448 SEC. 12. APPLIED MECHANICS.
1928h. Model of Wheel (probably for grinding). With
sliding axle.
19281. Fragment of Model (probably a pump bucket).
1928k. Models on a Stand, of four trussed beams, probably
used experimentally for testing the strength of different methods of
trussing.
19281. Fragment of a Model of a Frame for a Ma-
chine.
1928m. Fragment of a Frame.
1928n. Model of a Horse Mill, with roller and trough,
apparently designed for crushing material.
1928o. Model of a Train of Wheels.
1928p, Model of Beam and two connecting Bods with
universal motion at their upper ends, and connected to transverse
hinged links at their lower ends.
1928q. Model of Beam Pumping Engine, single acting
and condensing, worked by tappet valve motion.
1928r. Model of double acting Beam Condensing En-
gine, conical valves worked by eccentric.
1928r. Model of inverted Cylinder direct-acting
Pumping Engine, with tappet valve motion.
1928s. Sectional Model of Beam Engine, worked by
eccentric and hollow valve.
19 2 St. Sectional Model of Engine, with shifting eccentric
for altering valve.
1928u. Model of a Pair of Tilt Hammers, alongside each
other. Two beams and connecting rods, with cranked pins at an
angle to each other, and one of the wheels provided with a
balance weight.
(NOTE. Part of the above model missing.)
1928v. Fragment of a Model with part of Sun and planet
motion.
1928w. Fragment of a Model with Sun and planet motion
and weighted disc.
1928x. Fragment, an arch head.
1928y. Model of a Water Wheel.
III. PRIME MOVERS. 449
1928z. Measuring Apparatus, with Micrometer Screw,
for taking end measures.
1928aa. Model of Garnet's Patent Friction Hollers.
192 8bb. Model used for Testing Pressure due to
Vacuum.
1928cc. Model of Valve with Universal Joint.
1928dd. Brass Model in two Pieces.
1928ee. Model used in experiments on Governor.
1928ff. Experimental Model.
1928gg. Experimental Model.
1928hh. Experimental Model.
1928ii. Original Model of Cylinder with separate
Condenser.
1828jj. Model of Surface Condenser.
III. PRIME MOVERS.
a. STATIONARY ENGINES.
2019d. Papin's Steam Cylinder.
Royal Museum, Cassel (Director, Dr. Pinder).
This cast-iron cylinder was to have formed part of a large pumping
engine, which, however, was never completed. The object was to supply a
canal at the level of Hofgeismar with water, whereby the Landgraf Charles
hoped to draw the traffic of the Weser to Cassel. An explosion which took
place in Papin's laboratory when the Landgraf was contemplating a visit, led
to the bold investigator withdrawing from the influence of his enemies. He
came to England (1707), but did not succeed with his plans, and died in
poverty. Papin's sketch of his contemplated pumping engine is exhibited
with the cylinder. It was a peculiar combination of the Savery engine and
the piston engine recommended by Papin for other purposes. In the closed
boiler A (with safety-valve of Papin's design) , steam was generated, which (on
opening the cock C) could pass through pipe B to cylinder D. Here it
pressed down the close fitting piston or float E which rested on water that
had been supplied through the funnel I from a reservoir. The water was
thus forced into the chamber F ; its return was prevented by a valve at H ;
and the steam-cock C being now shut and the condensed steam allowed to
escape from the upper part of D, water from the reservoir was admitted
anew, and the process repeated. The water raised into F could be further
directed through the tube G. Papin proposed to add to the effect by
introducing red hot irons through the opening in the cover of the cylinder D.
Of the two cylinders it is probably D that is exhibited.
40075. F f
LIBRARV
OF TIM
UNIVERSITY OF CALIFORNIA
OIF-T OR
Received CL
Accession No. 3~? / ^ f . Class No.
^y
...
gtiente antr &rt
of tye Committee of (ffounril on (Strurattom
I s===s==s====
CATALOGUE
OF THE
SPECIAL LOAN COLLECTION OF
SCIENTIFIC APPARATUS
AT THE
SOUTH KENSINGTON MUSEUM.
V
MDCCCLXXVI.
THIRD EDITION.
TJKIVEESIf?
LONDON:
PRINTED BY GEORGE E. EYRE AND WILLIAM SPOTTISWOODE,
PRINTERS TO THE QUEEN'S MOST EXCELLENT MAJESTY.
FOU HER MAJESTY'S STATIONERY OFFICE.
1877.
SCIENCE AND ART DEPARTMENT
OF THE COMMITTEE OF COUNCIL ON EDUCATION.
SOUTH KENSINGTON.
ESTABLISHED in connexion with the Board of Trade in March 1853 as a develop-
ment of the Department of Practical Art, which in 1852 had been created for the
re-organisation of Schools of Design. Placed under the direction of the Committee of
Council on Education in 1856.
Lists of Presidents and Vice-Presidents.
Board of Trade.
1852. Rt. Hon. H. Labouehere, M.P., President.
Rt. Hon. J. W. Henley, M.P.. President.
1853. Rt.Hon.Edward Cm-dwell, M.P., President.
1855. Rt. Hon. Lord Stanley of Alderley, Pros.
Committee of Council on Education.
185G. Rt. Hon. Earl Granville, K.G., Lord Presi-
dent.
Rt.Hon.W. E.Cowpcr,M.P.,Vioe-President.
1858. Most Hon. Marquess of Salisbury, K.G.
Rt. Hon. Sir C. B. Adderley, K.C.M.G.,
M.P., Vice- President.
1859. Rt. Hon. Earl Granville, K.G.
Rt. Hon. Robert Lowe, M.P., Vice-Pros.
1864. Rt. Hon. H. A. Bruce, M.P., Vice-Pres.
1866. His Grace the Duke of Buckingham and
Chandos.
Rt. Hon. H. T. Lowry Corry, M.P., Vice-
President.
1867. His Grace the Duke of Marlborough, K.G.
Rt. Hon. Lord Robert Montagu, M.P., V.-P.
1868. Most Hon. the Marquess of Ripon, K.G.
Rt. Hon. W. E. Forster, M.P., Vice-Pres.
1873. Rt. Hon. Lord Aberdare.
Rt. Hon. W. E. Forster, M.P., Vice-Pres.
1874. His Grace the Duke of Richmond and
Gordon, K.G., Lord President.
The Right Hon. the Viscount Sandon,
M.P., Vice President.
OFFICE HOURS, TEN TO FOUR.
GENERAL ADMINISTRATION.
Secret anj Sir Francis R. Sandford, C.B.
Assistant Secretary. Xorinnn MacLeod.
Chief Clerk. G. Francis Duncombe.
First-class Clerks. \. J. R. Trendell ; Alan S.
Cole ; F. R. Fowke ; A. S. Bury.
Second-class Clerks. J. B. Rundell ; H. W.
Williams ; E. Belshaw ; G. G. Millard ; A. F.
E. Torrens ; O. J. Dullea.
Postal Clerk Vi. Burtt.
Clerk nf Accou >ifx.V;\.cant.
Jiook-keeper.T. A. Bovrler.
Assistant Book-kecper.~E. Harris.
GENERAL STORES.
Storekeeper. W. G. Groser. Deputy. H.Lloyd.
Clerks J. Smith ; F. Walters.
SCIENCE DIVISION.
Director. Major Donnelly, R.E.
Occasional Inspectors. F. J. Sidney, LL.D. ;
('apt. Harris, E.I.C. (Navigation).
Official Examiner G. G. T. Bartlcy.
Assistant Professional Examiner. T. Healey.
Professional Examiners for Science.
Subjects.
L Practical, plane, and solid Geometry.
II. Machine Construction and Drawing.
W. C. Unwin, B.Sc.
III. Building Construction. Major Seddon,
R.E.
IV. Naval Architecture. W. B. Baskcomb.
V Pure Mathematics. C. W. Merrifield,
F.R.S. ; T. Savage, M.A.
VI. Theoretical Mechanics. Rev. John F.
Twisden, M.A.
VII.-Applied Mechanics. T.M.Goodeve.M.A.
VIII Acoustics, Light, and Heat. J. Tyn-
dall, LL.D., F.R.S. ; F. Guthrie,
F.R.S.
TX. Magnetism and Electricity. J. Tyn-
dall, LL.D., F.R.S.; H. Debus, F.R.S.
X. Inorganic Chemistry. E. Frankland,
D.C.L.. Ph.D., F.R.S.
40075.
Subjects.
XL Organic Chemistry. E. Frankland,
D.C.L., Ph.D., F.R.S.
XII. Geology. A. C. Ramsay, LL.D., F.R.S.
XIII Mineralogy W. W. Smyth, MA.,
F.R.S.
XIV. Animal Physiology. T. H. Huxley,
LL.D..F.R.S.
XV. Elementary Botany. W. T. T. Dyer,
M.A., B.Sc., F.L.S.
XVI. } General Biolosry. T. H. Huxley,
XVII. J LL.D., F.R.S. f W. T. T. Dyer, M.A.,
B.Sc., F.L.S.
XVIII. Mining. W. W. Smyth, M.A., F.R.S.
XIX. Metallurgy J. Percy, M.D., F.R.S.
XX. Navigation J. Woolley, LL.D.
XXL Nautical Astronomy. J. Woolley,
LL.D.
XXII Steam T. M. Goodeve, M.A.
(Physical Geography. D. T. Ansted,
XXI II J M.A..F.R.S.
C Physiography .
XXIV. Principles of Agriculture. H. Tanner,
F.C.S.
ART DIVISION.
Director. E. J. Poynter, R.A.
Assistant Director. H. A. Bowler.
Occasional Inspectors. S. A. Hart, R.A. ; F. B.
Barwell ; W. B. Scott.
Official Examiner. 1. Chesman, B.A., LL.B.
Professional Examiners. F. R. Pickersgill,
R.A.; W. F. Yeames, A.R.A. ; J. E. Boehm;
Val. Prinsep ; W. Morris ; G. Atchison ; J.
Marshall,F.R.S.,F.R.C.S. ; E. J. Poynter, R.A.,
and H. A. Bowler.
Assistant Professional Examiner. J. A. D.
Campbell.
Occasional Examiners. G. M. Atkinson; G.
R. Redgrave.
Inspectors of Local Schools of Science and Art.
R. G. Wylde ; J. F. Iselin, M.A. ; E. P.
Bartlett; Captain W. de W. Abney, R.E.,
F.R.S.
Organising Master of Science and Art Classes.
J. C. Buckmaster, F.C.S.
a 2
iv
NATIONAL ART TRAINING SCHOOL.
Principal. TO,, J. Poynter, R.A.
Head Master. J. Sparkes.
Registrar. R. W. Herman.
Mechanical and Architectural Draiving.
H. B. Hagre^n.
Geometry and Perspective. E. S. Bnrchett.
Painting, Freehand Drawing of Ornament, &c.,
the Figure and Anatomy, and Ornamental
Design. 3. Sparkes; C. P. Slocombe ; T.
Clack, and F. M. Miller.
Modelling . M. Miller.
Lady Superintendent of Female Classes.
Miss Trulock.
Instructors. Mrs. S. E. Casabianca : Miss
Channon.
Occasional Lecturers. E. Bellamy, F.R.C.S.,
Eng., Anatomy; Dr. Zerffi, Historic Orna-
ment; R. W. Herman, Principles of Orna-
mental Construction; F.W.Moody, TheFigure.
Teacher of Etching Class. A. Legros.
Teacher of Wood Engraving Class. C. Roberts.
SOUTH KENSIXG-TOX MUSEUM.
Director. -P. Cunliffe Owen, C.B. (temp, absent) .
Acting Director. E,. A. Thompson.
Assistant Directors Major E. R. Fcsting, R.E. ;
Col. Sir H. B. Sandford.
Director ofNeio Buildings. Major-Gen. Scott,
C.B., F.R.S.
Decorative Artist. R,. Townroe.
Instructor in Decorative Art and Decorative
Artist F. W. Moody.
Museum Keeper (Art Collections}. -G. Wallis.
Museum Keeper (National Art Library). R.
H. Soden Smith, M.A., Trinity College, Dub-
lin, F.S.A.
Museum Keeper (Educational Library and
Collections). A. C. King, F.S.A.
Assistant Museum Keepers. W. Matchwick,
F.L.S.; H. Sandham; K.Laskey; C. B. Wor-
snop ; R. F. Sketchier, B.A., Exeter College,
Oxford; H. E. Acton; J. W. Appcll, Ph.D.;
J. Barrett, B.A. ; C. H. Derby, B.A.
Museum Clerks.- -M. Webb ; H. M. Cundall ;
L. Finding.
Technical and Special Assistants. R. Vernon ;
A. Masson ; W. E. Streatfeild ; A. Reid ; F.
Coles ; W. G. Johnson ; G. H. Wallis ; S. Cow-
per ; O. Scott.
Superintendent for Examples and Publica-
tions. J. Cundall.
BETHNAL GREEN BRANCH OF THE
SOUTH KENSINGTON MUSEUM.
(Opened on June 24, 1872.)
GEOLOGICAL SURVEY.
Director-General. A.C. Ramsay, LL.D., F.R.S.
Director for England and Wales. H. W.
Bristow, F.R.S.
Director for Ireland. E. Hull, M.A., F.R.S.
Director for Scotland. A. Geikie, F.R.S.
Naturalist T. H. Huxley, LL.D., F.R.S.
Paleontologist R. Etheridge, F.R.S.
ROYAL SCHOOL OF MINES AND MU-
SEUM OF PRACTICAL GEOLOGY.
Director of Museum of Practical Geology
A. C. Ramsay, LL.D., F.R.S. =
Keeper^ of Mining Records. Robert Hunt,
F.R.S.
Assistants. Richard Meade ; James B. Jordan *
Registrar, Curator, and Librarian. T. Reeks.
Assistant Librarian -T. Newton.
Assistant Curator. A Pringle.
PBOFESSOES.
Chemistrff.~-%faa.rd. Frankland, D.C.L., Ph.D.,
F.R.S.
\ahiral History T. H. Huxley, LL.D., F.R.S.
Physics F. Guthric, B.A., PhJ)., F.R.S.
Applied Mechanics T. M. Goodeve, M.A.
Metallurgy J. Percy, M.D., F.R.S.
Geology. S. W. Judd.
Mining and Mineralogy* W. W. Smyth, M.A.,
F.R.S.
Mechanical Drawing Ttev. J. II. Edgar, M.A.
Museum open every week-day but Friday, and
on Saturdays and Mondays till 10 p.m., except
from the 10th of August to the 10th of Sep-
tember.
EDINBURGH MUSEUM OF SCIENCE AND
ART.
Director. 'Prof. T. C. Archer, F.R.S.E.
Keeper of Natural History Collections. Prof.
R. H. Traquair, M.D.
Curator. Alexander Galletly.
Assistant in Natural History Museum. J.
Gibson.
Assistant in Industrial Museum. W. Clark.
Clerks. C. N. B. Muston ; T. Stock.
ROYAL COLLEGE OF SCIENCE, DUBLIN.
Dean of Faculty. J. P. O'Reilly, C.E.,M.R.I.A.
Secretary F. J. Sidney, LL.D.
Curator of Museum. A.. Gages.
Clerk G. C. Penny.
PEOFESSOES.
Physics W. F. Barrett, F.C.S.
Chemistry. B* Galloway. F.C.S.
Geology E. Hull, M.A., F.R.S.
Applied Mathematics. II. Hennessy, F.R.S.
Botany. W. R. McNab, M.D.
Zoology.^. Leith Adams, M.B., F.R.S.
Descriptive Geometry and Drawing. Thomas
F. Pigot, C.E.
Mining and Mineralogy J. P. O'Reilly, C.E.,
M.R.I.A.
Demonstrator in Paleontology. W. H. Baily,
F.L.S.
Assistant Chemist. W. Plunkett.
Assistant Physicist. A. E. Porte.
ROYAL DUBLIN SOCIETY.
President His Grace the Duke of Leinster.
Secretaries G. J. Stone, A.M., F.R.S. ; C. Kelly,
J.P., Q.C.
Registrar and Assistant Secretary. W. E.
Steele, M.D.
Treasurer, cfcc.-H. C. White.
Director of Natural History Museum. A..
Carte, M.A., M.D.
Keeper of Minerals R. J. Moss, F.C.S.
Librarian -W '. Archer, F.R.S.
Temporary Assistant. H. W. D. Dunlop,
A.B., C.E.
Director of Botanic Gardens, Glasnevm.D.
Moore, Ph.D.
ZOOLOGICAL GARDENS, DUBLIN.
Sesretary. 'B&v. S. Haughton, M.D., D.C.L.,
F.T.C.D., F.R.S.
SOUTH KENS1
1.0 AN COLLECTION OF 9
PLAN OF GALLERIES LENT BY H . IV
Royal
REFERENT!
G R O U
A E D U CAT 10 N A L
B.C. APPLIED M E c
D NAVAL ARCHIT
E Lie HT-H o u s
F MAGNETISM
C ARITHMETIC AN
.K. MEASUREMENT .
L . ASTRONOMY AI
(M) GEOGRAPHY, CE
(N) BIOUOCY,
O) CONFERENCE
(P) CHEM ISTRY .
LIGHT, HEAT, Soui
JTON MUSEUM.
ENTIFIC APPARATUS
OMIV1ISSIONERS OP THE EXHIBITION or 1851
or tic ultural
FLOOR
GY, AND MINING.
(ND MOLECULAR PHYSICS
CONTENTS.
PAOK
PREFACE TO THIRD EDITION - - vii
INTRODUCTION, LISTS OF COMMITTEES, &c. - ix
LIST OF CONTRIBUTORS, WITH ADDRESSES - xxix
SECTION 1. ARITHMETIC - ... 1
2. GEOMETRY - - - - 15
3. MEASUREMENT - - 42
4. KINEMATICS, STATICS, AND DYNAMICS - 131
5. MOLECULAR PHYSICS - - 155
6. SOUND- - - - 178
7. LIGHT - - - 203
8. HEAT - - - 252
9. MAGNETISM - - - - - . 279
10. ELECTRICITY - - 298
11. ASTRONOMY - - 391
12. APPLIED MECHANICS - 444
13. CHEMISTRY - - 563
14. METEOROLOGY .... 573
15. GEOGRAPHY ... 725
16. GEOLOGY AND MINING * 815
17. MINERALOGY, CRYSTALLOGRAPHY, &c. - 884
18. BIOLOGY - - 900
19. EDUCATIONAL APPLIANCES - - 1004
20. MISCELLANEOUS - - - 1064
PREFACE TO THE THIRD EDITION.
THE receipt of a large number of objects since the com-
pilation of the Second Edition has rendered necessary the
publication of a Third Edition, to afford a complete record
of the collection for future reference. Every endeavour
has been made to ensure its correctness. Slips from the
former edition have been sent, wherever practicable, to the
several contributors for their corrections, in order that all
errors might, as far as possible, be eliminated.
Although a considerable amount of re-arrangement has
been found necessary, it has been thought advisable to
retain the numbers given to the objects in the former
edition, as those numbers have already been quoted in the
Handbook and other publications.
This edition has been revised and passed through the
press by Mr. A. T. Atchison, to whom the thanks of my
Lords are due for the great care and trouble he has bestowed
upon it.
South Kensington Museum,
May 1877.
INTRODUCTION.
By Minute dated 22nd January 1875, the Lords of the
Committee of Council on Education approved of a proposal
to form a Loan Collection of Scientific Apparatus, which
was to include not only apparatus for teaching and for
investigation, but also such as possessed historic interest
on account of the persons by whom, or the researches in
which, it had been employed. Their Lordships then in-
vited some of the leading men of science of the country
the Presidents of the learned Societies and others to act
on a Committee to consider the matter, and aid them with
their advice. This Committee, to whose exertions the
formation of the collection is so largely due, consisted of
The Right Hon. the Lord Chancellor.
Professor F. A. Abel, F.R.S., Presi-
dent of the Chemical Society.
The Right Hon. Lord Aberdare,
President of the Horticultural
Society.
Capt. W. de W. Abney, R.E., F.R.S.
Professor H. W. Acland, M.D.,
E.R.S., President of the Medical
Council of the United Kingdom.
Professor J. C. Adams, M.A., F.R.S.
Professor W. G. Adams, ALA.,
F.R.S.
Sir G. B. Airy, K.C.B., D.C.L.,
F.R.S., the Astronomer Royal.
Dr. G. J. Allman, F.R.S., President
of the Linnaan Society.
Mr. J. Anderson, LL.D., C.E.
Mr. D. T. Ansted, M.A., F.R.S.
Professor E. Atkinson, Ph.D.
Professor R. Stawell Ball, LL.D.,
F.R.S.
Professor W. F. Barrett,
Rev. A. Barry, D.D.
Mr. W. B. Baskcomb.
Mr. H. Bauerman.
Mr. G. Benthain, F.R.S.
Mr. Hugh Birley, M.P.
Professor Bloxam.
Major Bolton.
Professor F. A. Bradley.
Mr. F. J. Bramwell, F.R.S.
Mr. T. Brassey, M.P.
Mr. H. W. Bristow, F.R.S.
Mr. C. Brooke, M.A., F.R.S.
Mr. G. Busk, F.R.S.
Major -General Cameron, C.B., F.R.S.
Dr. W. B. Carpenter, C.B., F.R.S.
Mr. C. O. F. Cator.
Mr. W. Chappell.
Mr. H. W. Chisholm, Warden of the
Standards.
Lord Alfred Churchill, Chairman of
Council of Society of Arts.
Mr. G. T. Clark.
Mr. Latimer Clark.
Professor R, Bellamy Clifton, M.A.,
F.R.S.
Sir Henry Cole, K.C.B.
Vice-Admiral Sir R. Collinson,
K.C.B., Deputy Master of the
Trinity House.
Dr. Debus, F.R.S.
Mr. Warren De La Rue, D.C.L.,
F.R.S.
Mr. G. Dixon, M.P.
Professor P. M. Duncan, M.B.,
F.R.S., President of the Geological
Society.
Professor W. T. Thiselton Dyer,
M.A., B.Sc.
Major-General F. Eardley-Wilmot,
R.A., F.R.S.
INTRODUCTION.
Mr. H. S. Eaton, President of the
Meteorological Society.
Sir P. De M. G. Egerton, Bart.,
M.P., F.R.S.
Mr. K. Etheridge, F.R.S.
Capt. Evans, R.N., C.B., F.R.S.,
Hydrographer of the Navy.
Mr. J. Evans, F.R.S.
Professor W. H. Flower, F.R.S.
Mr. D. Forbes, F.R.S.
Professor G. Carey Foster, B.A.,
F.R.S., President of the Physical
Society.
Professor Michael Foster, M.D.,
F.R.S.
Colonel Lane Fox, F.R.S., President
of the Anthropological Institute.
Professor Frankland, Ph.D., D.C.L.,
F.R.S.
Mr. A. H. Garrod, M.A., F.R.S.
Dr. Gilbert. F.R.S.
Dr. J. H. Gladstone, F.R.S.
Mr. D. Glasgow.
Professor Goodeve, M.A.
Mr. A. C. L. G. Giinther, M.A.,
M.D., F.R.S.
Professor Guthrie, Ph.D., F.R.S.
Mr. J. Baillie- Hamilton.
The Right Hon. Lord Hampton,
G.C.B., F.R.S., President of the
Institute of Naval Architects.
Mr. T. E. Harrison.
Sir J. Hawkshaw, F.R.S.
Mr. T. Hawksley, President of the
Institute of Mechanical Engineers.
The Hon. Alan Herbert.
Mr. J. Hick, M.P.
Dr. J. D. Hooker, C.B., President of
the Royal Society.
Mr. J. Hopkinson, B.A., D.Sc.
Mr. W- Huggins, D.C.L., F.R.S.,
President of the Royal Astrono-
mical Society.
Professor W. Hughes.
Professor T. H. Huxley, LL.D., Sec.
R.S.
Lieut.-General Sir H. James, R.E.,
F.R.S.
Rev. J. H. Jellett, B.D.
Professor E. Ray Lankester, M.A.,
F.R.S.
Lord Lindsay, M.P., F.R.S.
Mr. J. Norman Lockyer, F.R.S.
Rev. R. Main, M.A., F.R.S.
Dr. R. J. Mann.
Mr. N. Story-Mr.Pkeljne,M.A.,F.:R.S.
Professor J. Clerk Maxwell, M.A.
F.R.S.
Mr. C. W. Merrifield, F.R.S.
Professor Miller, M.A., LL.D.,
F.R.S.
Professor Morris.
Mr. A. J. Mundella, M.P.
Professor Odling, M.A., F.R.S.
Mr. W. K. Parker, F.R.S.
Dr. Percy, F.R.S.
Mr. J. A. Phillips.
The Right Hon. Lyon Playfair, C.B,,
M.P., F.R.S.
Dr. Pole, F.R.S.
Professor Prestwich, F.R.S.
Professor A. C. Ramsay, LL.D.,
F.R.S.
Major-General Sir H. C. Rawlinson,
K.C.B., F.R.S., President of the
Royal Geographical Society.
The "Right Hon. Lord Rayleigh,
F.R.S.
Professor A. W. Reinold, M.A.
Professor Roscoe, Ph.D., F.R.S.
The Right Hon. the Earl of Rosse,
D.C.L., F.R.S.
Mr. G. W. Royston-Pigott, M.A.,
M.D., F.R.S.
Mr. J. Scott Russell, F.R.S.
Dr. W. J. Russell, F.R.S.
Professor W. Rutherford, M.D.,
F.R.S.
Mr. B. Samuelson, M.P.
Professor J. S. Burdon Sanderson,
M.D., F.R.S.
Mr. T. Savage, M.A.
Mr. R. H. Scott, M.A., F.R.S.
Major Seddon, R.E.
Professor Shelley.
Sir J. P. Kay-Shuttleworth, Bart.
Mr. C. W. Siemens, D.C.L., F.R.S.
Professor H. J. S. Smith, M.A.,
F.R.S.
Mr. W. Warington Smyth, M.A.,
F.R.S.
Mr. H. C. Sorby, F.R.S., President
of the Royal Microscopical Society.
Mr. W. Spottiswoode, M.A., LL.D.,
Treasurer of the Royal Society.
Mr. G. R. Stephenson, President of
the Institution of Civil Engineers.
Professor Balfour Stewart, LL.D.,
F.R.S.
Dr. W. H. Stone.
Major -General Strachey, C.S.T.,
F.R.S.
'INTRODUCTION.
XI
Lieut.-Col. Strange, F.R.S. (since
deceased).
Professor P. G. Tait, M.A.
Mr. J. Torr, M.P.
Rev. J. F. Twisden, M.A.
Professor Tyndall, LL.D., F.R.S.
Professor W. C. Unwin, B.Sc.
Mr. C. V. Walker, F.R.S., Presi-
dent of Society of Telegraphic
Engineers.
Mr. F. H. Wcnham.
Sir C. Wheatstone, F.R.S. (since de-
ceased).
Sir J. Whitworth, Bart., F.R.S.
Professor A. W. Williamson, Ph.D.,
F.R.S.
Mr. Bennet Woodcroft, F.R.S.
Dr. J. Woolley, F.R.S.
Colonel H. Stuart Wortley.
The first meeting of this Committee was held on the 13th
February 1875 ; the number of those who were present
showing the interest already felt in the subject. The Lord
President of the Council, the Duke of Richmond, and the
Vice-President, Viscount Sandon, in explaining the objects
of the Collection, took occasion to refer to the recommen-
dations of the Royal Commission on Scientific Instruction,
with regard to the creation of a Science Museum.
Their Lordships stated their conviction that the develop-
ment of the Educational, and certain other, Departments of
the South Kensington Museum, and their enlargement into
a Museum somewhat of the nature of the Conservatoire
des Arts et Metiers in Paris, and other similar institutions
on the Continent, would tend to the advancement of
science, and be of great service to the industrial progress
of this country. While expressing their hope that the
Loan Collection might forward this desirable object, their
Lordships guarded themselves against committing Her Ma-
jesty's Government, which had not yet fully considered
the subject, to any definite scheme.
On the motion of the President of the Royal Society,
Dr. Hooker, it was unanimously resolved by the meeting
that an exhibition such as that proposed would be most
instructive and valuable.
The question of the limits of the collection were dis-
cussed, and Sub-Committees were appointed to consider the
limitations it might be desirable to place on the term
" scientific apparatus " in the respective sections, while
bearing in mind the space disposable for the exhibition in
the Museum. As a provisional arrangement five Sub-Com-
mittees of sections were appointed, to whom it was left to
suggest such modifications in classification as might be found
advisable.
Xll INTRODUCTION.
The sections were
1. Mechanics (including pure and applied mathe-
matics).
2. Physics.
3. Chemistry (including metallurgy).
4. Geology, Mineralogy, and Geography.
5. Biology.
The Committees for the several sections are given at
page xxv.
The question of classification, having been carefully con-
sidered at numerous meetings of these Sub-Committees, was
brought before the General Committee on the 1 2th May, and
the several schemes were referred to a special Sub-Com-
mittee, formed of three members from each sectional Sub-
Committee. It was also decided to postpone the Exhibition,
which it was originally intended to open in June 1875, to
March 1876. The large number of objects sent from abroad,
and the late period of their arrival, have necessitated a
further postponement of the opening to May 1876.
The Sub-Committee appointed to revise and report on
the classification of the Collection after three meetings,
under the chairmanship of the President of the Royal
Society, submitted a scheme of classification to the General
Committee on June 22nd. After having been carefully
considered, it was, with some slight alterations, approved,
and is given at page xix. This programme was imme-
diately issued, and the classification into sections is that
adopted for the catalogue and exhibition, though the nature
of the Galleries has necessitated some alteration in the order
of the sections.
It had been the intention from the first to give the Loan
Collection an international character, so as to afford men of
science and those interested in education an opportunity of
seeing what was being done by other countries than their
own in the production of apparatus, both for research and
for instruction an opportunity which it was hoped would
be of advantage also to the makers of instruments. As soon,
therefore, as the programme had been definitely settled, steps
were taken to interest foreign countries in the Exhibition ;
and it was determined to obtain the co-operation of men of
science on the Continent, who, while acting as members of
INTRODUCTION. Xlil
the General Committee, should form special Sub-Committees
charged with the due representation of the science of their
respective countries.
It was necessary to take special precautions to prevent
misunderstanding as to the character of the Collection.
The mention of internationality at once suggested the idea
of an International Exhibition similar in its character and
arrangements to the numerous Industrial Exhibitions which
have been held in various countries. A wrong impression
of this kind would have entailed serious inconvenience.
In International Exhibitions a certain amount of space is
allotted to each country. These spaces are then divided by
the Commissioners of each country among its exhibitors,
who display their objects subject to certain general rules
of classification as they consider most advantageous, retain-
ing the custody of their own property. The expenses of
transport, arrangement, &c., are borne by the countries who
exhibit. And the Exhibitions appeal naturally, more or
less exclusively, to the industrial or trade-producing interests
of those countries.
This was not the idea of the proposed Loan Collection at
South Kensington. For that Collection it was desired to
obtain not only apparatus and objects from manufacturers,
but also objects of historic interest from museums and
private cabinets, where they are treasured as sacred relics,
as well as apparatus in present use in the laboratories of
professors. The transport of all objects was undertaken
by the English Government, and they were to be handed
over absolutely to the custody of the Science and Art
Department for exhibition ; the arrangement being not by
countries but strictly according to the general classification.
So soon as the object and scope of the Collection were
thoroughly understood, the Committee of Council on Edu-
cation met with the most gratifying responses to their
invitations, which were communicated officially through
the Foreign Office. Her Majesty's Ministers at Paris, Berlin,
St. Petersburgh, Vienna, Florence, Brussels, the Hague,
Stockholm, Madrid, Berne, and Washington, have personally
interested themselves in the matter. And the Foreign
Governments have afforded every facility and encourage-
ment in forwarding this strictly international undertaking.
XIV
INTRODUCTION.
The subjoined list of the foreign members of the General
Committee speaks for itself by the eminence and European
reputation of its members.
BELGIUM.
M. Stas, Membre de 1'Academie
Royale (President).
M. le General Brialmont, President
de 1'Academie Royale et Inspecteur
General du Genie.
M. Dewalque, Membre de 1' Academic
Royale, Professeur de Geologic et
de Mineral ogie it 1'Universite de
Liege.
M. Maus, Membre de 1'Academie,
Inspecteur General des Ponts et
Chaussees.
M. Plateau, Membre de 1' Academic
Royale, F.R.S.
M. Schwann, Membre de 1'Academie
Royale, Professeur a. 1' Universite de
Liege.
M. Van Beneden, Membre de 1'Aca-
demie et Professeur a 1'Universite
de Louvain, F.R.S.
M. le General Liagre, Secretaire per-
petuel de 1'Academie Royale, et
Commandant et Directeur des
Etudes de l'E"cole Militaire (Secre-
tary).
FRANCE.
M. le General Arthur Jules Morin,
Membre de 1'Academie des Sciences,
Directeur du Conservatoire des
Arts et Metiers (President).
M. Alexre. Edmond Becquerel,
Membre de 1'Academie des
Sciences, Professeur au Conserva-
toire des Arts et Metiers, F.R.S.
M. Henri Marie Bouley, Membre de
1'Academie des Sciences, Inspec-
teur General des ficoles Veteri-
naires.
M. Gabriel Auguste Daubree, Mem-
bre de 1'Academie des Sciences,
Directeur de 1'^cole des Mines.
M. Jean Louis Armand de Quatre-
fages de Breau, Membre de 1'Aca-
demie des Sciences, Professeur au
Museum d'Histoire Naturelle.
M. Jean Baptiste Dumas, Secretaire
perpetuel de 1'Academie des
Sciences, F.R.S.
M. Herve Auguste Etienne Albans
Faye, Membre de 1'Academie des
Sciences, President du Bureau des
Longitudes.
M. Edmond Fremy, Membre de
1'Academie des Sciences, Profes-
seur au Museum d'Histoire Natu-
relle.
M. Jules Celestin Jamin, Membre de
1'Academie des Sciences, Profes-
feur a 1'ficole Polyetcbnique.
M. Leuglet,Consul General de France
& Londres.
M. Urbain Jean Joseph Le Verrier,
Membre de 1'Academie des
Sciences, Directeur de 1'Observa-
toire, F.R.S.
M. Eugene Melchior Peligot, Mem-
bre de 1'Academie des Sciences,
Directeur des Essaish, la Monuuiu.
M. Henri Edouard Tresca, Membre
de 1'Academie des Sciences, Sous-
Directeur du Conservatoire des
Arts et Metiers (Secretary).
GERMANY.
I. BERLIN COMMITTEE.
Dr. A. W. Hofmann, Professor of
Chemistry, F.R.S. (President).
Dr. Beyrich, Professor of Geology.
Dr. du Bois-Reymond, Professor of
Physiology.
Dr. Dove, Professor of Physics,
F.R.S.
Dr. Forster, Director of the Obser-
vatory.
Dr. Hagen, President of the Board of
Works.
T. G. Halske, Telegraphic Engi-
neer.
INTRODUCTION.
XV
Dr. Hauchecorne, Director of the
School of Mines.
Dr. Ilelmholtz, Professor of Physics,
F.fc.S.
Dr. Kiepert, Professor of Geo-
graphy.
Dr. G. Kirchhoff, Professor of Phy-
sics, F.R.S.
Dr. Kronecker, Professor of Mathe-
matics.
Dr. C. D. Martius, Chemist.
Von Morozowicz, General.
Dr. Neumayer, Hydrogvapher of the
Imperial Admiralty.
Dr. Reuleaux, Director of the Poly-
technic Academy.
Dr. Schellbach, Professor of Mathe-
matics.
Dr. Werner Siemens, Telegraphic
Engineer.
Dr. Virchow, Professor of Patho-
lo gj-
Dr. C. H. Vogel, Astronomer.
Dr. Websky, Professor of Minera-
logy.
II. COMMITTEE REPRESENTING OTHER CITIES AND TOWNS OF
GEKMANV.
Dr. Von Babo, Professor of Che-
mistry, Freiburg.
Dr. Beetz, Professor of Physics,
Munich.
Dr. Buff, Professor of Physics, Gies-
sen.
Dr. Clausius, Professor of Physics,
Bonn, F.R.S.
His Excellency Dr. Von Dechen,
Director of the Mining Depart-
ment, Bonn.
Dr. Von Fehling, Professor of Che-
mistry, Stuttgart.
Dr. Vou Feilitzsch, Professor of
Physics, Greifswald.
Dr. Graebe, Professor of Chemistry,
Konigsberg.
Dr. Von Groddeck, Director of the
School of Mines, Klausthal.
Dr. Ileeren, Professor of Chemistry,
Hanover.
Dr. Hittorf, Professor of Chemistry,
Miiuster.
Dr. Karsten, Professor of Physics,
Kiel.
Dr. Karsten, Professor of Physics,
Rostock.
Dr. Knapp, Professor of Chemistry,
Braunschweig.
Dr. Knoblauch, Professor of Physics,
Halle.
Dr. Kolliker, Professor of Physiology,
"\Viirzburg, F.R.S.
Dr. Kundt, Professor of Physics,
Strasburg.
Dr. Launhardt, Director of the Poly-
technic School, Hanover.
Dr. Mohl, Cassel.
Dr. Poleck, Professor of Chemistry,
Breslau.
Dr. Preyer, Professor of Physiology,
Jena.
Dr. Vou Quintus-Tcilius, Professor
of Physics, Hanover.
Dr. Reusch, Professor of Physics,
Tubingen.
Dr. Romberg, Professor in the Nau-
tical School, Bremen.
Dr. Rosenthal, Professor of Physio-
logy, Erlangen.
Dr. Riimker, Director of the Obser-
vatory, Hamburg.
Dr. Serlo, Director of the Mining
Department, Brcslau.
Dr. C. Von Siemens, Professor in
the Agricultural Academy, Hohen-
heim.
His Excellency Dr. Von Steinbeis,
President, Stuttgart.
Dr. W. Weber, Professor of Physics,
Gottingen, F.R.S.
Dr. Wiedemunn, Professor of Phy-
sical Chemistry, Leipzig.
Dr. Winkler, Professor cf Metal-
lurgy, Freiberg.
Dr. Wohler, Professor of Chemistry,
Gottingeu, F.R.S.
Dr. Wulluer, Professor of Physics,
Aachen.
Dr. Zeuner, Director of the Poly-
technic School, Dresden.
Dr. Zetzsche, Director of the Poly-
technic School, Chemnitz.
XVI
INTRODUCTION.
ITALY.
II Com. Blaserna, Professor of Phy-
sics and Kector of the Royal Uni-
versity of Rome.
II Com. Cantoni, Professor of Phy-
sics at the Royal University of
Pavia.
II Cav. Respighi, Professor of Astrc
nomy in the Royal University c
Rome, and Director of the Obsei
vatory of the Campidoglio.
THE NETHERLANDS.
Professor Dr. P. L. Rijke, Conseiller
d'etat (President).
Professor Dr. H. G. de Sande Bak-
huyzen.
Professor Dr. C. II. D. Buys Ballot
Professor Dr. J. Bosscha.
Professor Dr. F. C. Donders, F.R.S.,
President of the Royal Academy of
Science, Amsterdam.
Professor Dr. J. W. Gunning.
Professor Dr. R. A. Mees.
Professor Dr. V. S. M. Van de
Willigen.
Dr. D. de Loos, Director of the Se
condary Town-School of Leyde
(Secretary).
NORWAY.
Professor Esmark.
Herr Mohn, Director of the Meteoro-
logical Institute of Norway.
Professor Waage.
RUSSIA.
M. Struve, Conseiller Prive, Directeur
de 1'Observatoire Central Nicolas
(President).
M. Ovsiannikow, Membre de 1'Aca-
demie.
M. Gadolin, Membre de 1' Academic.
M. Gruber, Professeur de 1'Academie
de Medecine et de Chirurgerie.
M. Stubendorf, Colonel d'^tat-Major.
M. Wyschnegradsky, Professeur d
1'Institut technologique.
M. Beilstein, Professeur de FInstitu
technologique.
M. Barbot de Marny, Professeur d<
1'Institut des Mines.
M. Koulibine, Professeur de FInstitu
des Mines.
SWITZERLAND.
Professor E. Wartmann (President).
Professor J. Amsler Laffon.
Professor D. Colladon-Ador.
Professor Dr. F. A. Forel.
Professor Dr. E. Hagenbach-Bischoff.
Professor Ad. Hirsch.
Professor Albert Mousson.
M. E. Sarasin-Diodati.
Professor L. Soret.
Colonel Gautier (Secretary).
AUSTRIA AND HUNGARY.
The Minister of Public Instruction has appointed Sectionschef Fidler tc
organise the contributions from these countries.
SPAIN.
No committee has been formed, but the Government has promised to contri-
bute, and Senor Riano has been specially appointed to make the necessary
arrangements.
INTRODUCTION.
UNITED STATES.
The Government has, through Mr. Fish, replied that it is in communication
with the various departments and scientific institutions with the object of
forwarding the Exhibition.
When men of this position in all branches of science have
given their adhesion to the programme of such an Exhi-
bition, its success might well be considered as secured. But
these gentlemen did not rest satisfied with merely giving
their names in recognition of its value : they have spared
no time and labour in making the undertaking a real
success. And the Lords of the Committee of Council on
Education feel assured that, in offering them their thanks
for their invaluable services, they convey not only their
own sentiments but the grateful recognition of their labours
by the country at large.
It will be readily understood from what has been said
of the nature, scope, and method of the Exhibition that
a large staff was required, in addition to the permanent
staff of the Museum, to organise and arrange the collec-
tion in the limited time which could be afforded for that
purpose. Special arrangements had, therefore, to be made ;
and their Lordships have great satisfaction in recording
the names of those gentlemen who have rendered very
valuable services many of them as volunteers greatly
aiding the staff of the Museum in their laborious duties.
These were Captain Abney, RE. ; Dr. Atkinson ; Mr. Bart-
lett ; Dr. Brunton ; Dr. Biedermann ; Professor Crum-
Brown; Captain Fellowes, RE.; Professor Carey Foster;
Dr. Michael Foster ; Herr Kirchner ; Professor Goodeve ;
Dr. Guthrie ; Commander T. A. Hull, RN. ; Mr. Iselin ;
Mr. Judd ; Mr. Norman Lockyer ; Dr. R. J. Mann ; Mr. Cle-
ments Markham ; Professor H. MacLeod ; Professor Roscoe ;
Professor Shelley ; Dr. Burdon Sanderson ; Dr. Schuster ;
Dr. Voit ; and Mr. R Wylde.
To those men of science, who, in this matter and in the
work of the General Committee and Sub-Committees, have
given much valuable time, and have afforded them the
benefit of their great knowledge and experience, the Lords
of the Committee of Council on Education feel their best
thanks are due, and they trust that the immediate success
and future results of the Exhibition, which owes so much to
40075. b
XVlil INTRODUCTION.
them, will reward them for the labours which they have
ungrudgingly devoted to it.
In order to make the Collection as useful and interesting
as possible, a Handbook containing introductory notices to
the several sections has been prepared. For writing these
notices the Lords of the Committee of Council on Education
have been fortunate in securing the services of gentlemen
the mention of whose names will be a sufficient indication
of the character of the work. These gentlemen are
Capt. W. de W. Abuey, R.E. ; Mr. N. Story Maskelync, M.A.,
Professor W. Kingdon Clifford, M. A., I F.R.S.
F.R.S. i Professor J. Clerk Maxwell, M.A.,
Capt. J. E. Davis. F.R.S.
Professor G. Carey Foster, B.A., Mr. R. H. Scott, M.A., F.R.S.
F.R.S. J Professor H. J. S. Smith, M.A.,
Professor Geikie, F.R.S.
Professor Goodeve, M.A.
Professor Guthrie, F.R.S.
Professor T. H. Huxley, LL.D.,
F.R.S.
Mr. W. Warington Smyth, M.A.,
F.R.S.
Mr. H. C. Sorby, F.R.S.
Secretary of the Royal Society^ | Mr. W. Spottiswoode, M.A., LL.D.,
Mr. J. Norman Lockyer, F.R.S. F.R.S.
Professor MacLeod. j Dr. W. H. Stone.
Mr. Clements Markham, C.B., j Professor P. G. Tait, M.A.
F.R.S. |
It had been originally proposed to exhibit the Collection
of Scientific Apparatus in the South Kensington Museum ;
but various circumstances, which could not be foreseen,
having rendered it necessary to abandon this intention,
Her Majesty's Commissioners for the Exhibition of 1851,
most liberally placed the galleries on the western side of the
Horticultural Gardens at the disposal of the Science and
Art Department. Though, unfortunately, these galleries
are disconnected from the Kensington Museum, they are
admirably adapted to the present purpose, and afford an
accommodation which could not otherwise have been ob-
tained.
By order,
F. R. SANDFORD,
Secretary, Committee of Council
on Education.
INTRODUCTION. XIX
CLASSIFICATION OF THE COLLECTION.
Arithmetic.
Apparatus for teaching arithmetic. Calculating machines.
Instruments for solving equations. Slide rules. Numbering and
enumerating apparatus, &c.
Geometry.
Instruments used in geometrical drawing. Methods of copying
Pantigraph, micrograph. Peaucellier's cell and parallel motion
Machines for description of curves and specimens of the curves
they describe, including geometric turning. Instruments for giving
graphic representations of phenomena. Models to illustrate de-
scriptive geometry. Specimens to illustrate the process of making
models according to a design. Models to illustrate solid geometry,
perspective, crystallography, &c. Stereoscopic illustrations of
solid geometry.
Measurement.
Of length. Standard yard, metre, &c. Comparator for stand-
ards of length (sight and touch). Gauges, measuring wheels,
steel tapes, &c. Micrometers and verniers. Cathetometers.
Of area. Planimeters, &c.
Of volume. Standard gallon, litre, &c. Pipettes, burettes.
Meters for gas, water, &c.
Of angles. Divided circles, theodolites, clinometers, gonio-
meters, &c.
Of mass. Standard pound, kilogramme, &c. Vacuum and
other balances.
Of density. Specific gravity bottles, areometers, &c.
Of time. Clocks and pendulums, chronometers, watches, and
balance wheels. Tuning forks for measuring small intervals of
time. Chronographs.
Of velocity. Such as Morin's machine. Strophometers, cur-
rent meters, ships' logs, &c.
Of momentum. Ballistic apparatus.
Of force. Spring balances, pressure gauges, torsion balances,
&c.
Of work. Indicators, dynamometers, &c.
Kinematics, Statics, and Dynamics.
