaré. In the present

communication the authors deal mainly with the special case of the nitrates of potassa and soda, their object being to ascertain whether it be possible to deduce the electric conductibility of a mixture of saline solutions, without chemical action, from the conductibility of each, assuming this to be a known quantity.On the production of ozone by electric shocks, by MM. Bichat and Guntz. Here the authors propose to study the various circumstances which influence the production of ozone by means of explosive discharges. The results obtained show that the formation of ozone is primarily connected with the greater or less elevation of the temperature of the oxygen under the action of the electric shocks.-Notes follow, by M. A. Carnot, on the lithine present in mineral waters; by M. J. Ribau, on a method

of analyzing and separating zinc; by M. de Forcrand, on the giycol-alcoholate of soda; by M. J. Meunier, on a dibenzoic ether derived from mannite; by M. E. Gley, on the comparative toxic properties of wabaine and strophanthine; and by M. Prillieux, on an efficaceous treatment of black rot, a disease of the vine which has spread from America to France.

BOOKS, PAMPHLETS, and SERIALS RECEIVED.

The Speaking Parrots, Part 4: Dr. K. Russ (L. U. Gill)-British Dogs, No. 22: H. Dalziel (L. U. Gill). -Challenger Expedition Reports-Zoology. vol. xxvi. (Eyre and Spottiswoode). -Contributions to the Natural History of Alaska, No. 2: L. M. Turner (Washington)-A New Theory of Parallels; C. L. Dodgson (Macmillan).-Atlantic Weather Charts, Part 4 (Eyre and Spottiswoode).-Arithmetical Exercises and Examination Papers: H. S. Hall and S. R. Knight (Macmillan).-Entomology for Beginners: Dr. A. S. Packard (Holt, New York).-Catalog der Conchylien-Sammlung. Liefe 8: F. R. Paetel (Berlin).-The Structure and Classification of the Mesozoic Mammalia: H. F. Osborn (Philadelphia). - Insect Life (Washington) Il Terremoto nel Vallo Cosentino del 3 Dicembre, 1887 : G. Agamennone (Roma).-Morphologisches Jahrbuch, Band 14, Heft 1 (Williams and Norgate) - Annalen der Physik und Chemie, 1888. No. 9 (Leinz g).-Verhandlungen des Naturhistorischen Vereines, 5 Jahrg. Erste Hälfte (Bonn). Annual Report of the American Museum of Natural History, Central Park, New York, for the Year 1887-88.

NATURAL PHILOSOPHY.

On Sound and Atmospheric Vibrations.

With the Mathematical Elements of Music. Designed for the Use of Students in the University. By Sir G. B. AIRY, K.C.B., formerly Astronomer-Royal. Second Edition, Revised and Enlarged. Crown 8vo. gs.

A Treatise on Magnetism. Designed for the Use of Students in the University. By the same Author. Crown 8vo. gs. 6d.

Gravitation: an Elementary Explanation of

the Principal Perturbations in the Solar System. By the same Author. Second Edition. Crown 8vo. 7s. 6d.

Elementary Applied Mechanics. Being the

simpler and more practical Cases of Stress and Strain wrought out individually from First Principles by means of Elementary Mathematics. By T. ALEXANDER, C.E.. Professor of Civil Engineering in the Imperial College of Engineering, Tokei, Japan. Crown 8vo. Part I. 4s. 6d. Elementary Applied Mechanics. By Thomas

ALEXANDER, C. E., Professor of Engineering in the Imperial Col lege of Engineering, Tokei, Japan; and ARTHUR WATSON THOMSON, C.E., B.Sc., Professor of Engineering at the Royal College, Cirencester. Part II. TRANSVERSE STRESS; upwards of 150 Diagrams, and 200 Examples carefully worked out. Crown 8vo. 10s. 6d.

Experimental Mechanics. A Course

of Lectures delivered at the Royal College of Science for Ireland. By Sir R. S. BALL, M.A., Astronomer-Royal for Ireland. Crown 8vo. [New and Cheaper Edition in the press. Com

Four-Figure Mathematical Tables.

prising Logarithmic and Trigonometrical Tables, and Tables of Squares, Square Roots, and Reciprocals. By J. T. BOTTOMLEY, M.A., F.R.S.E., F C.S., Lecturer in Natural Philosophy in the University of Glasgow. 8vo. 2s. 6d.

The Science of Weighing and Measuring,

AND THE STANDARDS OF MEASURE AND WEIGHT. By H. W. CHISHOLM, Warden of the Standards. With Numerous Illustrations. Crown 8vo. 4s. 6d. [Nature Series. Mechanical Theory of Heat. By R. Clausius. Translated by WALTER R. BROWNE, M. A., late Fellow of Trinity College, Cambridge. Crown 8vo. IOS. 6d. Applied Mechanics: An Elementary General Introduction to the Theory of Structures and Machines. By JAMES H. COTTERILL, F.R.S., Associate Member of the Council of the Institution of Naval Architects, Associate Member of the Institution of Civil Engineers, Professor of Applied Mechanics in the Royal Naval College, Greenwich. Medium 8vo. 18s.

An Introduction to the Theory of Electricity. By LINNÆUS CUMMING, M.A., one of the Masters of Rugby School. With Illustrations. Crown 8vo. 8s. 6d.

A Text-book of the Principles of Physics.

By ALFRED DANIELL, M.A., LL.B., D.Sc., F.R.S. E., late Lecturer on Physics in the School of Medicine, Edinburgh. With Illustrations. Second Edition. Revised and Enlarged. Medium 8vo. 215.

Electric Light Arithmetic. By R. E. Day, M.A., Evening Lecturer in Experimental Physics at King's College London. Pott 8vo.

25.

Units and Physical Constants. By J. D.

EVERETT, M.A., D.C.L., F. R.S., F.R.S. E., Professor of Natural Philosophy, Queen's College, Belfast. Second Edition. Extra Fcap. 8vo. 5s.

Absolute Measurements in Electricity and

MAGNETISM. By ANDREW GRAY, M.A., F.R.S. E., Professor of Physics in the University College of North Wales. New Edition. 2 Vols. Crown 8vo. [Vol. I. immediately.

Elementary Statics. By John Greaves,

M.A., Fellow and Mathematical Lecturer of Christ's College, Cambridge. Crown 8vo, Second Edition. 6s. 6d. A Dictionary of Music and Musicians. By Eminent Writers, English and Foreign. Edited by Sir GEORGE GROVE, D.C. L., Director of the Royal College of Music, &c. Demy 8vo.

(A.D. 1450-1888).

Vols. I., II., and III. Price 215. each.

Vol. I. A to IMPROMPTU. Vol. II. IMPROPERIA to PLAIN SONG. Vol. III. PLANCHE to SUMER IS ICUMEN IN. Demy 8vo, Cloth, with Illustrations in Music Type and Woodcut. Also published in Parts. Parts I.-XIV., Parts XIX.-XXII., Price 3s. 6d. each. Parts XV., XVI., Price 78. Parts XVII., XVIII., Price 75. * Part XXII., recently published, completes the DICTIONARY OF MUSIC AND MUSICIANS as originally contemplated. But an Appendix and a full general Index are in the press.

"Dr. Grove's Dictionary will be a boon to every intelligent lover of music."-Saturday Review.

Introductory Primer of Science. By T. H.

LOCK, M.A., Senior Fellow, Assistant Tutor, and Lecturer in Mathematics and Physics, of Gonville and Caius College, Teacher of Physics in the University of Cambridge, &c._Globe 8vo. Statics for Beginners. By the same Author.

Globe 8vo.

38. 6d.

[In the press. Numerical Tables and Constants in EleMENTARY SCIENCE. By SYDNEY LUPTON, M.A., F.C.S. F.I.C., Assistant Master at Harrow School. Extra Fcap. 8vo. 2s. 6d Physical Arithmetic. By Alexander MacFARLANE, D.Sc., Examiner in Mathematics in the University of Edinburgh. Crown 8vo. 78. 6d.

Kinematics and Dynamics. An Elementary Treatise. By JAMES GORDON MACGREGOR, M.A., D.Sc., Fellow of the Royal Societies of Edinburgh and of Canada, Munro Professor of Physics in Dalhousie College, Halifax, Nova Scotia. With Illustrations. Crown 8vo. 10s. 6d.