Elementary illustrations. Position and displacement of a point,
a rigid body, or a material system. Composition and resolution of
displacements. Velocity and acceleration, their composition and
2
XX INTRODUCTION.
resolution. Displacements of a connected system. Principles of
mechanism. Rolling contact, sliding contact, belting, link con-
nexions, shafting, universal joints, &c. Transmission of work.
Relation between the displacement of two pieces of a machine and
the forces which they transmit. The mechanical powers. Instru-
ments for illustrating the laws of motion, such as pendulums,
gyroscopes, dynamical tops.
Laws of fluid pressure ; stability of floating bodies.
Discharge of fluids through orifices, and their motion in
channels.
Hydraulic and pneumatic transmission of power.
Molecular Physics.
Instruments and apparatus employed in teaching, and in the
investigations and observations connected with :
Pressure on Matter. Tension, Compression (piezometer) Tor-
sion, Flexion ; Relation of volume to pressure ; Elasticity of
liquids and gases. Hardness (of solids and liquids), Toughness,
Brittleness, Malleability, &c.
Communication of Pressure through Fltiids. Pressure of air, its
consequences and applications. Barometers, Air-pumps, Siphons,
Suclion-pumps, Spirators, &c. ; Pressure of water, its consequences
and applications, Levels, Side pressure, &c.
Density. Methods of measuring densities of Gases, Vapours,
Liquids, Solids.
Adhesion and Cohesion. Condensation of gases in solids, Solu-
tion of gases in liquids, Mixing of gases with gases (Diffusion,
Transpiration, &c.), Absorption of liquids by solids (Capillarity,
&c), Absorption of liquids by gases (Evaporation, &c.), Mixing of
liquids with liquids (Osmose, Diffusion Dialysis). Evaporation of
solids, Solution of solids, Mixture of solids with solids (Cementa-
tion, &c.).
Sound.
Instruments and apparatus employed in teaching, and in the
investigations and observations connected with :
Geometrical, Mechanical, and Optical methods of Illustrating
the Laws of Wave .Motion. Progressive waves, Composition of
Vibrations, Interference, Stationary waves.
Generation of Sound. Fog-horn, &c.
Conduction of Sound. Through solids, liquids, and gases,
Stethoscopes.
Velocity of Sound.
Detection of Sound. Sensitive flame, &c.
Reflexion and Refraction. Ear trumpets, Acoustic lenses, vie.
Dispersion and Absorption.
INTRODUCTION. XXI
Musical Sounds. Pitch, Standards of Pitch, Standard Tuning
Forks. &c. ; Methods of measuring and comparing rates of vibra-
tion ; Toothed wheels, Syrens, &c. ; Vibration Microscopes, &c. ;
Methods of illustrating the nature of musical intervals; Mano-
ni( trie flames, Mirrored Tuning Forks, &c.
Musical Quality. Illustrations of the different quality of the
sounds of various instruments, Harmonics, and overtones. Resul-
tant rones, Instruments for studying quality, Resonators, Phonau-
tographs, &c.
Musical Instruments Illustrating the above. Methods o ex-
hibiting the mode of vibration of various instruments and the
quality of the sounds yielded by them.
Light.
Instruments and apparatus employed in teaching, and in the
investigations and observations connected with:
Production. Combustion, Electric discharge, &c.
Measurement of Intensity, Velocity.
Action of Matter on Light. Reflection, Refraction, Dispersion,
Achromatism, Direct vision prisms, Polarization, Absorption
(colour), Fluorescence, &c.
Action of Light on Light. Interference, Diffraction, Measure-
ment of wave length (optical banks), &c.
Action of Light on Matter. Photography, Radiometry, Phos-
phorescence, &c.
Technical Applications of Optical Principles. Lighthouse
illumination, &c.
Heat.
Instruments and apparatus employed in teaching, and in the
investigations and observations connected with :
Sources of Heat. Chemical, Electrical, Dynamical, Solar,
Calorescence, &c.
Effects of Heat on Matter. Changes of Temperature, Expan-
sion and change of Elasticity, Liquefaction, Vaporization, &c.
Measurement of Temperature. Thermometers, Pyrometers,
&c.
Propagation of Heat. Radiant Heat, Radiometer, Re-
flexion, Refraction, Radiation, Absorption, Polarization ; Conduc-
tion, Solids, Liquids, Gases ; Convection, Ventilation, &c.
Effect of change of Molecular State on Temperature. Freez-
ing mixtures, Ice machines, &c.
Effect of change of Pressure and Volume.
Heat Quantity. Unit of Heat, Calorimeters, Specific Heat, &c.
Licthods of determining Latent Heat.
Mechanical Equivalent of Heat. Methods of determining.
Illustrations of Thermodynamics.
INTRODUCTION.
Electrical Equivalent of Heat. Methods of determining.
Analysis of Solar Radiation.
Magnetism.
Instruments and apparatus employed in teaching, and in the
investigations and observations connected with :
Natural Magnets.
Permanent Artificial Magnets.
Electro- Mag nets.
Methods of Magnetization. Effects of Magnetization. Con-
ditions affecting intensity of Magnetization : Temperature (che-
mical), Composition, Strains, &c.
Magnetic Induction of all Substances. Diamagnetism.
Measurement of Intensity of Magnetization, Magnetic moment.
Terrestrial Magnetism. Instruments for observation and auto*
matic registration of the magnetic elements.
Electricity.
Instruments and apparatus employed in teaching, and in the
investigations and observations connected with :
Production and Maintenance of Difference of Potential.
Electrical machines acting by friction, induction (doubters, re-
plenishers, &c., Holz's and Toppler's machines, &c.) ; Galvanic
batteries ; Thermo-electric piles ; Magneto-electric machines.
Other sources, such as Pyro-electricity, Pressure electricity, Cleav-
age, Capillarity, Osmose, &c.
Detection and Measurement of Difference of Potential. Elec-
troscopes, Electrometers, Standards of electro-motive force, Me-
thods of comparison.
Accumulation of Electricity. Insulators, Condensers, Accumu-
lators, Effects due to accumulated electricity, Distribution on con-
ductors, Polarization of dielectrics, &c.
Measurement of Electric Quantity. Torsion balances, Stand-
ard accumulators, Methods of comparing electric capacities and
dielectric coefficients.
Detection and Measurement of Electric Currents. Galvano-
scopes, Galvanometers, Voltameters, Electro- dynamometers, &c.
Resistance. Standards of resistance, Methods of comparing
resistances, Methods of establishing absolute standards (British
Association unit appar.).
Effects of Electric Currents. Production of light, heat,
Electrolysis, Electro-diffusion. Action on magnets, soft iron
(electro-magnets), Action of currents on currents.
Technical Application of Electricity. Electric telegraph, &e.
INTRODUCTION. XX Hi
Astronomy.
Star maps, catalogues, globes, orreries, &c.
Meridian instruments.
Arrangements for communicating true time.
Altazimuths, zenith-sectors, sextants, &c.
Equatoreal Telescopes
Micrometers.
Driving clocks.
Special arrangements for
Celestial photography.
Spectroscopic observations.
Thermo-electric observations.
Siderostats.
Applied Mechanics.
As the Exhibition must be regarded as chiefly referring to edu-
cation, research, and other scientific purposes, it must in this
division consist principally of models, diagrams, mechanical draw-
ings, and small machines, illustrative of the principles and progress
of mechanical science, and of the application of mechanics to the
arts.
Properties of Materials.
Structures at Rest and in Motion.
Prime Movers.
Reservoirs of Energy.
Regulators.
The Application of the Principles of Mechanics to Machinery
as used in the Arts.
Shipping, Naval Architecture, and Marine Engineering.
Chemistry.
Scientific instruments, apparatus, and materials employed in the
investigation and teaching of Chemical Science, and in the appli-
cation of its principles to scientific purposes.
Diagrams and models.
Illustrations of analytical results.
Specimens of chemicals, (a) organic, (b) mineral.
Apparatus and fittings for laboratory and lectures.
Apparatus for gravimetric and volumetric operations.
Apparatus for distillation and filtration.
Apparatus for operations by the dry or hot method, such as
furnace, blowpipe, &c.
Refrigeratory apparatus.
Apparatus for spectrum analysis.
XXIV INTRODUCTION.
iSoTE. Operations of the following nature may be illustrated,
viz. :
Organic analysis.
Mineral analysis.
Electrolysis.
Water analysis.
Gas analysis.
Spectrum analysis.
Methods of investigation connected with vegetation and re-
spiration.
Meteorology.
Thermometers and barometers, of special construction.
Anemometers, rain gauges, hydrometers, &c.
Self-recording meteorological apparatus.
Illustrations of various systems of storm signals.
Weather maps.
Instruments illustrating the phenomena of atmospheric elec-
tricity.
Instrument stands.
Geography.
Instruments used in surveying.
Instruments used in Geodesy and Hydrography, including
hypsometrical instruments, tide gauges, &c.
Projections, maps, charts, models, and globes.
Deep-sea sounding apparatus. Seismographical instruments.
Geology and Mining.
Instruments for field and underground surveying.
Typical collections of rock specimens, including vein stones.
Typical fossils arranged stratigraphically.
Maps in different stages, and finished maps.
Geological models, horizontal and vertical sections.
Diagrams and plates of fossils, and general geological diagrams
used in lecture rooms.
Microscopic sections of rocks and minerals, and apparatus for
cutting such sections.
Anemometers, water gauges, mining barometers, and thermo-
meters.
Mining plans, sections, and models of workings.
Mineralogy, Crystallography, &c.
Goniometers.
Apparatus for studying and exhibiting the optical characters of
crystals.
INTRODUCTION.
XXV
Sections for optical examination.
Blowpipe and other portable apparatus for determining mi-
nerals.
Collections of crystals, models of crystals, plates of crystals, and
apparatus for drawing them.
Educational collections of minerals, &c.
Diagrams and models for lecture rooms.
with
Biology.
accessory apparatus
for biological re-
1. Microscopes
search, &c.
2. Physiological apparatus for investigating
a. The growth and mechanical movements of living organ-
isms and their parts.
b. The chemical phenomena of living organisms.
c. The electrical phenomena of living organisms.
d. The functions of the nervous and other systems.
3. Apparatus for anatomical research.
4. Apparatus for collecting and preserving object of natural
history.
5. Appliances for teaching biology.
A limited number of examples illustrating the performances of
the apparatus will be admissible.
Sub-Committees of Sections.
SECTION I. MECHANICS, INCLUDING PURE AND APPLIED MATHEMATICS
AND MECHANICAL DRAWING.
Professor J. C. Adams, M.A.,
F.R.S.
Mr. J. Anderson, LL.D., C.E.
Professor R. Stawell Ball, LL.D.,
F.R.S.
Rev. A. Barry, D.D.
Mr. W. B. Baskcomb.
Mr. Hugh Birley, M.P.
Major Bolton.
Professor F. A. Bradley.
Mr. F. J. Bramwell, F.R.S.
Mr. T. Brassey, M.P.
Mr. H. W. Chisholm, Warden of the
Standards.
Mr. G. T. Clark.
Mr. Latimer Clark.
Professor R. B. Clifton, M.A.,
F.R.S.
Sir Henry Cole, K.C.B.
Mr. G. Dixon, M.P.
Major-General F. Eardley-Wilmot,
R.A., F.R.S.
Mr. D. Glasgow.
Professor T. M. Goodeve, M.A.
The Right Hon. Lord Hampton.
G.C.B., F.R.S., President of the
Institute of Naval Architects.
Mr. T. E. Harrison. .
Sir J. Hawkshaw, F.R.S.
Mr. T. Hawksley, President of the
Institute of Mechanical Engineers.
Mi-. J, Hick, M.P.
Professor J. C. Maxwell, M.A.,
F.R.S.
Mr. C. W. Merrifield, F.R.S.
Mr. A. J. Mundella, M.P.
Dr. Pole, F.R.S.
The Right Hon. Lord Rayleigh,
F.R.S.
Mr. J. Scott Russell, F.R.S.
Major Seddon, R.E.
Professor Shelley.
Mr. C. W. Siemens, D.C.L., F.R.S.
Professor H. J. S. Smith, M.A.,
F.R.S.
XXVI
INTRODUCTION.
Mr. G. li. Stephenson, President of
the Institute of Civil Engineers.
Professor P. G. Tait, M.A.
Mr. J. Torr, M.P.
Eev. J. F. Twisden, M.A.
Professor W. C. Unwin, B.Sc.
Sir C. Wheatstonc, F.R.S. (since
deceased).
Sir J. Whitworth, Bart., F.R.S.
Mr. Bennet Woodcroft, F.R.S.
Dr. J. Woolley, F.R.S.
Colonel H. Stuart Wortley.
SECTION II. PHYSICS.
Capt. W. de W. Abney, R.E.
Professor W. G. Adams, M.A., F.R.S.
Sir G. B. Airy, K.C.B., D.C.L.,
F.R.S., Astronomer Royal.
Professor E. Atkinson, Ph.D.
Professor R. Stawell Ball, LL.D.,
F.R.S.
Professor W. F. Barrett.
Mr. C. Brooke, M.A., F.R.S.
Mr. C. O. F. Cator.
Mr. W. Chappell.
Professor R, B. Clifton, M.A., F.R.S.
Vice- Admiral SirR. Collinsou,K.C.B.,
Deputy Master of the Trinity
House.
Dr. Debus, F.R.S.
Mr. Warren De La Rue, D.C.L.,
F.R.S.
'Mr. H. S. Eaton, President of the
Meteorological Society.
Professor G. Carey Foster, B.A.,
F.R.S., President of the Physical
Society.
Dr. J. H. Gladstone, F.R.S.
Professor Guthrie, Ph.D., F.R.S.
Mr. J. Baillie-Hamilton.
Mr. J. Hopkinson, B.A., D.Sc.
Mr. W. Huggins, D.C.L., F.R.S.,
President of the Royal Astrono-
mical Society.
Lord Lindsay, M.P.
Mr. J. Norman Lockyer, F.R.S.
Reverend R. Main, M.A., F.R.S.
Dr. R. J. Mann.
Mr. C. W. Merrifield, F.R.S.
Dr. Pole, F.R.S.
The Right Hon. Lord Ray leigh, F.R.S.
Professor A. W. Remold, M.A.
Earl of Rosse, D.C.L., F.R.S.
Mr. R. II. Scott, M.A., F.R.S.
Mr. W. Spottiswoode, M.A., LL.D.,
F.R.S.
Dr. W. H. Stone.
Lieut.- Colonel Strange, F.R.S. (since
deceased).
Professor P. G. Tait, M.A.
Professor Tyudall, LL.D., F.R.S.
Mr. C. V. Walker, F.R.S., President
of Society of Telegraphic Engineers.
Sir C. Wheatstone, F.R.S. (since de-
ceased).
Dr. Woolley.
SECTION III. CHEMISTRY.
Professor F. A. Abel, F.R.S., Chemist
to the War Department.
Professor Bloxam.
Sir Henry Cole, K.C.B.
Mr. Warren De La Rue, D.C.L.,
F.R.S.
Professor Frankland, Ph.D., D.C.L.,
F.R.S.
Dr. Gilbert, F.R.S.
Dr. J. H. Gladstone, F.R.S.
i Professor Odling, M.A., F.R.S., Pre-
sident of the Chemical Society.
Dr. Percy, F.R.S.
Mr. J. A. Phillips.
The Right Hon. Lyon Play fair, Ph.D.,
C.B., M.P., F.R.S.
Professor Roscoe, Ph.D., F.R.S.
Dr. W. J. Russell, F.R.S.
Professor Williamson, Ph.D., F.R.S.
SECTION IV. PHYSICAL GEOGRAPHY, GEOLOGY, AND MINERALOGY.
Mr. D. T. Ansted, M.A., F.R.S.
Mr. H. Bauerman.
Professor F. A. Bradley.
Mr. H. W. Bristow, F.R.S.
Major-General Cameron, C.B., F.R.S.
Mr. C. 0. F. Cator.
Vice-Admiral Sir R. Collinson,
K.C.B., Deputy Master of the
Trinity House.
Professor P. M. Duncan, M.B.,
F.R.S., President of the Geological
Society.
INTRODUCTION.
XXV11
Mr. H. S. Eaton, President of the
Meteorological Society.
Sir P. De M. G. Egcrton, Bart.,
M.P., F.R.S.
Mr. K. Etheridge, F.R.S.
Captain Evans, R.N., C.B., F.R.S.,
Hydrographer of the Navy.
Mr. J. Evans, F.R.S.
Mr. D. Forbes, F.R.S.
Professor Hughes.
Lieut.-General Sir H. James, R.E.,
F.R.S.
Dr. R. J. Mann.
Mr. N. Story-Maskelyne, M.A.,
F.R.S.
Mr. C. W. Merrifield, F.R.S.
Professor Miller, M.A., LL.D.,
F.R.S.
Professor Morris.
Professor Prestwich, F.R.S.
Professor A. C. Ramsay, LL.D.,
F.R.S.
Major-General Sir H. C. Rawlinsou,
K.C.B., F.R.S., President of the
Royal Geographical Society.
Mr. R. H. Scott, M.A., F.R.S.
Mr. W. Warington Smyth, M.A.,
F.R.S.
Mr. H. C. Sorby, F.R.S., President
of the Royal Microscopical
Society.
Major-General R. Strachey, C.S.I.,
F.R.S.
SECTION V. BIOLOGY.
The Right Hon. Lord Aberdare, Pre-
sident of the Royal Horticultural
Society.
Professor H. W. Acland, M.D.,
F.R.S., President of the Medical
Council of the United Kingdom.
Dr. G. J. Allmau, F.R.S., President
of the Linuaeau Society.
Mr. G. Bentham, F.R.S.
Mr. C. Brooke, M.A., F.R.S.
Mr. G. Busk, F.R.S.
Dr. W. B. Carpenter, C.B., F.R.S.
Professor W. T. Thiselton Dyer,
M.A., B.Sc.
Professor Flower, F.R.S.
Professor Michael Foster, M.D.,
F.R.S.
Colonel Lane Fox, F.R.S., President
of the Anthropological Institute.
Mr. A. H. Garrod, M.A., F.R.S.
Mr. A. C. L. G. Guiithcr, M. A., M.D.,
F.R.S.
The Hon. Alan Herbert.
Dr. J. D. Hooker, C.B., President of
the Royal Society.
Professor T. H. Huxley, LL.D,,
F.R.S.
Professor E. Ray Lankester, M.A.,
F.R.S.
Mr. W. K. Parker, F.R.S.
Mr. G. W. Royston-Pigott, M.A.,
M.D., F.R.S.
Professor W. Rutherford, M.D., F.R. S.
Professor J. S. Burdon Sanderson,
M.D., F.R.S.
Mr. H. C. Sorby, F.R.S., President
of the Royal Microscopical Society.
Mr. F. H. Wenham.
XXIX
LIST OF CONTRIBUTORS, WITH
ADDRESSES.
%* The numbers refer to the Pages of the Catalogue.
UNITED KINGDOM.
AUKL, F. A., F.R.S., Royal Arsenal,
Woolwich-, 377-8.
AP.KUCROMBY, HON. R., 21, Chapel
Street, Mai/fair, London ; 684.
ABNEY, CAPT. W. DE W., R.E., Chat-
ham ; 234, 424, 707.
ABRAHAM, C., University of Edin-
burgh ; 595.
ACLANI), DR., F.R.S. on behalf of the
Iladcliffe Trustees, Oxford; 851,
861.
ADAMS, PROF. A. L., M.A., F.R.S. ,
Royal College of Science, Dublin ;
994.
A;>AMS, J. C., Cambridge University ;
400.
ADIK, P., 15, Pall Mall, London-,
55, 444, 677, 751, 756, 872.
ADMIRALTY (Hydrographic Depart-
ment), Whitehall, London; 95, 287-
9, 731-8, 774-6, 795-8.
AERONAUTICAL SOCIETY OF GREAT
BRITAIN (F. W. Brearey, Hon.
Sec.), Maiden stone Hill, Green-
wich ; 108.
AGRICULTURAL SOCIETY OF ENG-
LAND, ROYAL, 12, Hanover Square,
London ; 474.
AIIKBECKER, H. C., 117, Stamford
Street, London; 74, 531.
ALLKN, H., Homewood, South Orange,
Neio Jersey, U.S.A. ; 429.
ALLPOUT, S. B., 50, Whittall Street,
Birmingham ; 59.
AMIIURST-TYSSEN, W. A., Didd-
lington Hall, Norfolk ; 471.
ANATOMICAL DEPARTMENT, Oxford
University Museum ; 983-4.
ANDREWS, DR., F.R.S., Queen's Col-
lege, Belfast; 162, 168, 169, 268,
325, 570, 575, 671.
ANDREWS, W., Indo-European Te-
legraph Company, Old Broad
Street; 368.
Arrs, A., 433, Strand, London ; 216,
311, 760.
ARCHBUTT, J. AND W. E., 201,
Westminster Bridge Road, London:
76.
ASTON AND MANDER, 25, Old Comp-
ton Street, Soho, London ; 1, 2, 20.
ASTRONOMER ROYAL, THE (Sir G.
B. Airy, K.C.B., F.R.S.), Green-
wich, London; 413, 421-2.
ASTRONOMICAL SOCIETY, ROYAL,
Burlington House, Piccadilly, Lon-
don ; 413.
AUSTEN, MAJOR G., 17, Bessborough
Gardens, S. W. ; 803.
AUSTIN AND HUNTER, Sunderland ;
513, 528.
AUTOTYPE COMPANY, 36, Rathbone
Place, London ; 243-4, 433.
AVELING AND PORTER, 72, Cannon
Street, London ; and Rochester ; 459.
BABBAGE, MAJOR-GENERAL, Dainlon
House, Bromley, Kent ; 5, 6, 532-
3.
BADEN-POWELL, MRS., 1, Hyde Park
Gate South, London ; 230.
BAGOT, A. C., Pembroke College,
Cambridge; 10.
BAILEY, WALTER, 176, Haversloch
Hill, London; 217.
BAILEY, W. H., & Co., Albion Works,
Salford, Manchester ; 98, 267, 445,
456, 548.
BAKER, W. CLINTON, Bayfordbury,
Herts. ; 420.
BALDWIN, A. C., 37, Chester Square,
S.W.;391, 419.
XXX
LIST OF CONTK1BUTOES.
BALL, R. S., LL.D., F.R.S., Royal
Astronomer of Ireland, The Obser-
vatory, Dunskin, co. Dublin ; 35.
BARKER, R.E., Clifton, Bristol; 762.
BARLOW, W. H., F.R.S., High
Combe, Old Charlton, S.E. ; 189,
552.
BARRETT, PROF. W. F., F.C.S., Royal
College of Science, Dublin ; 166
-8, 177, 180-2, 184, 190-1, 246,
259, 285-6, 298, 304, 306, 339, 464,
535, 813, 1072.
BASHFORTH, REV. F., Minting Vi-
carage, Horncastle, Lincolnshire ;
101.
BASSETT, H., 44, St. Paul's Road,
Camden Toivn, London ; 196.
BAXTER, BROTHERS, Dundee ; 530.
BECK,J.,31, Cornhill, London ; 905-6.
BECK, R. AND J., 31, Cornhill, Lon-
don ; 905-6, 916-7, 920.
BEL, A., & Co., 34, Maiden Lane,
Strand, London-, 13, 196-7, 202,
667, 1004-6.
BELCHER, ADMIRAL SIR E., K.C.B.,
13, Dorset Street ; 523.
BELL, J., Rushpool, Saltburn-by-
Sea ; 830.
BEST, E., 23, Jermyn Street, S. W. ;
828.
BIDDER, S. P., 24, Great George
Street, Westminster 878-9.
BIRD, P. H., F.R.C.S., I, Norfolk
Square, London ; and Lytham, Lan-
cashire ; 258.
BISCHOFF, G., 4, Hart Street,
Bloomsbury, W.C. ; 672.
BLACKMORE, T., 2, Apsley Road,
Wandsworth, S. W. ; 550.
BLAGDIN, J. A., Petworth, Sussex-,
419-20.
BLAKE, H. WOLLASTON, F.R.S., 8,
Devonshire Place, Portland Place,
London ; 400.
BOARD OF TRADE, Standards De-
partment of, London ; 42-7.
BOARD OF WORKS, London 6, 1002.
BONOMI, J., 13, Lincoln's Inn Fields,
London; 939.
BOSANQUET, R. H. M., St. John's
College, Oxford ; 191,223.
BOUCK & Co., LIMITED, Miles Plat-
ting, Manchester ; 661.
BOWLING IRON COMPANY, Bowling,
Bradford, Yorkshire; 669.
BRACEY, J., Yarmouth, Norfolk ; 449.
BRADY, REV. NICHOLAS, M.A., Rain-
ham Hall, Romford, Essex ; 216,
222, 670, 885, 895-7.
BRAMWELL, F. J., C.E., F.R.S., Par-
liament Street, Westminster ; 546-
7.
BRIGHTON FREE LIBRARY AND MU-
SEUM, Brighton ; 843.
BRION, H. F., 231, Albany Road,
London ; 810, 839.
BRISTOL MUSEUM AND LIBRARY,
Bristol ; 829.
BRISTOW, H. W., F.R.S., Director,
Geological Survey for England and
Wales, Jermyn Street, London ;
757, 803, 861.
BRITISH HOROLOGICAL INSTITUTE,
35, Northampton Square, London ;
123-5.
BRITISH TELEGRAPH MANUFACTORY,
374, Eustnn Road, London ; 118-9,
150, 184, 333, 365-7, 375-6, 379.
BRODIE, SIR B. C., BART., Brockham
Warren, Reigate ; 570-5.
BRODRICK, THE HON. Miss, 18,
Queen Square, Bath ; 413.
BROOKE;, C., F.R.S., 16, Fitzroy
Square, London ; 151, 295-6, 712,
885.
BROOKE, MRS. CROFT, Tunbridqe
Wells-, 545.
BROOKE, SIMPSON, AND SPILLER, 50,
Old Broad Street, London; 654.
BROTHERHOOD AND HARDINGHAM,
52 and 56, Compton Street, Gos-
wellRoad-, 525.
BROUN, COLIN, Andersonian Uni-
versity, Glasgow; 193.
BROWN, J. A., F.R.S., 3, Newcastle
Place, Clerkenwett ; 106.
BROWN, PROF. A. CRUM, University
of Edinburgh ; 593-4, 630, 897,
936-7.
BROWNING, JOHN, 63, Strand, Lon-
don; 206, 209-10, 226, 311,395,
398, 400, 403, 412, 756, 908.
BRUNTON, T. L., F.R.S., 23, Somer-
set Street, Port man Square ; 952-3.
BUDDEN, E. R., Elm Villa, Horn
Lane, Acton ; 902.
BURGH OF STIRLING, THE, Stirling,
Scotland; 55.
BURT, T., Society for- Promoting
Christian Knowledge, 77, Great
Queen Street, London; 829.
LIST OF CONTRIBUTORS.
XXXI
Bu,SK,G., 32, Hm ley Street, London ;
938.
BUTLER, P. J., 55, De Beauvolr
Road, London ; 128.
CALVERT, F. C., & Co., Tower
Chemical Works, Bradford, near
Manchester ; 654.
CAMBRIDGE OBSERVATORY, Cam- \
bridge ; 400.
CAMPBELL, JOHXSTOM: & Co., 6,
Founders Court, Lothbury, E.C.
520.
CAMPBELL, LIEUT.-COL. A. C. (of
Blythswood}, 2, Seamore Place,
Mayfair, London ; 420.
CAMPBELL'S SHIPBUILDING AND
FLOATING DOCK COMPANY, Silver
Town, North Woolwich; 521.
CANN-LIPPINCOTT, E. C., JUN., Over- I
court, Bristol ; 715-6.
CAPRON, Jonx RAND, Guildford ;
217.
CASARTELLI, J., 43, Market Street,
Manchester-, 99,267, 741, 751-2,
872-3.
CASELLA, L. P., 147, Holborn Bars,
London ; 85, 95, 394, 683, 685, 687,
689, 691, 694, 702-3, 741, 759, j
762, 770, 781, 872.
CASSELL, PETTER, & GALPIN, Belle
Sauvage Yard, Ludgate Hill,
E.G.-, 1069.
CATOR, C. O. F., M.A., The Hall,
Beckenham, Kent ; 707.
CAULFIELD, R., LL.D., F.S.A.,
Queen's College and Royal Institu-
tion, Cork ; 740.
CAVENDISH LABORATORY, Cam-
bridge; 109, 383.
CAYLBY, PROF., F.R.S., Garden
House, Cambridge ; 34.
CETTI, E., & Co., 11 and 31, Brooke
Street, Holborn, London ; 163, 166,
264, 305, 322, 626, 629, 639, 659, i
661, 672, 683, 698, 700, 872, 944-5,
1003.
CHANCE BROTHERS & Co., Bir-
mingham ; 412.
CHAPMAN AND HALL, 193, Picca-
dilly; 1011.
CHAPPE DE LEONVAL,T. F., 29, Stan-
ley Gardens, Notting Hill Gate,
London ; 20.
CHAPPELL, W., F.S.A., 49, Strafford
Lodge, Oatlands Park, Surrey ;
194-6.
CHATHAM, School of Military En-
gineering ; 237.
CHAUMONT, SURGEON-MAJOR F. DE,
Netley, Southampton ; 700.
CHESNBY, COL. G., Royal Indian
Engineering College, Cooper's Hill,
Staincs; 461.
CHISHOLM, H. W., Warden of the
Standards, 7, Old Palace Yard,
London ; 82, 87.
CHISHOLM, MRS., Church Lane
House, Haslemere, Surrey"; 50.
CHRISTY, T., & Co., 155, Fenchurch
Street, London ; 171.
CHURCH, PROF. A. H., Agricultural
College, Cirencester ; 86.
CLARE, T. D., Heathfield Place,
Handsworth, Birmingham ; 368.
CLARK, LATIMER, 5, Westminster
Chambers; 346-7.
CLIFTON, R. B., F.R.S., Clarendon
Laboratory, University Museum,
Oxford; 189,427.
COHEN, J. & Co., Charterhouse Street,
London ; 95.
COLE, A. C., AND SON, 62, St. Do-
mingo Vale, Evert on, Liverpool ;
983.
COLLEGE OF SURGEONS, ROYAL,
Lincoln's Inn Fields, London; 976.
COMMISSIONERS OF NORTHERN
LIGHTS, Edinburgh; 536-8, 545-6.
COMMISSIONERS OF PATENTS, Patent
Office Museum, South Kensington,
London; 4, 65, 116, 283, 451-2,
457, 460, 462, 465, 467, 469-72,
477, 480, 491, 498, 529.
COODE, SIR J., 2, Westminster Cham-
bers, London ; 545.
COOKB, C. W., C.E., M. Soc., T. E.,
57, Landor Place, Clapham Rise,,
S. W. ; 246 , 324.
COOKE, J., Lang fey Hall, Langley
Moor, Durham ; 870.
COOKE, T. AND SONS., Buckingham
Works, York; 128.
CORK, THE EARL OF, K. P., Marston,
Frome; 428.
COWPER, E. A., 6, Great George
Street, Westminster; 173, 254,
265, 479, 548.
COWPER, MRS. C., 3, The Residences,
South Kensington Museum; 383.
CRAIG, JOHN., Washington Street,
Glasgow; 630-3.
CRAMPTON, T. R., 4, Victoria Street,
Westminster ; 348, 458, 668.
TXXU
LIST OF CONTRIBUTORS.
CRIPPS, W. H., F.R.C.S., 53a, Pall
Mall, London- 691-2.
CRISP, F., 134, Adelaide Road, Lon-
don ; 911-2.
CROSSLEY BROTHERS, Great Marl-
borough Street, Manchester ; 455.
CROSSLEY, E., F.R.A.S., Bermerside,
Halifax; 53.
CROSSLEY, L. J., Moorside, Halifax,
Yorkshire; 369.
CROUCH, H., 66, Barbican. London ;
907, 916.
CULLEY, R. S., General Post Office,
London ; 347.
CURTIS, PROF. A. H.,LL.D., Queen's
College, Galway ; 227.
CURWEN, J., Plaistow, Essex; 192.
CUTTELL, F. G., 52, New Compton
Street, Soho, London ; 850.
DAGLISH, R., & Co., St. Helen's,
Lancashire ; 453.
DAINTREE, R., Tralee Lodge, Bourne-
mouth ; 928.
DALE, R, S., B.A., Owen's College,
Manchester; 592.
DALLAS, D. C., 362, Gray's Inn
Road, London ; 233.
DALLINGER, REV. W. H., F.R.M.S.,
4, Fair holme Road, Great Crosby,
Liverpool ; 916-7.
DALLMEYER, JOHN H., 19, Blooms-
bury Street, London ; 240-3.
DAMON, R., Wey mouth ; 860, 975-6.
DARLING, W. H., Owen's College,
Manchester; 591.
DARTON, F., & Co., 72, St. John
Street, West Smithfield, London;
693, 699.
DARWIN, G. H., Trinity College,
Cambridge; 809-10.
DAVEY, H., Sun Foundry, Leeds ;
464.
DAVIDSON, J., University of Edin-
burgh ; 596-7.
DAVIS, CAPT. J. E., R.N., F.R.G.S.,
Douglas House, Maze Hill, Green-
wich; 402, 755-6.
DAVIS, J., AND SON, All Saints
Works, Derby; 99, 100, 870-1,
874.
DAVIS, REAR - ADMIRAL, C. H.,
United States Naval Observatory,
Washington ; 434-5.
DEACON, H., Widnes, Lancashire ; 99,
100. 647.
DENT, E.,& Co., 61, Strand, London ;
117, 122, 123, 127, 128, 414-5.
DE LA RUE, W.,F.R,S, 73, Portland
Place, London; 236, 303, 424,
426.
DE MICHKLE, V., Higham Hall,
Rochester ; 445.
DENTON, S.G., 128, Gray's Inn Road,
Holborn, London ; 260, 689-90.
DENTON, W., Sunderland ; 513.
DE RANCE, C. E., F.G.S., Geological
Survey, Jermyn Street, London;
829.
DE RATTI, A., Bradford Grammar
School, Bradford, Yorkshire ; 303.
DEWAR, PROF., Cambridge; 310.
DEWRANCE, J. & Co., 176, Great
Dover Street, Borough ; 551.
DICKINSON, J., Engineer, Sunder-
land ; 525.
DIXON, A., St. Anne's, Howard Road,
Penge, Surrey ; 419.
DONKIN, A. E., M.A., Rugby ; 21.
DONKIN, BRYAN, Engineer Works,
Bermondserj ; 65.
Dow, T., Exeter; 451.
DOWNING, T. J., 38, Whiskin Street,
London ; 867, 884, 888, 1042.
DOXFORD, W., AND SONS, Sunder-
land; 515,527.
DRING AND FAGE, 19 & 20, Tooley
Street, London ; 2, 3, 5, 8, 56, 169
-72, 260-1, 687, 690.
DRYSDALE, J. J., M.D., 4, Fairholme
Road, Great Crosby, Liverpool ;
917.
DUDGEON, R. E., M.D., 53, Mon-
tague Square, London,' W. ; 531.
DUER, S., B.Sc., 6, Westminster
Chambers, Victoria St., London ;
472.
DUNCAN. R., & Co., Ship-builders,
Port Glasgow 527-8.
DUNN, E. J. ; 828.
DUNSCOMHE, M. W., 10, St. Augus-
tine's Parade, Bristol; 1024-6.
DUPRAT, LE YICOMTE, Consul-
General of Portugal, St. Mary
Axe, E.C. ; 102, 428.
EAMES, M., 40, Sclater Street, Shore-
ditch, London ; 17.
EDINBURGH MUSEUM OF SCIENCE
AND ART, Edinburgh ; 220, 257,
285, 347, 563-4.
EDINBURGH UKi\EnsiTY,Edi?iburgh ;
276, 295,316, 398, 451, 721.
LIST OF CONTRIBUTORS.
XXX111
EDWARDS, B. J., Co., G, Lincoln
Terrace, Kit burn, London ; 232.
ELDER, J., & Co., Govan, near Glas-
gow ; 498.
ELKINGTON & Co. ,22, Regent Street,
London ; 379.
ELLIOTT BROTHERS, 449, Strand,
London; 2, 3, 51,57, 74, 75,77,
95-6, 99, 103, 109, 147, 152,
181-3, 229, 250, 259, 261, 279,
281, 290, 298, 300, 305, 308, 316
-8, 327, 333-4, 339-45, 370, 375,
419, 4(i5, 475-6, 681, 689, 693,
699, 708, 722, 747, 751, 780, 870.
ENOCH, F., 30, Russell Road, Hollo-
way ; 924, 978.
ERARD, MESSRS., 18, Great Marl-
borough Street, London ; 192.
ESSEX AND ClIELMSFOliD MUSEUM,
Chelmsford ; 903-4.
ETLER, C., 1st Battalion Grenadier
Guards, Chelsea Barracks, S. W. ;
302.
EVANS, L., Hemcl Hempsted; 8, 17.
FAIJA, H., 4, Great Queen Street,
Westminster; 103.
FARADAY, MRS., Barnsbury Villa,
320, Liverpool Road, London ;
382-3.
FARWIG, J. F., 36, Queen Street,
Cheaps ide, London ; 252.
FAULKNER, J., 13, Great Dude
Street, Strangeways, Manchester ;
281-2, 319.
FELLOWES, I. H., 46, South Quay,
Great Yarmouth; 515.
FLANNERY, J. F., G, Broadway Cham-
bers, Westminster; 103,524-5.
FLETCHER, A. E., 21, Overtoil Street,
Liverpool ; 97-8, 657.
FLETCHER, T., F.C.S., Museum
Street, Warrinyton; 252-3.
FORSTER, P., Sunderland ; 515.
FOSTER, ROBERT. Sunderland ; 74.
FOWLER, J., C.E., 2, Queen Square
Place, Westminster; 548.
FRANCIS, G., C.E., Chester ; 745.
FRANKLAND, PROF., Ph.D., D.C.L.,
F.R.S., Royal School of Mines,
Jermyn Street, London ; 580-6,
623-4, 672.
FRODSHAM, C., & Co., 84, Strand,
London ; 118.
FROUDE, W., F.R.S., Chelston Cross,
Torquay; 487-9.
FULLER, G., Belfast; 381.
40075.
| FULTON, J., University of Edinburgh ;
592-3.
GAIRDNER, 45, South Bridge, Edin-
burgh; 923.
GALLETLY, A., Museum of Science
and Art, Edinburgh ; 159, 160.
I GALLOWAY, PROF. R., Royal College
of Science, Dublin ; 658.
1 GALTON, F., F.R.S., 42, Rutland
Gate, London; 13, 14, 21, 178,
767, 769, 802.
| GARDNER, J. STARKIE, Park House,
St. John's Wood Park, London ;
88, 437-8, 549, 552, 866-7.
I GARDNER, J., AND SONS, 453, Strand,
London; 250.
GARNER, R., F.R.C.S., Stoke-upon-
Trent ; 257, 904.
GARNHAM & Co., Sash Court, Wilson
Street, Finsbury, London ; 376.
j GASKELL, DEACON, & Co., Widnes,
Lancashire; 644-5.
j GEIKIE,PROF., Di RECTOR, Geological
Survey of Scotland, Edinburgh ;
827.
GEOGRAPHICAL SOCIETY OF LON-
DON, ROYAL, 1, Savile Row, Bur-
lington Gardens, London ; 798, 801.
GEOLOGICAL MUSEUM, Jermyn Street;
668.
GEOLOGICAL SECTION, UNIVERSITY
MUSEUM, Oxford ; 844.
GEOLOGICAL SOCIETY OF LONDON,
Burlington House, Piccadilly,
London; 815-21.
GEOLOGICAL SURVEY OF ENGLAND
AND WALES, Jermyn Street, Lon-
don-, 821-3.
GEOLOGICAL SURVEY OF SCOTLAND
(Prof. Geikie, F.R.S., Director),
Edinburgh-, 827.
GEOLOGICAL SURVEY OF THE
UNITED KINGDOM (A. C. Ram-
say, LL.D., F.R.S., Director-Ge-
neral), Jermyn Street, London ;
823-8.
GEORGE, CAPT. C., Royal Geographi-
cal Society, 1, Savile Row, London ;
754-8, 769.
GLADSTONE, J. H.. Ph.D., F.R.S.,
17, Pembridge Square, London ;
579-80.
GLASGOW MECHANICS' INSTITU-
TION ; 451,460,497.
GOODMAN, G. H., 55, Penrose Street,
Newinyton, S.E. ; 472.
XXXIV
LIST OF CONTRIBUTORS.
GORDON, J. E. H., B.A., Gonville
and Caius College, Cambridge ;
705.
GORE, G., F.R.S., 50, Islington Row,
Edgbaston, Birmingham { 163, 256,
285-7, 308-9, 316-7, 323, 325-7,
335, 340, 576-7, 1069-70.
GOSSAGE, W., AND SONS, Widiies,
Lancashire ; 652-3.
GRANTHAM, MRS. J., Kirkby Cottage,
Cray don, Surrey ; 549.
GRAY, J. W., AND SON, Mary Street,
Rhodcswell Road, Limeliouse, Lon-
don; 318.
GREEN, R. AND H., Blackwall,
London; 505-6.
GREENHILL, A. G., Royal Artillery,
Woolwich; 21.
GREGORY, J. R., 88, Charlotte Street,
Fitzroy Square, London; 861, 884,
888, 893, 1042.
GRIESBACH, MRS., Holland Street,
Kensington, London ; 197.
GRIFFIN, J. J., AND SONS, 22, Gar-
rick Street, Covent Garden, Lon-
don; 1026-34.
GROVE, THE HON. SIR VV. R.,
115, Harley Street, London; 304.
GROVES, W., 89, Bolsover Street,
London ; 181, 426.
GRTTBB, H., F.R.A.S., Dublin ; 400-
1, 432.
GUEST ANDCHRiMES,J?oAer/JGfm; 80.
GURNEY, S., 20, Hanover Terrace,
N.W.; 814.
GTJTHRIE, PROF. F., Ph.D., F.R.S.,
Royal School of Mines, Jermyn
Street, London; 104, 151, 163,
178, 182-3, 190, 275, 280, 282,
298-9, 311, 320, 323, 327, 337,
591, 885, 1006-9.
HAMILTON, J., 2, Granby Terrace,
Glasgow; 491.
HAMILTON, J. BAILLIE, Greenwich
Park; 200-1.
HANKEY, T., 71, Chester Square,
S.W.; 129.
HARDING, A. B., F.P.S., 1, Albion
Villas, Forest Hill, London ; 323.
HARDING, T. R., AND SON, Tower
Works, Leeds ; 102-3.
HARGREAVES, J., Widnes, Lanca-
shire; 273.
HARGREAVES AND ROBINSON, Wid-
nes, Lancashire ; 643.
HARRISON, W. J., F.G.S., Curator,
Town Museum, Leicester ; 839.
HARVEY, REYNOLDS, & Co., 14,
Commercial Street, Leeds; 239,
257, 263, 280, 301, 309, 315, 334,
641, 913, 926, 942-3.
HASWELL, J., Sunderland ; 514.
HATHORN & Co., Sun Foundry,
Leeds; 464.
HAWKINS, S. J., 27, Lichfield Grove,
Finchley ; 16, 75.
HAWKSLEY, T., 300, Oxford Street,
London; 53, 179, 462, 915,922,
926-7, 931, 933-6, 939, 944, 948-
50, 952, 954, 995, 1001.
HAY, R. H., Sunderland ; 514.
HAYDEN, W., Little London, Chiches-
ter; 477.
HEAD, J., M.I.C.E., Middlesborough ;
453, 469, 479, 548-9, 667.
HECTOR, J., C.M.G., M.D., F.R.S.,
7, Westminster Chambers, London ;
830.
HEDGES, K. W., & Co., 36, King
William Street, London, E.C.;
462.
HENDERSON, D. AND W., & Co.,
Meadowside Works, Glasgow ;
509-12.
HENDERSON, R., Timsbury, Bath;
762,873.
HENNESSV, PROF. H., F.R.S., Royal
College of Science, Dublin ; 7, 35,
51, 87, 109, 724.
HENRICI, PROF. O., F.R.S., Univer-
sity College, London ; 34, 35.
HERMANN, I., 21, Northampton
Square, E.G.; 125.
HERSCHEL, PROF. A. S., College of
Physical Science, Newcasile-on-
Tyne; 207, 234, 247, 412.
HICKS, J., 8, 'Hatton Garden, E.G. ;
171, 680, 689-90, 698, 714.
HIGHAM, A. J., 13, Blackheath Ter-
race, London, S.E. ; 118.
HILGER, A., 192, Tottenham Court
Road, London ; 59, 88, 204, 213,
227, 230, 402-3, 405, 438, 763.
HILL, CAPT. H., 53, Marine Parade,
Brighton ; 346.
HIRSCH,H., 25, Craven Street, Strand,
W.C.; 525-6.
HIRST, I3ROOKE, AND HIRST, Leeds ;
661.
HODGKIN, NEUHAUS, & Co., 61,
63, Queen Victoria Street, E.G. ;
463.
LIST OF CONTRIBUTORS.
XXXY
HOGGAN, G. & E. E., M. D., 13,
(rrenrille Place, Portnutn Square ;
977.
HOLMAN, D. S., Philadelphia, U.S.A.-,
928.
HOLMK.S, J . M., Town Hall Chambers,
ttirminyham ; 549.
HOLMES, N. J., 8, Gt. Winchester
Street Buildings, E.C. ; 534-5.
HOLT, H. P., C!E., Royal Insurance
Buildings, Leeds ; 75, 453, 456,
469, 474, 498.
HOOKER, J. D., M.D., P.R.S., Royal
Gardens, Kew, Surrey ; 112, 904.
HOPKINS & WILLIAMS, 16, Cross
Street, Hatton Garden, E.C. ;
620.
HORNER, C., Fern Villa, Mortlake,
Surrey, 231.
HOROLOGICAL INSTITUTE, BRITISH,
35, Northampton Square, London ;
123-5.
How, J., & Co., 5, St. Bride Street,
Fleet Street, late 2, Foster Lane,
London ; 166, 214, 280, 290, 305,
313, 339, 380-1, G29, 839, 884,
907,916,979.
HOWE, \V., Clay Cross, Chesterfield ;
146.
HULL, E., DIRECTOR, (Geological
Society of London) -, 815-21.
HULL, PROP. E., M.A., F.R.S.,
Royal College of Science, Dublin ;
813.
HUNT, R., Craven Hotel, Strand ;
550.
HUXTER ENGLISH, Bow ; 525.
HUSBANDS, H., Bristol 743, 753.
HUTCHINSON, J., & Co., Windes,
Lancashire ; 645-7.