Sound: a Series of Simple, Entertaining, and

Inexpensive Experiments in the Phenomena of Sound, for the Use of
Students of every age. By A. M. MAYER, Professor of Physics in
the Stevens Institute of Technology, &c. With Numerous Illustrations.
Crown 8vo.
2s. 6d.
[Nature Series.

Light: a Series of Simple, Entertaining, and Inexpensive Experiments in the Phenomena of Light, for the Use of Students of every age. By A. M. MAYER and C. BARNARD. With Numerous Illustrations. Crown 8vo. 2s. 6d. [Nature Series.

Newton-Principia. Edited by Prof. Sir

W. THOMSON and Prof. BLACKBURNE. 4to, Cloth. 31s. 6d. The First Three Sections of Newton's Principia. With Notes and Illustrations. Also, a Collection of Problems, principally intended as Examples of Newton's Methods, By PERCI VAL FROST, M.A. Third Edition. 8vo. 125.

A Treatise on Optics. By S. Parkinson,

D.D., F.R.S., Tutor and Prælector of St. John's College, Cambridge.
Fourth Edition, Revised and Enlarged. Crown 8vo.
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Steam, An Elementary Treatise. By John
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the Technical College, Finsbury. With Numerous Woodcuts and
Numerical Examples and Exercises. 18mo.
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Experimental Proofs of Chemical Theory

FOR BEGINNERS. By WILLIAM RAMSAY, Ph.D., Professor of Chemistry in University College, Bristol. Pott 8vo. 2s. 6d. The Theory of Sound. By Lord Rayleigh, M.A., F.R.S., formerly Fellow of Trinity College, Cambridge. 8vo. Vol. I., 12s. 6d. ; Vol. II., 12s. 6d. [Vol. III. in the press. The Kinematics of Machinery. Outlines of

a Theory of Machines. By Prof. F. REULEAUX. Translated and
Edited by Prof. A. B. W. KENNEDY, F.R.S., C. E.
With 450
Illustrations. Medium 8vo.

215.

Spectrum Analysis. Lectures delivered in

1868 before the Society of Apothecaries of London. By Sir HENRY E. ROSCOE, LL.D., F.R.S., formerly Professor of Chemistry in the Owens College, Victoria University, Manchester. Fourth Edition, Revised and considerably Enlarged by the Author and by ARTHUK SCHUSTER, F.R.S., Ph.D., Professor of Applied Mathematics in the Owens College, Victoria University. With Appendices, Numerous Illustrations, and Plates. Medium 8vo.

215.

Polarization of Light. By the late W.
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35. 6d.

Primer of Physics. By Balfour Stewart,
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New
Edition, with Questions. 18mo. IS.
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Lessons in Elementary Physics. By the

same Author. With Numerous Illustrations and Chromolitho of the Spectra of the Sun, Stars, and Nebula. New Edition. Fcap. 8vo. 4s. 6d.

Questions on Balfour Stewart's Elementary

LESSONS IN PHYSICS. By Prof. THOMAS H. CORE, Owens College, Manchester. Fcap. 8vo. 25.

VICTORIA UNIVERSITY.

AN ENTRANCE EXAMINATION IN ARTS (introductory to the Faculty of Medicine) will be held in OWENS COLLEGE (MANCHESTER), UNIVERSITY COLLEGE (LIVERPOOL), and (YORKSHIRE COLLEGE (LEEDS), on MONDAY, September 24, and following days.

A PRELIMINARY EXAMINATION (introductory to the Faculties of Art, Science, and Law) will be held in OWENS COLLEGE (MANCHESTER), UNIVERSITY COLLEGE (LIVERPOOL), and YORK. SHIRE COLLEGE (LEEDS), on MONDAY, September 24. following days.

and

Notice (in writing) of intention to be present should be sent on or before MONDAY, September 10, to the UNIVERSITY REGISTRAR, from whom Conditions of Entrance, and further Particulars as to those and other Examinations can be obtained.

Manchester, 1888.

CITY AND GUILDS OF LONDON

INSTITUTE.

TECHNICAL COLLEGE, FINSBURY.