HUXLEY, PROF., F.R.S., Royal School
of Mines, Jerniyn Street, London ;
993-4.
HYDRAULIC ENGINEERING Co.,
Chester ; 455.
INDIA, SECRETARY or STATE FOR,
India Office, Whitehall, London;
729-30, 787-9.
IRELAND, GENERAL VALUATION OF,
Dublin; 803.
IRELAND, ROYAL COLLEGE OF
SCIENCE FOR, Stephen's Green,
Dublin. (See ROYAL COLLEGE
OF SCIENCE.)
JACKSON, REV. J. C., 67, Amherst
Road, Hackney, London ; 116, 391.
JACKSON, M., 65, Barbican, Lon-
don ; 1009-10.
JEBB, G. R., Chester ; 553.
JELLETT, REV. J. H., B.D., Trinity
College, Dublin; 21 7.
JOHNSON, MATTHEY, & Co., Hatton
Garden, London ; 53, 88, 641,
669.
JOHNSTON, W. & A. K., 18, Pater-
noster Mow, E.C. ; 1034-5.
JORDAN, J. B., Museum of Practical
Geology, Jennyn Street, London ;
681, 815, 851.
JOULE, J. P., D.C.L., F.R.S.,
Broughton, Manchester; 163, 281,
287, 290.
KEMPE, A. B., B.A., 7, Crown Office
Row, Inner Temple, London ; 1 45
-6.
I^ESSELMEYER, CH. A., Manchester ;
439. >:->'.'
KEW COMMITTEE OF THE ROYAL
SOCIETY, Kew Observatory, Sur-
rey ; 212, 261, 291, 293-6, 299,
332-3, 398, 421, 424, 694, 697,
701, 711, 738-9, 768.
KEW MUSEUM, Royal Gardens, Kew,
Surrey, 982.
KING'S COLLEGE, LONDON, COUNCIL
OP, Somerset House, Strand,
London ; 13, 147, 150, 162-3,
166,202,204, 223, 237, 258,283,
301-2, 311, 321, 324, 342, 368-9,
382, 426, ' 450, 464-5, 479, 529;
547, 553, 702, 1046.
KINGSTON, G. T., Meteorological
Office of the Dominion of Canada ;
Toronto, Canada ; 695-6.
KNOBEL, E. B., F.R.A.S., F.G.S.
20, Avenue Road, Regent's Park,
London ; 406, 438.
KULLBERG, V., 135, Liverpool Road,
N. ; 127.
LADD, W., & Co., 11 and 12, Beak
Street, Regent Street, London ; 223,
224,313, 909.
LAIDLER, W. H., 9, Edward Street ;
Bow Common, London ; 60.
LAING, J., Deptford Yard, Sunder-
land; 517.
LAIRD BROTHERS, Birkenhead Iron
Works, Birkenhead; 500-5, 531.
LASLETT, T. N., 97, Mary on Road t
Charlton, S.E. ; 748.
LATHBURY, R., JUN., Park House,
Chiswick, Middlesex ; 499.
c 2
XXXVI
LIST OF CONTRIBUTORS.
LAW, C., Champion Park, Camber-
well, S.E.; 567.
LA WES, J. B., F.R.S., Rothamsted, St.
Albans ; 661, 662, 994-5.
LAWRENCE AND PORTER, 36, Parlia-
ment Street, London ; 464.
L AWT ON, W., 49, High Street, Hull ;
412.
LEARD, A., M.D., 12, Old Burling-
ton Street, W. ; 948.
LECKEY, K. J. , F.R.A.S., Scientific
Club, 7, Saville Row; 391, 398,
750.
LETTS, DR. E. A., University of
Edinburgh ; 262, 592-7.
LETTSOM, W. G., 2, Thurlow Place,
Lower Norwood ; 249.
LEY, H.-W., 16, Bear Street, Leices-
ter Square, London ; 11921.
LIDSTONE,T., Dartmouth, Devon ;450.
LIGGINS, H.,3, Ladbrohe Square, W. ;
510.
LIGHTS, NORTHERN, COMMISSION-
ERS or, Edinburgh ; 536-8, 545-6.
LINN LAN SOCIETY, Burlington House,
London; 980-2.
LIPPINCOTT. See CANN-LIPPINCOTT.
LITERARY AND PHILOSOPHICAL SO-
CIETY OP MANCHESTER ; 564-7.
LLOYD, KEY. H., D.D., F.R.S.,
Trinity College, Dublin ; 168, 182,
217, 223, 228, 229, 274, 290, 339-
40, 386.
LLOYD'S REGISTER OF BRITISH AND
FOREIGN SHIPPING, Cornhill, Lon-
don ; 508.
LOCKYER, J. NORMAN, F.R.S., 5,
Alexandra Road, London ; 404,
420, 424-6, 432-34, 717, 814,
1064.
LOCKYER, MRS. NORMAN, 5, Alex-
andra Road, London ; 433.
LONDON, GEOLOGICAL SOCIETY OP,
Burlington House, Piccadilly,
London ; 815-21.
LONDON INSTITUTION, Finsbury
Circus, London ; 304.
LONDON MATHEMATICAL SOCIETY,
22, Albemarle Street, London ;
30-4.
LONDON ORDNANCE Co., Vavasseur
Street. Southwark ; 55 1-2.
LONDON, ZOOLOGICAL SOCIETY or,
11, Hanover Square, London ;
995-7.
LONGMANS, MESSRS., Paternoster
Row, London ; 1068-9.
LOVELL, T. M., INST. C. E. per
GARNHAM AND Co., Wilson Street,
Finsbury, London ; 548.
LOWNE, 11. M., Leicester House,
East End, Finchley, London ; 98-9,
945.
LUVINI, PROF., per METEOROLOGICAL
OFFICE, 116, Victoria Street, S.W.;
717.
MACLAUCHLAN, J. (Chief Librarian),
Dundee Free Library and Mu-
seum ; 203, 476, 479.
McLEOD, PROF. H., Cooper's Hill
College, Staines ; 163, 172, 620,
625.
MACMILLAN & Co., Bedford Street,
Strand; 1065-8.
McNAB, PROF. W. R., M.D., Royal
College of Science, Dublin ; 926,
994.
MADDOX, DR. (See How AND Co.,
5, St. Bride Street, Fleet Street,
E.G., London.}
MAIN, REV. R., F.R.S., Director of
the Radcliffe Observatory, Oxford ;
411, 717.
MAJOR, DR. H., West Riding
Asijlum, Wakefield ; 664.
MAKINS, G. H., Danesfield, Walton-
on-Thames ; 478.
MALLET, R., C.E., F.R.S., The
Grove, Clapham Road, S. ; 773.
MANCHESTER, COUNCIL OF THE
LITERARY AND PHILOSOPHICAL
SOCIETY OF ; 564.
MANN, R. J., M.D., 5, Kingsdown
Villas, Wandsworth Common, Lon-
don. ; 323, 337, 425, 805, 839, 1064.
MARRATT, J. S., 63, King William
Street, London ; 428.
MARSDEN, 11. S., University of Edin-
burgh ; 595.
MARSHALL, A., Perseverance Iron
Works, Hencage Street, White-
chapel, E. ; 457-8.
MARSHALL, J., SONS AND Co., Leeds,
661.
MARTIN, J., 58, Arundel Square,
London; 234.
MASKELYNE, PROF. N. S., F.R.S.,
112, Gloucester Terrace, Hyde
Park, London 227, 887, 895.
MASSEY ; E., Openshaw Works, Man-
chester; 95, 770.
MASTER OF THE MINT, THE, Lon-
don; 665-6.
LIST OP CONTRIBUTORS.
XXXVll
MATHEMATICAL SOCIETY, LONDON,
22, Albemarle Street, London;
.30-4.
MATHIESON, N., & Co., Widnes,
Lancashire ; 647-8.
MAFDSLAY, SONS, AND FIELD, Lam-
beth, London; 455, 483-5, 491-2,
518-20.
MAXWKLL, PUOF. CLERK, 11,
Xrroope Terrace, Cambridge ; 40,
276, 341-2.
MAYLAND, W.. 236, Regent Street,
London-, 237.
MECHANICS' INSTITUTION, Glasgow ;
451, 460, 497.
MENZIES AND BLAGUUKX, King Street,
Newcastle-upon- Tyne ; 477.
MERRIFIELD, C. \V., F.R.S., Edu-
cation Department, Whitehall,
London ; 813.
METEOROLOGICAL COMMITTEE OP
THE ROYAL SOCIETY, LONDON ;
243, G73-6, 698, 705, 711, 721.
METEOROLOGICAL OFFICE, 116, Vic-
toria Street, S.W. ; 676, 717-8.
METEOROLOGICAL SOCIETY, 30, Great
George Street, Westminster; 673-
4,676.
METEOROLOGICAL SOCIETY, SCOT-
TISH, General Post Office JBuild-
ings, Edinburgh ; 225, 674, 680,
686, 689, 692, 697, 713, 716, 718-
20, 7ti3.
MILLAR, W. J., C.E., 100, Wellington
Street, Glasgoio ; 446.
MILLER, W. H., M.A., F.R.S., Pro-
fessor of Mineralogy, Cambridge ;
126, 767, 886.
MILTON, J. L., Sion House, King's
Road, London ; 252.
MINES, ROYAL SCHOOL OF, Jcrmyn
Street, London ; 59, 553-62.
MINING AND MECHANICAL ENGI-
NEERS, NORTH OF ENGLAND
INSTITUTE OF, Newcastle-upon-
Tyne; 876-8.
MITCHELL, C., & Co.. Newcastle-on-
Tyne ; 508-9.
MITCHELL, W. S., LL.B. ; 823.
MOLINEUX, T., 8, Park Village East,
Regent's Park ; 193.
MOODY, W., 2, Nightingale Vale,
Woolwich, Kent ; 500.
MOON, G. W., 164, Regent Street,
W.; 685.
MOORE, B. T. ; Spring Grove,
Meworth ; 95, 97.
MORISON, D. P., 21, Collinywood
Street, Newcastle-upon-Tyne ; 869-
70.
MORRIS PATENTS ENGINEERING
WORKS, 50, High Street, Bir-
mingham ; 75-6.
MORRISON, R. M., University of
Edinburgh; 597.
MOTTERSHEAD & Co., Manchester ;
321, 102fi.
MoY,T. ; Institution of Naval Archi-
tects, John St., Adelphi, London ;
524.
MULLER, HUGO W., F.R.S. ; 303.
MULLER, J. A., C.E., 30, Craven
Street, Strand, London ; 96.
MURBY, T., 32, Bouverie Street, E.C. ;
431, 1046.
MURRAY, CAI-T. (per F. BUCKLAND) ;
781.
MURRAY & Co., Chester-le-Street,
Durham ; 550.
MURRAY, R. C., 69, Jermyn Street,
London ; 229.
MUSEUM OF SCIENCE AND ART,
Edinburgh ; 220, 257, 285, 347,
563-4.
MUSPRATT, J., & SONS, Widnes,
Lancashire ; 651-2.
MYLNE, R. W., C.E., F.R.S., F.G.S.,
21, Whitehall Place, London;
828-9.
NAPIER AND ETTKICK, LORD, 40,
Queen Anne's Gate'; 7.
NAPIER, R., West Shandon, Dumbar-
tonshire, Scotland ; 491, 509.
NASMYTH, J., Hammerfield, Pens-
hurst, Kent ; 473.
NAVAL ARCHITECTS, INSTITUTE OF,
20, John Street, Adelphi; 516, 529.
NAVAL MUSKUM, ROYAL, Greenwich,
117,391,499, 781.
NESBITT, A., F.S.A., Oldlands, Uck-
field; 74.
NEGRETTI AND ZAMBRA, Hatton
Garden, London ; 675, 677-9, 684,
687-9, 691, 700.
NELSON DOCK Co., LIMITED, 16,
London Street, Rotherhithe, Lon-
don ; 515.
NE\VALL AND Co. ; 130, Strand, Lon-
don; 530.
NEWTON, E. T., Museum of Practical
Geology, Jermyn Street, London ;
978.
XXXV1J1
LIST OF CONTRIBUTORS.
NICHOLAS, J., 90, Brunswick Street, \
Manchester 67, 467.
NICKOLL AND CREWS ; 36, St. Mary j
Axe, London ; 522-3.
NICOL, W. J., University of Edin- |
burgh ; 595-6.
NORRIS, TV. J., AND BROTHER,
Colder Chemical Works, Sowerby
Bridge, Halifax ; 654.
NORTH OF ENGLAND INSTITUTE OP ,
MINING AND MECHANICAL ENGI-
NEERS, Newcastle - upon - Tyne ; ;
876-8.
NORTHERN LIGHTS, COMMISSIONERS <
OF, Edinburgh ; 536-8, 545-6.
OERTLING, L., Turnmill Street,
London-, 15, 81, 88, 171.
OLRICK, L., 37, Leadenhall Street,
E.G.; 446.
OMMANEY, ADMIRAL, 6, Talbot \
Square, Sussex Gardens, W.; 741. j
ORDNANCE SURVEY (Maj.-Gen. Ca- j
meron, R.E., F.R.S., Director Gene- j
ral), Southampton ; 725-8, 783-5.
ORDNANCE SURVEY OF PALESTINE,
9, Pall Mall East, London ; 786.
O'REILLY, PROF. J. P., Royal College
of Science, Dublin ; 214,679,849-
50, 879, 885, 888, 894.
ORTON, REV. W. PREVITK, M.A.,
Ornesby , Rugby ; 221.
OXFORD, UNIVERSITY OF ; 885-6.
OXFORD UNIVERSITY MUSEUM, Ox- \
ford ; 840, 844, 983-4.
PALESTINE, ORDNANCE SURVEY OF, \
9, Pall Mall East, London; 786.
PARKES, MRS., 17, Wimpole Street,
W.; 208.
PARKINSON AND ERODSHAM,4, Change
Alley, E.C. ; 126, 636.
PASTORELLI, E., 208, Piccadilly, Lon-
don ; 96, 99, 675, 682, 685-6, 689-
90, 694-5, 698, 708, 742, 752, 871
-2, 942.
PATENTS, COMMISSIONERS OF, Patent \
Office Museum, South Kensington,
London-, 4, 65, 116, 283, 451-2,
457, 460, 462, 465, 467, 469-72,
477, 480, 491, 498, 529.
PEARSON, A. A., 44 and 46, Queen's ,
Place, Leeds ; 438.
PENDRED, V., Streatham Hill, Surrey ;
508.
PERIGAL, H., E.R.A.S., 9, North
Crescent, Bedford Square, Lon- \
don-, 21, 147-8.
PERKIN, W. H., F.R.S., The Chest-
nuts, Sudbury, Harrow 586-90.
PHORSON, P., Sunderland 518.
PICHLER, S. F., 162, Great Portland
Street, London-, 17S, 196, 250,
475, 530, 916.
PIGOT, PROF. T. F., C.E., M.K.I. A..
Royal College of Science, Dublin ;
39,' 55, 476, 551.
PILLISCHER, M., 88, New Bond
Street, London ; 679,684, 703, 907,
916.
POOLE, J., & Co., 33, Spencer Street,
Clerkenwell, London ; 117.
PORTER, H., 181, Strand, London ;
17, 680, 685, 741, 752, 756, 768.
POSTMASTER -GENERAL, II. M., St.
Martin We- Grand, London ; 349-
61, 550.
PREECE, W. H., General Post Office,
London; 336.
PRESTWICH, PROF. J., E.R.S., Ox-
ford; 844.
PRICE, W., 181, Burrage Road,
Plumstead; 656.
PRITCHARD, URBAN, M.D., 41, Guil-
ford Street, Russell Square, Lon-
don ; 920.
PROSSER, W. H., 108, South Hi/I
Park, Hampstead; 5, 477.
PURVES, W. L., 7, Hanover Street,
Hanover Square, W.; 929-30,
933.
RANSOMES, SIMS, & HEAD, Orwell
Works, Ipswich ; 454.
RATTI, AUREL DE, Bradford Gram-
mar School ; 303.
RAYLEIGH, LORD, E.R.S., 4, Carlton
Gardens, London ; 165, 191.
RAYNOR, W., Radcliffe, Manchester;
315.
READ, MRS., 27, Sussex Place, South
Kensington, London ; 194.
REID, J., & Co., Port Glasgow ;
490, 497.
REID, BROTHERS, 1 2, Wharf Road,
City Road, London; 347-9. '
RENNIE, J. & G., Holland Street,
BLickfriars, S.E. ; 520-2.
REYNOLDS, PROF. O., Owen's Col-
lege, Manchester ; 39, 108.
RIANO, SENO-R E., 23a, Connaught
Square, W. ; 374.
RICHARDSON, DUCK, & Co., Stockton-
on-Tees; 508.
RICHARDSON, T. & SONS, Hartlepool ;
522.
LIST OF CONTRIBUTORS.
XXXIX
RITCHIE, J., & SON, 25, Leith Street,
Edinburgh; 415-9.
ROBERTS, W. H., Snodland, Kent ;
781.
ROBERTS, W. CHANDLER, F.R.S.,
Royal Mint, London ; 208, 568-70.
ROBERTS, DALE, & Co., Manchester
and Warriju/ton ; 653.
ROSCOB, PROF., F.R.S., Owen's Col-
lege, Manchester; 217,' 563, 567,
577-9, 644, 670, 705-7.
Ross AND Co., 7, Wigmore Street,
Cavcndisk Square, London ; 239,
905.
Ross, MAJOR W. A., 3, Mayland
Row, Shepherd's Bush ; 638.
Ros8E,EARL OF,F.R.S., Birr Castle,
Parsonstown, Ireland; 401, 406,
412,432, 438.
ROUND, J., 196, Camberwcll Road,
London ; 376.
ROWLEY, W., C.E.,F.G.S., 74, Albion
Street, Leeds ; 874, 879-80.
ROYAL AGRICULTURAL SOCIETY OF
ENGLAND, 12, Hanover Square,
London ; 474.
ROYAL ASTRONOMICAL SOCIETY,
Burlington House, Piccadilly,
London ; 41 1, 413.
ROYAL COLLEGE OF SCIENCE FOR
IRELAND, Stephen's Green, Dub-
lin ; 8. See also PROFESSORS
ADAMS, BARRETT, GALLOWAY,
HENNESSY, HULL, McNAB,
O'REILLY, and PIGOT.
ROYAL COLLEGE OF SURGEONS OF
ENGLAND, Lincoln's Inn Fields,
London ; 976.
ROYAJL COMMISSIONERS FOR THE
INTERNATIONAL EXHIBITION, 1851 ;
724, 814.
ROYAL GEOGRAPHICAL SOCIETY OF
LONDON, 1, Savile Row, Burlington
Gardens, London ; 740, 798-801.
ROYAL INDIAN ENGINEERING COL-
LEGE, Cooper's Hill ; 461.
ROYAL INSTITUTION OF GREAT BRI-
TAIN, 2 1 , Albemarle Street, London ;
257, 286, 302, 381-2, 477, 563,
567-8, 878.
ROYAL MICROSCOPICAL SOCIETY,
King's College, London ; 475, 902-3.
ROYAL MUSEUM, SALFORD, Peel
Park, Salford; 1, 8, 119, 250, 281,
476-7, 487, 550, 681, 901-2.
ROYAL NAVAL MUSEUM, Greenwich ;
117, 391, 781.
ROYAL OBSERVATORY, Greenwich ;
129.
ROYAL POLYTECHNIC INSTITUTION,
Regent Street, W.; 312.
ROYAL SCHOOL OF MINES, Jermyn
Street, London ; 59, 553-62.
ROYAL SOCIETY, Burlington House,
Piccadilly, London; 57, 89, 111,
117,159,171,291,298,399,410-11,
413,421,431, 690, 699, 738, 741,
750, 875.
ROYAL UNITED SERVICE INSTITU-
TION, Whitehall Yard, London ;
115-6,392.
ROYDEN, T., (Shipbuilder} Liver-
pool; 507.
ROYSTON-PlGOTT, G. W., M.D.,
F.R.S., Hartley Court, Reading,
57, 908, 919.
RUBIE, G. P. ; 527.
RUCKJSB, PROF. A. W., M.A., York-
shire College of Science, Leeds; 63.
RUHMKORFF, 11, Beak Street, Regent
Street; 311, 314.
RUSSIAN EMBASSY, THE, Chesham
Place, S.W.; 516.
RUTHERFORD, PROF., Edinburgh ;
944.
RUTLEY, F., Geological Survey Office,
Jermyn Street, London ; 826-7.
RUTTER, H. L., 1, St. Barnabas
Villas, Lansdowne Circus, South
Lambeth, S.W.; 281,316.
RUTTER, J. O. N., F.R.A.S., Black
Rock, Brighton; 313.
SABINE, R., 2o, Cumberland Terrace,
Regent's Park, Lo.ndon ; 181, 203,
208, 233-4, 244, 348.
SALFORD ROYAL MUSEUM, Peel Park,
Salford; 7,8,119,250,281,476-7,
487, 550, 681, 901-2.
SAMUDA, BROTHERS, Poplar ; 522.
SAMUELSON, B., M.P., Middles-
borough ; 668.
SANDERSON, DR. B., F.R.S., 49
Queen Anne Street, W. ; 948.
SANDERSON AND PHOCTOR, Shore
Works, Huddersfield, and 19 and
21, Queen Victoria Street, London ;
277, 318.
SCHERZER, DR. K. von, Austrian
Consulate General, 29, St. Sivithin's
Lane, London ; 748.
SCHOOL OF MILITARY ENGINEERING,
Chatham; 237.
SCHORLEMMER, C., F.R.S., Owen's
College, Manchester; 591-2.
LIST OF CONTIUBUTORS.
SCHUNK, DR., Owen's College, Man-
chester; 663.
SCIENCE SCHOOLS, South Kensington
Museum ; 1063.
SCOTLAND, GEOLOGICAL SURVEY OF,
Edinburgh-, 827.
SCOTT-MONCRIEFF, W. D., 9, Great
Queen Street, Westminster', 468,
489-90.
SCOTT, R. H., F.R.S., Director, Me-
teorological Office, 116, Victoria
Street, Westminster-, 689.
SCOTTISH METEOROLOGICAL SO-
CIETY-, General Post Office Build-
ings, Edinburgh-, 225, 674, 680,
686, 689, 692, 697, 713, 716, 718-
20, 723.
SECRETARY OF STATE FOR INDIA,
India Office, Whitehall, London ;
729-30, 787-9.
SHAND, MASON, & Co., 75, Upper
Ground Street, London ; 463.
SHARMAN, G., St. Leonard's Villa,
West End Lane, Kilburn, Lon-
don-, 861.
SHORT, BROTHERS, Sunderland; 528-
9.
SIEBE AND GORMAN, Mason Street,
Westminster Bridge Road ; 531.
SIEMENS, DR. C. W., London 250,
265-7, 468.
SIMEY, A., & Co., Sunderland ; 518.
SINCLAIR, J., 104, Leadenhall Street,
London ; 487.
SKERTCHLY, SYDNEY B. J., F.G.S.,
Geological Survey, Jermyn Street,
London; 712.
SKINNER, (Shipbuilder} Sunderland ;
518.
SMITH, DEW, 7a, Eaton Square,
S.W.; 950.
SMITH, EDWIN, Bath ; 411.
SMITH'S INSTITUTE, Sttriinc/ ; 79.
SMITH, LIEUT.- GEN. M. ' W., 58,
Gloucester Crescent, Hyde Park,
W.; 19.
SMITH, T. AND W., Neivcastlc-on-
Tyne ; 530.
SMITH, W., V.^Newcastlc-on-Tyne;
523-4.
SMITH, W. G., 15, Mildmay Grove,
N.-, 985.
SMYTH, J., JUN., M.I.C.E.I., Milltown,
Banbridge, Ireland 714-5.
SMYTH, PROF. PIAZZI, Royal Obser-
vatory, Edinburgh-, 50, 51, 111,
239, 258.
[ SOCIETY FOR PROMOTING CHRISTIAN
KNOWLEDGE, Lincoln** Inn Fields,
W.C.; 829.
SOMERVILLE, J., 20, Wcstlatid Row,
Dublin; 472.
SORBY, II. C., F.R.S., Broomfield,
Sheffield-, 845-6, 905.
SOUTH KENSINGTON MUSEUM, Lon-
don; 22-30, 129, 193-4,203, 205,
227, 379, 395, 447-9, 454-5, 458,
464, 465-7, 470, 480-3, 492-7, 532,
546, 782.'
I SPEECHLY, H., 43, King's Road, St.
Pancr as, London; 194.
SPEKE, W., jun., Jordans, llminster,
Somersetshire; 741.
I SPENCE, P., Pendleton Alum Works,
Manchester ; 65 1 .
j SPILLER, J., F.C.S.,2, St. Mary's Rd.,
Canonbury, London ; 205,207, 905.
SPOTTISWOODE, W., F.H.S., 50, Gros-
venor Place, London ; 220, 222.
SPOTTISWOODE, MRS. W., 50, Gros-
renor Place, London ; '222.
SPRAGUE, J. T., 315, Green Lane,
Birmingham ; 337.
SPKENGEL, H., 44, Charlwood Street,
Pimlico, London ; 165.
STANDARDS DEPARTMENT, BOARD OF
TRADE (H. W. Chusholm, War-
den), 7, Old Palace Yard, Lon-
don ; 42-7.
STANFORD, E., Charing Cross, Lon-
don; 824, 827-8.
STANLEY, A. AND F. New Britain,
35, Chambers St., New York ; 53.
STANLEY, W. F., 3, Great Turnstile,
Holborn, London; 17.
STEELE, R. & Co., Greeiiock ; 517-8.
STEPHENSON, G. 1&.,Albemarlc Lodge,
Wimbledon Park ; 457.
STEPHENSON, J. W., Equitable As-
surance Office, Mansion House
Street, London ; 906.
STEVENSON, D. AND T., Northern
Lighthouse Office, Edinburgh ; 546.
STEWART, PROF. BALFOUR, F.R.S.,
Owen's College, Manchester ; 243,
276, 692.
STIFF AND SONS, London Pottery,
Lambeth ; 655.
STIRLING, THE BURGH OF, Stirling ;
55.
STONE, DR. W. II., Dean's Yard,
Westminster; 153, 166, 181, 183,
193, 196, 207, 246,281,287,298,
300, 426.
LIST OF CONTRIBUTORS.
xli
STRAWSON, G. W., 9, Pancras Lane,
London-, 17, 112, 747, 75u, 752,
873.
STRUTHERS, PROF., Aberdeen Uni-
versity, 937, 979.
SUB-WEALDEN EXPLORATION COM-
MITTEE (W. Topley, F.G.S., and
H. Willett, F.G.S.) ; 837-9.
SUGG, W., Vincent Works, Vincent
Street, Westminster ; 22. r >, 249.
SULLIVAN & Co., British Alkali
Works, Widnes, Lancashire ; 642-
3.
SUNDERLAND, CORPORATION OF ;
518.
SWIFT, J., 43, University Street,
Tottenliam Court Road, London ;
907-8,917,927.
SYMONS, G. J., 62, Camden Square,
London ; 289, 682, 686-7, 698,
700, 702, 717, 720-1, 743.
TAIT, PROF. P. G., M.A., University
of Edinburgh ; 275, 310, 321, 324.
TALBOT, H. 'Fox, F.R.S., Lacock
Abbey, Chippenham ; 237.
TANGYK BROTHERS, AND HOLMAN,
10, Laurence Pountney Lane, Lon-
don ; 454.
TAYLOK, MAJOR M. L., R.A., Royal
Artillery Institution, Woolwich ;
104, 117,741.
TEASDALE, W., Headingley, Leeds ;
908.
TENNANT, PROF., Piccadilly, Lon-
don ; 829.
THAMES IRON WORKS AND SHIP-
BUILDING Co., Orchard Yard,
Blackwall ; 506, 507.
THERMO-ELECTRIC GENERATOR Co.,
27, New Street, Cloth Fair, Lon-
don; 310.
THOMAS, J. W., The Laboratory,
Cardiff, Wales ; 473, 640.
THOMSON, PROF., JAS. University,
Glasyuw ; 460-1.
THOMSON, PROF. SIR W., F.R.S.,
The University, Glasgow; 11, 12,
49, 50, 152, 321, 329-31, 335-6,
342, 349, 371, 373, 445, 451, 770,
776-9.
THOMPSON, J. L., AND SONS, Sunder-
hind; 518.
THOMPSON, R., Junr., Sunderland;
514.
THORPE, PROF., Yorkshire College
of Science, Leeds-, 217, 653.
TIIWAITES AND CARBUTT, Bradford
Yorkshire ; 473, 643-4.
TISLEY AND SPILLER, 172, Brompton
Road, London; 149, 302-3, 318,
716.
TOPLEY, W r ., F.G.S., Geological
Surveij, Jermyn Street, London ;
815-6.
TRIBE, A., 17, Pembridge Square,
London ; 579.
TRINITY COLLEGE, DUBLIN, Dublin.
(See JELLETT AND LLOYD.)
TRINITY HOUSE, LONDON, CORPO-
RATION OF, Trinity Square, Tourer
Hill, London ; 532-6.
TROUGHTON AND SIMMS, 138, Fleet
Street, London ; 1 12, 394, 741.
TURNBULL, R., 823.
TURNER, B. B., 31, Haymarkct,
S.W.; 239.
TYLER, HAYWARD & Co., 84, Upper
Whitecross Street, London ; 455, 463.
TYLOR, J., AND SONS, 2, Newgate
Street, E.C.; 80.
TYNDALL, PROF., F.R.S., 21, Albc-
marle Street, London; 190, 274
287.
UNITED SERVICE INSTITUTION,ROYA L,
Whitehall Yard, London; 115-6,
392.
UNIVERSITY of EDINBURGH, Edin-
burgh; 276, 295, 316, 398, 451,
721.
UNIVERSITY OF OXFORD, 885-6.
UNIVERSITY OF OXFORD MUSEUM,
Oxford ; 840, 844, 983-4.
UN WIN, PROF. W. C., Cooper's Hill
College, Staines ; 96, 461.
VARLEY, S. A., Hatfield, Herts ; 314,
373.
VICTORIA, THE AGENT-GENERAL OF,
Victoria Chambers, S. W. ; 803.
WALLACE, J. (TANGYE BROTHERS &
RAKE), 3, St. Nicholas Buildings,
Newcastle-upon-Tyne ; 633-5.
WALTER, J., M.P., 40, Upper Grcs-
venor Street, London ; 479.
WAR OFFICE, Pall Mall, London ;
56, 379.
WARD, J. CLIFTON, Greta Bank
Cottage, Keswick ; 823-6.
WARD, W. S., Denison Hall, Leeds ;
167, 335, 370, 563, 754, 904.
WARDEN, MUIRHEAD, AND CLARK,
29, Regent Street, Westminster,
London ; 304, 336-7, 344-6, 368-
73, 377.
xlii
LIST OF CONTRIBUTORS.
WARWICK, J. A., Derby ; 348.
WATERHOUSE, A., 20, New Caven-
dish Street, London ; 1070-2.
WATKIN, LIEUT. H., R.A., 1, Ux-
bridge Villa, Page} Road, Shooters
Hill, London ; 100.
WATSON AND Sox, 313, High Hoi-
born, London ; 394, 397, 750, 757.
WAUGH, J., 29, Tyrrell St., Brad-
ford; 915,918.
WEAR, COMMISSIONERS OF THE
KIVER, Sunderland ; 471.
WEBB, F. W., Locomotive Depart-
ment, L. and N. W. Railway,
Crewe ; 458-9, 547-8.
WEDEKIND, II., 4, Great Tower
Street, London ; 254, 655.
WEST WOOD, PROF., Oxford,-, 986.
WHEATSTONE COLLECTION OF PHY-
SICAL APPARATUS, King's College,
London. (See KING'S COLLEGE,
London.')
WHEATSTONE, the late SIR C. ; 346.
WHEELER, E., 48, Tollington Road,
Holloway, London ; 909, 918.
WHITE, J., 241, Sauchiehall Street,
Glasgow ; 329,498.
WHITE, J., Cowes, Isle of Wight ;
498.
WHIT WELL, T., Stockton -on-Tees ;
668.
WHITWORTH, SIR JOSEPH, F.R.S.,
& Co., 44, Chorlton Street, Man-
chester ; 48-49, 444, 669.
WIDNES METAL Co., West Bank,
Widnes, Lancashire ; 648-50.
WILLIAMS, J., F.C.S., 16, Cross
Street, Hatton Garden, London ;
263.
WILLIAMS, THOMAS, AND DOWER,
Star Chemical Works, Hrentford,
Middlesex ; 655.
WILLIS, W-, 49, Palace Grove,
Bromley, Kent ; 232, 525, 553.
WILTSHIRE, EEV. T., M.A., Secre-
tary, Geological Society, Burlington
House, Piccadilly, London ; 852.
WINCHESTER, CORPORATION OF, Win-
chester; 478.
WOLLASTON COLLECTION, Cavendish
Laboratory, Cambridge ; 57, 205.
WOLLASTON, G. H., 117, Pembroke
Road, Clifton, Bristol; 183, 205,
567, 885.
WOOD, G. S., 20, Lord Street, Liver-
pool; 908.
WOOD, J., Ivy Cottage, Burnley
Lane; 456.
WOODBURY PERMANENT PHOTOGRA-
PHIC PRINTING Co., 157, Great
Portland Street, London ; 232,
240, 470-2, 474, 481, 487, 490,
492.
WOODBURY, W. B., Manor House,
South Norwood; 233, 245, 700.
WOODCROFT, BENNET, F.R.S., Great
Seal Patent Office, London ; 8, 17,
83,97, 279, 451-3, 457-8,470-2,
474, 480, 487, 490, 492.
WOODWARD, C. J., Birmingham and
Midland Institute, Birmingham ;
150,205.
WORKS, H.M. OFFICE OF, London
6, 1002.
WORNUM AND SONS, 16, Store Street,
London ; 193.
WORTLEY, COL. STUART, Patent
Museum, South Kensington, Lon-
don ; 233.
WRIGHTS ON, T., Sunderland; 513.
YE ATE s AND SON, 2, Grajton Street,
Dublin; 181, 189, 214, 265, 311,
339, 400, 694, 698.
YEO, PROF. GERALD, King's College,
W.C.; 950.
YOUNG, J., West Docks, South
Shields ; 512-3.
YORKSHIRE COLLEGE OF SCIENCE,
COUNCIL OF, Leeds; 5, 75, 153,
176, 653.
YORKSHIRE PHILOSOPHICAL SO-
CIETY. COUNCIL OF, York ; 399. .
ZANM, G., 31, Compton Road, High-
bury, and 1 , James Street, Old
Street, City Road, London ; 370,
373, 376-7.
ZOOLOGICAL SOCIETY or LONDON,
11, Hanover Square, London ;
995-7.
ATJSTRO-HUNGARIAN EMPIRE.
ARZBERGEK, PROF. F., Imp. Sf Royal
Technical High School, Brilnn ;
639, 770.
BAUER, PROF. DR. A., Polytechnic
Institute, 20, Kamtnerstrasse,
Vienna ; 253, 671.
BORRICKY, DR. E., Prof, of Mineral-
ogy, University of Prague ; 894.
LIST OP CONTRIBUTORS.
xliii
ETTINGSHAUSEN, BARON C. von, Prof,
of Botany, University of Gratz ;
852-60.
EXNER, DR. W. F., Professor of
Engineering, High School of Agri-
culture and Forestry, Vienna ; 475.
FORESTS, IMP. AND KOYAL INSTITU-
TION FOR CARRYING OUT EXPERI-
MENTS RELATING TO (Dr. W.
Velten, Physiologist to the Institu-
tion), Vienna ; 993.
FRIG, V., Prague ; 989.
GONDA, HERR BELA, Magyar, Ovar,
Hungary ; 663.
GROHMANN, ED., Vienna ; 7.
HANTKEN, PROF. M., University of
Buda-Pest; 867.
IIOPFGARTNEK, LlKI'T. Y. (Imp. and
Royal Navy}, Vienna ; 769-70.
IMP. AND KOYAL CENTRAL INSTITUTE
OF METEOROLOGY AND MAGNETISM,
Vienna ; 119, 705, 712, 717.
IMP. AND ROYAL MARITIME GOVERN-
MENT, Trieste ; 534.
INSTITUTE OF PATHOLOGY, Univer-
sity of Vienna (Prof. S. Strieker,
Director) ; 944.
JENNY, C., Professor, Imperial and
Royal Polytechnic Institute, Vienna;
445.
KLEBS, DR. E. B., (Pathological In-
stitute}, Prague ; 927-8, 999, 1000.
LANG, PROF. V. von, University of
Vienna ; 1 54.
MILLER, F., Innsbruck ; 751, 759.
MOSER, PROF. I., Director of the
Imp. and Royal Chemical Institu-
tion for Agricultural Researches,
Vienna ; 939, 978-9.
OSNAGHI, PROF. F., Imp. and Royal
Central Institute of Meteorology,
Hohe Warte, Vienna; 119, 705,
712, 717.
PATHOLOGY, INSTITUTE OF, Univer-
sity of Vienna (Prof. S. Strieker,
Director) ; 944.
PAUGGER, DR. F., Director of the
Imp. and Royal Commercial and
Nautical Academy, Trieste ; 703-
4,780.
PFAUNDLER, DR. L., Prof, of
Physics, University of Innsbruck ;
150, 152-3, 261, 273.
PHYSIOLOGICAL INSTITUTE, Prague
936, 939, 947-8.
PRAGUE, PATHOLOGICAL INSTITUTE
OF THE UNIVERSITY OF (Dr.
E. Klebs, Djrector) ; 927-8, 999-
1000.
RICHTER, C. W., Oedenburg, Hun-
gary, 251.
ROESLER, PROF. DR. L., Director
of the Imp. and Royal Experi-
mental Station for the Cultivation
of the Vine and Fruits, Kloster-
neuburg ; 664, 919.
SCHLBSINGER, PROF. J., High School
of Agriculture, Vienna; 747, 759.
SCHOEN, PROF. J. G., Polytechnic
Institute, Briinn ; 705.
SCHOPFLKI TIIXKR, DR. F., 9, Wallen-
stein Strasse, Vienna ; 529-30, 870.
STREINTZ, PROF. DR. H., University
of Gratz; 60.
STRICKER, PROF. S., University of
Vienna (Institute of Pathology);
944.
SZABO, PROF. DR. J., University of
Buda-Pest ; 867.
TILLE, J., PROF., Bohemian Poly-
technic Institute, Prague ; 473.
TINTER, PROF. DR. W., Polytechnic
Institute, Vienna ; 683, 764-6.
TLLSER, PROF. F., Bohemian Poly-
technic Institute, Prague ; 35-4J6.
TRIESTE, IMPERIAL AND ROYAL
MARITIME GOVERNMENT AT ; 534.
UNIVERSITY OF GRATZ ; 60.
UNIVERSITY OF VIENNA, INSTITUTE
OF PATHOLOGY ; 944.
VELTEN, DR. W., Imp. and Royal
Institution for carrying out experi-
ments relating to Forests, Vienna ;
993.
VIENNA, IMP. AND ROYAL CENTRAL
INSTITUTE OF METEOROLOGY AND
MAGNETISM ; 119, 705, 712, 717.
VIENNA UNIVERSITY, INSTITUTE OF
PATHOLOGY; 944.
WALTENHOFEN, DR. A. von, Prof,
of Physics, German Polytechnic
Institution, Prague ; 283.
ZENGER, C. W., Prof, of Physics,
Bohemian Polytechnic Institution,
Prague; 89, 209, 225, 318, 403,
423/427, 929.
xliv
LIST OP CONTRIBUTORS.
ZMURKO, DR. L., Prof, of Mathe-
matics, University, and Polytechnic
Institute, Lembery ; 18,20,21.
ZULKOWSKY, PROF. C., Imp. and
Royal Technical High School,
Brilnn ; 639.
BELGIUM.
ARENS, ANTOINE MARIANUS, Rue de
Bruxelles, Namur ; 1012.
BRUVLANTS, G., Laboratory of
General Chemistry, University of
Louvain ; 592.
COUGNET, J., Ixelles, Brussels; 165.
GERARD, A. J., 5, Place St. Lambert,
Liege ; 100, 107-8, 128.
GOCHET, PROF. A. M., Normal
School, Carlsbourq, Luxembourg ;
813, 1026.
HENRY, L., Professor of Chemistry,
University of Louvain ; 592.
LE BOULENGE, MAJOR, 23, Thier de
la Fojitaine, Liege-, 56, 100.
LEURS, LIEDT.-GENERAL, 9, Hue de
la Longue-haie, Brussels; 100.
MALAISE, PROF. C., MEMBER OF THE
ROYAL ACADEMY OF BELGIUM,
State Agricultural Institute, Gem-
bloux, Province of Namur ; 836.
MARTINOT, A., Nismes, Mariem-
bourg; 1011.
NAVEZ, LIEUT. COL., Schaerbeeth,
Brussels.
PIRON, FRERE M., Director of the
Normal School, Carlsbourg ; 13, 39.
REXARD, A., 11, Rue des Recollets,
Louvain ; 845.
SACRE, E., 30, Rue Cantersteen,
Brussels ; 83.
SCHWANN, PROF. T., 11, Quai de
V Universite, Liege ; 954-5, 1002.
SIMONAN AND TOOVEY, Chausse de
Lille, Tournai; 236.
VAN RYSSELBERGHE, F., Paymaster,
Royal Navy, Antwerp, late Pro-
fessor at the School of Navigation,
Ostend ; 74, 709.
VAN SCIIERPENZEEL TlIINI, J.,
Director of Mines, 34, Rue Nysten,
Liege ; 878, 880.
FRANCE.
ALVERGNIAT FRERE s, 10, Rue de la
Sorbonne, Paris ; 250, 322, 641.
Auzoux, DR., 96, Rue de Vaugirard,
Paris; 982-3.
BAUDIN, 276, Rue St. Jacques, Paris ;
171, 723.
BECQUEREL, M. E., 47, Rue Cuvier,
Paris ; 237, 425.
BERTHELOT, M., 97, Boulevard St.
Michel, Paris ; 1035.
BIARD, M., 10, Rue Mont Theibord,
Paris ; 813.
BONIS, MADAME, 18, Rue Mont-
martrc, Paris; 317.
BONTKAIPS, Telegraph Inspector,
Paris; 377.
BOURDON, C., 74, Rue du Faubovrg
du Temple, Paris; 128, 146, 166,
456, 470.
BOURGOGNE, E., 34, Rue Cardinal
Lemoine, Paris ; 977.
BREGUET, 81, Boulevard Mont Par-
nasse, Paris; 173, 280-1, 306-7,
316, 328, 426, 669, 711, 781, 878.
CACHELEUX, 6, Rue des Vieilles
Haudriettes, Paris ; 549.
CARRE, E., 24, Rue d'Assas, Paris ;
166, 299, 328.
CHAMEROY, 162, Faubourg St. Martin,
Paris; 83.
CLETJET, 196, Rue d'Allemagne,
Paris; 469.
COLLEGE OF FRANCE, PARIS ; 147,
182, 222, 255, 258, 268, 312, 327.
COLLIN & Co., 6, Rue de VEcole de
Medecine, Paris ; 945.
COLLOT, BROTHERS, Boulevard de
Montr ouge, Paris ; 79, 83, 87.
CONSERVATOIRE DES ARTS ET
METIERS, Paris ; 3, 12, 21, 128,
162-9, 182, 196, 234, 255, 261, 268,
274, 295, 305, 307, 324, 338, 381,
414, 420, 427, 430, 460, 487, 638,
683, 696, 743, 887.
CRETES, M., 66, Rue de Rennes,
Paris ; 204, 227, 930, 933.
DAUBREE, M., Membre de 1'Institut,
Director of the School of Mines,
Paris; 847.
LIST OF CONTRIBUTORS.
xlv
D'ABBORDRE, A., 120, Rue du Bac,
Paris; 746-7.
DELAGRAVE, M., 58, Rue des Ecoles,
Paris; 813.
DELES SE, M., Chiej Engineer of
Mines, Paris; 811-2, 844.
DELEUIL, 42, Rue des Fourneaux,
Paris ; 85, 87.
DEPARTMENT OF LIGHTHOUSES,
France; 538-45.
DEPOT OF MARINE CHARTS AND
PLANS, Part's; 813.
DEPREZ, M., 16, Rue Cassine, Paris ;
370, 467.
DESAINS, MEMBRE DE L'INSTITUT,
78, Rue d' Arras, Paris ; 274.
DESCIIIENS, )23, Boulevard St.
Michel, Paris ; 372.
DIGKON, 13, Rue de Marseille, \
Paris ; 153, 446, 476.
DOLFUS, E., 9, Rue St. Fiacre, Paris ;
470.
DUBOSCQ, J., 21, Rue de VOdeon, j
Paris; 183, 190,205-6, 215,218,
240, 250, 328, 337, 420.
DUMOULIN-FROMENT, 85, Rue Notre
Dame des Champs, Paris ; 21, 60,
75, 101, 374, 781.
DUMAS, J., 69, Rue St. Dominique,
St. Germain, Paris ; 568.
EASTERN RAILWAY OF FRANCE,
Pan's ; 1 1 1 .
COLE DE PHARMACIE, Rue de I'Ar-
baletc, Paris ; 223.
ECOLE POLYTECUNIQUE, Paris; 63,
169,182, 191, 203, 255,268,281,
343, 383.
ENFER FILS, 10, Rue de Rambouillet,
Paris; 669.
ERHARD, 12, Rue Duguay Trouin,
Paris; 236, 381.
EVRARD, 30, Rue des Blancs Man-
teaux, Paris ; 413.
FACULTY OF SCIENCES, Par is ; 168,
275.
FEIL, 56, Rue Lebrun, Paris; 215.
FIZEAU, M., MEMBRE DE L'INSTITUT,
3, Rue de la Vieille Estrapade,
Paris ; 234, 237.
FONTOURE, H., 92, Rue St. Georges,
Paris ; 314.
FORTIN HERMAMN, MM., 122, Boule-
vard Mont Parnasse, Paris ; 56,
66, 458.
FRENCH COMMISSION FOR OBSERVING
THE TRANSIT OF VENUS IN 1874;
413,423.
GAVARD, A., 70, Quai des Orfevres,
Paris; 16,21.
GILLOT, Madame, 179, Rue du Fau-
bourg, St. Martin, Paris ; 234.
GIRARD, A., Prof., Conservatoire
des Arts et Metiers, 292, Rue St.
Martin, Paris ; 918.
GOLAZ, 24, Rue des Fosses, St.
Jacques, Par is; 169, 268-72, 620-
3, 625-6.
GONDOLO & Co. (misprinted TON-
DOLA), 9, Boulevard du Palais,
Paris ; 129.
GOUPIL & Co., 9, Rue Chaptal,
Paris; 234.
GROS, 94, Rue de Montreuil, Paris ;
467.
GUEROULT, G., 2, Rue de Vienne,
Paris; 192.
GUYOT D'ARLINCOURT, 102, Rue
Neuve des Mathurins, Paris; 373-4.
HANICQUE DE ST. SENOCH, 19, Rue
Denwurs, Paris ; 810.
HAYAUX DU TILLY, 15, Rue de Lis-
bonne, Paris ; 803, 813.
HIRN, G. A., 3, Logelbach, Colmar ;
110.
HONZEAU, M., Rouen ; 663.
ISOARD FILS, 78, Rue St. Maur,
Paris-, 59.
JAMIN, 24, Rue Soufflot, Paris ; 280.
JANNETTAZ, 9, Rue Linne, Paris;
275-6.
JANSSEN, M., Membre de 1'Institut,
33, Rue Labat, Paris ; 423.
KASTNER, F., 43, Rue de Clichy,
Paris; 179.
LABORATOIRE DU COLLEGE DE
FRANCE, Place Cambrai, Paris ;
590.
LANCELOT, 11, Rue des Poitevins,
Paris; 196.
LARREY, BARON, 91, Rue de Lille,
Paris ; 927.
LA UNA Y, PROF., Lycte, Caen ; 802.
LAURENT, LEON, 21, Rue de VOdeon,
Paris ; 214, 218, 221, 223, 226, 248,
255, 277, 391,412, 914-5.
LAUSSEDAT, COL., PROF., Conserva-
toire des Arts et Metiers, Paris ;
768.
LEMAIRE DOUGHY, 64, Rue Taiibout,
Paris; 879.
xlvi
LIST OF CONTRIBUTORS.
LETELLIER ; 90, Rue Chateau Lan-
don ; 1043.
LOISEAU FILS, 29, Rue Richelieu,
Paris; 166,282-3,311.
LUIZARD, 43, Rue St. Andri des
Arts, Paris ; 166, 250, 337.
LUTZ, M., Paris; 117, 122, 204-5,
215, 218, 219, 221, 223, 226-30,
250, 438, 886, 916.
MALLIGAND FILS, 1, Boulevard St.
Michel, Paris ; 663.
MANNHEIM, PROF., Ecole Polytech-
nique, Paris ; 3.
MARIAIS, 260, Rue St. Honore,
Paris-, 376.
MARET, PROF. (College of France*),
13, Rue Dug ay Trouin, Paris ;
970-5.
MASCART, PROF. ( College of France) ,
Paris; 230.
MATHIEU, M. L., 16, Carrefour de
VOdeon, Paris ; 955-6.
MERCADIER, M., Ecole Poly technique,
Paris; 189.
MOLTENI, J. AND A., 44, Rue du
Chateau d*Eau, Paris ; 39, 226,
430, 438, 750.
MOTTRET, 8, Cour des Petites Ecu-
ries (Redier), Paris ; 428.
NACHET, A., 17, Rue St. Severin.
Paris ; 205, 911, 930, 934, 936, 945.
ORSAT, M., 29, Rue de la Victoire,
Paris; 657.
PARIS OBSERVATORY ; 215, 247, 398,
420.
PARIS, VICE-ADMIRAL, President de
VAcademie des Sciences, Paris ;
498.
PHARES DE FRANCE, SERVICE DES,
Place du Trocadero, Paris ; 538-
45.
Pi CART, A., 20, Rue Mayet, Paris ;
909, 914.
POLYTECHNIC SCHOOL, Paris ; 63,
169. 182, 191, 203, 230, 255, 268,
281, 343,383.
REDIER, Rue des Petites Ecuries,
Paris ; 128, 328, 682, 712.
KENAUD-TACIIET, AIM., 17, Rue
Richelieu, Paris ; 4, 15, 17, 21.
EICHARD, M., Paris ; 683.
ROULOT, 3, Rue des Vielles Hau-
driettes, Paris ; 929-31, 934.
RUHMKORFF, 15, Rue Champollion ,
Paris; 261, 300, 950.
SAUTTER, LEMONNIER, ET CIE.,
26, Avenue de Souffren, Paris ; 538.
SCHLOESING, M., 27, Quai d'Orsay,
Paris; 638.
SCHOOL OF PHARMACY, Paris ; 223.
SCIENCES, FACULTE DES, Paris ; ] 68,
275.
SEGUIER, M. LE, 3, Rue du Regard,
Paris ; 86, 457, 492, 499, 550.
SERVICE DES PHARES DE FRANCE
(Lighthouse Service of France),
Place du Trocadero, Paris ; 538-
45.
SOCIETE DE L' ALLIANCE, LA, 25, Rue
Dufrenoy, Paris ; 313-4.
SOCIETE FRANAISE DE PHOTO-
GRAPHIE, 20, Rue Louis le Grand,
Paris ; 234, 237.
TAVERNIER GRAVET, 39, Rue de
Babylonc, Paris ; 3, 56, 752.
TELEGRAPH DEPARTMENT, Paris ;
375.
THIEL, AINE, 75 & 77, Rue Lacon-
damine, Paris ; 235-6.
TRAMOND, 9, Rue de I 'Ecole de Mede-
cine, Paris; 997-8.
TROUVE, G., 6, Rue Therese, Paris ;
147, 283, 377, 380, 951-2.
VIDAL, L., 13, Quai Voltaire, Paris ;
233, 237.
VILLARCEAU, Y., Membre de I'ln-
stitut, 18, Avenue de I'Observa-
toire, Paris ; 128.
WENTZEL, MADAME, 6, Rue Breton-
viller, Paris ; 39.
WERLEIN, 38, Rue d'Ulm, Paris;
887-8, 936.
WIESNEGG, 64, Rue Gay Lussac,
Paris ; 636.
WINNEREL, M., 35, Galerie Mont-
pensier (Gabriel), Paris ; 104, 127.
GERMANY.
ACADEMY OF MINES, KOYAL (Prof.
Hauchecorne, Director), Berlin ;
452-3, 485-6, 835.
ACADEMY OF MINES, ROYAL (Prof.
Richter, Director), Freiberg,
Saxony; 172, 472, 657,849,870,
874, 884-5, 894, 897.
ADMIRALTY, IMPERIAL, HYDRO-
GRAPHIC DEPARTMENT AND NAU-
TICAL OBSERVATORY, Berlin and
LIST OF CONTRIBUTORS.
xlvii
Hamburg; 259,293,681,712, 721-
2, SU2.
VLHERT, J. W., 34, Nette Mainzer,
stnisse, Frankfort-on-Maine ; 188,
20G.218, 245.
ALBKECIIT, Tubingen; 180,189,896.
ALTIIAUS, E., Superintendent of
Mines, Breslau; 277.
ANATOMICAL INSTITUTE (Prof. Dr.
B. Gerlach), Erlangen ; 991-2.
APEL, W., Gottingen ; 219, 713,897.
APPUUN, G., AND SONS, Hanau ;
198-9.
ASSOCIATION FOR THE MANUFAC-
TURE OF ANILINE, Rnmmelsburg,
near Berlin ; 598.
Ai:<;i:.-iT, 1-hi. F., Humboldt-Gt/mna-
sium, Berlin ; 436-7.
BABO, Piior. von (Chemical Labora-
tory), Freiburg, /irdsgau; 182.
BACH, DR. O., Leipzig; 637.
BAEYER, LIETT.-GENERAL (Presi-
dent of the Geodetic Institute),
Berlin; 67.
BALL, JULIUS, Freiburg, Rrcisgau ;
639.
BAMBERG, C., 158, Linienstrassc,
Berlin; 63, 290, 401-2, 721, 740,
780.
BAU-DEPUTATION, Hamburg ; 746,
763, 806-9.
BAUERNFEIND, PROF. DR. von
(Geodetic Institute, Royal Poly-
technic School), Munich ; 22, 744,
761.
BAUR, GUSTAV, Stuttgart; 314, 338.
BECKER, AUG. (DR. MEYERSTEIN'S
Workshops), Gottingen; 211, 212,
928.
BEETZ, PROF. DR. (Polytechnic
School), Munich; 102, 262, 306,
333, 341, 343, 986.
BERGGEWERKSCHAFTSKASSE (Dr.
Heintzmann), Bochum; 80,419,
549, 629, 657, 880, 1036.
BERLIN, PHYSICAL INSTITUTION OF
THE UNIVERSITY (Dr. Helmholtz);
282.
BERNSTEIN, A., AND Co., 50, Mark-
grafen Strasse, Berlin ; 85.
BERNSTEIN, PROF. (Director), Phy-
siological Institute, University of
Halle; 78.
BEZOLD, PROF. W. von (Poly-
technic School), Munich ; 248, 324.
BIEDERMANN, DR. B., Berlin ; 598.
BLATTNKR, C. (Polytechnic School),
Munich; 245.
BLATZBECKER, Dr. A. A., Cologne ;
599.
BOCK AND HANDRIK, 2, Falken-
strasse, Dresden ; 17,20, 55, 469 ;
478-9, 552.
BOHN, PROF. DR., Aschaffenburg ;
169, 680.
BONSACK, A., 27, Prinzenstr, Ber-
lin; 80, 744, 753, 771.
BORCHARDT, PROF., Berlin ; 38.
BORCHARDT, E., 37, Heinrichstrasse,
Hanover ; 302, 320.
BORNEMANN, F., Verden; 599.
BRAUN, DR. O., Berlin ; 487.
BREITIIAIMT, F. W., AND SON,
Cassel ; 53, 78, 403, 433, 744-5,
749, 753, 874-5, 886, 1069.
BRENDEL, E., Kurfiirstendamm,
Berlin; 988.
BRESLAU COMMITTEE FOR THE
SCIENTIFIC APPARATUS EXHIBI-
TION, LONDON, Breslau ; 16, 130,
203, 257, 324, 393, 398, 419, 430,
667, 670, 701, 900.
I BRILL, PROF. DR. A. (Polytechnic
School), Munich ; 36.
i BROCKING, W., Hamburg ; 129.
BRUHNS, PROF. DR., Leipzig ; 396.
BiiciiLER, J. H., Breslau; 657, 659.
BUFF, PROF. DR., Giessen ; 84, 154,
225, 245, 340.
BUNGE, P., Hamburg ; 94.
CARL AND HOMANN, Nuremberg;
804.
CECH, Dr. C. V., Berlin ; 600.
CHEMICAL INSTITUTE, STRASBURQ
UNIVERSITY ; 620, 1036.
CHEMICAL LABORATORY OF THE
UNIVERSITY, Freiburg, Breisgau
(Prof, von Babo) ; 182.
CHEMICAL LABORATORY, POLY-
TECHNIC INSTITUTION, Carlsrulie;
599, 600.
CHEMICAL LABORATORY OF THE UNI-
VERSITY (Prof. A. W. Hofmann),
Berlin; 165.
CHEMICAL SOCIETY, GERMAN ; Ber-
lin, 597-610.
CHEMICAL WORKS COMPANY
(UNITED), Leopoldshall, Stassfurt;
604.
GLAUS, PROF. DR. A. (Institute of
Physics), Freiburg University ;
1063.
xlviii
LIST OF CONTRIBUTORS.
COAL MINING Co., UNITED (Director
Hilt), Kohlscheid,Aix-la-ChapeUe ;
880.
COIIN, PROF. DR. F., Breslau ; 904,
924, 987, 999, 1000.
COHN, PROF. DR. H., Breslau ; 932-3,
936.
" COLLEGIUM CAROLINUM " (Prof-
Weber), Brunswick', 158.
CONSERVATORIUM OF THE MATHE-
MATICAL AND PHYSICAL COLLEC-
TIONS OF BAVARIA (Prof. Seidel),
Munich ; 397.
DE DIETRICH & Co., Niederbponn ; 67.
DENCKER, C., Hamburg ; 129-30.
DENNERT AND PAPE, Altona; 743,
745.
DEPARTMENT FOR PUBLIC WORKS
(" Ban-Deputation "), Hamburg ;
746, 763, 806-9.
DESAGA, C., Heidelberg ; 635-6.
DEUTSCHBEIN, R., Hamburg ; 684-5.
DICKERT, TH., Pnppelsdorf, Bonn ;
839.
DOLL, DR. M. (Polytechnic School),
Carlsruhe ; 37.
DORFFEL, P., 46, Unter den Linden,
Berlin; 309-10.
DOVE, PROF. DR., Berlin-, 55, 64,
286, 307, 374, 935.
DRE VERM ANN, DR., Hoerde, West-
phalia; 627.
DREYER, ROSENKRANZ, AND DROOP,
Hanover ; 80.
DURRE, PROF. DR., Aix-la-Chapelle ;
669-70.
EBERMAYER, PROF. DR. (Director,
Academy of Forestry), Aschaffen-
burg; 686, 713.
EDELMANN, M. T. (Polytechnic
School), Munich; 100, 102, 128,
206, 291-2, 319, 324, 332, 338-40,
343, 403, 426.
ELBE, M., Ellwanycn ; 430.
ENGEL, F., 21, Graskeller, Ham-
burg ; 485-6.
ENGLER, PROF. DR., Halle ; 600.
ERIIARDT AND METZGER, 47, Elisa-
bethcn Strasse, Darmstadt ; 663.
ERNECKE, F., 6, Wilhelmstrasse,
Berlin; 144, 145, 154, 165, 179.
FEILITZSCH, PROF. Baron von, Greifs-
wald; 54, 64, 112, 164, 886.
FEIN, C. AND E., Stuttgart ; 67, 375.
FENNEL, O., Cassel ; 18, 742, 875.
FISCHER, H., Hanover ; 640.
FISCHER, PROF. L. H., Freiburg,
Breisgau ; 898.
FISCHER, PROF. DR. R., Breslau ;
306, 1002.
FISCHER, T., Cassel; 805, 814.
FRIEDERICHSEN, L., & Co., Ham-
burg ; 40, 41, 805.
FRIEDLANDER, DR. C., Strasburg ;
946.
FRITSCH, PROF. DR., Berlin ; 925.
FUESS, R., 108, Jacobstrasse, Ber-
lin; 60, 423, 847-8, 851, 886-7,
912.
FURTENBACH ANO OEHIAFEN, Rei-
chelsdorf, Number g ; 600.
GABLER, C. D., Hamburg; 173, 174.
GASSER, DR., Marburg ; 923.
GASWORKS, MUNICIPAL, Berlin ; 600.
GEHREN, F. W. von (STAUDINGER
& Co.), Giessen ; 60, 64, 84, 164.
GEISSLER, C. F., & SON, Berlin ;
172,259, 263, 627, 641,702,925,
943, 1001, 1035.
GEISSLER, DR. H., Bonn; 164,172,
225, 263, 322, 627-8,641, 700.
GEISSLER, P. C., Nuremberg ; 894.
GEODETIC INSTITUTE, Berlin ; 63.
GEODETIC INSTITUTE, Munich; 22,
744, 761.
GEOLOGICAL SURVEY OF BAVARIA
(Dr. Giimbel), Munich ; 835-6.
GERLACII, PROF. DR., Erlangen;
991-2.
GERLAND, DR. E. (Polytechnic
School), Cassel ; 64,293,887.
GERSTKyHdmR,M., Freiberg, Saxony;
100.
GIESSEN, UNIVERSITY OF, (Dr. Buff,
Prof.) ; 84, 154, 225, 245, 319, 340.
GIZYCKI, PROF, von (Polytechnic
School) , Aix-la- Chapelle ; 456, 470.
GODEFFROY, J. C., Museum
Godeffroy, Hamburg ; 814.
GOLDSCHMIDT, T., Berlin ; 600.
GOPPERT, PROF. DR., Royal Bota-
nical Garden and Museum of the
University of Breslau ; 988-9, 995.
GOTTINGEN, INSTITUTE OF VEGE-
TABLE PHYSIOLOGY OF (Prof. Dr.
Grisebach, Director) ; 1000.
GOTTINGEN OBSERVATORY ; 414, 767.
GOTTINGEN, UNIVERSITY OF; 219,
293, 348, 601, 1040.
GREIFSWALD, UNIVERSITY OF ; 164.
GREINER, PAUL, Hamburg ; 738.
GRUNEBERG, Cologne ; 738.
LIST OF CONTRIBUTORS.
xlix
GUMBKL, DR. (Geological Survey of
Bavaria) ; 835-6, 848.
HAAK, W., Neuhaus, Thilringen ; 172,
255, 262, 691, 702, 759, 944.
HAEDICKE, G., Uemmin; 103, 109,
111, 169, 177, 763.
HAIIN, A. & R,, Cassel; 89-94,
741-2, 873.
HALLE, INDUSTRIAL SCHOOL (Dr.
Kohlmanii) ; 54, 80, 85, 147, 455.
HALLE, TOWN SCHOOL (Meyer) ; 54.
HALLE, UNIVERSITY OP (Physical
Institute), Prof. Knoblauch; 85-
7, 148.
HALLE, UNIVERSITY OF (Physiologi-
cal Institute) ; 78.
HAAEMANN,Dll.W.,.ffo/.2Wen ; 607.
HAHTNACK,DR. E., Potsdam; 912-3.
IlAuciiECORNE, PROF. (Director,
Royal Geological Institute and
Mining Academy), Berlin; 452-3,
485-6, 835.
HEINTZ, PROF. DR., Halle-, 601.
HKINZERLING, PROF. DR. (Poly-
technic School), Aix-la-CJiapeUe ;
552.
HEIS, PROF. DR. E., Miinster; 38,
296, 436.
HELLER, F., Nuremberg; 1002.
HELMERT, PROF. DR. (Polytechnic
School), Aix-la-C handle ; 746,
761.
HELMHOLTZ, PROF. DR., Berlin ;
282.
HENNEBERG, PROF. DR., Gottingen ;
1000.
HENSEN, PROF. DR., Kiel ; 925.
HERBST, A., 26A, Krautstrasse,
Berlin; 207,369,428, 627.
HERMANN, PROF. G. (Polytechnic
School), Aix-la-Chapelle; 9.
HEUSTREU, H., Kid ; 404.
HIMLY, PROF. DR., Kiel ; 263.
HIRSCHBERG, F., 9, Weidenstmsse,
Breslau; 192.
HITTORF, PROF. DR., Miinster ; 322-
3, 326, 341,601.
HOFMANN, PROF. DR. A. W.,
Berlin ; 165, 602, 603.
HONIGMANN, M., Aix-la-Chapelle ;
603.
HORNUNG, F., Langenbeutingen ; 428.
HUBNER, PROF. DR., Gottinqen ; 601,
1040.
HTTGERSHOFF, F., Leipzig ; 640, 657,
663, 1035.
HULWA, PROF. DR., Breslau ; 603.
40075.
HUTSTEIN, J., Breslau ; 603.
IMPERIAL GERMAN NAVY ; 745,753.
INDUSTRY, ROYAL HIGH SCHOOL OF,
(Dr. Wiecke, Director), Cassel;
15, 38, 39, 64, 293, 887.
INDUSTRIAL SCHOOL (Dr. Kohlmann,
Director), Halle ; 54, 80, 85, 147,
455.
INSTITUTE OF PHYSICS (Prof. Dr.
A. Glaus), University of Freiburg,
Baden ; 1063.
INSTITUTE OF PHYSICS (Prof. Kars-
ten, Director), University of Kiel ;
60.
INTZE, PROF. O. (Polytechnic
School), Aix-la-Chapelle ; 96.
JACOBSEN, PROF. DR., Rostock ; 626.
JESSEN, PROF. DR., Eldena, Pome-
rania ; 923, 941, 987.
JOBST, F., Stuttgart.; 603.
JOLLY, PROF. DR. von, Munich ; 54,
164,263,275, 629.
JUNG, R., Heidelberg ; 248, 325, 333,
925, 936.
KAHLBAUM, 0. A. F., Berlin ; 603.
KARSTEN, PROF. DR., Kiel; 60.
KARSTEN, PROF. DR., Rostock; 219,
| 754.
KAUFMANN, K. J., Konigsberg,
Prussia ; 604.
KEISER & SCHMIDT, 14, Johannis
Strasse, Berlin ; 249, 305, 311-2,
338.
KLEEMANN, Halle ; 54, 85, 88.
KLINKERFUES, PROF.DR., Gottingen ;
56,701.
KNOBLAUCH, PROF. DR., Halle ; 85-
7, 148, 187.
KNOBLICH, T., 24, Amiralitdt Strasse,
Hamburg; 129.
KNY, PROF. DR., Berlin ; 986.
KOBELL, PROF. DR. F. von,
Munich ; 220.
KOHLMANN, DR., Director, Indus-
trial School, Halle ; 54, 80, 85,
147, 455.
KRAMER, C., Freiburg, Breisgau ;
639,641.
KRAUSE, PROF. DR., GQttingen ; 924.
KREBS, PROF. DR. G., Frankforl-on-
Maine ; 143.
KRONECKER, PROF. DR. (Physiolo-
gical Institute), Leipzig; 954.
KRUSS, A., Hamburg ; 206.
KUHNEMANN, DR. G., Dresden ; 604.
KUHTZ & Co., Brandenburg -on-
Havel; 939.
d
1
LIST OP CONTRIBUTORS.
KUMMER, PROF. DR. E. E., Berlin ;
153.
KUNDT, PROF. DR., Strasburg; 211,
291.
LANDOIS, PROF. DR., Miinster ; 990.
LANDOLT, PROF. DR. (Polytechnic
School), Aix-la-Chapelle; 224,
620, 1041-2.
LANDSBERG & WOLPERS, Hanover ;
8, 59, 368, 1010.
LAQUETJR, PROF., Strasburg ; 934-5.
LASAULX, PROF, von, Breslau ; 604,
772-3, 849, 869.
LASPEYRES, PROF. (Polytechnic
School), Aix-la-Chapelle -, 96.
LEITZ, E., Wetzlar; 910-11.
LENTZ, E. A., 36 & 37, Spandauer
Strasse, Berlin; 638, 1036.
LEPSIUS, PROF. DR., Royal Library,
Berlin-, 158,159.
LEYBOLD, E. (Successors to), Co-
logne; 1047-54.
LEYSER, G. MORITZ, Leipsic Uni-
versity; 926.
LIEBERMAN, PROF. C., Berlin ; 604.
LINGKE, A., & Co. (M. Hildebrand
and E. Schramm), Freiberg,
Saxony; 396-7, 745, 753, 873, 875,
884.
LIST, DR. K., Hagen ; 173.
LISTING, PROF. DR., Gottingen ; 219.
LOCHMANN, P., Zeitz; 456, 459,
LOCKERMANN, DR., Hamburg ; 430.
LOHDE, L.,33, Haide Strasse, Berlin ;
37.
LOHMANN, K., 3, Briickenstrasse,
Berlin; 84.
LOHSE, DR., C. (Astronomer of the
Royal Astro-Physical Observa-
tory'), Potsdam; 425-6.
LOMMEL, PROF. DR., Erlangen ; 247-
8.
LUCAE, PROF. A., Berlin ; 1 83.
MAGNUS, DR., Breslau ; 934.
MAJER, E., Strasburg ; 923.
MARBURG, MATH. AND PHYSICAL
INSTITUTE (Prof. Melde) ; 53.
MATTHIESSEN, PROF. DR., Rostock;
714.
MEIDINGER, PROF. DR. H., Carlsruhe,
278, 367.
MEISSNER, A.(Muller andReinecke),
Berlin ; 60, 746, 749, 751.
MELDE, PROF. DR., Mathematical
and Physical Institute, Marbura
53.
! MERCK, E., Darmstadt ; 605.
1 MEYER, L., Berlin 263.
MEYER, PROF. L., Carlsruhe ; 599.
MEYER, DR. O. E. (The University),
Breslau; 176.
MEYER (Town Sclwol), Halle ; 54.
MICHAELIS, PROF. A., Carlsruhe ;
600.
MINISTERIAL COMMISSION FOR THE
SCIENTIFIC EXPLORATION OF THE
GERMAN SEAS, Kiel ; 771.
MITSCHERLICH, PROF. A., Mimden,
Hanover-, 164, 213, 262, 570, 629,
641, 886, 889, 894, 1036.
MlTTELSTRASS BROTHERS, Magde-
burg; 319.
MOBIUS, PROF. DR., Kiel ; 925.
MOHL, DR. H. (Royal High School of
Industry), Cass'el ; 839, 848, 883.
MOLLER, L., Giessen ; 888.
MULLER, DR. E., Osnabrilck ; 704.
MUNICH, UNIVERSITY OF ; 54, 84,
86, 106, 263, 275, 629.
NARTEN, DR. W. (Royal High School
of Industry), Cosset-, 15, 748, 754,
875.
NAUTICAL OBSERVATORY-"DEUTSCHE
SEEWARTE " (Dr. Neumayer,
Director), Hamburg ; 259, 293,
681, 712, 721-2, 802.
NORDLINGER, PROF. DR., Hohenheim ,
Wurtemberg ; 89, 445-6, 1001.
OPPEL, PROF., J. J., Frankfort-on-
Maine; 36,179, 188,245-6,427,
429, 431.
OPPEL, DR. K. Frankfurt ; 429.
OPPENHEIM, PROF. A., Berlin ; ^05.
ORTH, PROF. DR., Berlin ; 835.
OSTERLAND, C., Freiberg, Saxony ;
638, 667, 873, 875.
OTT & COR ADI, Kemptcn, Bavaria ;
15, 77, 750, 753.
PANSCH, DR., Kiel ; 989.
PERNET, DR. (Assistant, Cabinet of
Physics), Breslau ; 262-3.
PETTENKOFER, PHOF. DR. MAX,
Munich ; 950.
PFAFF, PROF. DR., Erlangen ; 255,
887,897.
PHARMACEUTICAL INSTITUTE OF THE
UNIVERSITY, Breslau ; 599.
PHYSICAL INSTITUTE, Freiburg ; 255.
PHYSIOLOGICAL INSTITUTE, Prague ;
954.
PIEL, H., Bonn ; 897.
LIST OF CONTRIBUTORS.
H
PJNDEK, DR. (Director of the Royal
Museum), Cosset-, 56, 160-1,393,
398, 410, 449-50, 900-1, 976.
PINNER, DR. A., Berlin ; 605.
PINZGER, C. G., Breslau ; 164.
POLECK, DR., Breslau; 599, 701,
900.
POLYTECHNIC SCHOOL (Dr. E. Ger-
land), Cassel; 64.
POLYTECHNIC SCHOOL (M. T. Edel-
inami), Munich ; 100, 102, 128, 206.
PRESTEL, PROF., Emden; 9, 431,
436, 693, 701, 714, 722, 898.
PROELL, Dit. R., Civil Engineer,
Gorlitz; 469.
PRUGGER, B utter melc her Strasse,
Munich; 1011.
RAMME AND SODTMANN, Hamburg;
990.
RAPHAEL, M., Breslau ; 17, 221, 320,
629, 641,781, 889,926.
RATH, PROF. DR. G. vom, Bonn ;
897.
RECKE, H., Freiburg, Saxony ; 693.
RECKLINGHAUSEN, PROF. DR., Stras-
burg; 912.
RECKNAGEL, DR. (Royal School of
Industry), Kaiserslautern ; 174,
693.
REIMER, D. (Reimer and Hoefer),
Berlin; 431, 805, 810-1.
REPSOLD & SONS, Hamburg ; 395-6,
400-1, 423, 739, 749.
REULEAUX, PROF. (Director of the
Royal Polytechnic Academy), Ber-
lin ; 9, 103, 132, 143, 429.
RHENANIA COMPANY, Stolberg, Aix-
la-Chape/le; 657.
RICHTER, E. O., & Co., Chemnitz,
Saxony; 18, 19.
RIECKE, PROF. DR., University of
Gottingcn ; 293, 348.
RODIG, C., Hamburg; 993.
ROHRBECK, LUHME, & Co., Berlin ;
148, 152, 154, 658, 1055-63.
ROSENTHAL. PROF. DR., Erlangen ;
943, 953-4.
ROYAL LIBRARY (Prof. Dr. Lepsius,
Chief Librarian), Berlin ; 158-9.
ROYAL MUSING DIRECTORY, Saar-
brilck; 881-2.
ROYAL MT:SEUM (Dr. Pinder, Di-
rector), Cassel; 56, 160, 161, 393,
398, 410, 449-50, 900-1, 976.
40075.
ROYAL POLYTECHNIC (GEWERKE)
ACADEMY (Prof. F. Reuleaux,
Director), Berlin; 9, 103, 132-
43,429.
ROYAL POLYTECHNIC SCHOOL, Aix-
/a-Chapelle; 96.
ROYAL PRUSSIAN GENERAL STAFF,
ORDNANCE SURVEY (Lieut.-Gene-
ral von Morozowitsch), Berlin ;
728-9, 746, 786-7.
ROYAL PRUSSIAN UPPER MINING
COURT, Breslau; 873, 882-3,
1010, 1043-5.
ROYAL RHENISH WESTPIIALIAN
POLYTECHNIC SCHOOL, Aix-la-
C/iapelle; 146.
ROYAL SURGICAL CLINICAL SOCIETY
(Prof. Dr. R. Fischer), Breslau;
306, 1002.
RCMANN, C., Gottitigen ; 924-5.
SAAME & Co., Ludwigshafen-am-
Rhein; 606.
SARTORIUS, F., Gottingen ; 82, 83,
169, 639.
SCHAFFER, H., Darmstadt; 76.
SCHEIBLER, DR. C., Berlin ; 659-61.
SCHEBING, PROF. DR., Gottingen ;
292-3, 414, 767.
SCIIERING, E., Berlin, Fentistr ; 606.
SCIIICKERT, H., Dresden ; 83, 84, 87.
SCHMIDT AND HAENSCII, 2, Neue
Schonhauser Stras&e, Berlin ; 211,
212, 218, 220, 221, 225, 230, 407,
640, 760, 910, 935, 998.
SCHOBER, J., 35, Adalbert Slrasse,
Berlin ; 576, 626-7, 629, 633, 638,
1035-6.
SCHOTTE, E., Potsdamer Strasse,
Berlin; 428,811.
SCHREIBER, DR., Chemnitz ; 709-11.
SCHRODER, H., Hamburg ; 402-4.
SCHUBRING, G., Erfurt; 191, 202,
439.
SCIIUCHARDT, DR. T., Gorlitz; 231,
607, 899.
SCHUR, DR. (Assistant, Observatory),
Strasburg; 424.
SCHUTTE, O., Cologne ; 265.
SCHWERD, L. E., Carlsruhe ; 367-8.
SEIBERT ANDKRAFFT, Wetzlar ; 910,
915.
SEIDEL, PROF. ( Conservator! um of
the Mathematical and Physical
Collections of Bavaria), Munich ;
397.
Hi
LIST OF CONTRIBUTORS.
SIEMENS, DR. W., Berlin ; 101-2,
104-5, 338, 716.
SIEMENS BROS. & Co., Cliarlotten-
burg, Berlin; 175,363-5,468,474.
SIEMENS AND HALSKE, Markyrafen
Strasse, Berlin ; 67, 79, 102, 225,
309, 315-6,328, 338, 343,345-6,
372.
SIEVERS, F., Wehlheiden, Cassel ;
839-40.
SITTE, K., JBreslau ; 931.
SOHNCKE, PROF., Carlsruhe ; 899.
SOMMERBRODT, DR., Bresluu ; 946.
SOMMERING, C., Fran kf or t-on- Maine,
346.
SPRENGER, E., 75, Ritterstrassc,
Berlin ; 55, 745, 753-4.
STAUDINGER & Co. (F. W. von
Gehren), Giessen ; 60, 64, 84, 164.
STEEG, W., Hamburg vor der Hake ;
277, 887, 889, 893-4.
STEGER, A., Kiel ; 255.
STEGEU, ~L.,Kiel; 54, 771.
STEGER & HONIKEL, Leipzig ; 986.
STEIN, DR. S. T., Frankfort-on-
Maine ; 945, 986, 998.
STEINHEIL, C. A. AND SONS, Munich ;
402.
STERN, H., Obn-siein ; 54, 84, 88.
STOHRER, E., Leipzig-, 282,302, 331,
338, 929, 932, 935, 1000, 1046.
STOLLNREUTHER, AND SONS, Mu-
nich; 949.
STURTZ, B., Bonn ; 868, 888-9.
STRASBURG, CHEMICAL INSTITUTE
OF THE UNIVERSITY OF ; 620,
1036.
Suss, F., Marburg; 184-7, 218,
922-3.
TALBOT, R., 68, Auguststrasse,
Berlin ; 240, 244.
TORNOW, R. von, Berlin ; 250.
TASCIIE, DR., Giessen ; 306, 319.
TELEGRAPH DEPARTMENT, IM-
PERIAL GERMAN, Berlin ; 361-3.
TELLER, JUL., Munich ; 302, 306, 318.
TESCHNER, W. (Successor to J.
Annul), 180, Friedrichstrasse, Ber-
lin; 914-5.
TOLLENS, PROF. B., Gottingen ; 607.
TIEFTRUNK, DR., Municipal Gas-
works, Berlin ; 600.
TIEMANN, DR. F., Berlin ; 607.
TONINETTI, P. (Pathological Institu-
tion, Prof. Dr. Virchow, Director),
Berlin; 992-3.
TROMMSDORFF, DR. II., Erfurt ;
607-9.
TRUNK, C., Eisenach; 430.
UHLENHTJTH, J. t Anclam, Pomerania ;
21, 810.
URACH, H. H. THE DUCHESS OF,
Stuttgart; 8.
VAAST AND LITTMANN, Halle ; 275.
VETTER C. (formerly L. Hester-
mann), Hamburg ; 1055.
VIERORDT, PROF. DR. \ou, Tubin-
gen; 945.
VOCJEL, DR. H. C. (Astronomer of
the Royal Astro-Physical Observa-
tory), Potsdam ; 425-6.
VOGEL, PROF. DR. H. W., Berlin ;
423-5, 677.
VOIGT, G. (Voigt & Hochgesang)
Gottingen ; 66, 849, 881, 924.
VOIGTLANDER AND SON (Chevalier
von Voigtlander), Brunswick ;
203, 204,240.
VORSTER AND GfiUNEBERG, Kalk,
Cologne ; 609-10.
Voss, T. R., Berlin, 19, Pallisa-
denstr; 282, 301, 324,331.
WAIBLER, L., Darmstadt ; 345.
WANNSCHAFF, J., 63, Gros&beercn
Strasse, Berlin ; 743-4, 749.
WARMBRDNN, QUILITZ, & Co., 40
Roscnthaler Strasse, Berlin; 165,
230, 249, 259, 274-5, 286-7, 298,
302, 320-1, 325, 343, 691, 701,
1001, 1036-41.
WASSERLEIN, R., 34, Bernburyer
Strasse, Berlin ; 910, 922.
WEBER, DR. A., Darmstadt; 929,
931-2, 934-5.
WEBER, PROF. DR. H. (" Collegium
Carolinum"), Brunswick ; 158, 159.
WEBER, PROF. R. (Academy of
Forestry), Aschaffenburg ; 8, 620.
WEBER, A., Wiirzburg; 166,946.
WEBER, Cii., Eisenach ; 851.
WEINIIOLD, PROF., Chemnitz; 225.
WEINZIERL, J., Glogau, Silesia ; 16.
WELCKER, PROF. DR., Halle ; 926,
993.
WALDENBURG, PROF. DR., Berlin ;
946-7.
WESSELHOFT, Halle ; 263.
WESTPHAL, G., Celle, Hanover ; 84,
87.
WICHELHAUS, PROF., Berlin; 610.
WICHMANN, A., n,Johannis Strasse,
Hamburg; 813,938,1001.
LIST OF CONTRIBUTORS.
liii
WIECKE,DR., Cosset-, 38, 39.
WIKNKK, PROF. DR. C., Carlsruhe ;
37.
WIXKEL, R., Gottingen ; 912.
WINKLER, PROF., Freiberg ; 610.
WJNNECKE, PKOF. DR., Strasburg ;
404, 432, 740.
WINTER, E., Hambwy, Einisbiittel ;
207.
WUILER, PROF. DR., Gotlingen ;
601.
WOHLERS (Successor to Campbell),
Hamburg ; 930, 936.
WOLFF & SONS, Heilbronn and
Vienna ; 639, 641,672, 1036.
WULLNER, PROF. DR. (Polytechnic
School), Aix-la-Cliapelle ; 331,
460.
ZEISS, C., Jena-, 211, 215, 230,
909-10.
ZIEGLER, DR. A., Freiburg, Baden ;
898, 984.
ZIM.MER BROTHERS, Stuttgart; 89,
744, 759.
ZORN, W., Berlin, 17, Schoneberger
Sir.; 174.
HOLLAND.
ASSEN SECONDARY GOVERNMENT
SCHOOL; 118, 258, 278.
BAKHUYZEX, H. G. VAN DE SANDE,
Director, Observatory, Ley den ;
392-4, 398-9, 428-9, 438.
BECKERS SONS, West Zeedyk, Rot-
terdam ; 82.
BLEEKRODE, DR. L., The Hague ;
299, 1041-2.
BOCGAARD, PROF.DR. J. A., Director
of the Museum of Anatomy, Aca-
demy of Ley den ; 900.
BOSSCIIA, PROF. J., Royal Polytech-
nic School, Delft ; 255, 342, 345,
579,885, 888, 921.
BRONDGEEST, DR., Physiological La-
boratory and Ophthalnwlogical
School, Utrecht; 958.
BUYS-BALLOT, PROF., Utrecht ; 53,
127, 184,264,391, 413, 700, 766,
904, 934.
DE Loos, DR. D., Director of the
Secondary Town School, Lcyden ;
259,671.
DONDERS, PROF., Physiological La-
boratory and Ophthalmoloyical
School, Utrecht; 178, 318, 957-
60, 962-70.
ENGELMANN, PROF., Physiological
Laboratory and Ophthalmological
School, Utrecht; 167, 317, 957,
959-60.
FERHAAR, A. T., Utrecht; 977-8.
GRONEMAN, DR. F. G., Director of
the Secondary Government School,
Groningen-, 149.
; GUNNING, DR. J. W., Professor of
Chemistry. " Athen&um Illustre"
Amsterdam, and Scientific Adviser
to the Treasury Department, Hol-
land, Amsterdam ; 156-7, 259.
HARTING, PROF. DR. P., University
of Utrecht; 938.
HOOGEWKIUTF, S.,Pii. D., Rotterdam*,
176, 255.
JIui/iNGA, PROF., Director of the
Physiological Laboratory, Univer-
sity of Groningen ; 940, 976.
MEES, PROF. R. A., Director of the
Physical Laboratory, University of
Groningen; 162, 189, 190, 335,
475.
MULDER, DR. M. E., Groningen ; 920.
OTTMANS, H., 141, Amstel Hooge
Sluis, Amsterdam ; 901.
OUDEMANS, PROF. A. C., Hoyal
Polytechnic School, Delft ; 591.
ROYAL POLYTECHNIC SCHOOL (Prof.
J. Bosscha), Delft ; 255, 342, 345,
579, 885, 888, 921.
RUKE, PROF. DR. P. L., Director of
the Cabinet of Physics, University
of Leydcn; 81, 131, 178, 246, 255,
321, 410, 413, 427, 462, 900.
SCHOOL, SECONDARY GOVERNMENT,
Assen; 118,258, 278.
SCIENTIFIC SOCIETY OF ZEELAND
(G. N. de Stoppelaar, Sec.), Mid-
delburgh; 900.
SNELLEN, DR., Physiological Labora-
tory and Ophthalnwlogical School,
Utrecht ; 748, 961-2, 964-5, 967.
SNYDERS, J. A., Lecturer, Royal
Polytechnic School, Delft; 176,
936.
liv
LIST OF CONTRIBUTORS.
SURINGAR, W. F. R., Professor of
Botany, University of Leyden, and
Director of the Royal Botanic
Gardens and Royal Herbarium ;
918.
TEYLEU FOUNDATION, THE, Haarlem ;
209, 229, 279-80, 285, 319-20,
322, 328, 410, 1064.
VAN ANKUM, PROF. U. J., Zoological
Laboratory, University of Groniu-
gen-, 1002.
VAN DE SANDE BAKHUYZEN, II. (T.,
Director of the Observatory, Ley-
den ; 392-4, 398-9, 428-9, 438.
VAN RUN, H. B. J., Venlo ; 651.
ZEELAKD, SCIENTIFIC SOCIETY OF
(G. N. de Stoppelaar, Secretary),
Middelburgh ; 900.
ITALY.
ACCADEMIA DEL CiMENTO, Florence ;
155-6, 256, 257, 279, 699, 941-2.
ALBINI, PROF. G., Director of the
Physiological Institute, Royal Uni-
versity of Naples ; 949,
BLASERNA, PROF., Director of the
Institute of Physical Science, Royal
University of Rome; 1073-4.
CACCIATORE, PROF. G., Director of
the Royal University, Palermo ;
1083.
CANTONI, PROF. G., Director of the
Institute of Physical Science, Uni-
versity ofPavia ; 1082-3.
CECCHI, PRO*. F., (Z. Pelli Sf Co.),
]2, Viale Militare, Florence ; 299,
389-90.
COLLEGIO ROMANO (OBSERVATORY),
Rome ; 405, 709.
FELICI, R., Director of the Univer-
sity of Pisa; 1084.
FLORENCE, ROYAL INSTITUTE "DI
STUDII SUPERIORI " (Sig. Peruzzi,
President); 16,77, 113-5,256,276,
279, 307, 312, 334, 393, 397, 403,
407-10, 431, 437, 439, 703, 780,
900-1.
GAMBARA, PROF. G., Liceo Volta,
Conio; 381.
GIORDANO, PROF. G., Director of
the Cabinet of Physical Science,
University of Naples ; 1083.
LEGNAZZI, PROF., Royal University,
Padua ; 1074-8.
LICEO VOLTA, COMO, CABINET OF
PHYSIC AND CHEMISTRY (Prof.
G. Gambara) ; 381.
Mossi, DR. A., Director of the Uni-
versity, Turin ; 949.
NAPLES, ROYAL UNIVERSITY OF ; 20.
NAPLES, VESUVIAN AND METEORO-
LOGICAL OBSERVATORY ; 1084.
OBSERVATORY OF THE ROYAL UNI-
VERSITY (Prof. D. Ragoua, Di-
rector), Modena ; 1083.
OBSERVATORY, ROYAL, Palermo ;
1083.
OBSERVATORY, COLLEGIO ROMANO,
(Padre Secclii, Director), Rome ;
405, 709.
PADUA, ROYAL UNIVERSITY OF:
1074-8.
PALMIERI, PROF., Director of the
Vesuvian and Meteorological Ob-
servatory, Naples ; 1084.
PAVIA, UNIVERSITY OF ; 1082-3.
PELLI, L., 12, Viale Militare, Flo-
rence ; 749.
PERUZZI, SIG., President of the Royal
Institute " di Studii Sitperiori,"
Florence; 16, 113, 115, 256,276,
279, 307, 312, 334, 393, 397, 403,
407-10, 431, 439, 703, 780, 900
-1.
PISA, UNIVERSITY OF, Pisa ; 1084
PIZZORNO, F., Bologna ; 264, 300.
RAGONA, PROF. D., Director of the
Observatory, Royal University of
Modena; 1083.
RESPIGHI, PROF. L., Director of the
Royal Observatory oj the Campi-
doglio, Rome ; 394, 405.
RIGHI, PROF. A., Royal Technical
Institute, Bologna ; 204, 300, 332.
ROME, COLLEGIO ROMANO (OBSER-
VATORY) ; 405, 709.
ROME, ROYAL UNIVERSITY, INSTI-
TUTE OF PHYSICAL SCIENCE (Prof.
Blaserna, Director) ; 1073-4.
ROSSETTI, PROF., Director of the
Cabinet of Physical Science, Royal
University, Padua ; 1078-82.
LIST OF CONTRIBUTORS.
IV
ROYAL INSTITUTE " di Studii Superi-
or!," Florence (Sig. Peruzzi, Presi-
dent). (See FLORENCE, ROYAL
INSTITUTE.)
ROYAL LOMBARDIAN INSTITUTION OP
SCIENCE AND LETTERS ; 386.
ROYAL UNIVERSITY, MODENA (OB-
SERVATORY) ; 1083.
ROYAL UNIVERSITY OF NAPLES,
CABINET OF PHYSICAL SCIENCE
(Prof. G. Giordano, Director) ;
1083.
ROYAL UNIVERSITY OF NAPLES,
PHYSIOLOGICAL INSTITUTE (Prof.
G. Albini, Director) ; 949.
ROYAL UNIVERSITY OF PADUA,
CABINET OF GEODESY AND HY-
DROMETRY (Prof. Legnazzi, Di-
rector) ; 1074-8.
ROYAL UNIVERSITY OF PADUA,
CABINET OF PHYSICAL SCIENCE
(Prof. Rossetti, Director) ; 1078-
82.
ROYAL OBSERVATORY OF PALERMO
(Prof. G. Cacciatore, Director) 5
1083.
ROYAL OBSERVATORY OF THE CAM-
PIDOQLIO (Prof. L. Respighi,
Director), Rome ; 394, 405.
ROYAL UNIVERSITY OF ROME, IN-
STITUTE OF PHYSICAL SCIENCE
(Prof. Blaserna, Director) ; 1073-4.
SECCHI, PADRE, Director of the Ob-
servatory of the Collegia Romano,
Rome ; 405, 709.
TABANELLX, T., Prof, of Physical and
Natural Science, Technical School,
Udine; 832.
TURIN, UNIVERSITY OF (Director,
Dr. A. Mossi) ; 949.
UDINE, TECHNICAL SCHOOL ; 832.
VESUVIAN AND METEOROLOGICAL
OBSERVATORY (Prof. L. Palmieri,
Director), Naples ; 1084.
NORWAY.
DIETRICIISON, J. L. W., Christiania ;
771-2.
ESMARK, L., Prof, of Zoology, Uni-
versity of Christiania ; 1002.
HOLLER, DR. F., Selbo, Drontheim ;
112.
HOLST, ELLING, B., The University,
Christiania ; 35.
MOHN, PROF. H., Director of the
Meteorological Institute of Norway ,
Christiania-, 697,717, 723.
OLSEN, C. H. G., Christiania, Nor-
way ; 374.
SURVEY OFFICE, Christiania ; 762.
WAAGE, PROF. P., University of
Christiania, Norway ; 627, 639, 723,
WELLESEN, Christiania ; 278.
RUSSIA.
ACADEMY OF SCIENCES, THE IM-
PERIAL, St. Petersburg; 63, 342,
347, 373,410.