S. P. THOMPSON, Principal.

DAY DEPARTMENT for Students not under 14 years of age. The College Courses of Instruction in Laboratory, Lecture-room, Work. shop and Drawing Office for Mechanical Engineers, Electrical Engineers, and Technical Chemists, commence on TUESDAY, October 2.

Chemical Laboratories specially organized for Instruction in Technical manufacturing processes.

Fee for Session, inclusive of Laboratories, Workshops, and Drawing Office, £9.

The Entrance Examination will take place on WEDNESDAY, September 26, at 10 o'clock a.m.

Scholarships of £30 a year each, and the Holl Scholarship of £20 a year, all tenable for two years, will be awarded (in accordance with the several schemes) on the results of the Entrance Examination.

For particulars of Scholarships and Programmes of Instruction, apply at the Technical College, Leonard Street, City Road, E.C.; or at. Gresham College, E.C.

JOHN WATNEY,

WALTER S. PRIDEAUX,} Hon. Secs. HOSPITAL

THE MIDDLESEX

MEDICAL SCHOOL.

The WINTER SESSION, 1888-89, will commence on MONDAY, October 1, when the Prizes will be distributed by Sir Arthur T. Watson, Bart., Q.C., and an Introductory Address will be delivered by W. Foster, Esq., M. A., F.C.S.

Two Entrance Scholarships (value £100 and £60) will be open for competition on September 27 and 28.

The School Buildings have been recently enlarged, comprising new Theatre, Library, Physiological Laboratory, Materia Medica Museum, Students' Room, and Luncheon Room.

Besides Scholarships and Prizes there are annually SIXTEEN RESIDENT Hospital Appointments open to Students.

The Composition Fee for the whole Medical Curriculum is £100. Special provision is made for Dental Students and for Candidates for the Preliminary Scientific (M.B.) Examination.

The Residential College adjoins the Hospital, and provides accommodation for thirty Students and a Resident Warden.

Prospectuses and all particulars may be obtained from the Resident Medical Officer at the Hospital, or from

A. PEARCE GOULD, Dean. GUY'S HOSPITAL MEDICAL SCHOOL.

The WINTER SESSION commences on MONDAY, OCTOBER 1. The Hospital contains 695 Beds, of which 500 are in constant occupation. There are Wards for Obstetric and Ophthalmic cases, and other special De partments. Special Classes are held in the Hospital for Students preparing for the Examinations of the University of London, and other Higher Examinations.

APPOINTMENTS. The House Surgeoncies. House-Physiciancies, Dresserships, and all other Appointments, are made strictly in accordance with the merits of the Candidates, and without extra payment. There are also a large number of Jumor Appointments, every part of the Hospital practice being systematically employed for instruction, so that students who have completed their preliminary studies elsewhere may enter at once upon the practice of the Hospital.

ENTRANCE SCHOLARSHIPS.-Open Scholarship of 125 Guineas in Classics, Mathematics, and Modern Languages. Open Scholarship of 125 Guineas in Chemistry, Physics, and Biology.

PRIZES are open to Students in their various years, amounting in the aggregate to more than £300. During the past year the accommodation in the PHYSIOLOGICAL and PATHOLOGICAL Departments has been greatly increased, and a STUDENTS' CLUB has been opened in the Hospital, containing a Dining Room, Reading Rcoms, and a large Gymnasium. COLLEGE.-A Residential College is in course of erection upon a site immediately contiguous to the Hospital, to accommodate about Fifty Students in addition to the Resident Staff of the Hospital.

For Prospectus and further information apply to the Dean, Dr. PERRY, Guy's Hospital, London, S.E.

LIVING SPECIMENS FOR THE MICROSCOPE.

GOLD MEDAL awarded at the FISHERIES EXHIBITION to THOMAS BOLTON, 83 CAMDEN STREET, BIRMINGHAM, Who last week sent to his subscribers Conochilus volvox, with sketch and description. He also sent out Cristatella mucedo, Alcyonella fungosa, Leptodora hyalina, Brachionus pala. Lophopus crystallinus, Melicerta ringens, Stephanoceros, Argulus foliaceus, Volvox globator; also Amœba, Hydra, Vorticella, Crayfish, and other Specimens for (Huxley and Martin's) Biological Laboratory work.