ARSENAL, THE, St. Petersburg-, 57.
BAIHD, G., St. Petersburg ; 491,499.
BtNG, E., Riga ; 14.
BRAUKU, G., Wasili-Ostrof, 22,
No. 5, St. Petersburg-, 58, 781.
CHEMICAL LABORATORY (Agricul-
tural Institute), St. Petersburg-,
611.
CHEMICAL LABORATORY (Imperial
Berg-Institute}, St. Petersburg-,
612.
CHEMICAL LABORATORY (Michailow
Artillery Academy) ; 613.
CHEMICAL LABORATORY (Imperial
Academy of Sciences), St. Peters-
burg; 613.
CHEMICAL LABORATORY ( Technologi-
cal Institute}, St. Petersburg;
613-7.
CHEMICAL LABORATORY, University
of St. Petersburg ; 611.
CHEMICAL SOCIETY or RUSSIA, Uni-
versity of St. Petersburg ; 610.
COMMITTEE OF THE PEDAGOGICAL
MUSEUM, St. Petersburg ; 1012,
1065.
CZECHOVICZ, C., Gymnasium of
Belostok; 231,1010-11.
Ivi
LIST OF CONTRIBUTORS.
DADIANE, P. NICHOLAS, 80, Grand
Sadorai (log No. 13), St. Peters-
bury ; 7, 13.
DEGEN, COLONEL, Bobruisk ; 781.
ERMOLIN (Pedagogical Museum), St.
Petersburg-, 1017.
ESERSKY, THEOD., St. Petersburg ; 7.
FOENULT (Pedagogical Museum); St.
Petersburg ; 1017, 1019.
GADOLIN, M., St. Petersburg ; 58.
GIVOTOVSKY (Pedagogical Museum},
St. Petersburg ; 1023.
GLOUKHOFF, W. (Warden of Stan-
dards, Ministry of Finance), St.
Petersburg; 175, 260, 278, 679,
1045.
HERBST, M. W., Observatory, Pul-
kowa ; 758.
ILYIN (Pedagogical Museuni), St.
Petersburg; io 18-19.
IMPERIAL ESTABLISHMENT FOR THE
PREPARATION OF OFFICIAL PA-
PERS, St. Petersburg ; 238.
IMPERIAL Moscow UNIVERSITY,
Moscow ; 619, 638.
IMPERIAL OBSERVATORY, Pulkowa ;
406, 432, 720, 749.
IMPERIAL TECHNICAL SOCIETY, St.
Petersburg ; 444.
IMPERIAL UNIVERSITY, St. Peters-
burg ; 284, 295, 308, 317, 334, 1073.
KOVALSKY (Pedagogical Museum),
St. Petersburg; 1019.
KRESTEN (Pedagogical Museuni), St.
Petersburg; 1012.
KRUEGER, PROF. DR. A., Helsingfors ;
126, 681.
LEMSTROM, PROF. S., Helsingfors,
Finland; 386-9.
LERMONTOFF (Pedagogical Museum),
St. Petersburg ; 1012,1014.
MARKOVNIKOFF, Professor of Che-
mistry, Moscow University; 613,
638.
MECHANICAL LABORATORY, TECH-
NOLOGICAL INSTITUTE, St. Peters-
burg; 446.
MENDELEEFF, PROF., St. Peters-
burg ; 63.
MICHAILOFF (Pedagogical Museum),
St. Petersburg; 1020.
MINING INSTITUTE, St. Petersburg,
830-2.
MINING SCHOOL, St. Petersburg; 861-
6, 868-9, 889-93.
Moscow JUVENILE AND PEDAGOGI-
CAL LIBRARY (Pedagogical Mu-
seum), St. Petersburg ; 1017-8.
NIPPE, R., St. Petersburg; 172,464.
OBSERVATORY, THE IMPERIAL, Pul-
kowa ; 406, 432, 720, 749.
OBSERVATORY, Wilna ; 425.
OETTINGEN, PROFESSOR DR. A. von,
Imperial University, Dorpat ; 693,
708.
OUSSOFF, DR. M., Zoological Museum
of the University, St. Petersburg ;
976.
OVSIANNIKOW, PH., M. ACAD. Sc.,
Professor of Physiology, University
St. Petersburg; 984-5, 991.
PASCHKIEWITCH, CAPTAIN W., Cen-
tral Administration of Artillery,
St. Petersburg ; 108.
PEDAGOGICAL MUSEUM, St. Peters-
burg; 1012.
PENKIN (Pedagogical Museum), St.
Petersburg ; 1019.
PETROFF, Kalouga ; 13.
PHYSICAL SCIENCE CABINET (//-
perial Academy of Sciences), St.
Petersburg ; 63, 342, 347, 373,410.
ST. PETERSBURG WORKSHOP OF
SCHOOL APPARATUS (Pedagogical
Museum), St. Petersburg; 1013,
1016-7, 1020, 1023.
SCHILDKNECHT (Pedagogical Mu-
seum), St. Petersburg ; 1017.
SCHINDHELM (Pedagogical Museum),
St. Petersburg; 1021.
SHULGIN (Pedagogical Museum), St.
Petersburg; 1018.
SKIBINEVSKY (Pedagogical Museum),
St. Petersburg ; 1023.
SOKOLOFF, N. W., Imperial Medica I
Academy of St. Petersburg ; 617.
STATISTICAL COMMITTEE (Pedago-
gical Museum), St. Petersburg;
1018.
STREMBITSKY (Pedagogical Museum),
St. Petersburg; 1020-3.
STROOKOFF (Pedagogical Museum),
St. Petersburg; 1013, 1017, 1023.
TCHEBICHEFF, PROF. P., The Univer-
sity, St. Petersburg ; 22, 146.
TECHNICAL SOCIETY, THE IMPERIAL,
St. Petersburg ; 444.
TECHNOLOGICAL INSTITUTE, St. Pe-
tersburg; 59, 111, 446, 458.
LIST OF CONTRIBUTORS.
Ivii
TECHNOLOGICAL INSTITUTE, The
Physical Laboratory of, St. Peters-
burg ; 171, 341.
TELEGRAPHS, GENERAL DIRECTION
OF; 363.
TOPOGRAPHICAL DEPARTMENT OF
THE IMPERIAL RUSSIAN GENE UAL
STAFF, St. Petersburg-, 237-8,
760, 803.
TOPOGRAPHICAL DEPARTMENT OF
THE IMPERIAL RUSSIAN GENERAL
STAFF, Tiflis ; 804.
WILD, DR. H., Central Physical
Observatory, St. Petersburg ; 680.
ZINGER, COLONEL, Pulkowa ; 395.
SPAIN.
ACADEMIA DE ClENCIAS NATURALES
Y AKTES DE BARCELONA, Spain ;
1064.
ACADEMY OF SCIENCES, Madrid;
442.
ARCHAEOLOGICAL MUSEUM, Madrid ;
7, 78, 87, 392-3, 397, 419, 443,492,
814.
ASTRONOMICAL OBSERVATORY, Ma-
drid-, 411.
BOTELLA Y DE HORNOS, B. FliDE-
RICO DE, 34, Calle de San Andres,
Madrid; 833-4.
CALDERON, S., Plaza de Santa Bar-
bara, Madrid ; 849.
COMISION DEL MAP A GEOLOGICO DE
ESFAXA, 23, Calle de Isabel la
Catolica, Madrid ; 832-4.
DIRECCION GENERAL DE CORREOS
Y TELKGRAFOS, Madrid ; 1064.
GEOGRAPHICAL ATD STATISTICAL
INSTITUTE OF SPAIN, Madrid ;
789-95.
GONZALEZ, MANUEL, Madrid ; 671.
MINISTRY OF MARINE, Madrid; 116,
393, 754, 782.
QuiROGA, F., 8, Union, Madrid;
840-3.
ROYAL SCHOOL OF MINES, Madrid ;
6, 146, 451, 868, 873, 881, 1065.
SAAVEDRA, E., 14, Calle de SanJua-
quin, Madrid ; 1065.
SWITZERLAND.
BAUMGARTNER, H., 14, Heumatt-
strasse, Basle ; 52, 79, 88, 126.
BERNOULLIANUM, THE, Basle ; 257,
280, 289.
BROCUER, L., 45, Boulevard des
Tranchees, Geneva ; 758.
CAUDERAY, J., 15, Rue St. Pierre,
Lausanne ; 369.
COLLADON, PROF. D., 1, Boulevard
du Phi, Geneva; 109, 145, 182,
231,327, 335, 460, 476.
DE LA RIVE, L., Geneva; 10, 273,
386.
DE LA RIVE COLLECTION, Geneva ;
172, 224, 383-6.
DE SAUSSURE, H., Geneva ; 328, 679,
701, 717.
EKEGREN, H. R., Geneva; 117.
FAVRE, E., 6, Eue des Granger,
Geneva ; 803, 805.
FOREL, PROF. DR. F. A., Morals ;
709.
GENEVA ASSOCIATION FOR THE CON-
STRUCTION OF SCIENTIFIC INSTRU-
MENTS, Geneva; 17, 52, 57, 59,
63, 147, 162, 176-7, 208, 210, 249,
253, 274, 307, 319, 326, 335, 340,
405, 679, 701-2, 743,913-4,920-2,
932, 945.
GOLDSCHMID, J., Zurich ; 684.
IlAGENBACH-BlSCHOFF, PROF. DR. E.,
Institution for Physical Science at
the Bernoullianum, Basle; 257,
280, 289.
HERMANN, PROF. T)R.L.,Physiolo</ic<il
Laboratory, University of Zurich;
209, 934, 944, 950.
LINDER, G., 29, Gerbergasse, Bas^e ;
319,321.
MONNIER, D., Geneva ; 626.
Iviii
LIST OP CONTRIBUTORS.
Morssox, PROF. A., Zurich; 167,
226.
PICTET (RAOUL) & Co., Geneva ; 274.
RAMBOZ AND SCHUCHARDT, Geneva ;
717.
RKCORDON, PROF. E., 53, Terrassiere,
Geneva ; 428, 430, 474, 813.
RENEVIER, PROF. E., Lausanne,
Switzerland:, 829.
SARASIN, G., Tour de Balessart,
Geneva ; 18, 442, 766.
SCHMID, A., Engineer, Zurich ; 79.
SORET, J. L., Geneva ; 219, 229, 274,
570.
SORET, PERROT, AND SARASIN (De
la Rive Collection), Geneva ; 172,
224, 383-6.
STAPFF, DR. F. M., Geological and
Mining Engineer, St. Got hard
Railway; 2.
STUDKR, PROF. B., Commission of
Switzerland, Geological Survey,
Berne; 829.
WARTMANN, E., Professor of Natural
Philosophy, University of Geneva ;
273, 327-8, 370-1.
WOLF, PROF. R., Director of the
Observatory, Zurich; 722.
CATALOGUE,
SECTION 1. ARITHMETIC.
WEST GALLERY, GROUND FLOOR, ROOM G.
L SLIDE RULES.
1. Slide Rule, of box wood, arranged by Mr. Dixon, Lowmoor
Ironworks. Aston fy Mander.
In addition to the lines of the ordinary slide rule this instrument contains :
Lines of common and hyperbolic logs and numbers.
Lines of sines, cosines, and numbers.
Lines of cubes and roots, direct.
A copy of Dixon's " Slide Rule Practice " is issued with each rule.
2. Slide Rule, of ivory, showing the actual and racing tonnage
of yachts. Aston $ Mander.
The length and breadth of beam being " set together," as directed in the in-
structions, the racing tonnage of yachts of any size is shown as marked.
3. Slide Rule, of boxwood, adapted to brickwork measurement
in all its branches, cubing stone, &c. Aston 3? Mander.
In this adaptation of the rule to brickwork measurements, all the results
are obtained by one setting, viz., " length to height :) ; while, immediately oppo-
site, any thickness will be found ; the superficial area in square feet ; the con-
tents in rods of reduced work 1^ bricks, in cubic feet, in cubic yards, and
the number of bricks required.
4. Slide Rule, of boxwood, adapted to timber measurement
in all its branches, giving the superficial or cubic contents of
round and unequal sided timber, St. Petersburg standard, price,
c. Aston fy Mander.
5. Slide Rule, of boxwood, with reversible slides, movable
inverted lines, &c. Arranged by Chas. Hoare. Aston $ Mander.
Uses explained in Hoare's " A. B. C. of Slide Rule Practice."
6. Slide Rule, of ivory, with reversible slides, movable inverted
lines, &c. Arranged by Chas. Hoare. Aston 8? Mander*
Uses explained in Hoare's " A. B. C. of Slide Rule Practice."
40075. Wt. 7183. A
2 SEC. 1. ARITHMETIC.
7. Slide Rule, of ivory, adapted for use in iron and steel plate
and sheet rolling mills. Designed by Okas. Hoare.
Aston Sf Mander.
This rule will show directly the precise net and waste weight of iron and
steel plates, and sheets, of any size, shape, and thickness. It may be applied
to all ordinary metals, and to find areas, cubic contents, liquid capacity, &c.
8. Slide Rule, of boxAvood, adapted for sheet iron and steel
manufacturers. The dimensions, thicknesses, and weights are
given both in English and metrical standards. Designed by
Chas. Hoare. Aston fy Mander.
The length of the sheet or plate (on the slide) being first set to the width,
then immediately below any thickness (on the top lines) will be found (on
the slide) the actual weight of the sheet either in pounds (avoirdupois) or
kilogrammes, metrical Or English measures being used without previous
conversion.
9. Slide Rule, of ivory, adapted for use in iron and steel-bar
rolling mills, showing instantly the precise net and waste weights
for bars of any length, size, and form. Designed by Chas. Hoare.
Aston $ Mander.
24. Scales, of boxwood, to show cubes, squares, and roots,
areas, diameters, circumferences, and decimal equivalents. De-
signed by Chas. Hoare. Aston $ Mander.
The bevel edged set square is used to read the divisions, and dispenses with
the need of voluminous printed tables.
9a. Three Slide Rules. Elliott Brothers.
10. Estimator. A slide rule, by which the volume of
prismoidal bodies (embankments, ditches, cuttings, &c., occurring
in the construction of railroads, canals, fortifications, c.,) is cal-
culated mechanically.
Dr. F. M. Stapff, Geological and Mining Engineer at the
St. Gotthard Railway. ^
This instrument, invented by the exhibitor, is patented in Sweden and the
United States of America.
lla. Timber Rule, for finding the content of timber of
any form, regular or irregular. The rule has eight gauge points
or divisors for reducing dimensions in inches to contents in square
feet. Dring and Page.
lib. " Verie " or Excise Officer's Rule.
Dring and Page.
Verie is probably a corruption of " Vero," a revenue officer who made an
alteration in the method of laying down some of the lines on the rule ;
previously to which they were called Everard's rules.
I. SLIDE KULES. 3
The lines on the rule are the A, B, C, D, MD, (or malt depth) 6x or variety
lines, viz., 1st, 2nd, 3rd, 4th, Dr. Button's and Dr. Young's, and two ullage
lines (segment standing and segment lying).
The A, B, C, and D lines are commonly called Gunter's lines (from Gunter,
the celebrated mathematician, who was the first to apply a logarithmic line
to the instrument for the solution of arithmetical problems) of which the A,
B, and C, are merely repetitions of each, and laid down to single radius, and
the D to double radius.
The MD line is similar to the A, B, and C, but is a broken line of two radii,
with the figures and divisions in an inverted order (reading from right to left),
commencing at 2218 192 in the right-hand radius, and ending at the same
point in the left-hand radius, 2218- 192 being the number of inches in a
bushel. By the method in which this line is arranged and used in conjunction
with the A, B, and C lines the contents in bushels of rectangular and similar
figures may be found at one operation.
The X or variety lines or lines of special gauge points (invented by Mr.
Woolgar) for finding the mean diameter of a cask whatever its form ; these
lines commence at 18 789, the circular gauge point, and are extended accord-
ing to each variety to which they may be applied.
The ullage lines are rules for finding the contents of a cask by comparison
with a standard cask holding 100 gallons, a form nearest those frequently
occurring in practice.
It cannot be ascertained by whom these lines were invented.
The fixed gauge points on the rule are those for the imperial gallon and
bushel, both square and round.
These rules are principally used by excise officers and maltsters. So ad-
mirable is the arrangement, that nearly every problem to which the principle
of the slide rule is applicable can be solved on one of these rules.
lie. Slide Rule, invented by Mr. Coulson, of Redan, used
for setting out railway curves, finding the weights of materials
from their specific gravities, breaking strains, &c.
Dring and Page.
The applications of this rule are so varied that the author's description of
them exceeds 400 octavo pages of closely printed matter.
12. Slide Rule, by M. Mabire.
Conservatoire des Arts et Metiers, Paris.
12a. Cylindrical Beckoning Rule. (The property of the
Conservatoire des Arts et Metiers.)
M. Mannheim, Professor at the Polytechnic School, Paris.
13. Calculating Rules, 1 of 50 cm., 1 of 36 cm., 1 of 26
cm., as arranged by M. Mannheim.
M. Tavernier Gravet, Paris.
13a. Small Cylindrical Calculating Machine. Arranged
by M. Mannheim. Conservatoire des Arts et Metiers, Paris.
14. Pocket Calculator, arranged by Major-General A. De
Lisle, R.E., for the use of engineers. ' Elliott Brothers.
A 2
4 SEC. 1. - ARITHMETIC.
This slide rule is useful for finding the weight of various materials, with the
help of the small tables on the back, for checking bills of quantities, and for
all approximate calculations required in engineering practice. The slides
are:
On Face.
On Stock A. The ordinary logarithmic line.
I. The same inverted.
On Slides Upper I. Inverted line.
D. Line of squares.
Lower B. Ordinary logarithmic lines.
an (^ Trigonometric lines.
Special Marks
M. Modulus of logs, to find prop, parts of logs.
A. Reciprocal of M. to find hyperbolic logs.
S" To find length of arcs, &c.
R' Radius for minutes.
R" Radius for seconds.
On Bach.
On Stock D. Line of squares.
On Slide E. Line of cubes read with D on line of % powers read with A.
* F. Line of f powers read with D, or of ^ powers read with A.
Tables and useful Numbers.
Line E with A gives variation in depth of water running over weir due to
alteration of length of weir. Neville's Hydraulics, page 22, 3rd edition.
A l4B=d __
E 220=1 ~" " " 60^7
Line F with D assists in finding the dimensions of a pipe or channel, with
a given hydraulic inclination to discharge a given quantity from the calculated
discharge of a pipe or channel of known dimensions and the same incli-
nation. Thus, if a pipe 4" diameter discharge 15 cubic feet per minute, what
diameter will discharge 33 cubic feet ? Neville's Hydraulics, page 245.
D _____
F _ ~l5 = D 33 =D'
D 4 = d 5.48 = d'
The two slides on the face working together solve the following equations :
al> ale abed
X ~; X = - X -
cde de e
15. Slide Rule, of boxwood, with double slide.
Renaud- Tachet, Paris.
16. Routledge's Original Engineers' Slide Rule and
manuscript book of instructions for using it.
PI. M. Commissioners of Patents.
II. CALCULATING MACHINES. 5
17. Kentish's Compound Slide Rule.
Thing and Page.
This is a new and ingenious arrangement of Gunter's lines, by means of
which problems in trigonometry and navigation can be solved, in addition to
those ordinarily done on the slide rule.
17a. Dr. Roget's Slide Rule of Involution.
W. H. Prosser.
This rule exhibits at one view all the powers and roots of any given number.
It is a measure of the powers of numbers, in the same way as Gunter's scale
is a measure of their ratios. Described in Phil. Trans. 1815, Part 1.
17b. Slide Rules (3), with double sliders, being suggested*
improvements on the ordinary slide rule, giving greater clearness
in reading off, and avoiding complication in the lines.
W. PL Prosser.
17c. Glass Slide Rule, invented by Leon Lalanne.
W. ff. Prosser.
This rule is made of two slips of card, upon which the scales are printed.
The slider, nlso made of card, has scales, constants, and gauge points printed
on both sides, and moves between the two slips. The whole is enclosed
between two pieces of glass.
17d. Slide Rule, with only one slider, adapted for the pocket-
book. Arranged by J. W. Woollgar. W. H. Prosser.
18. Sailer en's Slide Rule for reduction of volumes of gases
to standard temperature and pressure.
The Council of the Yorkshire College of Science.
19. Salleron's Slide Rule for reducing barometric heights
to standard temperature.
The Council of the Yorkshire College of Science.
II. CALCULATING MACHINES.
20. Calculating Machine, adapted to trigonometrical
computations, invented by Sir Samuel Morland (1625-1695), and
constructed by Henry Sutton and Samuel Knibbs of London, in
1664. Formerly belonging to Mr. C. Babbage, F.R.S.
Major- General Babbage.
On the lid of this machine is the following inscription :
" Machina Cyclologica Trigonometrice Qu& Tribus datis, reliqua oninia iu
Triangulis Planis Quaesita faciliter atque unico intuitu expediuntur a Samuele
Morlando inventa Anno Salutis MDCLXIII.
6 SEC. 1. ARITHMETIC.
21. Calculating Machine, designed by Viscount Mahon,
afterwards third Earl Stanhope (1753-1816), and constructed by
James Bullock in 1775. Formerly belonging to Mr. C. Babbage,
F.E.S. Major- General Babbage.
22. Calculating Machine, designed by Viscount Mahon,
afterwards third Earl Stanhope (1753-1816), and constructed by
James Bullock in 1777. Formerly belonging to Mr. C. Babbage,
F.R.S. Major- General Babbage.
23. Babbage's Calculating Machine ; or Difference
Engine. H.M. Board of Works.
This machine was invented by the late Mr. Charles Babbage, F.R.S., who
was born on the 26th December 1791, and died on the 18th October 1871.
Its construction was commenced in 1823 by authority, and at the cost of
the Government, and was carried on for several years under Mr. Babbage' s
gratuitous supervision. The work was suspended in 1833, and after many
delays, Mr. Babbage was informed in November 1842 that the Government
regretted the necessity of abandoning the machine, alleging the expense of
its completion as the ground for their decision.
At the time of its suspension about 17,000/. had been expended by Govern-
ment upon its construction, and a large part of the machinery had been
made. The small portion now exhibited was put ogether in 1833, prior to
the suspension of the work, in order to show the action of the machinery.
The whole engine, when completed, was intended to have had 20 places of
figures and 6 orders of differences.
This machine was expressly designed for the purpose of calculating and
printing tables, and not to perform single arithmetical sums.
If a single article is wanted, it is not, generally speaking, worth while to
construct a machine to make it ; but, when large numbers are required, their
production comes within the true province of machinery, and in this sense the
Difference Engine is emphatically a machine for manufacturing tables.
The mode in which the Difference Engine calculates tables is, by the con-
tinual repetition of the simultaneous addition of several columns of figures to
other columns, in the manner more particularly described below, and printing
the result.
In the small portion put together, and now exhibited, the figure opposite
the index on the .lowest wheel visible, in all cases, represents units ; the
figure on the next wheel above, tens ; that on the one above it, hundreds ;
the next thousands, and so on.
The right hand column of wheels shows the result of the calculation or the
tabular number ; for instance, series of squares, cubes, or logarithms, &c.
appear upon it, according to the nature of the calculation the machine is
making.
The next or central column represents the First Difference, and the left
hand column the Second Difference. At the bottom of the central column is
a figure wheel, covered, which can be used as a third difference, so as to
enable this portion of the machine to calculate tables of which the Third
Difference does not exceed 9. This will be better understood if this last
wheel is supposed to represent the lowest wheel of a fourth column of figures
standing beyond the left hand side of the machine, as it would be if it formed
part of the complete machine.
This arrangement is effected by a movable platform, with axles, and gearino-
wheels upon them, which are used for adding from the third difference wheel
II. CALCULATING MACHINES. 7
at the bottom of the central column to the second difference which is shown
on the left hand column. The effects capable of being produced by this
mechanism, when the gearing is altered, and the loose wheels belonging to it
are put into gear with certain figure wheels, is explained in Cabbage's Ninth
Bridgewater Treatise, together with the new views which it opened up to him
upon the subject of natural laws.
The three upper wheels of the left hand column are separated from the rest
of the machine, and are employed in counting the natural numbers. In other
words, they register the number of calculations made by the machine, and give
the natural numbers corresponding with the respective terms of the table.
Four half turns of the handle, two backwards and two forwards, are
required for each calculation, and the words " calculation complete " come
round upon a wheel at the top of the central column to show when this is
done. This wheel also shows, by the word "adjust," in what position of the
handle the figure wheels may be freely moved by hand, in order to introduce
different numbers or a different table.
24b. Cabinet, containing tablets for making mathematical
calculations. Archceological Museum, Madrid.
Rose wood cabinet, inlaid with ivory. In three divisions are thirty small
drawers, containing ivory plates with numbers and divisions for making mathe-
matical calculations. In the inside are the arms of the monastery of the
Escorial. Milanese work of the 16th century.
25. Fanometer, or Calculating Machine.
Edward Grohmann, Vienna.
By this extremely simple apparatus, various arithmetical computations can
be performed with great readiness.
25a. Calculating Machine for Multiplication.
P. Nicholas Dadiane, St. Petersburg.
26. Calculating Machine, for performing complex arith-
metical operations ; invented by M. Thomas of Colmar.
Professor Henncssy, F.R.S.
2 6 a. Calculating Machine for Adding, Subtracting,
Multiplying, and Dividing.
Theodore Esersky, St. Petersburg.
26b. Small Calculating Machine, encased in a pocket-
book. Theodore Esersky, St. Petersburg.
26c. Ten Copies of Multiplication and Division Tables.
Theodore Esersky, St. Petersburg.
27. Wertheimber's Calculating Machine, applicable to
wheel work. Patent, No. 96161843.
The Committee, Royal Museum^ Peel Park, Salford.
28b. Original Calculating Machine, known as " Napier's
Bones." Lord Napier and Ettrick.
One of the earliest attempts to construct a calculating machine, made by
John Napier, the inventor of logarithms. His method of calculating by rods
was published in a volume (which is exhibited with the machine) at Edin-
burgh in 1617. The apparatus was commonly known as " Napier's Bones."
8 SEC. 1. ARITHMETIC.
28. "Napier's Bones" or Bods. Made about 1700.
Dring and Fage.
Invented by Baron Napier, the originator of logarithms, used for per-
forming division and multiplication.
28a. Set of " Napier's Bones." 16th century.
Lewis Evans.
29. Calculating Disc, size about 18 centimeters, with double
divided circle ; constructed on the system of Prof. Soune.
Landsberg and Wolpcrs, Hanover.
30. Calculating Disc, with index of logarithms.
Landsberg and Wolpers, Hanover.
31. Calculating Disc, pocket apparatus.
Landsberg and Wolpers, Hanover.
32. Calculating Circle, O'OS meter in diameter, with single
scale of brass. Rudolf Weber, Ascliaffenburg.
33. Calculating Circle, O'lo meter in diameter, with single
square and cubic scale. Rudolf Weber, Ascliaffenburg.
The circles are on account of their continuous scale more convenient and
more accurate than straight slide rules. They are, therefore, peculiarly
adapted as pocket instruments for practical purposes, and can be relied on to be
as accurate as logarithms to four places.
34. Cubing Circle, 08 meter in diameter, for ascertaining
the cubical contents of trees in forests.
Rudolf Weber, Ascliaffenburg.
The cubing circle is to be noted as giving the index numbers for obtaining
the cubical contents of standing (not felled) timber ; these have been ob-
tained from practical experiments carried out by the Government Department
of Forests in Bavaria 011 more than 40,000 trunks of different kinds of trees.
The circle may be relied on for great accuracy in forest valuation.
35. Calculating Instrument, invented by Sir S. Morlaud.
Sennet Woodcraft, F.R.S.
35a. Calculating Planisphere.
Royal College of Science for Ireland, Dublin.
35b. McFarlane's Calculating Planisphere.
The Committee, Royal Museum, Peel Park, Salford.
36. Calculating Machine, designed by the Vicar Hahn
of Echterdingen, in 1770-1776; constructed by his son, Court
Mechanician in Stuttgart, in 1809 ; fourth specimen.
Her Highness the Duchess of Urach.
The machine which is exhibited is on exactly the same principle as that of
the one now in general use which was invented by Thomas, the only differ-
ence being that in Thomas's machine the numbers are placed in straight lines,
and in that of Hahn in a circle. It must have served as a model for
the machine of Thomas. The machine is to the present day in perfect order,
and works calculations up to numbers of 1 2 digits.
II. - CALCULATING MACHINES. 9
37. Logarithmic Calculation Apparatus, with one folding
scale, equivalent to five meters in length.
Prof. Gustav Hermann, Aix-la-Chapelle.
Calculation by means of this instrument is effected with the use of only one
scale. The two revolving arms are used like a compass. When the logarithm
a
of a quotient has been fixed between the arms, the plate must be
turned until the one arm is brought to a factor c, the product , c will then be
read on the other arm. This arrangement admits of the scale being made as
long as may be necessary by breaking it into lengths, without rendering the
instrument inconvenient. In the exhibited instrument ten circles are used,
by which means the scale attains a length of five meters, and is accurate up
to 16 06 . In using the instrument care must be taken to mark the number
of each scale circle, which can be fixed by small sliding buttons. The
number of the circle on which the result is to be read is found by the same
rules as the characteristic of a logarithm, on the supposition that the ten scale-
circles form a graphic table of logarithms of all the natural numbers, the base
of the system being ^
38. Arithmetical Disc, a very simple calculating machine,
with accompanying description. Prof. Prestel, Emden.
39. Calculating Machine, of the last century.
The Royal Gcwcrbe Academy, Berlin (Director, Prof.
Rculcaux).
This calculating machine formed part of the legacy of Hofrath Beireis,
the well-known ph} r sicist and chemist in the 18th century, and is very
similar to the calculating machine, No. 36. The following description
which accompanies this calculating machine is especially interesting, as it
was probably drawn up and written by the maker.
On the Use of the Calculating Machine.
There are on the small number-discs [Zahlen-Scheiblein] in the smallest
[circles], as well as on the large, in the great circles, the numbers 1,
10, 100, 1,000, and so on ; these indicate that the numerals on the first disc,.
where the (1) is marked, are units, on the second disc, where the numeral (10)
is marked, the tenfold of the numbers, and on the third, the hundredfold,
and so on ; and this applies also to those arcs on the largest circles. And if
on its first six discs respectively the following numerals were placed, 357,862,
they would indicate multiples of the numbers 1, 10, 100, which are on the
respective discs. On the sixth disc, where the numeral (3) is placed, is to
be found the number 100,000 ; thus indicating three times a hundred thousand.
On the fifth disc the numeral 5 represents 50,000, similarly the numeral 7,
7,000, and so on ; this would, in the first place, be " ciphering.'"
Now follows, iu the second place, addition. In calculating use is made of
the same numbers that are placed in the openings on the number disc, the
black numbers on the large discs are used for addition and multiplication,
and at the commencement noughts must be placed in all the apertures. As
q , an example, the following numbers will now be added together.
These numbers must be placed on those arcs which are found con-
r* secutively in the outer circle. The handle must then be turned,
when the numerals 352 will have come in the place of the noughts,
~7~~ on the three first large discs under the opening. Then the second
_'__ an( i Aird row are placed on the discs and by turning the handle
added to the preceding.
10 SEC. 1. ARITHMETIC.
Iu the third place comes subtraction, and it must first of all be understood
that the red numbers are to be used on the larger discs ; for the rest the
method is very easy.
The following is an example:
The numbers 5,786, as the larger numbers are placed in red figures
5,786 in the openings of the large discs ; (6) in the units, (8) in the tens,
3,524 and so on. The smaller number, which is to be subtracted, must
be placed on the arcs, in the same order as was shown for addition.
2,262 And in the same manner likewise must the handle be turned round
=: once, and then all is done, and the remainder appears in the
openings in which the larger amount was previously to be seen.
For multiplication (as for addition) the black numbers must be used on the
large discs, and before anything else, plain noughts must be placed in the
openings. And because in this method of reckoning small discs are also
used, noughts must at first be placed on them. Let the numbers
365 365, as in the case of addition, be placed on the arcs. One of the
24 hands, working from the centre, points to the units on the small
discs, and shows that multiplication will be effected with the units
1,460 as long as the hand is unaltered. Now if the handle be turned
7,300 round once, the numbers 365 will appear on the larger discs, instead
of the noughts which were there previously. But on the smaller
8,760 discs where the hand points, the number (1), and this proves, that
= the numbers 365 have been carried once under the aperture of the
large disc. The handle is again turned, and there will be seen on
the large disc the numbers 730 and on the smaller one the number (2). But
it must in the units' place be multiplied by (4), and so the handle has to be
turned four times round, and there will then appear on the large disc the
number 1,4CC, and on the smaller the number (4), and therefore, in this
problem, enough has been done with the units. Since 365 had to be multi-
plied by 24, the operation is repeated twice in the tenfold numbers, and the
desired result obtained ; this is effected in the following way :
The hand acting from the centre must be placed on the second disc, which
corresponds to tens. Near to the spot where the handle has its resting-
point, there is at the circumference of the machine a steel catch pressed down
in a notch;' this must be lifted up, and so turned round at the circumference of
the machine that the hand working from the centre comes to point on the
tens disc, and as in this case the catch will be pressed into the newly found
notch, the handle being turned round twice, the product 8,760 will be found
in the openings of the large discs.
For division the red figures must be used, as in the case of subtraction.
As an example take the number 8,760, which was obtained by the first
multiplication, and divide it by 365. The number 8,760 must be placed on
the large discs, in red figures, under the openings. The divisor 365 must be
placed on the arcs ; the first digit of the divisor (3) must be turned round
under the first digit of the dividend, viz., under the number (8) ; on the
small discs noughts must everywhere be placed. The catch must be left in
the notch. Now 3 can be taken from 8, the handle is turned once round,
and the numbers 5,110 appear, which is the remainder after 3,650 has
been taken from 8,760. 3 can again be taken from 5 ; the handle is again
turned round once more, and the remainder 1,460 appears. Since 3 cannot
be taken from 1, the catch is lifted, and 3, the first digit of the divisor,
brought under the 4 in the dividend. The handle is then turned 4 times,
and the remainders, 1,095, 730, 365, and 0, appear in succession, being those
due to the successive subtractions of 365 from 1,460. The value of the
quotient is seen to be as follows, 3,650 or 365 x 10 is subtracted twice, giving
20 as the first part of the quotient, then 365 is subtracted 4 times, giving 4
as the second part, with no remainder ; thus the quotient sought is 24.
II. CALCULATING MACHINES. 11
40. Tide Calculating Machine.
Sir William Thomson, F.R.S.
The object is to predict the tides for any port for which the tidal con-
stituents have heen found by the harmonic analysis from tide gauge obser-
vations : not merely to predict the times and heights of high water, but the
depth of water at any and every instant, showing it by a continuous curve,
for a year, or for any number of years in advance.
This object requires the summation of the simple harmonic functions repre-
senting the several tidal constituents to be taken into account, which is per-
formed by the machine in the following manner : For each tidal constituent
to be taken into account the machine has a shaft with an overhanging crank,
which carries a pulley pivoted on a parallel axis adjustable to a greater or
less distance from the shaft's axis, according to the greater or less range of
the particular tidal constituent for the different ports for which the machine
is to be used. The several shafts, with their axes all parallel, are geared
together so that their periods are to a sufficient degree of approximation pro-
portional to the periods of the tidal constituents. The crank on each shaft
can be turned round on the shaft and clamped in any position : thus it is set
to the proper position for the epoch of the particular tide which it is to pro-
duce. The axes of the several shafts are horizontal, and their vertical planes
are at successive distances one from another, each equal to the diameter of one
of the pulleys (the diameters of these being equal). The shafts are in two
rows, an upper and a lower, and the grooves of the pulleys are all in one
plane perpendicular to their axes. Suppose, now, the axes of the pulleys to
be set each at zero distance from the axis of its shaft, and let a fine wire or
chain, with one end hanging down and carrying a weight, pass alternately
over and under the pulleys in order, and vertically upwards or downwards
(according as the number of pulleys is even or odd) from the last pulley to a
fixed point. The weight is to be properly guided for vertical motion by a
geometrical slide. Turn the machine now, and the wire will remain undis-
turbed, with all its free parts vertical and the hanging weight unmoved. But
uow set the axis of any one of the pulleys to a distance T from its shaft's
axis, and turn the machine. If the distance of this pulley from the two on
each side of it in the other row is a considerable multiple of T, the hanging
weight will now (if the machine is turned uniformly) move up and down with
a simple harmonic motion of amplitude (or semi-range) equal to T in the
period of its shaft. If, next, a second pulley is displaced to a distance T', a
third to a distance T", and so on, the hanging weight will now perform a
complex harmonic motion equal to the sum of the several harmonic motions,
each in its proper period, which would be produced separately by the displace-
ments T, T', T". Thus, if the machine was made on a large scale, with T,
T'... equal respectively to the actual semi-ranges of the several constituent
tides, and if it is turned round slowly (by clockwork, for example), so that
each shaft goes once round in the actual period of the tide which it represents,
the hanging weight would rise and fall exactly with the water level as affected
by the whole tidal action. This, of course, could be of no use, and is only
suggested by way of illustration. The actual machine is made of such mag-
nitude that it can be set to give a motion to the hanging weight equal to the
actual motion of the water level reduced to any convenient scale : and pro-
vided the whole range does not exceed about 30 centimetres, the geometrical
error due to the deviation from perfect parallelism in the successive free parts
of the wire is not so great as to be practically objectionable. The proper
order for the shafts is the order of magnitude of the constituent tides which
they produce, the greatest next the hanging weight, and the least next the
fixed end of the wire : this so that the greatest constituent may have only one
pulley to move, the second in magnitude only two pulleys, and so on. In the
12 SEC. 1. ARITHMETIC.
actual machine there are 10 shafts, which, taken in order from the hanging
weight, give respectively the following tidal constituents :
1. The mean lunar semi-diurnal.
2. The mean solar semi-diurnal.
3. The larger elliptic semi-diurnal.
4. The luni-solar diurnal declinational.
5. The lunar diurnal declinational.
6. The luni-solar semi-diurnal declinational.
7. The smaller elliptic semi-diurnal.
8. The solar diurnal declinational.
9. The lunar quarter-diurnal, or first shallow-water overtide of mean lunar
semi-diurnal.
10. The luni-solar quarter diurnal, shallow-water tide.
The hanging weight consists of an ink bottle with a glass tubular pen
which marks the tide level in a continuous curve on a long band of paper moved
horizontally across the line of motion of the pen, by a vertical cylinder geared
to the revolving shafts of the machine. One of the five sliding points of the
geometrical slide is the point of the pen sliding on the paper stretched on the
cylinder, and the couple formed by the normal pressure on this point, and on
another of the five, which is about 4 centimetres above its level and ] centi-
metres from the paper, balances the couple due to gravity of the ink bottle
and the vertical component of the pull of the bearing wire, which is in a line
about a millimetre or two farther from the paper than that in which the centre
of gravity moves. Thus is ensured, notwithstanding small inequalities of the
paper, a pressure of the pen on the paper very approximately constant, and as
small as is desired.
Hour marks are made on the curve by a small horizontal movement of the
ink bottle's lateral guides, made once an hour ; a somewhat greater move-
ment, giving a deeper notch, to mark the noon of every day.
The machine may be turned so rapidly as to run off a year's tides for any
port in about four hours.
It is intended that each crank shall carry an adjustable counterpoise, to be
adjusted so that when the crank is not vertical the pulls of the approximately
vertical portions of wire acting on it through the pulley which it carries shall,
as exactly as may be, balance on the axis of the shaft, and that the motion of
the shaft shall be resisted by a slight weight hanging on a thread wrapped
once round it and attached at its other end to a fixed point. This part of the
design, planned to secure against " lost time " or " back-lash " in the gearings
of the shafts, and to preserve uniformity of pressures between teeth and teeth,
teeth and screws, and ends of axles and " end-plates," was not carried out,
but can easily be applied to the machine now exhibited.
The general plan of the screw gearing for the motions of the different
shafts is due to Mr. Lege, the maker of the machine. The construction has
been superintended throughout by Mr. Roberts, and to him is due the whole
arithmetical design of the gearing to give with sufficient approximation the
proper periods to the several shafts.
4Oa. Sir William Thomson's Instrument for Harmonic
Analysis of Tidal Observations, and for other uses.
It includes a disc-ball and cylinder integrator of Professor James
Thomson. For explanations, reference may be made to proceed-
ings of the Royal Society for February 3, 1 876.
Sir William Thomson.
41. Pascal's Calculating Machine (1642).
Conservatoire des Arts et Metiers, Paris.
III. MISCELLANEOUS. 13
42. Fetroff's Arithmetical Apparatus.
M. Petroff, Kalouga.
43. Arithmometer, with measuring apparatus, and the full
size skeleton of the square metre and cubic metre, folding up by
means of a hinge. frere Memoire Piron.
43a. Counting Machine.
P. N. Dadiane, St. Petersburg.
43b. Calculating Machine.
P. N. Dadiane, St, Petersburg.
45. Model of Gas Meter Counting Machine.
Council of King's College, London.
46. Cavendish's Original Counting Machine.
Council of King's College, London.
III. MISCELLANEOUS.
48. Apparatus for the Statistical Treatment of large
numbers of Seeds, &c., to sort them rapidly into classes
differing by regular gradations of magnitude, with the view of
testing how far the relative numbers in the several classes accord
with the results of the Law of Error or Dispersion.
Francis Gqlton, F.R.S.
It consists of a square box, having parallel bars fixed across its top at
equal distances apart. An equal number of similarly arranged bars are con-
nected by means of rods running along 1 tbeir ends, like the bars of a gridiron,
thus forming a framework that is laid on the top of the box. Hence there
are two systems of parallel bars in the same plane, one of which is fixed and
the other movable. When the frame is pulled forwards as far as it can go,
each of its bars presses along its whole length against one of the fixed bars,
and when it is pushed gently back the framework bars separate simultaneously
and equally from the fixed bars, and any objects that may have been laid
between their edges, and are small enough, will drop through. The bars are
bevelled along their opposite faces, in order to receive these objects. The
framework is moved by a screw turned by a ratchet wheel, which is itself
moved by the to-and-fro action of a handle between stops, one of which is
adjustable at pleasure. Hence, every time the handle is worked, the space
between the bars is widened by a definite space, and all the seeds, &c., whose
diameter is greater than the original and less than the final space, will drop
through. A tray, divided into compartments, slides beneath the box ; it is
pushed forward through the space of one compartment before giving a fresh
movement to the handle, and thus the seeds become sorted into the different
compartments. (This instrument was used to illustrate a lecture before the
Royal Institution on Friday evening, February 27, 1874.)
14 SEC. 1. ARITHMETIC.
49. Apparatus affording Physical Illustration of the
action of the Law of Error or of Dispersion.
Francis Galton, F.R.S.
Shot are caused to run through a narrow opening among pins fixed in the
face of an inclined plane, like teeth in a harrow, so that each time a shot passes
between any two pins it is compelled to roll against another pin in the row
immediately below, to one side or other of which it must pass, and, as the
arrangement is strictly symmetrical, there is an equal chance of either event.
The effect of subjecting each shot to this succession of alternative courses is,
to disperse the stream of shot during its downward course under conditions
identical with those supposed by the hypothesis on which the binomial law
of error is founded. Consequently, when the shot have reached the bottom of
the tray, where long narrow compartments are arranged to receive them, the
general outline of the mass of shot there collected is always found to assimi-
late to the well-known bell-shaped curve, by which the law of error or of
dispersion is mathematically expressed. (This arrangement was devised, by
the exhibitor, to illustrate a lecture before the Royal Institution on Friday
evening, February 27, 1874.) When using the machine, tilt it backwards
and all the shot will be returned to the receptacle at the top ; then set it in
its proper position, and the shot will run to the opening whence they distribute
themselves. It is now necessary to press to and fro a button at the top of
the frame, which sets a small rake in action, which prevents the shot from
getting jammed at the mouth of the opening.
50. Practical Approximation to the value of the circum-
ference in terms of the diameter, by means of a right angled
triangle having one acute angle =27 35' 49-636".
Edward Bing, Riga.
For the purpose of effecting this object, as well as for answering
kindred questions, use is made of a triangle, specimens of which are
here exhibited, and of which one angle is a right angle and another
is defined by an equation.
SECTION 2. GEOMETRY.
WEST GALLERY, GROUND FLOOR, ROOM G.
. i&
L INSTRUMENTS USED IN GEOMETRICAL
DRAWING.
52. Pantograph, by Breithaupt and Son.
Royal High School of Industry, Cassel. (JV. Narten.)
This pantograph was made for the geodetic collection of the school, in the
year 1866, by Messrs. Breithaupt nnd Son, Cassel. It is used for enlarging
and reducing maps and plans. The peculiarity of its construction is the
movement of all the arms between pairs of points, by which means friction
is as far as possible avoided. The employment of tubes instead of the usual
rectangular bars is also to be recommended, by which means bending, which
creates errors in the use of the instrument, is avoided ; besides which, the
weight of the whole is considerably decreased, thus also lessening friction in
the movement of the points.
The peculiar construction of this pantograph was invented and carried out
by Messrs. Breithaupt and Sou, and the instrument possesses great accu-
racy and facility of use.
53. Pantograph. Menaud Tachet, Paris.
54. Pantograph, with free hanging arms of new construction.
Ott and Coradi Kempten, Baviera.
By means of this instrument figures on a reduced or an enlarged scale can
be transferred either to paper, stone, or metal.
These pantographs differ in their construction from other similar instru-
ments by not resting on friction-rollers, but are freely suspended by means
of metal wires from cast-iron curved standards ; thus only a small portion of
the weight of the instrument rests on the table. The advantages of this con-
struction are these : easy and secure management of the instrument ; any
ordinary table may be used of a size sufficient to afford room for the stands,
the original, and copy ; the accuracy of the graphic representation is greater
at less cost.
The guidance of the instrument is so easy and so accurate that with a
little practice every outline can be reproduced. Drawings, likewise, can be
transferred to substances measuring a certain height, such as lithographic
stones, it being only necessary to place frame and original correspondingly
higher. In producing enlarged copies the guiding peg and the drawing pencil
must be exchanged, and the releasing cord fastened accordingly. The guidance,
in making enlarged copies, is also performed with the handle of the tracing
pencil with the same accuracy as when making reduced copies.
54a. Horizontal Pantograph, traversing a surface of 36
inches in length by 20 inches in width. Reduction from \ to T ^.
L. Oertlina.
16 SEC. 2. GEOMETRY.
54b. Pantograph, large model, with double scale and reverse
action, belonging to the Indian service. Four of these large in-
struments are now in use. M. Adrian Gavard, Paris.
54c. Frame, containing the Drawings of Pantographs
and Fantopoly graphs made by the exhibitor.
M. Adrian Gavard, Paris.
54d. Pantograph by Adrian Gavard, Paris.
S. J. Hawkins.
Size 56 centimeters.
A method of raising and lowering the tracer A by a rack and pinion
movement, for use when the reduction of a drawing has to be made on tracing
paper, enables the tracer to pass over any irregularity of surface, and thus
prevents injury to the paper.
There is also a method of ascertaining when the tracer A, the pencil or cen-
tral point B, and the fulcrum C, are in a straight line, for use with maps or
drawings of irregular scales, and for which there are not any corresponding
divisions on the Pantograph. The points A, b, C, D, e are removed when the
instrument is adjusted, and the two small screws f, f screwed into the head of
the tracer and fulcrum.
The instrument is adjusted for the reduction of Ordnance maps 25 '34
inches to the mile to 5 chains to the inch or 16 inches to the mile.
54e. Pantograph made at Madrid by Kostriaga, and which
has been used at the mines of Almadin since the end of the last
century. Royal School of Mines, Madrid.
Compass of Proportion, called also military compass,
invented by Galileo in 1596.
Royal Institute of " Studii Superiorly Florence.
On one side are engraved the arithmetical lines, the geometrical lines, the
stereometrical lines, and the metallic lines ; on the opposite side are the polygra-
fical lines, the tetragonical lines, and the joined lines for the squaring of figures
comprised by right angles and curves together. By means of it 40 important
operations can be carried on, and it has in addition a quadrant with a squadron
of bombardiers, and transversal lines to take the inclination of the scarp of
any wall.
Galileo presented compasses of a similar kind, in the year 1598, to the
Prince of Holstein, Sagredo, and Bentivoglio, who was afterwards made
Cardinal, to Ottone Brahe, to the Count of Luxemburg, and many other
gentlemen, both Italians and foreigners, who had gone to Padua to follow the
lectures of so eminent a philosopher. He also presented one made of silver
to the Archduke Ferdinand of Austria, and to the Landgrave of Hesse.
55. Large Collection of Mathematical Instruments
for Geometrical and Fortification Drawing, as well as for
Artillery purposes. The property of His Highness the Prince
Pless, Fiirstenstein. The Breslau Committee.
This ancient collection, dating from the commencement of the last century,
is remarkable for the excellent workmanship and good state of preservation
of the instruments.
I. GEOMETRICAL DRAWING. 17
It contains 19 compasses and 11 accessory parts, 28 rules and scales, two of
the same with two keys for fortification drawing, eight triangles and set
squares, 10 protractors, two pantographs, and 52 other instruments. In all,
134 pieces.
56. Case of Mathematical Instruments.
Renaud Tachet, Paris.
57. Proportional Compasses. Renaud Tachet, Paris.
58. T-squares, Set Squares, and Curves.
Renaud Tachct, Paris.
59. Diagonal Scale.
Geneva Association for the Construction of Scientific In-
struments.
60. Scales made of Mica, for use in geometrical drawing.
Max. Raphael, Breslau.
275. Meter-measures, constructed of mica.
Max. Raphael, Breslau.
These measures have the advantage of being transparent, and may serve
for copying geometrical drawings. Owing to their remaining unaffected by
the ordinary changes of temperature they may also be used as standard
measures.
61. Perspective Apparatus invented by James Watt.
Bennet Woodcroft, F.R.S.
62. Set of Mathematical Instruments, with all the
modern improvements : as used by professional draughtsmen, &c. ;
illustrated by diagrams of work performed. Win. Ford Stanley.
62a. Magazine Case of Drawing Instruments.
Henry Porter.
64. Case of Mathematical Instruments, probably Dutch,
made at the beginning of the 18th century. Lewis Evans.
65. Two Magazine Cases of Drawing Instruments.
Mark Eames.
65a. Large Magazine Case of Instruments.
G. W. Strawson.
65b. Magazine Cases of Instruments (2).
G. W. Strawson.
65c. Morocco Case of Instruments. G. W. Strawson.
65d. Napier's Compasses (Electrum). G. W. Strawson.
66. Beam Compass, T-squares, Set Squares, and
Curves. Bock and Handrick, Dresden.
40075. B
18 SEC. 2. GEOMETRY.
67. Models of Mathematical Instruments. The ortho-
compass and the addition compass. Prof. L. Zmurko, Lemberg.
The first of these instruments is constructed so that the points of the compass
are always parallel to each other, and perpendicular to the surface of the
paper. The second is a compass which can be used also as a protractor, as it
contains an apparatus which indicates the amount of opening between the
arms.
69a. Photographs of Mathematical Instruments.
Otto Fennel, Cassel.
69d. Revoil Tele-iconograph, altered for perspective draw-
ings enlarged to 20 times on a horizontal plane-table.
M. Georges Sarasin, Geneva.
The instrument consists of a telescope, adapted to a Wollaston camera lucida,
and fixed on a stand arranged so as to make it a mathematical or scientific
instrument ; while on a separate stand is placed a plane table for drawing. In
order to facilitate the exact grouping of the partial perspectives in accordance
with a general cylindrical perspective, and capable of being developed, and in
order to permit of drawing while the telescope is inclined at great angles,
the following additions have been made to the Revoil model: 1st. A
tightening ring with an adjusting screw, which fixes the prism to any point
on the thread of the screw by which it is fixed to the eye piece. 2d. A web
of six threads crossed at right angles in the focus of the object glass for
the purpose of setting the partial images in a straight line and in a direction
in accordance with the horizontal or vertical. 3d. A spirit level on the
telescope stand to ensure the verticality of the axis of rotation. 4th. A
socket and rack joint, permitting the height of the prism above the drawing
to be determined whatever be the angle of the telescope and, consequently,
the scale of the drawing. 5th. A graduated scale with vernier, giving a
reading to five minutes on the horizontal limb. 6th. A method of attaching
the instrument to its stand, so as to be at the same time firm and easy to
work.
69e. Patent Dotting Pen.
E. O. Richter and Co., Chemnitz, Saxony.
The arrangement is as follows :
A small toothed wheel adapted to the kind of dotted lines to be drawn is
attached to a plate, which, rolling on the paper, lifts a lever, which is again
dropped by means of a spring. Attached to this arm is a drawing-pen, easily
adjustable, by means of a hinge, to the correct position suited to the wheel.
The wheel itself is held in position by a small, somewhat elastic plate, which
can be displaced a little for fitting the different reserve wheels on which
the kind of lines to be drawn depends.
69f. Patent Compasses with stationary centre point.
E. O. Richter and Co., Chemnitz, Saxony.
These compasses differ from others, chiefly by the centre-point being
stationary on the paper, so that the tracing-pen, resting on the paper by its own
gravity, moves about the centre-point as axis, whilst the movable pen can be
displaced, without removing the compasses from the paper. By these advan-
tages speedy and neat tracing will be achieved, even when the smallest circles
are to be drawn.
I. GEOMETRICAL DRAWING. 19
69g. Patent Compasses, with drawing pen and leaden tube.
E. O. Richter and Co., Chemnitz, Saxony.
69h. Patent Diamond Compasses, for lithography.
E. 0. Richter and Co., Chemnitz, Saxony.
69i. Patent Diamond Compasses with drawing pen, for
lithography. E. O. Richter and Co., Chemnitz, Saxony.
69j. Patent Hatching Ruler (for shading by cross-lines in
drawing and engraving).
E. 0. Richter and Co., Chemnitz, Saxony.
A ruler is attached to a cylinder which, rolling on a plate, draws the
former after it. By means of an endless screw, working in a wheel, the
cylinder is moved forward. A cogwheel is attached to the endless screw,
in which a bar catches, and by the depression of which the mechanism is
put in motion. The depression can be regulated by a screw, by which means
the various distances of the lines are obtained. One finger is sufficient for
working the ruler by simply pressing on the screw, and holding it until
the line is drawn.
69k. Six Setter Diamonds, for lithography.
691. Five Machine Diamonds, for lithography.
69m. Six Scratching Diamonds, for lithography.
E. O. Richter and Co., Chemnitz, Saxony.
69n. Perspectograph. Lieut. -General M. W. Smith.
This instrument is employed to determine the perspective position of a
point on the surface of a picture corresponding to any point in nature, the
actual position of which is ascertained by means of ground plans, elevations,
sections, actual measurement, or otherwise, or else assumed in the composi-
tion of a picture. A horizontal line is drawn across the picture and a point
assumed upon it to represent the point or centre of view, the perspective point
(the two ordinates, of which one parallel and the other perpendicular to
the horizontal line are determined by the instrument) is then laid down from
the point of view by scale and offset. The manipulation of the instrument is
very simple and easily acquired ; and as the perspective representation of any
number of points, constituting lines, planes, solids, &c., can be rapidly
transferred to the picture, the most complicated problems of perspective,
whether rectangular or oblique, can be performed without lines of geometrical
construction, or the transferrence of the subject from a plan previously pre-
pared to the picture. A detailed description of the working of these instru-
ments, as well as of the system upon which their construction depends, will be
found in " Engineering," 1876.
69o. Pointfinder. Lieut.- General M. W. Smith.
This instrument is used in sketching from nature and is employed to
determine a point on the surface of the picture corresponding to any point in
nature to which the sights of the instrument may be directed, as follows :
Having drawn a line horizontally across the paper to represent the horizontal
line, and assumed a point upon it as the point of view, the instrument is set to
zero both on the horizontal, and side vertical graduated arcs ; and levelled by
means of the small plumb bob, the sights being at the same time upon any
B 2
20 SEC. 2.- -GEOMETRY.
point in nature which may be chosen as the point of view. The sights of the
instrument are then directed to any point in nature which it may be desirable
to introduce into the picture. This may be done by the lateral and vertical
movements of the horizontal disc and plate to which the sights are attached ;
the divisions and subdivisions indicated by the zero mark on the horizontal
disc, and index on the side arc, are then read off and transferred to the picture
by means of the graduated scale and offset, the zero of the scale being placed
to the point of view and the bevelled edge to the horizontal line, the offset is
then moved along the edge of the scale till the bevelled edge corresponds with
the division or subdivision read off from the circular disc, when a slight dot
with the point of a pencil at the division or subdivision on the offset corre-
sponding to the reading on the side vertical arc will indicate the point which is
the perspective representation of the point in nature. The scale can be in-
creased, if desired, by multiplying the number of divisions or subdivisions read
off on the graduated arcs by 2, 3, 4, or any other common multiplier. The
offset also may be dispensed with by placing the edge of the scale first to the
horizontal line, for the first reading making a slight mark on the line with a
pencil at the number indicated, and then perpendicular to it for the second
reading, this maybe the most convenient mode of laying down the points
when the sketching book is held in the hand. The stand of the instrument
folds up, and the apparatus when packed is very light and portable, consisting
of camp stool, drawing book, instrument and stand.
443a. Plate Glass Sector, designed for the purpose of
plotting angles on plans or charts where it is necessary to see the
work under the sector, and the divisions being . on the side next
the paper no variation in pricking off can take place,
Thos. F. Chappe, M. Inst. C.E.
Boxwood Beam Compasses.
Bock and Handrick, Dresden.
244. Scales, of boxwood, showing the equivalents of English
and Foreign measures of length. Aston fy Mander.
The bevel edged set square slide is used to show the divisions coinciding ;
and the equivalent values of English and Foreign measures of length may thus
be readily obtained.
245. Plotting Scales. Ivory. Two specimens, to show fine
and accurate dividing. Aston fy Mander.
No. 1 shows two chains to the inch, represented by 200 divisions to the
inch.
No. 2 shows one chain to the inch, represented by 100 divisions to the
inch.
II. INSTRUMENTS FOR TRACING SPECIAL CURVES.
7O. Conograph. An instrument by which the various conic
sections may be drawn. .
a. Ellipso-Pnrabolograph.
b. Hyperbolograph.
Dr. Lawrence Zmurko, Lemberg.
II. CURVE TRACING. 21
This instrument consists of two movements independent of, and perpendicu-
lar to, each other; the first of these is set in action by turning a disc, the
second by moans of a spring. These movements are so contrived that the
extent of the second motion shall be such a function of that of the first as to
cause a conic section to be described.
71. Cycloidograph. An instrument for tracing cycloids.
Dr. Lawrence Zmurko, Lemberg.
7 la. Instrument for tracing with accuracy ellipses and spirals
up to 25 centimetres. M. Adrian Gavard, Paris.
72. Instrument for drawing Conic Sections.
Edward Uhlcnhuth, Anc/am, Pommerania.
This instrument, which was invented by the exhibitor, shows in the first
place the formation of the parabola. By altering the arrangement, the con-
struction of the ellipse and hyperbola easily follows.
73. Elliptic Compass. Renaud- Tachet, Paris.
74. Colonel Feaucellier's Compound Compass.
Conservatoire dcs Arts et Metiers, Paris.
75. Compound Geometric Chuck, producing the kine-
matic retrogressive parabola, by continuous motion ; either on a
moving plane by a fixed point, or on a fixed plane by a moving
point. Henry Perigal.
76. Machine for Compounding two Simple Har-
monic Curves. Invented and constructed by the exhibitor.
A. E. Donkin.
A strip of paper is wound round the cylinder ; the little glass pen moving
backwards and forwards on it draws one curve, a similar motion of the
cylinder the other. Since both move at once the curves are combined, and
the result rendered visible to the eye by the revolution of the cylinder.
A. Eccentric for giving simple harmonic motion to pen.
B. cylinder C.
D. 1 wheels for determining relative numbers of vibrations of pen and
E. J cylinder.
F. Wheel for transmitting slow motion to pinion G which turns the
cylinder.
H. Idle wheel.
I. Change wheels to supply different ratios of vibration of pen and
cylinder.
76c. Bow and Scale for Exhibiting Elliptic Func-
tions. A. G. Greenhill.
76e. Spherical Rules and Squares for Spherical
Drawing. Dumoulin Froment, Paris.
76a. Bough Model of the Trace-Computer, designed by
the Exhibitor, for the use of the Meteorological Office.
Francis Galton, F.R.S.
Given two ordinates having the same abscissa, the instrument, of which this
is a working model, pricks out a third ordinate that shall be some desired
22 SEC. 2. GEOMETRY.
function of the other two. The original instrument was contrived for the use
of the Meteorological Office, where it is employed to derive the trace for
humidity from the traces of the dry and wet bulb thermometers. It consists
of a horizontal slab, whose upper surface has been shaped, as hereafter de-
scribed, in accordance with the numerical tables that have been calculated
from the desired function, the height of its surface at each point being the
tabular value corresponding to the two entries severally represented by the
distance of that point from the front and from one side of the slab. The
plate that carries the two traces is placed horizontally on a frame that travels
in front of the slab. Two slides move at right angles to this plate, and have
microscopes attached to them, that traverse the paper along ordinates having
the same abscissa. One of these slides is rigidly connected with a frame on
which the slab is able to move from front to back ; when this slide is pushed,
the frame and the slab together are pushed with it. When the other slide
is pushed, it also gives a sidelong movement to the slab on the frame by means
of a toothed wheel acting on a rack. Thus the particular point of the slab that
corresponds to the values of the two ordinates is brought vertically below a
descending rod, and this is caused to drop gently on the surface of the slab
by touching a treadle. The vertical space through which the rod descends
is consequently the function required. The rod carries a horizontal pricker,
with which it makes a dot on a plate held vertically in the same stage that
carries the plate on which the two traces are drawn. The slabs can readily
be fashioned Toy instrument-makers, who possess the necessary apparatus,
according to any required tables. They are drilled to the requisite depth at
various points, and are afterwards smoothed down. In the machine in use at
the Meteorological Office, there are many additional appliances not shown in
this rough model.
76b. Rule; with joint, which serves to curve an elastic plate
into an arc of the circle, of any radius.
Professor Tchebichejf, University of St. Petersburg.
3O99. Intersecting Compasses (Arcograph).
Geodetic Institute of the Royal Polytechnic School at
Munich, Prof. Dr. von Bauernfeind.
The Arcograph serves to describe upon a given chord a circle the arc
of which contains a given angle. The exhibitor, by this invention, has
supplied the wants of the practical geometrician in solving, graphically, and
without construction Pothenot's problem and all the problems which are
described in geometry as " Kuckwartseinschneiden ". See Bauernfeind's
"Elemente der Vermessungskunde," 5th edition, Vol. II., pp. 167-173.
III. MODELS OF FIGURES IN SPACE.
COLLECTION OP MODELS OF RULED SURFACES, CONSTRUCTED
BY M. FABRE DE LAGRANGE, IN 1872, FOR THE SOUTH
KENSINGTON MUSEUM.
This collection illustrates the principal types of the class of surfaces which
can be traced out m space by the motion of a straight line.
These surfaces, on account of the facility with which they can be con-
structed and represented, and of the ease with which their intersections can
termmed, are of more consequence than any others in the geometry of
III. MODELS. 23
the Industrial Arts. It is only in small work, -which can be put into the
lathe, that the class of surfaces of revolution approaches them, in respect of
general utility. The most important surfaces of all, the plane, the right
cylinder, the right cone, and the common screw, belong to both classes.
The representation of the surfaces by means of silk threads is of course
only approximate ; an approximation of the same character as the representa-
tion of a curve by a dotted or chain line, Fig. I, or by a series of right lines
touching the actual curve, Fig. 2.
The models are constructed with especial reference to the possibility of
changing their shape, by moving some of the supports of the strings, by altering
the lengths or positions of certain parts, or by converting upright forms into
oblique. This possibility of deformation, as the process is technically called,
greatly enhances the value of the models, by allowing them to represent a
much greater variety of surfaces than if they were fixed. They are, how-
ever, too delicate to be much pulled about, and, unless they are very cautiously
handled, the strings are apt to become entangled or break. They should never
be used except by a person who understands them, and they should not be
shifted without some good reason.
FIG. 1. FIG. 2.
Fig. 1 is an example of the first, and Fig. 2 of the second. In both cases,
the curve, although not actually drawn, is indicated with sufficient approxi-
mation for most practical purposes. Models Nos. 10 and 30 also afford illus-
trations of the principle exhibited in Fig. 2.
Geometrical drawings of most of the surfaces represented by these models
are contained in BRADLEY'S Practical Geometry (2 vols., oblong folio, pub-
lished by Chapman and Hall). Many of them will also be found in the
French treatises on practical and descriptive geometry, such as LEROY,
ADHEMAR, LEFEBURE DE FOURCY, DE LA GOURNERIE, and in their treatises
on Stereotomy and Stone-cutting (coupe des pierres). Many of them are also
given in SONNET'S Dictionnaire des Math^matiques Appliqu6es. A catalogue
of this collection of models, with an appendix containing an account of the
application of analysis to their investigation and classification, was prepared
for the South Kensington Museum in 1872, by Mr. C. W. Merrifield, F.B.S.
The following descriptions are extracted from this catalogue :
77. Hyperbolic Paraboloid generated by a single system
of right lines.
Two bars, each pierced with holes, equally spaced. One bar is fixed,
the other swings round an axis, which, moreover, can be inclined at different
angles to the fixed bar.
When the bars are parallel the strings indicate a plane. When they are
clined to one another, but still in the same plane, the strings still indicate a
24 SEC. -2. GEOMETRY.
plane ; but Avhen the bars are not in the same plane, the surface is the hyper-
bolic paraboloid.
The surface is sometimes called the twisted plane. But it must not be
supposed that it can be made by bending a plane. On the contrary, when
the surface is twisted, no two of the strings lie in the same plane, and, there-
fore, no part of the surface is plane. It can neither be flattened nor made
from a plane, without stretching or contraction.
The hyperbolic paraboloid is the natural surface proper for a ploughshare.
78. Hyperbolic Paraboloid.
Two bars, pierced -with holes at equal distances, the holes being connected
by two different systems of strings. The surface, as well as the arrangement,
is very nearly the same as in No. 77, only that there are two paraboloids in-
stead of one. As the movable bar swings round, one paraboloid opens out
while the other closes up. If the -bars are swung so as to be in the same
plane, one system of strings describes a plane by parallel lines, and the other
by lines radiating from a point. If one bar is now turned so as to be end for
end, we still get a plane, the set of parallel lines now passing through a point,
while the set Avhich previously passed through a point has now become
parallel.
The pair of paraboloids intersect in three right lines. There is also a
fourth intersection on the " line at infinity."
79. Hyperbolic Paraboloid.
Two bars equally spaced ; each turns on an arm perpendicular to itself,
and one arm swings on a pillar. These arms can be ranged in one plane, and
also turned end for end.
80. Hyperbolic Paraboloid generated by two systems of
right lines.
A skew quadrilateral with four equal sides, each pierced with the same
number of holes, equally spaced. The model exhibits the double generation
of the surface. The plane containing two of the sides turns about hinges
connecting it with the plane of the other two sides. By closing or opening
this hinge the paraboloid opens out or closes. When completely open, it
forms a plane divided into diamonds. When completely closed it again forms
a plane, but the division is no longer uniform. The strings then become
tangents to a plane parabola.
81. Hyperbolic Paraboloid.
A skew quadrilateral turning upon four hinges with parallel axes or pins.
The difference between this and the last is not in the kind of surface or
mode of generation, but in the manner of deforming the surface. In No. 80
the lengths of the strings alter ; while in this model they remain unaltered.
Moreover, although the surface flattens in two ways, yet in both ways the
strings become tangents to a plane parabola instead of parallel.
This model is well adapted for showing the leading sections of the solid
All sections parallel to the pins of the hinges are plane parabolas, which de-
generate into right lines when taken also parallel to the brass bars. Any
other sections, whether perpendicular to the hinges or inclined to them, give
hyperbolas, which degenerate into a pair of right lines when the plane of
section is a tangent to the surface.
It may b? worth while to remark that there is nothing absurd in the
tangent plane to a surface cutting that surface, as a student unaccustomed to
those subjects might at first think. On the contrary, when a surface is bent
one way in one direction, and the other way in the opposite direction, the
III. MODELS. 25
tangent plane must cut it. In this case, the plane passing through any two
intersecting strings is a tangent plane, and evidently cuts the surface along
each string.
If we imagine two planes parallel to the hinge pins, and each bisecting a
pair of opposite bars, we obtain the asymptotic planes of the paraboloid, each
of which is the assemblage of the asymptotic lines of the hyperbolas parallel
to the principal hyperbolic section. Their being asymptotic has reference to
these hyperbolas, and not to the parabolic character of the surface.
82. Hyperbolic Paraboloid.
A skew quadrilateral, with its opposite sides equal in length, and pierced
with holes at equal distances.
Nearly similar to No. 81, but differently mounted, and with the sides of
different lengths, the alternate sides only being equal. It is virtually a slightly
different aspect of the same surface as No. 81.
83. Hyperbolic Paraboloid.
A skew quadrilateral, with all its sides equal, and pierced holes at equal
distances.
As far as the curved surface is concerned, the same as No. 81. But the
hinges are altered in direction, and the model shows plans and elevations of
the right line generators of the surface. The rings also show parabolic sections
of the surface.
In consequence of the alteration in the direction of the hinges, the spacing
of the inclined bars, although equidistant, is at a different pitch from that of
the horizontal bars.
84. Hyperbolic Paraboloid.
A skew quadrilateral, with all its sides equal, and pierced with holes at equal
distances. It shows the plans and elevations of the right line generators.
The rings show the parabolas of the principal sections.
No. 83 represents one quarter of what is here shown. The upper corners
ofNos. 83 and 84 correspond; but the lower corner of the former corre-
sponds with the middle ring of the latter.
85. Hyperbolic Paraboloid.
A skew quadrilateral, with all its sides unequal. The surface is the same as
Nos. 83 and 84, but the proportions and the portion of the surface chosen for
representation are different. The quadrilateral base being irregular, the
strings alter in length as the surface is deformed by closing the hinges.
86. Hyperbolic Paraboloid.
Skew quadrilateral, pivoting on a single hinge. Intended to show the con-
struction of the parabola connecting two roads which meet obliquely. This
construction is used by engineers in laying out roads.
87. Hyperboloid of one Sheet.
Two rings or circles, in parallel planes, are pierced with equally spaced
holes. In a certain position the threads give, 1st, a cylinder; and 2ndly, a
cone.
The upper ring turns round a pin at its centre. In turning it, the cy Under
closes in and the cone opens out, each altering into a hyperboloid of one
sheet. We can go on turning the ring until these coincide in one hyperbo-
loid, of which we thus get both systems of generating lines.
if the rings are set on a slope the hyperboloid is elliptic. If the rings are
horizontal the hyperboloid is one of revolution.
26 SEQ. 2. GEOMETRY.
Sloping one ring, so as not to be parallel with the other, gives rise to some
curious ruled surfaces, but these are not in general hyperboloids.
88. Hyperboloid of one Sheet.
Two rings of different radius, in parallel planes, are divided into the same
number of equal parts. The smaller and upper ring turns round a pin at its
centre. In a particular position of the rings, the threads give two cones.
Turning the ring transforms each of the cones into a hyperboloid, and
when the two hyperboloids coincide, we get the two systems of right line
generators.
The same stand also has a model of a hyperboloid with only one set of
strings. By turning the upper ring either way it deforms into a cone ; in the
one case with its vertex between the rings, and in the other with its vertex a
a considerable height above the rings.
Both these can have their upper rings moved along the top bar so as
to incline the surfaces. We still get cones and hyperboloids, but it is only
when the rings are horizontal, and centre to centre, that we get surfaces of
revolution.
89. Hyperboloid of one Sheet, with its asymptotic cone.
90. Hyperboloid of one Sheet, with its asymptotic cone.
The tangent plane to the cone is also drawn. It meets the hyperboloid in
two parallel right lines.
One of these right lines is the line of contact of a hyperbolic paraboloid
with the hyperboloid, and the tangent plane is one of the director planes of
the paraboloid, both systems of generating lines of which are exhibited.
91. Hyperboloid of one Sheet.
A slight variation from No. 90. The paraboloid only shows one system of
right line generators, and the tangent plane is made by parallel instead of
radiating lines.
92. Hyperboloid of one Sheet, and its tangent para-
boloid.
This shows the transformation of a cylinder and its tangent plane into a
hyperboloid and its tangent paraboloid.
93. Conoid, with its director plane. The director curve is a
plane curve.
By shifting the position of the brasses the conoids deform into different
conoids or other allied surfaces.
94. Conoid, with a director cone. The director curve is of
double curvature.
By shifting the position of the brasses the conoids deform into different
conoids or other allied surfaces.
i
95. Conoid, showing both sheets of the surface.
By shifting the position of the brasses the conoids deform into different
conoids or other allied surfaces.
96. Conoids. Model showing the transformation of a cylinder
into a conoid and back again. Also model showing the trans-
formation of a cone into a conoid and back again. It is to
m. MODELS. 27
be noticed that the head lines of the two conoids, that is to say,
the right line in which the two sheets of each conoid meet, are
perpendicular to one another.
The transformation is effected by making the upper semicircle turn through
two right angles.
97. Conoids.
Intersection of two equal conoids having a common director plane. The
horizontal intersection is a plane ellipse.
98. Conoid, in contact with a hyperbolic paraboloid.
99. Conoids. Two equal circles in parallel planes, divided
equidistantly, are connected by threads, so as to form four surfaces.
A cylinder. A conoid.
A cone. A second conoid.
The director planes, as well as the head lines, of these conoids
are at right angles to one another.
100. Conoids.
Two equal circles in parallel planes are connected by threads so
as to form four surfaces.
A cylinder.
A cone.
A conoid.
A second conoid, with its director plane and line at right
angles to those of the former.
Same arrangement as No. 99, except that the lower ring is replaced by a
plane of section a little higher up. The section gives,
For the cone, a circle smaller than the upper ring.
For the cylinder, a circle of the same size as the upper ring.
For the conoids, two ellipses turned crosswise.
101. Model exhibiting the simultaneous transformation of a
conoid into a cylinder, a cylinder into a conoid, the paraboloid
touching the conoid into the tangent plane of a cylinder, and
the tangent plane of a cylinder into the tangent paraboloid of a
conoid, and reciprocally.
The changes may be arranged as follows :
From.
Conoid.
Tangent paraboloid.
Cylinder.
Tangent plane.
Into.
Cylinder.
Tangent plane.
Conoid.
Tangent paraboloid.
These changes are all effected simultaneously by one movement, which can
be reversed.
102. Model exhibiting the transformation, first, of a conoid
into a cylinder ; second, of the tangent paraboloid of the conoid
into the tangent plane of the cylinder.
28 SEC. 2. GEOMETRY.
1O3. Trench Skew Arch (biais passe).
The inner drum, of yellow thread, represents this surface. It
is a skew surface, with a right line director ; and its faces, the
planes of the two semicircles, are usually parallel, although the
model permits them to be placed obliquely to one another. The
horizontal line joining the centres of the two large semicircles is
the right line director.
The construction for any one of the generating lines is as follows : Draw
a plane through the right line director at any selected obliquity. It will, of
course, give the radii of the outside circles, and the line joining the points
at which it cuts the inside semicircles will be a generator of the surface.
This line will evidently pass through the director line, because it is in the
same plane with it.
In stone or brickwork, the sides of the voussoirs, will be given by the
auxiliary plane in question. When the openings are parallel the voussoir
joints are therefore plane, and the simplicity thus gained is the chief reason
for adopting this form of skew arch. It is usual to take the right line
direct or perpendicular to the openings, and symmetrical to them, that is to
say, passing through the middle point of the parallelogram of the springing
plane.
When the openings are not parallel the voussoir joints shown by the model
are deformed into hyberbolic paraboloids. This deformation is, however,
very slight, and in practical work would be avoided altogether by adhering to
tbe principle of drawing a plane througb the director line.
The opening of the voussoirs is usually determined by dividing the outer
semicircle into equal parts.
This form of arch is inconvenient when the obliquity and the length of
the barrel are excessive, for the generators are not generating lines of the
cylinder containing the opening semicircles, but chords of it, and, therefore,
at the middle, falling considerably inside it. The arch, therefore, droops in
the middle, and this would be ugly and inconvenient if the proportions were
excessive.
104. Staircase Vault for a square wall (vis St. Gilles carree).
105. Staircase Vault. Model for exhibiting some properties
of this ruled surface, by showing how it is obtained from the
deformation of a cylinder (douelle de la vis St. Gilles carree).
106. Cylinder with Helix and developable Helixoid.
The helix is simply a screw thread. The developable helixoid, shown by
the purple threads, is the surface swept out by the right line tangents of the
helix. If we consider that each gore can be turned a very little bit about
the thread which separates it from the next gore, we see that the surface can
be flattened out or developed into a plane, without any crumpling. This
happens because every two consecutive generating lines meet one another on
the helix. That is why its surface is called developable. Its section by a
horizontal plane is the involute of the circle.
The model allows the pitch of the helix to be shortened by lowering the
upper plate, and the cylinder can also be inclined. When oblique, however,
the curve which replaces the helix is not such a screw thread as can be turned
in the lathe.
III. MODELS. 29
107. Skew Helixoid.
This surface is described by a right line, which always passes through the
axis of a cylinder, and makes a constant angle with that axis. It also passes
through a helix or screw thread traced on the cylinder. The model only
shows the surface, not the cylinder. The section by a horizontal plane is the
spiral of Archimedes. It is the surface of what is known as the screw with
a triangular thread.
This is not the commonest form of the skew helixoid ; that is best seen on
the underside of a screw staircase, or on the driving face of a common screw-
propeller. In these, two generating lines are at right angles to the axis.
The surface may also be considered as generated by a line which makes a
constant angle with a given fixed line, and moves up that line, and at the
same time turns round it, at uniform rates.
108. Skew Surface with its tangent paraboloid, capable of
transformation into another skew surface while the paraboloid
deforms into a plane.
This is (for a certain position of the lower semicircle) a skew surface with
a director plane, the plane being vertical. The director carves are: one. of
them a circle divided equidistautly, the other a semicircle divided so as to
keep the strings parallel to the director plane.
109. Intersection of Two Cones having double contact
with one another, that is to say, having a pair of tangent planes
in common.
The consequence of their having double contact is that their curve of inter-
section breaks up into two plane ellipses.
The vertices of the cones slide along a rule which turns on a universal
joint. See also model No. 114.
110. Common Groin. Intersection of two cylinders having
a pair of common tangents. The model may be set square or
oblique.
111. Intersection of Two Cylinders, one piercing the
other so as to give two separate loops of intersection.
112. Intersection of Two Cylinders, having a common
tangent, so as to give a curve having a double point at the point
of contact.
113. Intersection of Two Cylinders, neither completely
piercing the other, so as to give only one loop of intersection.
114. Intersection of Two Cones, having double contact,
along a pair of plane ellipses.
115. Groin. Oblique intersection of two splayed vaults of the
same spring.
116. Pair of Intersecting Planes, which, by pulling the
brass ball so as to give simultaneous rotation to the two upper
rods, deform into paraboloids first, and then into planes described
by radiating strings.
30 SEC. 2. GEOMETRY.
117. Intersecting Cylinder and Plane. By pulling the
brass ball the head brasses rotate together, and the cylinder de-
forms into, first, a hyperboloid, and then a cone, while the plane
deforms into, first, a paraboloid, and then again into a plane with
radiating lines.
118. Fair of Intersecting Cylinders on circular bases.
By Dulling the brass ball the head brasses rotate together, and
the cylinders deform, first, into hyperboloids, and then into cones.
119. Pair of Intersecting Cylinders on irregular bases.
By pulling the brass ball the head brasses rotate together, and
the cylinders deform, becoming at last cones.
120. Groin.
Model showing the deformation of a common groin, both ob-
liquely, and by splaying the vaults. The model shows not only the
intersection, but the plans of the intersection and of the generating
lines.
121. Helix or Screw-thread.
Model showing the transformation of the right line genera-
tors of a right cylinder into screw threads of various pitch or
obliquity.
The pitch of a screw is the distance between two successive
turns, measured in a direction parallel to the axis. When this
distance is small, the screw is said to have a fine pitch ; when
great, a coarse or high pitch.
COLLECTION OF MODELS CONTRIBUTED BY THE LONDON
MATHEMATICAL SOCIETY.
123. Pliicker's Models (14) of certain quartic surfaces,
representing the equatorial form of complex surfaces.
London Mathematical Society.
At the meeting of the British Association at Nottingham, in 1866, Prof.
Pliicker read a paper on " Complexes of the Second Order." On this occasion
he showed a series of models constructed by Epkens, of Bonn, of which the
above are copies made for Dr. Hirst, and presented to the London Mathe-
matical Society.
The following is Prof. Cayley's description of the models, extracted from
Nos. 37 and 38 of the Mathematical Society's Proceedings, vol. iii., pp. 281-
285, supplemented by a description of models A, B, C, D, E, F, drawn up
by Prof. Henrici.
The Society possesses a series of 14 wooden models of surfaces, constructed
under the direction of the late Prof. Pliicker, in illustration of the theory
developed in his posthumous work " Neue Geometric des Raumes gegrvindet
" auf die Betrachtung der geraden Linie als Kaum-elemente," Leipzig, 1869.
III. MODELS. 31
These, all of them, represent, I believe, equatorial surfaces, viz., eight repre-
sent cases of the 78 forms of equatorial surfaces, " deren Breiten-Curven
" eine feste Axenrichtuug besitzen," vol. ii. pp. 352-363 ; the remaining
models, A, B, C, D, E, F, I have not completely identified. I propose to go
into the theory only so far as is required for the explanation of the models.
In a " complex," or triply infinite system of lines, there is, in any plane
whatever, a singly infinite system of lines enveloping a curve ; and if we
attend only to the curves the planes of which pass through a given fixed line,
the locus of these curves is a " complex surface." Similarly, there is through
any point whatever a single infinite series of lines generating a cone ; and if
we attend only to the cones which have their vertices in the given fixed line,
then the envelope of these cones is the same complex surface. In the case
considered of a complex of the second degree, the curves and cones are, each
of them, of the second order ; the fixed line is a double line on the surface,
so that (attending to the first mode of generation) the complete section by
any plane through the fixed line is made up of this line twice, and of a conic.
The surface is thus of the order 4 ; it is also of the class 4 ; the surface has,
in fact, the nodal line, and also 8 nodes (conical points), and we have thus
a reduction = 32 in the class of the surface.
In the particular case where the nodal line is at infinity, the complex
surface becomes an equatorial surface ; viz. (attending to the first mode of
generation), we have here a series of parallel planes each containing a conic,
and the locus of these conies is the equatorial surface.
It is convenient to remark that, taking a, b, //., to be homogeneous functions
of (r, w>) of the order 2 ; f, <jr, of the order 1 ; and c of the order (a constant) ;
then the equation of a complex surface is
y z 1 1=0;
y a h g
z k b f
1 9 f
and that, writing w?= 1, or considering a, h, b; f, y c, as functions of x of
the orders 2, 1, respectively, we have an equatorial surface.
A particular form of equatorial surface is thus, bcy~ + caz" + ab = Q, or
taking c= 1, this is fy/ 2 + a* 2 + a6 = 0, where a, b, are quadric functions of x.
The surface is still, in general, of the fourth order ; it may, however,
degenerate into a cubic surface, or even into a quadric surface ; the last case
is, however, excluded from the enumeration. The section by any plane
parallel to that of yz is a conic ; the section by the plane y = Q is made up of
the pair of lines a=0, and of the conic z 2 + &=0 ; that by the plane z=0 is
made up of the pair of lines 6 = 0, and of the conic ?/ 2 + a = ; the last-men-
tioned planes may be called the principal planes, and the conies contained in
them principal conies. The surface is thus the locus of a variable conic, the
plane of which is parallel to that of yz, and which has for its vertices the
intersections of its plane with the two pi'incipal conies respectively. And we
have thus the particular equatorial surfaces considered by Pliieker, vol. ii.
pp. 346-363 (as already mentioned), under the form
Ex- + 2U.r + C + For 2 2RrTl3 + l ''
and of which he enumerates 78 kinds, viz.: these are
1 to 17. Principal conies, each proper.
18 to 29. One of them a line-pair.
30 to 32. Each a line-pair.
33 to 39. Principal conies, each proper, but having a common point.
40 to 43. One of them a line-pair, its centre on the other principal conic.
44 to 61. One principal conic, a parabola.
32 SEC. 2. GEOMETKY.
62 to 73. One principal conic, a pair of parallel lines.
74 to 76. Principal conies, each a parabola.
77 and 78. Principal conies, one of them a parabola, the other a pair of
parallel lines.
Model 2. The form of the equation is here,
viz., the principal conies are one of them a hyperbola, the other imaginary ;
hence the generating conic has always two, and only two, real vertices, viz.,
it is always a hyperbola. There are no real lines.
Model 3. The form of the equation is
/ 2 [(;t- a) 2 + /8 2 ] 7 //2[(#_ a ')2 + 0/2-| ~
viz., the principal conies are each of them a hyperbola ; the generating conic
has four real vertices, viz., it is always an ellipse. There are no real lines.
Model 4. The form of the equation is
+ 1 = 0.
The principal conies are one of them an ellipse, the other imaginary ; for
values of x between y and 8, the variable conic has two real vertices, or it is
a hyperbola ; for any other values it is imaginary, so that the surface lies
wholly between the planes ^ = 7, a; = 5. The surface contains the real lines
y r=o, x = y, and y = Q, x = 5.
Model 9. The form of the equation is
/(*- 7 )(*-) + /' 2 (* /)<>- 80 +
where, say the values 7, 5, lie between the values y, 8', the principal conies
are each of them an ellipse, the vertices (on the axis or line ,y = 0, 2 = 0) of
the one ellipse lying between those of the other ellipse. The variable conic
for values of x between 7 and 5 has four real vertices, or it is an ellipse ; for
values beyond these limits, but within the limits 7', 8' say, from 7 to 7' and
from 8 to 8' there are two real vertices, or the conic is a hyperbola ; and
for values beyond the limits y, 8', the variable conic is imaginary.
There are four real lines (y = 0,z = y), (?/ = 0, x = 8), (z = Q, x = y r ), (2 = 0,
or = 8'). The surface consists of a central pillow-like portion, joined on by
two conical points to an upper portion, and by two conical points to an under
portion, the whole being included between the planes x = y, x = 8'.
Model 13. The form of the equation is
the values y, 8', lying between y, 8 ; the principal conies are one of them a
hyperbola, the other an ellipse, the vertices (on the axis or line z/ = 0, z = 0)
of the hyperbola lying between those of the ellipse. The variable conic, for
values of x between y f , 8', has two real vertices, or it is a hyperbola ; for
the values, say, from y to y, and 8' to 8, there are four real vertices, or
the conic is an ellipse ; for values beyond the limits y^ 8, there are two
real vertices, and the conic is a hyperbola. There are the four real lines
(# = 0, x=y\ (# = 0, x=8~), and (z=0, #=7'), (*=0, # = 8'). The surface
consists of eight portions joined to each other by eight conical points, but the
form can scarcely be explained by a description.
Model 32. The form of the equation is
r2
= 1
III. - MODELS. 33
riz.,the principal conies are each of them a line-pair, the variable conic is
always an ellipse.
There are the two real nodal lines (z/ = 0, #=7) and (2=0, #=/), each of
these being in the neighbourhood of the axis crunodal, and beyond certain
limits acnodal ; the surface is a scroll, being, in fact, the well-known surface
which is the boundary of a small circular pencil of rays obliquely reflected,
and consequently passing through two focal lines.
Model 34. The equation is
where x= Sis not intermediate between the values x=y and x=y ; say the
order is 8, 7, 7'. The surface is thus a cubic surface ; the principal conies
are ellipses, having on the axis a common vertex, at the point x=S, and the
remaining two vertices on the same side of the last-mentioned one. The
variable conic for values between 5 and 7 has four real vertices, or it is an
ellipse ; for values between 7 and 7' two real vertices, or it is a hyperbola ;
and for values beyond the limits 5, 7', it is imaginary. There are on the
surface the two real lines 0/ = 0, ^ = 7) and (z = 0, x = 7')- The surface
consists of a finite portion joined on by two conical points to the remaining
portion.
Model 40. The form of equation is
y 2 z 2
zV-7X*-5) + r*&=vy* +
The surface is thus a cubic surface ; the principal conies are, one of them
an ellipse, the other a pair of imaginary lines intersecting on the ellipse ; for
values of x between 7 and 5, the variable conic has thus two real vertices, and
it is a hyperbola ; for values beyond these limits it is imaginary, and the
whole surface is thus included between the planes #=7 and x=8. There are
the two real lines (y = 0, x = 7) and (2=0, x=5).
Taking / 2 =/ /2 = i } the surface is
y 2 2 2
Gr-7)(*-5) + (*=W 2 + l = (
which is a particular case of the parabolic cy elide.
The equatorial surfaces, not included in the preceding 78 cases, Pliicker
distinguishes (vol. ii. p. 363) as " gedrehte " or " tordirte," say, as twisted
equatorial surfaces, the equation of such a surface is
by 2 + 2hyz + az 2 + ab - A 2 =
where b = Fx 2 - 2R.r + B
A=K:r 2 Oar G (or in particular = O-r G).
Model A. is such a surface, being a twisted form of Model 9.
Model B. belongs to the case a = ; viz., the form of the equation is
The variable conic is a hyperbola, the direction of one of the asymptotes
being constant (vol. ii. p. 368).
There are, moreover, (p. 372) equatorial surfaces in which the variable conic
is always a parabola, and where there are on the surface four real or imaginary
singular lines.
In Model C the singular lines are all four real, but two of them coincide with
the nodal line at infinity. Consequently, the variable parabola has its axis in
a fixed direction. Its vertex moves along a hyperbola which has one asymp-
40075.
34 SEC. 2. GEOMETRY.
tote in that fixed direction. The other two singular lines are on opposite sides
of this asymptote and parallel to it. When the plane of the variable parabola
passes through one of these lines, the parameter vanishes and changes sign.
When it passes through the above-mentioned asymptote, the parabola, reduces
to the line at infinity and the plane becomes asymptotic to the surface. The
latter consists of four parts, two on opposite sides of the asymptotic plane
between this and one of the singular lines respectively, the other two extending
from the singular lines to infinity.
The remaining three models, D, E, F, represent twisted surfaces. Of the
four singular lines two are in each case imaginary. The remaining two are
real on the first, coincident on the second, and imaginary on the third.
Model D consists, therefore, of three, Model E of two, and Model F of one part.
The models are copies from some constructed by Epkens of Bonn. They
were presented to the London Mathematical Society by Dr. Hirst, F.ll.S.
They have been remounted under the direction of Prof. Henrici, by M. Nolet,
u student of University College, London.
Some account of complexes and complex surfaces will be found in Dr.
Salmon's Geometry of Three Dimensions (3rd edition, pp. 405, 493, 566, 570).
123a. Hough Model of Steiner's Surface.
Prof. Cayley.
Steiner's surface is the quartic surface represented by the equation
Vx+ \'y + Vz + \/w*=Q ; where the co-ordinates x, y, z, w, of a point are
proportional to arbitrary multiples of the perpendicular distances from four
given planes ; in the model, x, y, z, w are proportional to the perpendicular
distances from the faces of a regular tetrahedron, the co-ordinates being
positive for a point inside the tetrahedron.
The surface may be regarded as inscribed in the tetrahedron, touching each
face along the circle inscribed in the face. The general form is that of the
tetrahedron with its summits rounded off, and with the portions within the
inscribed circles scooped away down to the centre of the tetrahedron, in such
wise that the surface intersects itself along the lines drawn from the centre to
the mid-points of the sides (or, what is the same thing, the lines joining the
mid-points of opposite sides). The lines in question produced both ways to
infinity are nodal lines of the surface, but as regards the portions outside the
tetrahedron, they are acnodal lines, without any real sheet through them ; and
these portions of the lines are not represented in the model.
The sections by a plane parallel to a face of the tetrahedron are trinodal
quartics, which (as the position of the plane is varied) pass successively
through the forms :
1. Four acnodes.
2. Trigonoid, with three acnodes.
3. Tricuspidal.
4. Trifoliate, with three crunodes, cis-centric.
5. Do. with triple point at centre.
6. Do. with three crunodes, trans-centric.
7. Twice-repeated circle.
The three nodes are in each case the intersections of the plane by the nodal
lines, and the twice-repeated circle is the circle inscribed in the face of the
tetrahedron.
123b. Model of a Cubic Surface.
Prof. O. Henrici, F.R.S.
III. - MODELS. 35
The equation to this surface is xyz = k* (x + y + 2 I) 3 . There are 3 bi-
planar nodes as shown on the model. The 27 straight lines on the surface
are all real, but coincide 9 to each with the 3 black lines^ drawn on the model.