Weekly announcements will be made in this place of Organisms T. B. is supplying.

Specimen Tube, One Shilling, post free. Twenty-six Tubes in Course of Six Months for Subscription of £1 15. or Twelve Tubes for 10s. 6d.

Portfolio of Drawings, Eleven Parts, 1s. each. PRELIMINARY SCIENTIFIC (M.B.)

UNIVERSITY OF LONDON.

Students who have Matriculated and are intending to enter, or who have already entered, at any one of the London Medical Schools for the purely Medical Portion of their Studies, can prepare for the PRELIMINARY SCIENTIFIC EXAMINATION at University College, under Prof. RAMSAY, Ph.D., F.R.S., Prof. CAREY FOSTER, F.R.S, Prof. LANKESTER, LL.D., F.R.S., and Mr. F. W. OLIVER, B.A., D.Sc. The Curriculum commences in the First Week of OCTOBER. Prof. Ray Lankester will act as Tutor of the Preliminary Scientific Students, and advise them in regard to their Reading and Class-work.

Fee for the complete Course of Study required, including Lectures and Laboratory Work, 35 Guineas. For particulars apply to the SECRETARY, University College, London, Gower Street, W.C.

HERIOT-WATT COLLEGE.

Principal: F. GRANT OGILVIE, M.A., B.Sc., F. R.G.S. SESSION 1888-89 commences on MONDAY, October 8.

The COLLEGE is completely equipped for providing Higher TECHNICAL and COMMERCIAL EDUCATION.

The Calendar of the College contains full information as to the Courses of Instruction, Classes, Laboratories, and Fees. It may be obtained at the TREASURER'S OFFICE, 21 St. Andrew Square; or from the LIBRARIAN at the College, Price 6d.; by Post, 8d.

DAVID LEWIS, Treasurer.

Treasurer's Chambers, 21 St. Andrew Square,
Edinburgh, July 21, 1888.

ST. THOMAS'S HOSPITAL MEDICAL
SCHOOL.

ALBERT EMBANKMENT, LONDON, S. E.

The WINTER SESSION of 1888-99 will commence on OCTOBER 19 when an Introductory Address will be delivered by Dr. CULLINGWORTH, at 3 p.m.

TWO ENTRANCE SCIENCE SCHOLARSHIPS of 125 guineas and £60 respectively, open to all first-year Students, will be offered for com petition. The Examination will be held on the 26th, 27th, and 26th of September, and the subjects will be Chemistry and Physics, with either Botany or Zoology, at the option of Candidates.

Special Classes are held throughout the year for the "PRELIMINARY SCIENTIFIC" and "INTERMEDIATE M.B." Examinations of the UNIVERSITY of LONDON.

An additional Laboratory for the teaching of advanced Physiology has been recently provided.

All Hospital Appointments are open to Students without extra charge. Scholarships and Money Prizes of considerable value are awarded at the Sessional Examinations, as also several Medals.

The Fees may be paid in one sum or by instalments. Entries may be made to Lectures or to Hospital Practice, and special arrangements are made for Students entering in their second or subsequent years; also for Dental Students and for Qualified Practitioners.

Medical Practitioners, Clergymen, and private families residing in the neighbourhood receive Students for residence and supervision, and a register of approved lodgings is kept in the Secretary's office. Prospectuses and all particulars may be obtained from the Medical Secre. tary, Mr. GEORGE RENDle. E. NETTLESHIP, Dean.

BINOCULAR MICROSCOPE, by R. and J. BECK, of Cornhill, London; in Mahogany Case, with necessary Fittings. all in perfect order. To be disposed of immediately. Cost £23. Any reasonable offer not refused.-Apply, MICRO," 661 Fulham Road, Fulham Green, S.W.

THE SCIENTIFIC LANTERN SLIDES

Produced by E. WARD, MANCHESTER, last Season, having been received with so much favour, he respectfully invites EARLY ORDERS from Lecturers and others, while the light is most favourable for the production.

EDWARD WARD, F.R.M.S.,

249 OXFORD STREET, MANCHESTER. List for One Stamp.