123c. Sylvester's Amphigenous Surface, a surface of
the ninth order. Prof. O. Henrici, F.R.S.
This surface is connected with the reality of the roots of equations of the
ninth degree.
123d. Model representing the Right Lines on a
Surface of the Third Class, having a tangent-plane touching
along a conic (the singularity dualistically corresponding to a
double-point of the second order).
Elling B. Hoist, Stipendiary of the University of
Christiania.
The model is composed of twenty-one wires, six of which, painted light
red, lie in the same plane and touch the conic in points painted dark red.
Through the fifteen points of intersection of these six lines the others,
painted white, pass, again intersecting three and three, and are the lines in
which the surface cuts itself. All points on these lines have therefore two
tangent-planes ; where the latter are imaginary the lines are black. The
black is in part laid on schematically, especially where the black part contains
the point at infinity. The parabolic curve consists of the conic aforesaid
and two species of cuspidal curves, viz. :
1. One curve passing the dark red points and having cusps in those six
limiting-points between black and white which are nearest to the conic, the
curve therefore having a zig-zag course.
2. Four closed branches having cusps in the other twelve limiting-points.
All these parabolic curves together separate ten distinct ellipsoidally
curved parts from the surface everywhere else hyperboloidally curved.
124. Models. A series illustrative of Pliicker's Researches
in Geometry of Three Dimensions. See explanation No. 123.
Prof. Hennessy, Dublin.
126. Model of the ruled cubic surface called the Cylindroid.
Dr. Robert S. Ball, LL.D., F.R.S.
This surface was discussed by Pliicker in connexion with the theory of
the linear-complex. The kinematical and physical significance of the sur-
face will be found in the "Theory of Screws." The equation of the surface
is z (x* + ?/ 2 ) '2mxy = O.
125. Diagrams (48) showing the Fundamental Principles
of the exhibitor's " Organic Geometry of Form."
Prof. Franz Tilser, Prague.
The above work demonstrates the necessity for a reform in geometry, and
furnishes the necessary basis for establishing a new system adapted to satisfy
the requirements of an exact science. To the above are added 7 " Paragram "
Tablets, representing in natural organic connexion a synopsis of the principal
elements to be observed in every graphical representation.
127. Models (6) illustrating the relative bases of Descriptive
Geometry and the Organic Geometry of Form.
Prof. Franz Tilser, Prague.
C 2
36 SEC. 2. GEOMETRY.
128. Drawings. A collection, executed by the Students of
the Bohemian Polytechnic Institute, illustrative of the instruction
received in the subject of Organic Geometry of Form.
Prof. Franz Tilscr, Prague.
129. Two specimens of Wire Stereometrical Models,
with letters on cork.
Prof. J. Joseph Oppcl, Frankfort-on- Maine.
ISO. Two specimens of Wire Trigonometrical Models,
with letters. Prof. J. Joseph Oppel, Frankfort-on- Maine.
131. Two specimens of Wooden Stereometrical Mo-
dels, with letters.
Prof. J. Joseph Oppel, Frankfort-on- Maine.
The auxiliary lines, diagonals, &c. are distinguished by wires of different
colours or thicknesses. They are in many cases movable, so that the perfect
figure can be constructed before the eyes of the pupil.
Auxiliary planes are also distinguished by their colour. The angular
points are provided with metal pins, to which letters on cork discs can be
attached, so as to be turned upright towards the observer.
These models have proved highly serviceable for instruction during the
past 20 years.
132. Large Model of an Ellipsoid, of white cardboard,
on a turned stand. Prof. Dr. A. Brill, Munich.
133. Cardboard Models of Surfaces of the second
order, on frames. Made up of circular sections. The sections
are attached to each other. Prof' Dr. A. Brill, Munich.
This collection of models consists of :
1. Ellipsoid having 20 circular sections.
2. Ellipsoid having 30 circular sections.
3. Hyperboloid of one sheet.
4. Hyperboloid of two sheets.
5. Elliptic Paraboloid.
6. Cone in two sheets.
7. Hyperbolic Paraboloid.
141. Series of Cardboard Models of Surfaces, of the
second order, in a cardboard box. The sections are not
attached to each other. Prof. Dr. A. Brill, Munich.
These models, Nos. 132, 133, 141, are distinguished from those in common
use by their mobility, by means of which each one represents not only a single
ellipsoid or hyperboloid, but a series of surfaces of one or the other kind.
For when the angle of inclination of the circular sections is altered, in a direc-
tion easily recognised by pressing or drawing out the model, there will be
obtained a simple but infinite system, the individual forms of which can be
converted from a flat figure through gradually-changing solid bodies to just
such another figure with a different relation of axes, without, however, losing
its properties.
III. MODELS. 37
The equations representing these systems of surfaces are in rectangular
co-ordinates :
For central surfaces :
^ . v 2 /I 1\ . * 2
a 2 cos-V \a hi ksm^
For the elliptic paraboloid :
For the hyperbolic paraboloid :
a 2 cos 2 ^ ~ a^in 2 ^ ~ It =
WTiere 2^ is the inclination of the circular sections, and a and k are real con-
stants. From the first equation it appears that among the series of ellipsoids
there will always be a sphere.
142. Model of a Surface of the third order, made in
plaster of Paris, with 27 real right lines.
Prof. Dr. Christian Wiener, Carlsruhe.
The construction of the model is described on a placard fixed to the model.
143. Model of the same surface of the third order,
in discs of card-board, with 27 real right lines.
Prof. Dr. Christian Wiener, Carlsruhe.
144. Poinsot's Star Polyhedra. Dr. M. Doll, Carlsruhe.
These models show the star dodecahedron with 20 points, the star dode-
cahedron with 12 points, the icosahedron, and dodecahedron.
148. Curvilinear central surface of the Ellipsoid, in
four separate pieces. Proportions of the axes of the ellipsoid,
3:4:5. Ludwig Lohde, Berlin.
149. Dupin's Cyclide, according to the calculation of Pro-
fessor Kummer, at Berlin. Model 0*094 m. diameter.
(Sec Monatsbericht der Akademie der Wissenschaf ten zu Berlin,
1863, pp. 328 and 336.) Ludwig Lohde, Berlin.
150. Hummer's Cyclide. Ludwig Lohde, Berlin.
151. Minimum-surface in a recurring number of tetra-
hedral surfaces.
(Submitted to the Berlin Academy of Sciences by Professor
Kummer, on the 6th April 1865.) Ludwig Lohde, Berlin.
152. Maximum of Attraction of the Earth's Surface.
Ludwig Lohde, Berlin.
153. Geometric Body, executed in plaster of Paris, called
"Podoid"; a transcendental curved surface, which Js deter-
mined by the variable parallel co-ordinates p., <j>, and K, whose
equation represents the elliptic function
f* ^
38 SEC. 2. GEOMETRY.
The construction in plaster of Paris embraces the limits
K= -f 1 to K= 1 and <p0 to <=7r.
Prof. Dr. Edward Heis, Munster, Westphalia.
154. The same Fodoid 9 executed on a smaller scale, embracing
the limits K= + ! to K= l, 0>=0 to <p=2v.
Prof. Dr. Edward ffeis, Miinster, Westphalia.
155. Hight double circular Cone, of white wood.
Prof. Borchardt, Berlin.
On the one sheet of the double cone 'are shown, by sections, the circle,
the ellipse, and the hyperbola ; on the other, the circle, the parabola, and
the corresponding hyperbola. The model takes to pieces at the sections.
156. Elliptic Cone, of white and brown wood.
Prof. Borchardt, Berlin.
On the oblique cone are shown the two circular sections, and the elliptic,
hyperbolic, and parabolic sections. At the sections of the ellipse and parabola
the model takes to pieces ; the other sections are shown by the lines defined
by the dark and light wood.
157. Huled Surface of the fourth degree.
Prof. Borcha.rdt, Berlin.
This model represents a surface of the fourth order determined by the
equation
3* 2 8g =1
(2-0)2 ( + o) 2
The surface has two double right lines, between which lies a finite sheet
of the surface as shown on the model, whilst beyond each double right line
there extends a. second and third infinite sheet of the surface. Every hori-
zontal section of the surface is an ellipse. Of these are shown the circular
section corresponding to zQ, and the two ellipses corresponding to z = a
The model can be taken to pieces at each of these sections.
158. Bectangular Parallelepiped, intersected by a skew
surface. Prof. Borchardf, Berlin.
159. Bight Circular Cylinder, with spiral surface inter-
secting it. Prof Borchardf, Berlin.
These five models, Nos. 155-159, were executed by the late Ferd. Engel,
known from the drawings, which he has furnished to Pro/. Schellbach's
" Darstellende Optik."
160. String Model, representing a hyperboloid of one sheet.
On it are shown the principal ellipse, the asymptotic cone, and a
tangential surface, in threads of different colours.
Dr. Wiccke, Casscl.
This model represents by means of strings (kept tight by springs) of
different colours the hyperboloid of one sheet and its principal auxiliary-
surfaces. The two sides of the surface are shown by the green and red strings
respectively ; the principal ellipse is given by the points at which the strings
pass through the network stretched on the frame ; the asymptotic cone is
shown by yellow, and a tangent plane by white strings.
IV. DRAWINGS. 39
161. Model iii plaster of Vans, representing the eighth part
of the former (No. 160) with a developable normal surface, lines of
curvature, and edge of regression. Dr. Wiccke, Cassel.
This plaster model represents the eighth part of the surface of an hyper-
bolokl of one sheet ; it is constructed on the principal ellipse, and shows
the principal axes. It is also attempted to demonstrate on this hyperboloid
the lines of curvature of the first and second kind, first investigated byMonge.
On this account the hyperboloid is bounded on the side opposite to the
principal ellipse by a normal surface of which the directrix is one of the
lines of curvature of the first kind. The normals are drawn in this normal
surface, and produced to meet in the edge of regression,' which with two of the
normals will then become the boundaries of the normal surface.
161a. Collection of 45 geometrical solids in cut crystal, for
purposes of demonstration. Madame Wentzel.
162. Intuitive Method of Projection, by movable planes.
Cardboard models (19), practically illustrating problems of space.
Frerc Memoir e Piron.
162a. Open Frames containing Photographs for teaching
by projection. J. and A. Molteni, Paris.
162b. Projection Apparatus, polyorama for superposed
images. J. and A. Molteni, Paris.
IV. REPRESENTATION OF FIGURES IN SPACE BY
MEANS OF DRAWINGS ON A PLANE.
163. Diagrams and Models, illustrative of Descriptive
Geometry, executed by the Freres de la Doctrine Chretienne, of
Paris. Prof. Piaot, Dublin.
164. Drawings, executed in the college by the students,
showing the nature of the courses of Descriptive Geometry
and engineering. Prof. Pigot, Dublin.
165. Specimens of a series of simple folding models for
illustrating the various propositions in Descriptive Geometry.
Prof. Osborne Reynolds.
These are specimens of a series of models designed for illustrating the
various propositions in descriptive geometry. They are especially designed
for lecturing purposes, for which their simple construction, and the capability
which they possess of folding into small compass, well adapts them.
These models contain a complete drawing for each proposition. The hori-
zontal and vertical planes are hinged together, so that they can be folded
40 SEC. 2. GEOMETRY.
flat, and the Hues, planes, and surfaces are represented by coloured strings,
which assume their positions when the planes are at right angles.
1. Illustrating the relation between the projections, traces, directions, and
lengths of straight lines.
2. Illustrating the relation between the traces of planes, their inclinations,
and intersections.
3. Illustrating the relation between the projections of a line and the traces
of a plane ; also the normal to a plane.
4. Illustrating the relation between the projections of lines and the angles
between them.
5. Illustrating the relation between the traces of a cone and the traces of
its tangent plane, and hence the method of drawing a plane having a
given inclination.
6. Model, capable of opening out flat, so as to show how the horizontal and
vertical planes may be represented on a drawing^
166. Stereoscopic Figures, for demonstration and use in
the study of stereometry and spherical irigonometry. Edited
by Julius Schlotke. L. Friederichsen and Co., Hamburg.
166a. Stereograms of the Lines of Curvature of
Surfaces. Drawn by the exhibitor. Prof. J. Clerk Maxwell.
Lines of curvature of the cy elide of Dupiu (4).
Curves on a sphere (4) :
a Two systems of orthogonal circles.
/J Concyclic spherical ellipses. (This represents a spherical har-
monic of the second degree.)
7 Confocal spherical ellipses.
5 The projections of a spherical ellipse on the three principal
planes.
Quadric surfaces (4) :
Elliptic paraboloid, hyperbolic paraboloid, ellipsoid, and the surface
of centres of ellipsoid.
FresnePs wave surface (3):
The lines are in the direction of the vibrations of the two polarized
rays.
Steiner's surface (2).
Twisted cubics (2) :
tx a sin 26 (vertical).
Curves y = b sin 30 (horizontal).
[ z = c cos 50 (perpendicular to paper).
f x a sin 29.
\ y b sii
Curve < y = b sin 30.
[2 = c sin 70.
Icosahedrou in octahedron.
22 in all.
166b. Heal Image Stereoscope for showing the above.
Prof. "Clerk Maxwell.
The observer places his eyes about two feet from the large lens, and sees
the united real images of the figures at or near the surface of the lens.
IV. DRAWINGS. 41
167. The principal Problems of Descriptive Geo-
metry, represented by stereoscopic figures, by Julius Schlotke.
L. Friederichscn and Co., Hamburg.
168. Stereoscopic representation of a number of the most
important crystals, their combinations, &c., by Julius Schlotke.
L. Friederichsen and Co., Hamburg.
f? The stereoscopic figures of Schlotke are as yet the only ones of their kind
in use for illustrating instruction in descriptive geometry and crystallography,
in polytechnic and other higher educational institutions, where they are much
appreciated.
More particularly the division of crystallography is recommended, as it
renders unnecessary the usual expensive models, and, better than those
models, demonstrates the combinations and growth of crystals.
A stereoscopic apparatus is placed near the objects.
42
SECTION 3. MEASUREMENT.
WEST GALLERY, GROUND FLOOR, ROOMS H. K.
ISPECIAL COLLECTIONS.
COLLECTION OF STANDARD MEASURING APPARATUS CONTRIBUTED
BY THE STANDARDS DEPARTMENT OF THE BOARD OF TRADE.
A. Comparing Apparatus, Sf-c.for Standard Weights and
Measures.
169. Comparing Apparatus for End-Standards of length.
Used by Mr. Sheepshanks in the work of the Commission for
Restoration of the Imperial Standards, 1844-1850. Constructed by
Troughton and Simms.
The standard, and compared end-bars are placed successively on the V
supports, with one defining end in contact with the left hand stud and the
other defining end with the suspended gravity-piece interposed between it
and the screw on the right hand. The micrometer screw is to be gently
pressed forward until it just holds up the gravity piece in position, thus
ensuring constant pressure for each observation. The readings of the micro-
meter being taken, the difference of the two readings shows the difference in
length of the two end bars to less than O'OOOl inch, which is the value of
one division of the micrometer.
To obtain results with scientific precision the temperature of the measuring
axis of each bar during the comparison should be known, as well as its rate of
expansion. The temperature and length of the bar connecting the stud and
gravity piece and of the metal of the apparatus should also be constant.
170. Two Lever Frames, with rollers for supporting stand-
ard bars. Such lever frames are used for supporting all the Im-
perial Standard yards made by the Commission for restoring the
Standards. Constructed by Troughton and Simms.
Each bar is supported on the eight rollers of the two lever-frames, which
are placed symmetrically under the bar, so that the upward pressure of each
of the eight different rollers is necessarily equal, and the length between the
defining points of the bar is not altered by its flexure. Equal intervals of
length of bar
supports = . > where n is the number of supports.
171. Double Micrometer Microscope for comparing the
smaller subdivisions of standards of length. Constructed by
Troughton and Simms.
It has a movable eye-piece with a double lens, sliding upon a horizontal
plate, and two micrometers ; and has two object-glasses, each with a double
I. SPECIAL COLLECTIONS. 43
lens, sliding on a horizontal plate parallel to the other plate. The measuring
field is about two centimetres in extent, or a little less than 1 inch. Value
of one division of each micrometer = '00003097 inch, or 0'0007866 milli-
metres.
172. Apparatus for determining the Expansion of
Standard Bars. Constructed by Troughton and Simms.
The trough containing the steel bar with projecting points, distant 1 yard
and 1 metre respectively, is filled with melting ice to secure constant length
at the temperature of C. The standard bar is placed in the lower trough,
with two standard thermometers, and is raised gently against the points. Their
impression shows the constant length on the bar at its noted temperature in
ordinary air. Next fill the lower trough with melting ice, and take impressions
to show the constant length on the bar when at C. Then fill the lower
trough with water, and raise to boiling point, or other less high temperature,
by the heat from the gas jets underneath, and take impressions to show the
constant length on the bar when at 100 C., &c. From the difference of
these lengths accurately measured under micrometer microscopes, the rate of
expansion of the bar is deduced.
173. Large Callipers for measuring diameter and depth of
cylindrical or other measures. Constructed by Troughton and
Simms.
These are made on the same principle as the instruments used for measuring
shot and the bore of guns at Woolwich. They measure diameters up to
24 inches and within O'OOl inch by the aid of a vernier.
174. Model of Sub-divided Yard with comparing appa-
ratus, for Ihe use of local inspectors of weights and measures.
Constructed by Troughton and Simms.
The tested yard measure is placed with its zero defining line immediately
under that of the standard. By running the eye-piece along the upper guide
bar, each defining line is accurately compared and differences determined to
less than O'Ol inch by means of the small supplementary sub-divided inch
measure placed also under the eye-piece. This apparatus is described and
illustrated in Appendix III., 7th Annual Report of Warden of the Standards,
1873.
175. Spherometer for measuring spherical curves, with true
gun-metal plane. Used for measuring the flexure of the middle
of the glass disc placed upon the Imperial Standard bushel. Con-
structed by Troughton and Simms.
When the horizontal plane is made to rest with its three triangular flattened
points upon the true plane, the central screw with its micrometer head is
accurately adjusted in the same plane, and its reading noted. By substituting
for the plane the surface to be tested, its convexity or concavity is determined
from the difference of the reading of the micrometer, either or +. Value
of one revolution of the screw = 0' 01 inch, and of one division of the mi-
crometer=0 % 0001 inch. By interposing a bright beam of light between the
point of the screw and the surface tested, and by estimation of 0' 1 division,
accurate measurements have been made to 0' 00001 inch. This instrument
is described in Appendix X., 6th Annual Report of Warden of the Standards,
1872.
44 SEC. 3. MEASUREMENT.
176. Cathetometer for vertical measurements. Constructed
by Troughton and Simms.
For example, for accurately reading a barometer or manometer: place
the cathetometer at a convenient distance, and adjust the cross wire of the
upper telescope to the level of the mercury in the glass tube, and that of the
lower telescope to the level of the mercury in the reservoir. The difference
of the two readings on the graduated scale of 42 inches gives the length of
the column of mercury to 0' 001 inch, by aid of the vernier.
177. Stereometer for ascertaining the density of bodies by
determining their volume. Constructed by Troughton and Simms.
This instrument was invented by M. Say ( Annales de Chimie,t. xxiii. p. 1 ,1 797),
for determining the specific gravity of gunpowder, and was used with some
improvements by Professor W. H. Miller (See Phil. Trans. 1856, part hi. p. 800.)
for determining the density of the platinum Kilogramme des Archives, during
his work of restoring the imperial standard pound. The solid body tested is
placed in the receiver communicating with the upper end of a vertical glass
tube, the lower end of which communicates with that of a second glass tube
having its upper end open to the air. The body should nearly fill the receiver,
which is screwed up air-tight in its place. Mercury is poured into the second
tube, and can be discharged by a stopcock at its lower end. Differences in
the relative height of the mercury in the two tubes are noted by means of the
cathetometer, as indicating the volume of compressed air under the two condi-
tions, when the body is in the receiver and when it is removed. The volume
of the body is deduced from the volume, of the mercury contained in the
tube between the different heights noted.
178. Balance of new construction oscillating with steel
springs. This has been recently constructed by Oertling from a
design of Mr. Ar tings tall.
Its principle is, that, instead of the beam and pans being suspended on
knife-edges, thin elastic steel springs are used, and adjustments of knife
edges from time to time are thus avoided. It is similar in construction to
Steinheil's silk ribbon balance. Its advantages as a balance for weighings,
where extreme scientific accuracy is not required, consist in its simplicity and
durability ; but it appears to be wanting in the sensibility and stability re-
quisite for a balance of precision.
179. Model Kit of Apparatus for Local Inspectors of
Weights and Measures. Constructed by Oertling.
This portable collection of all the necessary apparatus for comparing
imperial weights and measures has been taken from the Necessaire des
Verificaleurs, employed in France for verifying metric weights and measures,
with a view to its adoption in this country. It includes a Septimal Balance
by means of which a weight of 56 Ibs. is compared against 8 Ibs., the sum of
the standard weights contained in the kit.
ISO. Experimental Gasholder for determining the internal
temperature. Constructed by Messrs. Wright & Co.
By raising and lowering the bulb of the thermometers, the tubes of which
are made to slide through the top of the gasholder, the temperature of the
gas or air at various heights inside the bell can be read off through the glass
side, and the mean temperature determined.
I. SPECIAL COLLECTIONS. 45
181. King's Pressure Gauge, showing mechanical pressure
of gas or air. Constructed by Mr. Sugg.
Standards Department, Board of Trade.
The amount of the mechanical pressure of gas or air contained in a gas-
holder is shown by this pressure gauge, when it is put in communication
with the gasholder by an air-tight tube. The surface of the water in the
cistern of the pressure gauge is depressed by the force of the gas or air, and
alters the level of a metal cup floating on it. A cord is attached to the float,
and passes over a pulley, the spindle of which, aided by friction rollers,
carries a pointer moving on a graduated dial, and thus indicates the amount
of pressure in huudredths of an inch.
Specimens of Standard Weights and Measures.
182. Copy of Standard Weight, 112 Ibs., of Queen
Elizabeth.
One of two similar bronze weights deposited in one of the old Treasuries of
the Exchequer, and fully described in App. IV. to the 7th Annual Report of
the Warden of the Standards.
183. Gilt Steel Yard, line measure, of the same form as the
imperial standard yard. Constructed by Troughton and Simms.
Well-holes are cut down to the mid-depth of the bar, where the defining
lines are cut upon gold studs, thus ( V ! ; i the measure being taken
at the middle portion of the central transverse line, intercepted between the
two longitudinal lines. These lines, including the two transverse guide lines,
one on each side of the defining Hue, are 0*01 inch apart.
184. Steel Yard End Measure, showing the form of end-
standard yard adopted by the Standards Commission. Con-
structed by Troughton and Simms.
The form of the defining ends is that of a spherical surface, whose centre is
the centre of the division-line at the middle of the bar's length. The material
of the defining end is a highly polished plug of agate, shrunk into a slightly
conical hole at the end of the steel bar.
185. Steel Foot End-Measure. Constructed by Troughton
and Simms.
186. Two Steel 6-inch End-Measures, one finished and
one unfinished. Constructed by Troughton and Simms.
187. lO-Poot Measuring Rod, of pine wood, bound with
brass. Constructed by Troughton and Simms.
188. 3-Foot Measuring Bod, of pine wood, bound with
brass. Constructed by Troughton and Simms.
46 SEC. 3. MEASUREMENT.
189. 1 Ib. Avoirdupois Weight, of gun-metal, electro-
plated with nickel.
Constructed as an experiment of coating brass or bronze with unoxidisable
metal. Oxidation, however, is found to occur at points on the surface of the
bronze under the nickel coating.
190. 1 Kilogram Weight, of gun-metal, nickel-plated.
191. Set of Glass Avoirdupois Weights, from 7 Ibs. to
1 oz ; , made experimentally of green bottle glass, not subject to
hydroscopic influences. The larger weights adjusted with lead
shot.
192. Set of Metric Weights, from 1,000 grammes to
] gramme. Constructed by Salleron, Paris, of opaque glass,
adjusted with mercury to the density of brass weights, and her-
metically sealed.
193. Specimen of an Enamelled Iron Weight of
56 Ibs*, made to resist oxidation, by De Grave, Short, and Co.
194. Specimen of a Patent Brass-cased Iron Weight
of 14 Ibs.
195. Section of a Patent Brass-cased Iron Weight
of 14 Ibs., showing mode of construction.
196. Copy of Standard Cubic Foot nickel-plated, with
filling apparatus. Constructed by G. Glover & Co.
This is a copy of the standard cubic foot bottle, the primary unit from which
the gas-measuring standards were derived. It was verified by weighing its con-
tents of distilled water = 62'321 pounds avoirdupois, according to Sir G. Shuck-
burgh's determination of the weight of a cubic inch of water. It is used as a
direct transferrer of a cubic foot of gas or air, which is driven out from it
by raising the cistern and thus introducing water from underneath up to the
defining line of a cubic foot. By this arrangement, the nearly undisturbed
surface of the water is carried upwards and gradually through the entire
height of the bottle, without risk of forming air bubbles.
197. Copy of five cubic feet Gas-measuring Standard,
made of anti-corrosive metal, by G. Glover and Co., with scale of
capacity graduated in feet and minute fractional parts.
The bell is equipoised when at various depths of its immersion in the water
of the cistern by a balance, a portion of which hangs from a cord working in
a groove in the circumference of a cycloidal wheel, and attached to the axis
of the wheel from which the bell is suspended.
198. Copy of a Standard Test Dry Gas Meter, with
testing table. Constructed by G. Glover & Co.
Such test gas meters are authorised to be used for testing stationary meters,
where the larger gas measuring standards cannot conveniently be used. The
accompanying testing table shows it fitted with thermometers and pressure
gauges, and with stand pipes for outlet and inlet communications.
I. SPECIAL COLLECTIONS. 47
199. Model of a Petroleum Testing Apparatus, for ascer-
taining the temperature at which its inflammable vapour ignites.
Designed by T. W. Keates, Ksq., and proposed as a standard for use
in accordance with authoritative uniform regulations. Constructed
by How & Co.
200. Brass Scale of 41 inches, divided into tenths, and of a
metre divided into millimetres ; both scales at 62 Fahr. Con-
structed by Dollond, tind now the property of Mr. Petrie.
This possesses some scientific interest, having been compared several times
with Shuckburgh's scale by Capt. Kater. He found in 1830, and again in
1831, that 36 inches of the scale = 35' 99893 inches of the imperial
standard yard, afterwards destroyed in 1834; and assuming the scale of
inches to be perfectly correct, that the metre = 39 '37045 inches.
Compared at the Standards Office in February 187 6, with the bronze official
yard, which has a standard metre at C. marked on the same bar. From the
mean of six comparisons, 36 inches of the scale = 35 '99961 inches of the
new imperial standard yard, and the metre = 0*999684 metre, being 0'316
millimetre less than the Metre, dcs Archives at the normal temperature
of C.
223b. Fraudulent Balance, seized from a butcher's shop
by an inspector of weights and measures.
Standards Department, Board of Trade.
An illustration of the principle of the balance. One of the suspending
hooks of an ordinary equal-armed balance is bent outwards thus lengthening
that arm of the beam, and enabling the butcher to make about 14 oz. of meat
counterbalance a 1 Ib. weight on the other end of the beam.
SET OF OLD STANDARD MEASURES LENT BY THE MAYOR AND
CORPORATION OF THE CITY OF WINCHESTER.
201. Very old Steelyard Weight, date unknown. Found
at Hyde Abbey, Winchester.
202. Set of Standard Troy Weights, from 256 oz. to
1 oz., of Queen Elizabeth. Dated 1588, being the year in which
she granted a charter to the city.
203. Set of Standard Weights (avoirdupois), 56 Ibs., 7 Ibs.,
8 Ibs., 2 Ibs., 1 Ib., of Queen Elizabeth, dated 1588, being the year
in which she granted a charter to the city. From the Muniment
Room, Winchester.
204. Standard Weights (56 Ibs., 28 Ibs., 14 Ibs., and 7 Ibs.).
Supposed to be of the date of Edward III. From the Muniment
Room, Winchester.
205. Standard Yard Measure. Henry VII. From the
Muniment Room, Winchester.
206. Standard Quart and Pint of William III. Dated
1700. From the Muniment Room, Winchester.
48 SEC. 3. - MEASUREMENT.
207. Standard Gallon, Quart, and Pint of Queen
Elizabeth, dated 1601. From the Muniment Room, Winchester.
208. Standard Winchester Bushel, given to the Cor-
poration by Henry VII. in the year 1487.
209. Standard Winchester Gallon, given to the Cor-
poration by Henry VII., in the year 1487.
SET OF MEASURING INSTRUMENTS CONTRIBUTED BY SIR J. WHIT-
WORTH, BART., D.C.L., F.R.S.
217. True Planes. The true plane is the foundation and
source of all truth in mechanism.
The patent hexagonal surface plate is constructed so as to be supported and
suspended from three points, and remains true in either position. The original
true planes first exhibited by Sir Joseph Whitworth at the meeting of the
British Association at Glasgow, in 1840, were rectangular, and were ribbed,
so as to allow of their being supported on three points ; but when large rect-
angular surface plates were suspended from the two handles a perceptible
alteration took place, and they were no longer as true as when supported on
the three points.
212. Whitworth's Workshop Measuring Machine, for
making difference gauges from correct cylindrical standards of
size.
One division of the micrometer wheel represents l6 ^ 00 of an inch, one
quarter of a division, viz., ?0 -^ 00 of an inch can be distinctly felt and gauged.
No proper size of bearing can be made for an axle to work in without
having a difference gauge of such size as experience has proved to be best.
214. External and Internal Standard Cylinder Gauge,
1 inch in diameter.
The standard gauges are usually made from y^th to 2 inches diameter, but
they are also made for larger diameters.
They are a necessary adjunct to the workshop measuring machine when
making difference gauges.
21O. Box of Standard Lengths, of end measure, 1 inch to
12 inches.
Either these standard lengths of end measure or the cylindrical standard
gauges are used for adjusting the workshop measuring machine ; for large
dimensions these are preferable.
213. Box of Cylindrical External and Internal Dif-
ference Gauges, differing by ^Vo^ 1 of an inch in diameter.
By means of these a workman can feel his way step by step and so make
the bore of any number of barrels or tubes exactly the same diameter. They
illustrate the importance of small differences in size ; while one fits, another
3-jJ;-^ of an inch less in diameter appears not to fit at all.
A tight fit is not a proper fit, there must be a certain difference in diameter
between an axle and the bearing in which it has to work ; what the difference
should be depends on a variety of circumstances which experience alone can
determine.
I. SPECIAL COLLECTIONS. 49
213a. Ten Standard Plat Surface Gauges, from ^th of
an inch to T ^th of an inch varying xoV^th of an inch.
They are standards for the thickness of sheet metal and the diameter of
small wire ; they serve for the correction of the wire gauge.
t Cylindrical standards are not made less than -j\jth of an inch in diameter.
216. Standard Screw Gauge of Whit worth thread.
This gauge is to show the form of the Whitworth standard thread. The
two cylindrical parts give the exact diameter of the top and the bottom of
the screw threads in universal use ; and the angle of the thread is 55, and
is rounded off th of its depth.
211. Millionth Measuring Machine.
The screw of this machine has 20 threads to the inch, the screw wheel 200
teeth, and the micrometer wheel is divided into 250, therefore each division
represents the one-millionth of an inch.
TJie end of the fast headstock and the end of the movable headstock are
true planes parallel to each other ; the ends of the piece to be measured
must also be parallel true planes ; the feeling piece is a piece of steel about
T %ths thick, its sides being parallel true planes, and it is introduced between
the standard to be measured and the true plane at the end of the fast head-
stock ; when the proper adjustment has been made the movement of the
micrometer wheel one division, viz., one millionth of an inch, will cause the
feeling piece to be suspended friction overcoming gravity.
The power of measurement and the true plane are the two great elements
in practical mechanics.
An idea may be formed of the millionth of an inch, from the fact that
if a sheet of foreign letter paper were divided into 4,000 thicknesses, each
thickness would represent the millionth of an inch.
APPARATUS USED BY DR. JOULE, F.R.S., FOR ASCERTAINING THE
MECHANICAL EQUIVALENT OF HEAT.
218. Revolving Electro-magnet, used in 1843 for ascer-
taining the Mechanical equivalent of Heat.
Part of the apparatus used in 1843 for the determination of the mechanical
equivalent of heat : viz., a revolving piece, holding a glass tube filled with
water, and containing an electro-magnet. This worked between the poles of
a powerful magnet ; and the heat evolved by the rotating electro-magnet was
measured by the rise of temperature of the water. In this manner the quan-
tity of heat lost by the circuit was ascertained when the machine worked as
an engine ; and, on the other hand, the quantity of heat produced when work
was done on the machine was also measured. 833 ft. Ibs. was the mechanical
equivalent of a degree Fahr. in 1 Ib. of water, as determined by these first
experiments.
219. Calorimeter, containing a revolving agitator. This
was employed in the experiments on the heat evolved by the
friction of water, made in 1849. The equivalent arrived at was
772 ft. Ib.
40075. D
50 SEC. 3. MEASUREMENT.
220. Cast-iron Vessel, containing Friction Disk, to
revolve under mercury. Used in 1 849 to determine the mecha-
nical equivalent of heat by the, friction of cast-iron against cast-
iron. The equivalent arrived at was 775 ft. Ib.
221. Electro-magnet consisting of a broad plate" of half-
inch iron, .having a bundle of copper wires coiled round it. Em-
ployed in the first determination of the mechanical equivalent of
heat.
222. Apparatus for determining the temperature of water
at its maximum density.
Used in the experiments on atomic volume and specific gravity by Play fair
and Joule (Memoirs of the Chemical Society, vol. iii., 1846). It consists of
two tall vessels, connected together by a stop-cock at the bottom, and a trough
at the top. A minute difference of the temperature of the water in one of the
vessels from that of the maximum density, determines a flow through the
trough to the vessel still nearer the temperature of maximum density.
The temperature of water at maximum density was thus shown to be 39 1 .
223. Paddle Apparatus, by means of which Dr. Joule
determined the dynamical equivalent of heat. Described in Philo-
sophical Transactions for 1850. page 65. Sir William Thomson.
II. MEASUREMENT OF LENGTH.
A, STANDARD SCALES.
223a. Model of an Ancient Egyptian Standard Cubit,
dated in the reign of King H^rus, 9th Pharaoh of the 18th dynasty
(1657 B.C.). Mrs. Chisholm.
The ancient standard measure, of which this is a copy, was found in the
ruins of Memphis, and is now in the Royal Museum at Turin. It is a Royal
cubit of seven palms : or 28 digits. The total length of this end standard
measure is 523 5 millimetres or 20 6 inches, and agrees very nearly with that
of several other ancient Pharaonic cubits still existing, as well as with the
length of the Royal cubit as deduced by Sir Isaac Newton from the dimensions
of the Great Pyramid, the mean length being 525 millimetres. The original
natural cubit, or cubit of a man, of 6 palms is also marked upon this measure,
being equal to 463 millimetres or 18-24 inches, and also the ancient Egyptian
foot of 16 digits, or f of the natural cubit, and equal to 12' 16 inches, or 1-013
English foot. The great span of 14 digits and the small span of 12 digits are
also marked.
227. Standard Scale , in porcelain, showing the relations of
modern British and ancient Great Pyramid inches.
Prof. Piazzi Smyth.
This scale was prepared to order by M. Casella, of London. It exhibits
side by side 25 modern British inches and the same number of ancient Great
Pyramid inches, similarly subdivided.
II. LENGTH. 51
The .0 divisions of both sets of inches coincide at the left hand exactly,
but from thence the gradual growth of the difference of 0*001 of an inch per
inch in favour of the Great Pyramid scale may be traced, until at the 25th
inch the difference amounts to 0-025 of the British inch. At that point,
however, it is to be noted that 25 Great Pyramid inches are just one 10
millionth of the earth's semi-axis of rotation, or the nearest earth commensur-
able and most scientific unit ever yet proposed as a standard of length.
228. Standard rive-Inch Scale, in smoky agate, for micro-
scope sight. Prof' Piazzi Smyth.
The material, which came from Brazil, and was worked up and divided
to order by M. Jules Salleron, Paris, was chosen as being a natural product
of almost infinite age, and therefore settled condition, harder than steel and
utterly unoxidisable. The particular standard length adopted is shown for
microscopic sight. It depends not on one pair only, but on 20 available pairs
- of lines, each five inches apart, drawn with a fine diamond point, and is in-
tended to typify both one fifth of the sacred cubit of Israel and one 50
millionth of the earth's semi-axis of rotation.
229. Standard Five-Inch Scale, in white chalcedony, for
microscope sight. Prof. Piazzi Smyth.
This material, which came out of some ancient Roman palace, is chosen
for the same reasons as that last described. The scale is divided on the same
system.
230. Standard Five-Inch Scale, in red porphyry, for
microscope sight. Prof. Piazzi Smyth.
This material came from an Imperial Roman palace to which it had been
taken under the Caesars from some far more ancient Egyptian temple. It was
originally quarried by the Egyptians of 3,500 years ago in the rich porphyry
district between Thebes and the Red Sea, and it has been adopted for the same
reasons as the preceding examples, and the scale is divided on the same
system.
232. Standard of Length, derived from the earth's polar
axis, which is unique and common to all terrestrial meridians.
Prof. Hennessy.
This standard, proposed by Professor Hennessy, is a bronze bar, which, at
15 of temperature centigrade, is equal to the fifty millionth part of the
earth's axis.
233. Steel Chain, of fifty links, whose total length is the
millionth part of the earth's axis, or very nearly 500*5 English
inches. It is nearly equal to the half chain of two perches in Irish
plantation measure. Prof. Hennessy.
235. Standard Yard Measure, German Silver, with one
chamfer divided to inches and lOths, for temperature 60 Fahr.
Elliott Brothers.
239. Steel Tape Measure, 66 ft. For testing tapes, divided
to feet and inches on one side and links on the other.
Elliott Brothers.
D 2
52 SEC. 3. MEASUREMENT.
247. Measure of Length, according to natural principles.
Hans Baumgartner, Basle.
250. Half Metre, maple, with points.
Geneva Association foi* the Construction of Scientific In-
struments.
251. Brass Metre. (Grand Duchy of Baden Model.)
Geneva Association for the Construction of Scientific In-
struments.
252. Steel 2-Metre Standard, with points. (German
Model.)
Geneva Association for the Construction of Scientific In-
struments.
253. Brass Standard Metre. (Swiss Model.)
Geneva Association for the Construction of Scientific In-
struments.
The Geneva Association for the Construction of Scientific Instruments
possesses in its laboratories a machine for the division of straight lines, to
the construction of which it has endeavoured to apply all the improvements
of modern science. These efforts have been crowned with success, and the
increasing reputation of this machine, which may be considered as the most
complete at present existing, has obtained for the Geneva Association orders
for metrical standards from several European Governments.
The machine is worked automatically, that is, all the process of dividing is
done mechanically. Thus, apart from the inaccuracy consequent on the tem-
perature of the operator, it avoids the errors proceeding from inattention
or fatigue on his part. Mechanical action has, moreover, the advantage of
being more regular, seeing that the motive power is always equal.
An ingenious contrivance enables the correction of errors due to a change
of outward temperature during the process of division, to be effected ; thus, at
any temperature a correct graduation corresponding to is obtained. By
the same means, a division of any length may be made, although the pitch
of the thread of the screw of the machine, and the length of the division re-
quired, may be incommensurable.
The pitch of the screw has been thoroughly examined and corrected, so as to
guarantee accuracy to the -^^ of a millimetre.
This machine for dividing straight lines has been used to effect the normal
division of the large machine for dividing circles which stands by its side on
the same bed of concrete. This application has been the means of exactly
ascertaining the coefficient of dilatation of the machine for dividing straight
lines. The maximum of error found in the division of the normal circle was
less than a second. It is impossible to expect greater accuracy when it is
remembered that the arc of a second on the circumference of the divided
circle represents about -^^ of the millimetre.
259. Standard Metre, with rack motion to be used as a
machine for dividing other metres.
Geneva Association for the Construction of Scientific In-
struments.
II. LENGTH. 53
This instrument may be used both as a comparing apparatus, and as a
machine for dividing fractions of the metre, for the use of comptrollers of
weights and measures. A small pointer or cutter is traversed, by means of
a rack, along the meter, while a very simple lock action enables the milli-
metric displacements of the indicator to be registered without reading the
divisions.
259b. Iridio -platinum Standard Metre, in course of
manufacture. Johnson, Matthey, and Co.
259c. Section of Metre when finished, showing the form
determined upon by the International Commission.
Johnson, Matthey, and Co.
26O. 6-foot Measuring Hod, for uneven ground, for en-
gineering and scientific purposes. .Designed by the exhibitor, and
made by Messrs. T. Cooke & Sons. Edward Crossley.
The apparatus consists of a wooden rod 6 ft. in length, with metal ter-
minations containing spherical cups fitting on to spherical heads upon tripod
stands. Three tripod stands are required. Each terminates in a flat ring
npon which the base of the short pillar carrying the spherical head is hori-
zontally adjustable, and to which it can be clamped. The rod is supported
by two tripod stands, while the third is set forward to receive the rod in
its next position. The inclination of the rod is read off to half-a-minute
in each position by means of a level and arc attached to the centre of the rod.
The true horizontal distance is then obtained by applying a tabulated cor-
rection for each inclination of the rod.
This instrument will give an accuracy of 1 in 10,000 on any sort of
ground, even with a gradient of one in four.
266. Ivory Pocket Measures. T. Hawksley.
Containing the Fahrenheit and centigrade temperature scales ; English
inches divided to $ in., and centimetres divided into millimetres ; designed
for the purpose of introducing into everyday use the decimal system of
measurement.
269. Poot-scale-plate. A rectangular brass-plate containing
twenty different foot-scales, made in 1769 by Adam Steitz in
Amsterdam. It is a copy from the original deposited in the Town
Hall of Amsterdam. Prof. Buys- Ballot, Utrecht.
269a. Meter Diagram. A. and F. Stanley, Neiv York.
289. Meter Scale with double divisions, for and 20 C.,
by Breithaupt and Son, in Cassel.
Mathematical and Physical Institute, Marburg {Prof.
Dr. Melde).
295. 2-Meter Standard Measure in steel.
F. W. Breithaupt and Son, Cassel.
54 SEC. 3. - MEASUREMENT,
This normal 2-meter standard is an end measure, as well as a line
measure, with divisions throughout in centimeters, and on both the end deci-
meters in millimeters. It was graduated on the longitudinal dividing machine,
constructed by George Breithaupt in the year 1850, for the temperature of
Celsius, as far as 0-01 mm. precision.
Such normal double meters have been made in large numbers on steel, as
well as simple normal meters on brass, for the Imperial Commission of Normal
Weights and Measures.
.With, this longitudinal dividing machine a length of one meter may be
graduated uninterruptedly even to the smallest subdivisions.
296. Star dard Scales in Bock Crystal, viz. :
a. Scale of 10 cm.
b. Scale of 15 cm.
c. Scale of 20 cm.
The scales are cut parallel to the axis of the crystal and are.
divided into millimeters ; the first and the last millimeters are.
divided into ten parts. The graduation has been carried out by
Mr. Brauer in St. Petersburg.
Hermann Stern, Ober stein, Principality of Birkenfeld.
299. Meter in Steely line measure divided into millimeters.
L. Steger, Kiel.
. a, i:*ji .1 ij;..'j {. ; ;-'< !;- ju-.t'>. ; afi
301. Apparatus for comparing Standard Measures of
Length, by Stollenreuther.
University of Munich (Prof, von Jolly).
302. Meter in the form of a ruler with subdivisions.
M. Meyer, Teacher of Mathematics at the Gymnasium,
Halle.
In order that the subdivisions of the meter should be clearly understood
by the scholars, one side of the square has no divisions, that side is of the
exact length of a meter ; the second side is divided into decimeters only, the
third into centimeters, and the fourth into millimeters.
303. Schonemann's Measuring Wedge, reading to '01
mm. Gewerbe Schule at Halle (Director, Kohlmann).
304. Schonemann's Measuring Wedge, reading to '01
mm. Kleemann, Mechanical Engineer, Halle.
, ,
3O6. Meter-scale in Brass.
.,. ;0 - Prof* Baron von Feilitzsch, Greifswald.
This scale was constructed at the workshops of Messrs. F. W. Breithaupt
and Son in Cassel (Province Hesse), and is remarkable for its great accuracy.
It is divided, on silver-plated brass, into centimeters, and at both ends
into millimeters.
309. Original Meter Scale, iron. One of the forty speci-
mens which were delivered to the members of the Meter-Corn-
H. LENGTH. 55
mission in the year vii. of the French Republic ; formerly in the
possession of Tralles. Prof* D r - -Dove, Berlin.
Original Meter Scale by Tralles (of iron). One of the 40 standards which
were delivered to the Commissioners.
Iron Meter a touts. This meter, which was presented to Hapler by Tralles,
was one of the three which the latter had made at the same time, by Lenoir,
with the 15 which were distributed among the members of the Commission.
After the completion of the new measurement of degrees performed by
Delambre and Mechain, the real length of the meter was determined by the
Commission, consisting of, Swinden, Tralles, Laplace, Legendre, Cizcar,
Mechain, and Delambre, in their report of the 6th Floreal year 7, to be
443 - 295936, and the distance of the Pole, by assuming an oblateness of ^fa,
from the equator having been calculated to be 5130 js toises, it was legally
accepted as " metre oral ct definitif" at 443-296.
" Cette unite uornmee metre qui est le dixmillioneme partie du quart du
meridian revient selon les anciennes mesures & 3 pieds 1T296 lignes^ en em-
ploy ant la toise du Peron a 13 degres du thermometre & mercure divise en
80 parties."
312. Standard Meter on brass in mahogany case.
Ed. Sprenger, Berlin.
313. Standard Meter on Steel. Ed. Sprenger, Berlin.
314. Standard Meter on Wood. Ed. Sprenger, Berlin.
315. Standard Tape Measure, 20 meters.
Ed. Sprenger, Berlin.
315a. Standard Stirling Ell, believed to be a copy of the
standard Scottish ell adjusted at Edinburgh, 26th of February
1 755. The Burgh of Stirling.
315b. Standard Meter. Bock and Handrick, Dresden.
Two Standard Meters (boxwood).
Bock and Handrick, Dresden.
2-Meter Standard Measure.
Bock and Handrick, Dresden.
B. TELEMETERS.
'226. Telemeter. For measuring the distance of inaccessible
obj ects. Patrick i Adie .
This instrument, the first of its name, was patented by Mr. Adie in 1863.
It consists of two powerful telescopes at the ends of a fixed base ; the united
rays, by total reflection, give simultaneous observation in the eye-pieces.
234. Telemeter, for determining distant inaccessible points
by one observation. Manufactured by Adie & Son, Pall Mall.
Prof. Pigot.
56 SEC. 3. MEASUREMENT.
242. Nolan's Range Finder.
1. Two-angle measures. Right and left.
2. Two Y supports.
3. Two tripods.
4. Two tripod buckets.
5. Two leather boxes with straps to contain items 1 and 2.
6. A 50 yards measuring tape.
7. A metal calculating roller.
8. Two magnifying glasses.
9. A leather case with strap to contain items 6, 7, 8.
10. A leather numnah which fits under the saddle of item 1, and
on which the two boxes, item 5, are strapped.
.-,;> War Office.
243. Two Instruments for Measuring Distances.
Constructed by Dr. Meyerstein.
Prof. W. Klinkerfiies, Gottingen.
262. Telemeter with prism by Col. Goulier for the rapid
measurement of distance. M. Tavernier Gravel, Paris.
263. Pocket Telemeter. By M. Gautier.
M. Tavernier Gravet, Paris.
264. Telemeters. Fortin Hermann Bros., Paris.
285. Collection of War Telemeters. These instruments,
which are based on the speed of transmission of sound, are
intended for measuring distances in the field.
Le Boulenge, Liege.
3O7. Instrument for Measuring Distances, according to
the systems of Kleinschmidt and Breithaupt.
Royal Museum, Cassel (Dr. Pindcr, Director).
The instrument for measuring distances was constructed entirely of brass
by J. C. Breithaupt during the second half of the 18th century. It consists
of a rail of 0-978 m. in length, serving as measuring-base, on both ends of
which is attached a movable telescope for sighting the object the distance
of which is to be determined. From the known length of the base, and the
indicated angles which the adjusted telescopes form with the base line, the
distance sought is ascertained by trigonometrical calculation.
C. GAUGES AND CALLIPERS.
11. Set of Gauging Instruments. Dring and Fage.
Head rod. For ascertaining the head diameter of a cask, and working out
the contents.
Bung rod and slide. For finding the bung diameter and diagonal of a cask.
The rod is divided into inches and tenths, with a line of imperial area and
diagonal line ; this last gives the approximate content without calculation,
and is computed on the assumption that most casks are similar to one another
in form, and therefore vary as the cubes of their like dimensions.
II. LENGTH. 57
Long callipers used for fmuing the internal length of a cask from head to
head.
Cross calliper. Used for finding the external diameter of a cask.
Stave gauge. For finding the thickness of the stave in a cask.
236. Sliding Calliper Gauge, with tangent screw and
vernier for reading TW<j tn ^ an ^ ncn ms ide an d outside measure-
ment. Elliott Brothers.
237. Decimal Gauge, German silver, with screw and ratchet
motion for measurin to ^h of an inch. Elliott Brothers.
246. Aerial Spider Line Micrometer of great delicacy,
measuring an object to the 100,000th of an inch.
Dr. Royston-Pigott, F.R.S.
The image of sets of spider lines of a recording micrometer placed beneath
the stage, is formed by a half inch objective, five inches from the spider
lines. This image is in fact a miniature diminished exactly seven times.
The micrometer reads to the l-20,000th of an inch, a ^ oa /r ; consequently
the image is measured seven times more minutely. This would be the
l-140,000th, or -j^i^^th of an inch (English). On the whole, therefore,
the instrument may be said to measure to the l-100,000th, i.e., l66 * 06o th of an
inch.
These aerial spider lines are made to move about the object to be measured
at the will of the observer, and come into the focus of the microscope by
regulating the plane of the aerial spider lines.
246a. Wollaston's Single Lens Micrometer.
Wollaston Collection, Cavendish Laboratory, Cambridge.
(Phil. Trans., 1813, p. 119.)
256. Callipers, for clock and watch making.
Geneva Association for the Construction of Scientific In-
struments.
Much used in clock and watch making for measuring thicknesses. This
instrument gauges to ^V tn f a nne > or TlM n f a millimetre.
The divisions traced on the steel arc are not equal, but are calculated to
measure equal increments of the interval between the two nibs. They
increase therefore with the chords.
257. Curious Steel Callipers for very accurate measure-
ment, by Paull of Geneva, 1777. Royal Society.
267. Apparatus for measuring the exterior diameter of the
Gun Barrel and the interior diameter of the rings to be shrunk
on the same ; constructed by G. Brauer.
Arsenal of St. Petersburg.
The apparatus consists of a bar, with two adjustable arms, which is sus-
pended across the cannon ; one arm being brought into contact on one side
with the surface of the cannon, the other arm with its contact lever is brought
into contact with the surface of the cannon on the other side, in such a
manner that this contact lever at its upward and downward motion, by means
of the vertical screw at the greatest diameter, indicates zero. In order to
exactly determine the diameter, the divided movable scale is adjusted, after
58 SEC. 3. MEASUREMENT.
taking off the apparatus from the barrel of the cannon, between the two
arms, so that the contact lever again indicates zero. The same scale serves
also for measuring the interior diameter of the rings. The apparatus has
been constructed and made by G. Brauer at St. Petersburg.
267a. Photograph of an Apparatus for measuring the
eccentricity of the chamber and the curve of the bore of cannons.
G. Brauer, St. Petersburg.
The apparatus consists of two parts :
1 . A body, wHich is pressed into the mouth of the cannon by means of
an endless screw. In this screw a telescope is fixed which can be turned
about its own axis, and is provided with a filar micrometer and a position
circle.
2. A piece, which can be slided along the barrel, being turnable about the
axis of the bore, and in whose centre is a glass plate with engraved cross.
This cross is viewed through the telescope before mentioned, and the deter-
mination of the position of the cross on the filar micrometer indicates the
elements for determining the curve of the bore and the eccentricity of the
chamber.
The apparatus was constructed by the exhibitor for the Russian Marine
Artillery Department.
267b. Instrument for Measuring the Bore of Cannons
(Etoile Mobile). G. Brauer, St. Petersburg.
This instrument consists of a ring, in which two parallel rods slide longi-
tudinally side by side, and one of which carries the scale, the other its
vernier. The sliding rods are pressed asunder by means of springs, so that
their exterior steel ends touch the side of the bore to be measured. As this
contact must not take place during adjustment, the sliding rods are brought
together by a bolt. A screw perpendicularly under the sliding rods is in-
tended for adjusting them according to the greatest diameter, which has to
be done afresh at each measurement. If the chamber of a breech-loading gun
is to be measured with the apparatus a set of two rings has to be added, of
which the one in front carries a telescope for viewing the scale. The two
exterior rings are joined to each other by four bars, and these bars have a
movement in the centre ring, which during the operation of measuring L
pressed into the back part of the cannon bore by means of four screws, and
the whole apparatus is then moved as required.
267c. Apparatus constructed for measuring the exterior
diameter of small cylinders with an accuracy of 0' 001 inch.
G. Brauer, St. Petersburg.
This apparatus, which was employed in the experiments on the elasticity
of gun-metals, steel, cast-iron, &c., in Bussia, is provided with an immovable
pillar and a contact-lever, which can be adjusted by means of a screw-move-
ment. The cylinder to be measured is placed between the two, and the screw
turned until the lever points to zero, and then the reading is effected by the
vernier of the longitudinal scale.
267a. Apparatus for Measuring the Breeches of
Large Guns. M. Gadolin, St. Petersburg.
II. LENGTH. 59
267d. Apparatus for Measuring the Length of the
Impressions made by the Rodman Scale.
Technological Institute at St. Petersburg.
The copper plate, on which is the impression to be measured, is placed on
the slide of the apparatus, and then one end of the impression after the other
is brought under the cross thread of the microscope by means of the screw of
the slide, when the reading can be made on the head of the screw. By-
means of a micrometer eyepiece also smaller dimensions can be measured.
The apparatus belongs to the Technological Institute at St. Petersburg.
267e. Micrometer for Guns and Tubular Objects.
Samuel B. Allport.
This is a tube, provided with three spring arms, radially disposed round its
end, between which a cone is inserted. The cone is connected with a screw
at the other end of the tube, whereby it is projected or withdrawn, and so con-
tracts or expands the spring arms.
The angle of the cone bears such a relation to the pitch of the screw tha 4
the expansion or contraction of the arms when inserted in a tube will indicate
the variations in its bore in thousandths of an inch by suitable divisions on
the head of the screw.
267e. Apparatus for measuring the eccentricity of the pivots
of a polar or transit axis, with an approximation of * 00001 inch.
A. Hilger.
271. Calliper, with Dial, of the English inch measure,
divided into eighths. M. Isvardfils.
272. Calliper, with Dial of two centimetres, divided into
tenths of a millimetre." M. Isvardjfils.
283. Cylindrical Gauges differing in diameter by one ten
thousandth of an inch. Other gauges and specimens of surfaces.
Royal School of Mines.
284. Universal Calliper, with slide and reverse action.
Geneva Association for the Construction of Scientific In-
struments.
Instrument of measurement, for ascertaining equally the thickness, the
inner diameter, and length of tubes.
286. Apparatus for measuring accurately the Diameter
of Wires, for testing whether pivots and other turned objects are
perfectly circular in form, and for the determination of the error
when they are not truly circular.
Landsberg and Wolpers, Hanover,
287. Apparatus for measuring the Thickness of thin
metal plates, sheets of paper, &c.
Landsberg and Wolpers. Hanover.
288. Calliper-Compasses for larger measurements.
Landsberg and Wolpers, Hanover.
60 SEC. 3. MEASUREMENT.
233a. Photographs, showing two kinds of machines i'or
measuring with great precision the alterations in shape produced
in metals by tension and compression. Dumoulin Froment, Paris.
291. Calliper Apparatus, for accurately determining dia-
meters and lengths up to 150 mm.
A. Meissner (ff. Muller and F. Reinecke), Berlin.
^L millimeter can be obtained by direct reading by means of a microscope,
and the T | 7 part of a millimeter by estimation.
293. Collection of Timber Callipers for the use of
foresters. C. Staudinger and Co. (F. W. von Gehren), Giessen.
A collection of tree-callipers (" Baumkluppen "), mostly in use for the pur-
pose of comparison with those of Staudinger's construction, by many autho-
rities recognised as the best. A list of the names is added to the collection.
298. Calliper Compasses, with plane contact lever.
Physical Institute of the University of Kiel (Prof. Dr.
G. Karsteri).
This appai-atus, which is in the possession of the Physical Science Institute
of the University of Kiel, was constructed in 1832 by liepsold, and made use
of by Schumacher for comparing the platinum kilogramme of the archives
with the Danish.
(See Schum. Astronom. Jahrbuch, 1836, p. 243.) 9
A description by G. Karsten of the instrument will be found in " Vom
Maasse und vom Messen," vol. I. of the " Encyclopedic der Physik," p. 506
and following.
308. Apparatus for measuring the Thickness of Thin
Plates. R. Fuess, Berlin.
308a. Improved Patent Measuring Gauge, with
patent releasing arm. Wm. Henry Laidler.
This gauge is constructed to enter a hole drilled in a plate ; the arm will
clear any rough edge or burr, and when the measurement is taken the arm
can be released, and the instrument withdrawn, without altering or interfering
with the indication. Each division on the vernier shows 1 - 1 00 part of an inch.
3O8b. Improved Ivory Calliper Gauge, with Engi-
neer's Slide combined. Wm. Henry Laidler.
D. CATHETOMETERS.
241. Differential Cathetometer, an apparatus designed
for measuring variations in the length of solid bodies, particularly
of rods and wires. Dr. Heinrich Streintz, University of Gratz.
The principle on which this apparatus is based is, reading by reflection from
two mirrors. Two levers, having small mirrors ss attached to them perpendi-
cular to their axis, are turned by the flat ends of the bar to be measured as
indicated in the drawing. If a telescope and a scale are placed, at some
distance, in such a position that the image of the scale reflected by the mirror
II. LENGTH.
Gl
is visible through the telescope, each variation in the position of the point at
the end of the lever will be magnified to a degree indicated by the quotient,
the numerator of which represents the double distance of the mirror from the
scale, and the denominator that of the point from the axis of rotation.
As the latter distance can be diminished to one centimeter in the apparatus,
and as, moreover, the telescope with the scale can be placed at any distance
within which distinct images will be seen, say five metres, a shifting of the
reflected image by one millimeter will be equal to displacement of the end-
surface of the bar to be measured by O'OOl millimeter. As, however, the
tenths of the millimeter even can be pretty accurately determined, the reading
will be correct as far as the 10,000th part. '
There is no doubt that the correctness of the reading with this apparatus
can be carried still further, if mirrors of superior quality and powerful
telescopes are employed.
In measuring the variations in the length of a wire a flat surface must be
given to that part to which the wire is to be suspended, as well as to the part
OH which the weights are placed, and to which the levers are to be applied.
62 SEC. 3. MEASUREMENT.
The arrangement of the apparatus is as follows :
To a solid brass pedestal, which rests on three adjusting screws, a strong
glass tube a 1^ meter long is cemented, to which two brass bars bb are
clamped. Each of these brass bars consists of two parts, of which one
moves or slides in the other in such a manner that it can be either lengthened
or shortened. The set screw c serves for fixing the chosen length. By means
of the joint d a horizontal rotatory or veering movement of the fore-part of the
bar can be effected. Close to its free end there is on each side a steel point
the two forming together an axis which is held by a bow ff carrying two
cups, in such a manner that the bow can be easily but surely turned round
this axis.
The lever gg which must be firmly connected with the bow, has longitu-
dinally a slit, or slide, with two sliding pegs placed in a level position with
the axis and fastened to the bow, along which the lever can be moved, so that
at whatever distance from the axis the extreme end of the lever may be fixed
it must always turn with the bow around the axis.
In order not to be obliged to take the measurement of the length of the
lever afresh at each experiment, it is provided at its upper surface with
conical-shaped cavities in which the screws hh catch. These conical-shaped
cavities would be, properly speaking, visible only in a drawing of a vertical
section, but not in a front view, as represented in the sketch, but they have
been marked in the drawing for the purpose of rendering the description more
intelligible.
The measurement of the length of the lever at the different cavities is
accomplished by means of a spherometer. The lower bar b is arranged in
a manner quite similar to the upper bar.
In order to meet the requirement that the levers should but lightly press
against or touch the end surfaces in the manner indicated in the drawing, small
balancing blocks II can be attached at any point to the levers.
For the purpose of reading, two telescopes with vertical scales are required,
which must be placed in juxtaposition, that is to say, by the side of each
other. Presuming the staff to move upwards and downwards without varying
its length, the difference in the reading in the upper and in the lower mirror
will naturally be of the same value in every position of the staff.
A glass tube has been chosen to serve as a column a, because glass possesses
a very small coefficient of expansion. Moreover, in using the instrument,
the tube must be filled with water and two thermometers placed in it, by means
of which any change in the temperature that may take place during the
process of measuring can be accurately determined.
A similar, although less perfect, apparatus has been employed by the
exhibitor in two experiments already, namely, " as regards the variations in
" the elasticity and the length of a wire under the influence of a galvanic
" current." See Transactions of the Academy of Sciences at Vienna,
Vol. LXVIL, Part II. , April 1873 ; and " respecting the moderation of
" the torsion oscillations of wires." See Transaction of the Academy of
Sciences at Vienna, Vol. LXIX., Part II., March 1874. Extracts of both
treatises have also been published in Pogg. Ann.
The apparatus can be employed in measuring the coefficients of expansion,
coefficients of elasticity, the after effects of elasticity, the expansion produced
by magnetism, &c., and will secure in every case an accuracy not hitherto
attained, not only by reason of the correctness of the readings, but also
on account of the correction of temperature rendered possible through the
employment of the glass column.
The measurement is likewise very easy of accomplishment, since a manipu-
lation such as is the case with ordinary cathetometers is not required, as the
II, LEXGTtf. 63
variations taking place in the wire can be perceived through the telescope
directly magnified and projected on the scale.
In most cases it will only be necessary in making such experiments to know
exactly the absolute length of the body to be measured in equal per cents, as
well as the elongation, for measuring which a good scale, or a very simple
cathetometer, is all that will be required.
24 la. Original Cathetometer by D along.
Polytechnic School, Paris.
241 b. Cathetometer, with two Levelling Micrometer
Telescopes.
Physical Science Cabinet of the Imperial Academy of
Sciences, St. Petersburg.
241 c. Drawing of a small Cathetometer, used by Prof.
Mendeleeff in his investigations on the tension of gases.
Prof. Mendeleeff.
In order to eliminate a source of many errors the eyepiece is fixed in the
telescope, and the whole cathetometer has to be put at the required distance
from the object to be observed.
The telescope is provided with a micrometer screw.
253. Great Cathetometer, for reading differential levels
more than a metre apart.
Geneva Association for the Construction of Scientific In-
struments.
This instrument is composed of a tripod supporting a central rod, which
bears on its upper part the brass column, or prismatic piece, along which
the telescope moves in a right line. The dimensions of the column are great,
so as to avoid all flexure. The division on the silver plate is in millimeters,
and the vernier of the slide gives readings to the 50th of a millimeter. This
instrument has two levels ; the one placed between the rings that support
the telescope, the other placed perpendicularly to the first upon the table
situated at the base of the column.
The universities of Berlin, Rome, Dorpat, Neuchatel, &c. have instruments
of this pattern.
273. Cathetometer, by Casella. The telescope moves on a
girder-shaped brass bar, to which the scale is attached, and is
furnished with a micrometer eyepiece, by means of which readings
can be taken without moving the telescope. The instrument is
supported by a massive iron frame- work.
Prof. A. W. Rucker, Leeds.
292. Cathetometer. C. Bamberg, Berlin.
The principal division of the instrument is executed on silver to centi-
meters. The division into single millimeters has been made on a scale con-
nected with the principal slide, whose divided surface is on a level with that
of the centimeter graduation. The millimeter-scale moves with the principal
slide, which carries the means for reading and adjustment (microscope and
^elescope). The reading of the meter-division is effected (as far as O'OOl
64 SEC. 3. MEASUREMENT.
mm.) by means of the eyepiece-micrometer of the microscope. The micro-
metrical displacement of the principal slide,; which is balanced in all posi-
tions round the longitudinal axis of the scale column, takes place by a pecu-
liar contrivance, which avoids all one-sided pressure. The slide with the
clamp is balanced by a counter-weight suspended from the ceiling or a trestle,
so that its ascending and descending motion is effected with great facility.
294. Photograph of a Cathetometer, constructed by
Staudinger and Co.
C. Staudinger and Co. (F. W. von Gehren}, Giessen.
The peculiarities of the construction may be learned from the photo-
graphs. The instrument has an available graduated length of one meter ;
the column with the counter-weight turns completely around the long ver-
tical axis, and is provided with adjustments, reversing telescope, and water-
level.
305. Cathetometer.
Prof. Baron von Feilitzsch, Greifswald.
The Cathetometer consists of a central axis, and a prism turning round
the same. For placing the central axis in a vertical position a cylindrical
water-level, indicating to 10 seconds, is employed. A scale on silver one
meter in length, and divided throughout into millimeters, is inlaid into the
prism. Sliding along this is a telescope, likewise fitted with a cylindrical
water-level, the supporter of which is provided with a vernier indicating
3 V mm -
There is also a water-level, for regulating the direction of the prism.
310. Cathetometer, so arranged as to be used for horizontal
measurement. Prof. Dr. Dove, Berlin.
311. Cathetometer, by Breithaupt and Son, Cassel, with
riding level. Polytechnic School, Cassel (Dr. E. Gerland).
The following improvements, contributing partly to more minute readings
with the apparatus, partly affording means of correction of the several parts,
have been added to the well-known constructions.
The firmly placed central axis, around which the long frame and prism
turns, can be placed vertically by a special cylindrical water-level, indicating
to 10 seconds, and which is fastened to the frame independently of
other parts, in order that the vertical position of the axis required in very
fine measurements may be readily ensured ; the more so, as all othe*r
observations are based on the correct adjustment of this water-level. The
vertical position of the axis is effected in the same manner as with an
ordinary levelling instrument, and any deviations of the water-level are cor-
rected half on the adjusting screw of the same, and half by the regulating
screws of the tripod.
The prism, the inlaid silver scale of which, 1 meter in length, is through-
out divided into millimeters, and fitted with a vernier for -J- mm., can be
placed in a horizontal position and parallel to the face of the scale. By means
of adjusting screws, and a reversible riding level, the telescope can be placed in
the required position.
If this is done, the bubble of the telescope water-level will remain unchange-
ably in the centre during the rotation of the whole instrument on its central
axis, as well as during the upward and downward motion of the slider.
II. LENGTH. 65
A very severe proof consists in sighting a distant object with the telescope,
which is then reversed in its sockets, and the apparatus turned round 180,
at which the object should be intersected again by the eyepiece cross.
The immovable cross in the ocular is cut on glass, in order to prevent
hygroscopical and other interruptions. For the purpose of obtaining the
rectangular position of the telescope, the supporter may also be placed with
one end between points, while an elevation screw is fixed to the other. The
essential point for effecting the before-mentioned correction by employing the
attaching or adjusting water-level consists simply in adjusting the water-level
axis exactly to the leaning face by means of the correction arrangement
marked a in the drawing. The proof is effected by reversing the angle
vertically, the water-level thus turning between its. points. If after the
proper attachment the bubble deviates from the centre, half of this deviation
must be corrected by the regulating screws of the tripod, and the other by the
correction arrangement a. It is, however, to be mentioned that, previous to
the above proof, the parallel position of the water-level axis towards its
points of attachment is to be examined, which can effected by reversing
between its two points, and thereby a deviation of the bubble, if there be any,
Avill be removed half by the adjusting screw b, and the other half by the
arrangement a. Finally, there remains the examination and correction of the
water-level sideways to be made, which is done in the usual manner by the
screw c. This attaching or adjusting water-level may also be recommended
for other purposes, for instance, in mounting of machines, &c.
Regarding the peculiar construction of the aforesaid adjusting water-level,
the suspension between two points, in general, it may be remarked that the
same has been derived from the compensation-level constructed by F. W.
Breithaupt and Son some years ago (vide Dingler's Polytechn. Journal,
vol. CLIV. p. 401). In what manner this principle has been adopted in other
mechanical workshops, and represented partly as an invention of their own,
has been proved by an article in Carl's Repertorium, vol. IX., p. 127, by the
addition of an arrangement or simplification totally at variance with the
construction.
E. DIVIDING ENGINES.
248. Instrument for dividing Mathematical Scales or
Rules.
H. M. Commissioners of Patents
This instrument is to be used for dividing scales according to the French,
Swiss, or English measures of length, and is provided with a vernier for
obtaining the smaller divisions of the scale. It can also be adapted to
the production of diagonal scales.
248 a. Dividing Engine, made by the late Mr. Bryan
Donkin, F.R.A.S., in the year 1828. Bryan Donkin.
The principle involved in the construction of the machine is the employ-
ment of a compensating arrangement, by which great accuracy is obtained,
notwithstanding the inequalities of the screw used in the machine for advancing
the cvitting tool. The machine consists, first, of a table moving upon wheels
on a railway. To the under side of the table is attached a clasp nut in two
parts, moved by the main screw, which is below the table, and exactly
parallel with the line of motion. To effect the compensation the table con-
sists of an upper and lower plate, the upper one being capable of a small
40075. B
66 SEC. 3. MEASUREMENT.
motion independent of the lower plate. The lower plate carries the fulcrum
of a bent lever, whose arras are at right angles and as 50 to 1. This lever
moves in a vertical plane, so that the longer arm lies by gravity alone on the
undulating edge of the compensation bar. The upper plate is pressed end-
ways against the shorter arm of the bent lever by means of a spring keeping
them always in contact. By a kind of parallel motion the two plates are
attached so as to allow of the very small motion required in the upper plate
independently of the lower. The compensating bar, which is of the length
of the screw, has 50 narrow slips of metal placed upon it, each having an
adjusting screw by which the ends of the pieces may be placed in a continuous
line, or above or below the line, as required by the mode of adjustment. This
bar is carried by a pivot at one end, and the other end is raised or depressed
by a screw, which adjusts the compensating bar to the total length moved
through by the guide screw.
In the case of dividing a scale, the swing frame carrying the cutter or
diamond point is attached to the framing of the machine, the scale to be
divided being placed upon the upper plate.
In the case of cutting a screw, the tool holder is fixed upon the upper plate
and the screw to be cut is placed between centres parallel to the motion of the
table and to the guide screw, having motion imparted to it by a train of
wheels connecting it with the screw of the machine. The compensating bar
being adjusted for total length, and the small pieces of metal upon the same
being adjusted to the intermediate errors of the guide screw, it will be seen,
that by the passage of the longer arm of the lever over the edge of the com-
pensating bar, a slight motion will be imparted to the upper plate independent
of the lower, so that, in other words, if by the error of the screw the lower
table is moved through too great a space, the upper table is made to move
(by the action of the lever) through a space equal thereto in the contrary
direction, and ewe versa.
Note. A description somewhat more in detail and of the manner of
adjustment will be found in " Holtzapffel's Turners' and Mechanics' Manufac-
tures," 2nd vol., p. 651 et seq.
Many scales were divided and many screws cut by this machine, of which
some were given to various scientific friends, and Sir ,T. Whitworth, amongst
others, had a scale and a screw about the year 1843 which have served him a&
standards.
265. Machine for dividing right lines, by Nicholas Fortin.
MM. Fortin Hermann Bros., Paris.
This machine is the one constructed by the celebrated inventor in 1787,
and used in the works connected with the adoption of the metrical system.
The pitch of the screw is exactly one millimetre. (Fortin's machine for
dividing circles, as well as this machine, was presented to the Conservatoire
des Arts et Metiers by MM. Fortin Hermann Bros., in 1876.)
297. Micrometer Dividing Machine.
Voigt and Hochgesang (Gust. Voigi), Gottingcn.
The pitch of the screw is mm., its head is divided into 200 parts ; each
part, therefore, corresponds to -gfa mm., reading by the vernier to ^ of this
value. By a spring fixed in the nut " loss of time " is completely removed.
The tracing appliance is constructed in the simplest manner possible. The
tracing point a diamond is lifted by a mechanical contrivance, and let
down again.
The slide allows of drawing a line of 30 millimeters in length.
II. LENGTH. 67
The slide which carries the tracing point moves without greasing between
six finely polished carnelian plates ; by this arrangement any errors, which
might be caused by clotted grease, will be rendered absolutely impossible.
F. TIDE REGISTERS.
327b. Patent Indicator, for tanks or reservoirs.
John Nicholas.
This gauge is similar to that last described, but the atmosphere giving
comparatively a constant pressure the stand pipe can be dispensed with.
The brass tube referred to in the previous description may be seen in the tank
attached. It is not necessary to pierce or employ a tank when attaching one
of these gauges, and the small pipes can be laid in the walls in a similar
manner to gas tubes. In some cases one tube is sufficient, the water column
being balanced by mercury in a metal tube at the back of the gauge. This
gauge is suitable for tanks upon the roofs of mansions or hotels, where engines
are used for pumping.
255. Registering Water-mark, of new construction, which
records the curve of the water-level and its mean height.
Lieutenant- General Baeyer, President of the Geodetic
Institute at Berlin.
Invented by F. H. Reitz, civil engineer, of Hamburg. The apparatus
was made in the factory of Pape and Dennert. The clockwork is by
Knoblich.
278a. Magneto-Electric Water Level Indicator.
Siemens and Halskc, Berlin.
A float which rises or falls with the level of the water in the reservoir or
tank communicates motion by a metallic chain to a magneto inductor, which^
generating electric currents, works at any distance an indicator connected by
a cable or insulated wire.
1695. Apparatus for making contact to show the height of
water with float, rod-chain, counterpoise, and water tube.
C. # E. Fein, Stuttgart.
This is self-acting, and registers at any distance the water-level in a
reservoir, &c.
It consists of five parts :
(1.) The float with chain and counter weight which when acted on by the
rise or fall of the water impart their motion to the contact arrange-
ment
(2.) The contact arrangement which communicates the motion of the float
to the recording instrument by opening or closing the circuit.
(3.) The recording instrument ; this shows the level of the water at all
times, the pointer being acted on by the motion to and fro of two
electro-magnets.
(4.) The conducting wire.
(5.) The battery.
279. Three Gauges, in enamel cast iron, for registering the
height of a river or lake. De Dietrich and Co., Niederbronn.
E 2
68 SEC. 3. MEASUREMENT.
The first of these on the Niederbronn pattern is in black and white and
graduated to centimetres, the second on the Nancy pattern is graduated in
black and white for every two centimetres, and the third on the Paris pattern
is in blue and white graduated to five centimetres.
These water-mark plates are fixed by means of iron clamps to piers, vertical
embankments, &c., and serve for the observation of the level of the water in
rivers, canals, lakes, and reservoirs.
Placed at proper distances from one another in the chief water-courses and
its tributaries, they enable the rise of the water to be observed, and conse-
quently timely warning to be given, by telegraph or otherwise, to the inhabi-
tants of the districts concerned.
28O. Recording Tide Gauge, with self-acting indications of
the mean height of the water (system of F. H. Reitz, Hamburg) ;
executed by Dennert and Pape, in Altona.
Royal Prussian Geodetic Institute, Berlin.
The tide-measuring system exhibited by the Royal Prussian Geodetic
Institution of the European measurement of a degree, at the instance of its
president, General Baeyer, and constructed by Dennert and Pape of Altona,
with clock by T. Knoblich, of Hamburg, has a graphic apparatus for regis-
tering the tide-curve and an arrangement by which the mean water-level is
indicated automatically. The registration of the water-level is effected bj r
means of diamond points upon a cylinder placed horizontally for the accurate
division of the arc.
The mean water-level is indicated by means of two agate rollers with di-
visions, which slide upon a horizontal glass disc turned by the clock of the
tide-measurer, moved to and fro by the rising and falling water, and by the
rotation of the glass disc, and may be read off at any desired intervals of
time.
The calculation otherwise necessary of the mean water-level (the true level
of the sea) from the indications of the registering apparatus is saved by the
above-mentioned mechanical arrangement, and effected automatically with
very great accuracy by the tide-measurer.
The determination of the form and dimensions of the earth undertaken by
the European Committee for re-measuring degrees of longitude and latitude,
also contains the determination of the mean sea level at points on different
coasts, and its comparison by means of accurate levellings. During the last
few years the Committee has endeavoured, in consequence of these examina-
tions, to study the different apparatus and to promote a more exact observa-
tion of the tide corresponding to the exact levellings recently taken.
These circumstances were the cause of a eommissiou from his Excellency
General Baeyer, President of the Central Office of the European Committee
for higher geodetic purposes, and the Royal Prussian Geodetic Institution,
to F. R. Reitz, instructing him to prepare a tide apparatus according to his
system. The instrument now exhibited was made by Dennert and Pape, of
Altona. and the clockwork by Theodor Knoblich, of Hamburgh. It is in-
tended by the Imperial German Admiralty to place this new instrument,
after the close of the Exhibition, on the Isle of Sylt, Schleswig.
The commission given by his Excellency General Baeyer referred to the
construction cf a new instrument, combining a registering apparatus and
mechanical means of determining the mean level of the sea. The apparatus
here described is therefore a combination of both objects.
A buoy A, moved up and down by the tide in a vertical shaft, turns a disc
C, about a horizontal axis, by means of a copper wire B. During the ebb
the wire B descends and turns the disc C; during the flood the same is
II. LENGTH.
69
effected in the opposite direction by a weight D turning the disc E, connected
with the disc C upon the same axis. In order to reduce the movement of
the buoy A in a certain proportion, a pinion F, on the axis of the disc C
and E, moves a rack G, in a horizontal direction. On one end of G a
diamond-point H is fixed, on the other end two rollers J, J, with a horizontal
axis.
Fig. 1.
The clock of the instrument turns the cylinder round its axis in 24 hours by
means of a combination of wheels, and the glass disc M in six hours.
The tide-curves are engraved upon the cylinder L with the diamond-point
II. The rollers J, J move en the glass disc M by the combined action of the
buoy A, the weight D, and the clockwork.
All the different parts of the apparatus are fixed upon the same plate N, N
of cast iron, planed at the necessary points to insure their invariable position.
The plate N rests on three columns of cast iron, placed upon the coping of
the shaft.
The cylinder is covered with blackened chalk paper, whereon the diamond
engraves the tide-curves as white fine lines on a black ground.
The paper on the cylinder L is divided in half hours, and from meter to
meter of height. For this purpose a proper self-acting apparatus is con-
structed, by which both divisions are made with great exactness. Diamond-
points are used for this purpose also. It is necessary, for the sake of distinct-
ness, to renew the covering paper of the cylinder once a month. To avoid
waste of time a second exactly similar cylinder is prepared and carefully
divided, to replace the former cylinder.
For the observation of the constants of the apparatus, it is necessary to
note complete revolutions of the disc C and glass disc M. For this purpose
two indices are applied.
The circumference of the disc C, measured on the axis of the copper wir
B, is exactly two meters in length.
70
SEC. 3. MEASUREMENT.
The apparatus for the determinations of the mean height of the sea is
explained by the following remarks :
It is the question how to define the mean height of the water for a certain
period.
This height would be the arithmetical mean between high and low water,
supposing a regular form of the tide-curves. In fact, the real observed tide-
curves differ very much from this theoretically-defined regular form (curve of
sines). To show this the tide-curves of Cuxhaven, Southampton, and Ipswich
will suffice as examples. The irregularities in these curves are evident and
easily to be seen in figure 2, where the curve of sines is drawn for the purpose.
MEAN
MITT
SOUTHAMPTON. f 6 IPSWICH.
Fig. 2.
If h be the difference between high and low water, the mean height is
for Cuxhaven 0*527^, for Southampton 0'567/J, and for Ipswich 0'47lA
instead of 5 h, the amount of the mean height, supposing a regular form of
the curve. The mean height of the sea is one of the most important result*
of the tide observations. It is the only datum by which to define the invaria-
bility, or the measure of the variation, of height of the continent and islands.
The line of mean height acgi must be in such a position that the areas
abc and gfi (figure 2) together equal the area edge. This is to be found by a
tedious calculation of areas of the tide-curves drawn on the cylinder L.
The apparatus here described gives the requisite data for an easy deter-
mination of the mean height by means of two rollers ( JJ) (one of them con-
II. LENGTH. 71
trolling the other) moving in accordance with the level of the water on a disc
of glass (M). This disc is turned round its axis by the clockwork in 6 hours.
The axis of the rollers J, J is parallel to the direction of their motion on the
disc M. The number of the revolutions of the rollers is noted in certain
periods by means of the divided rim (the rim is divided in 100 parts, tenths
being estimated) and a numerical apparatus showing revolutions up to 100.
The height of the water may be taken from the point when the roller J
stands in the centre of the disc M.
If the height of the water taken from this point be x, and the diminution of
the movement of the buoy by the pinion F be -
.... (I.)
Is the expression for the movement of a point in the circumference of the
roller J in a period during which the disc M revolves through an arc </>.
The expression jx8<f> is the area of a figure with the ordinates x and the
base </> (x representing the height of the water and <f> the time). The mean
value of .r or the height of a rectangle of equal area with this figure and the
base </> is found by dividing by (j>. This mean value of x is the mean height
to be found, equal m suppose. Then
J^_ (2 .)
The movement of a point of the circumference of the roller J is equal to
-JxSQ. This is equal to the product of the circumference of the roller J
called p and the difference of readings on the margin of the roller J at the
beginning and end of the period. Hence, if the readings are called a l and Oj,
.-I**-'* .... (3.)
If z is the number of seconds corresponding to the arc </>, and b the con-
stant arc through which the disc M revolves in a second:
(4.)
Finally, if ~ =
the mean height of the sea.
The single constant c is easily to be determined by experiment and also
with great exactness without the knowledge of the dimensions of the appa-
ratus, as follows : In a certain position of the roller J a number of revolutions
is made by the disc M, representing a number of seconds z l (a revolution is
made in 21,600 seconds). At the beginning and end of these revolutions the
readings (a x and a 2 ) of the roller J are noted. After this a certain length (/)
of the copper wire upon the disc C is unrolled (measured by means of the
circumference of the disc C, equal 2 meters, and the index, or directly). In
the new position of the roller J a number of revolutions of the disc M again
is made, representing a certain number of seconds (z 2 ), and also the corre-
sponding two readings (a 3 and cr 4 ) of the position of the roller at the beginning
and end of these revolutions are now observed. All the requisite data for the
determination of c are now obtained. If the two values of m corresponding
72
SEC. 3. MEASUREMENT.
to the two positions of the roller are m 1 and
from equation (I.),
and their difference is equal /,
therefore :
a, a.
(II.)
When the constant c for both rollers is calculated, the constant difference
in 'the results for m is fixed by a number of revolutions of the disc M in the
same position of the rollers. The difference of m found in this way, of course,
is constant.
The equations (I.) for the apparatus exhibited, calculated as described, are :
For the roller on the left side :
m = 8656 -632 a2 ~ ai meters.
For the roller on the right side :
m = 8655* 983 -^^ meters.
The roller on the right side gives a constant difference for the value m
given with the roller on the left side equal 1'3252 meter. Respecting the
correction of the apparatus, it is only necessary to make the axis of the rollers
parallel with the direction of the movement on the disc M. In this parallel
position this movement, of course, has no influence on the revolution of the
rollers. The parallel position of the axis of the rollers may be tried by ex-
periment, by moving them on the disc M, turning the disc C. During this
experiment the disc M must remain at rest. No motion of the rollers will
then be observed. It seems requisite, at first sight, that the roller J move
through the centre of the disc M. But this is not necessary, an approxima-
tion only being needed for practical purposes. By a sidewards position no
difference in the revolution of the rollers is effected. This is proved in the
following way :
Fig. 4.
II. LENGTH.
73
As to the two positions I. and II. of the rollers, it needs be shown that a
motion d<j> of the disc M causes the same effect.
In the position I. the motion of the roller is :
pq = a8<f>.
In the position II. the motion of the roller is not equal nm.
But:
mo = nm cosj
consequently :
cos j = -- and nm=a l
therefore :
Fig. 5.
The motion of the rollers, therefore, in the two positions is equal.
To connect the distance of the points from which the mean height is
measured by the instrument to a point given by levelling, the height of a
point P of the buoy over the water is carefully measured.
This may be very exactly done by putting the buoy into a vessel filled with
water. The buoy afterwards is lifted a little by the weight D (Figure 1).
This is easy to calculate from the area of the buoy, the weight D, and
74 SEC. 3. MEASUREMENT.
the radius of the discs C and E. The buoy then is fixed at a certain height
by a wire O. In this position the height of P. below a point given by
levelling is carefully measured. The absolute height of the water represented
by the chosen position of the buoy is now known. After this the mean
height corresponding to the same position (viz., the constant height of this
position) is calculated according to the result by a number of 10 or more
revolutions of the disc M. If the measured height corresponding to the
position of the buoy be equal h, and if the height given by the instrument
be equal m, h m is the absolute height (according to the levelling) from
which the mean height given by the instrument is taken.
The diamond-point can then be fixed in a position to get a corresponding
diagram on the cylinder L to the absolute height given by levelling.
F. H. EEITZ,
Hamburgh, May 1876. . Civil Engineer in Hamburgh.
281. Self-recording Tide-gauge, improved.
H. C. Ahrbecker.
In this instrument the whole of the paper can always be seen, and requires
renewal only once a month. The clock goes for 32 days.
This instrument was designed to obviate the disadvantages which occur in
working the ordinary pattern.
A float which rises and falls with the tide in an iron tube is attached to
one end of a chain that passes over a wheel, at the other end a counterpoise
hangs. When the float rises or falls it communicates its motion (by means
of the before-mentioned wheel) to a sliding pencil that moves across a strip
of paper drawn under it by the clock.
In the model exhibited the distance between two lines across the paper,
= 2 hours, = 1 ft. in the length.
This instrument can be made to work without any attention whatever for
12 months if necessary.
282. Mareegraphe," or tide-gauge. Van Rysselberghe.
G. MISCELLANEOUS LENGTH -MEASURING INSTRUMENTS.
238. Measuring Wheel for determining distance by regis-
tering the number of revolutions ; the upper index pointing out
every single and the lower every 100 revolutions.
Elliott Brothers.
238a. Odometer or Way Measurer in gilt metal case
elaborately chased, an early example, probably made in the second
half of the 16th century. " Alexander Nesbitt.
In Beckmann's History of Inventions there is a description of two instruments
resembling this, which belonged to the Emperor Rudolph II. (1576-1612).
415b. Pare and Distance Indicator for Street Cabs.
Robert Foster s Sunderland.
This is an instrument for measuring the distance travelled by a cab or
other vehicle to which it may be attached. A driving band taking its motion
from the road wheel actuates counting wheels, and so pointers are made to
II. LENGTH. 75
indicate on dials the distance passed over and the fare. There is also an
appliance for registering on a slip of paper all the fares taken during the day.
The pointers can be brought back to zero by the driver, but they cannot be
moved forward except by the motion of the vehicle.
240. Improved Measuring Wheel or Mile Meter.
Elliott Brothers.
24Oa. Micrometrical Divisions in English and Metric
Measure. Dumoulin Froment, Paris.
27O. Holt's Diagr ammeter. This instrument is specially
made for measuring the ordinates of indicator-diagrams 6" long,
and is used much after the manner of a parallel rule, the register-
ing nut on the screw being first placed at zero ; when it is required
to register a measurement the break key is depressed, and when
all the measurements have been taken the distance the nut has
travelled gives the mean ordinate. Henry P. Holt.
274. Spherometer (by Salleron), to read to *001 mm.
The Council of the Yorkshire College of Science, Leeds.
276. The Wealemefna, E. R. Morris's patent. A pendant
for the watch-chain.
The Morris Patents Engineering fVorks, Birmingham.
To measure, it is merely necessary to advance the Wealemefna over the
object, when the large hand will register the inches and fractions of an inch,
and the small one the feet. The instrument registers to 25 feet.
276a. Schlagenheit's Measurer for Curved and Straight
Lines. S. J. Hawkins.
This instrument has a small wheel A, the periphery measuring one inch
and divided into five equal parts, indicated by fine points, marking when in
use each length by a slight indentation upon the map or plan. At each revolu-
tion of the wheel a small spring B is struck, indicating that one inch has been
traversed. Attached to the instrument is a small scale C, th of an inch in
lergth, divided into 10 parts for measuring distances less than one division
of the wheel.
276b. Opisometer. Instrument ordinarily used for the above
purpose. S. J. Hawkins.
277. Measuring Instrument, E. R. Morris's patent. (Silver
medal awarded at Manchester, 1875.) For the use of architects,
surveyors, builders, contractors, timber merchants, &c., &c., and
for general measuring purposes, in place of the rule or tape. It
measures to 100 ft., and weighs under 3 oz.
The Morris Patents Engineering Works, Birmingham.
To use the instrument it is merely necessary to advance it along the object
to be measured, when the large hand will register the inches and fractions of
an inch on the outer dial, the smaller hand on the inner dial, the feet and the
smallest hand on the recessed dial, the tens 'of feet travelled over. The in-
strument registers to 100 feet. Price, electro-silver, in leather case, 16s. 6d.
76 SEC. 3. MEASUREMENT.
278. Chartometer, E. K. Morris's patent. (Silver medal
awarded at Manchester, 1875.)
The Morris Patents Engineering Works, Birmingham.
The only instrument that measures and registers distances on maps, plans,
scaled drawings, &c., and that is adapted for various scales. By guiding the
small steel wheel along any route on a map, the hand registers the actual dis-
tance in miles, yards, &c., according to the dial in use and the scale of the
map, which should correspond. To deal with a map of a difficult scale, the
glass front is opened by pressing a spring ; the dial removed, and another
corresponding to the fresh scale slipped into its place. A set of dials adapted
to the scales of all the Ordnance maps, and the usual scales of travelling
maps, &c., &c., is contained in a recess of the leather case, beneath the
instrument.
277 a. Pedometer, of the latest and most approved form.
J. and W. E. Archbutt, Westminster.
This instrument has pendulum action, and is worn suspended in the waist-
coat pocket ; it is provided with a regulator whereby it can be set to accu-
rately record distances walked.
277b. Improved form of Pedometer, by Dollond, in which
the direct chain action is substituted for the lever ; made in the
early part of the nineteenth century.
J. and W. E. Archbutt, Westminster.
277 c. Pedometer or instrument for accurately register-
ing distances walked. This instrument was invented and made
by Spencer and Perkins in the latter part of the eighteenth
century. /. and W. E. Archbutt, Westminster.
290. Scale for Measuring Curves, Eschenauer's patent.
Hermann Schafer, Darmstadt.
The curve scale is intended for engineers, steam boiler makers, surveyors,
architects, and others, for copying maps, plans, &c.
It will be of great advantage in the projection of railway lines, the
curve scale requiring only to be adjusted to the situation in order to ascer-
tain how the line can be most favourably traced, and expensive cuttings
avoided. In regard to such surveys, as well as in the control or examination
of railway lines already traced and sketched (for which purposes either the
curves, cut of certain radii, or compasses, are used at present), the employ-
ment of the curve scale will save the trouble of trial, since the correct one can
be immediately determined and read by means of this instrument.
Boiler manufacturers, also, and almost all engaged in technical pursuits, will
find the curve scale very useful for determining the radius of an arc of a
circle, of which three points are given, as, for instance, in curved steam
boiler bottoms.
In fact, in all cases where part of an arc of a circle, or three points of the
samei are given, the radius can be read direct, and without loss of time, in a
manner hitherto unknown.
If it be desired to take the radius of a given curve by means of the scale,
the middle bar of the same is placed on the curve line, and the scale is then
III. AREA. 77
moved so far upwards or downwards until the curve line meets in three com-
niensurably described points of the scale. The number indicated gives the
radius of the curve in centimeters, if the curve is drawn in its natural size.
If, however, the drawing of which the radius of the curve is to be deter-
mined is, as is usually the case, on a reduced scale, the radius indicated must
be multiplied with the proportional number of the reduced scale.
For example, if the drawing should be to the scale of -^^ of the natural
size, and the curve radius on the curve scale is indicated with 52 5 cm., the
actual radius of the curve will be 52 '5 x 2,500 = 131,250 cm., or 1,3 12* 5 meters;
or, should the drawing be to the scale of -gfa, and the curve scale indicates
43 cm., the radius of the curve will be 43 x 500 = 21,500 cm., or 215 meters.
The curve scale can likewise be used as a reduction scale of every other
measure which is to be calculated in meter measure, as the radius in meters
can always be read directly, no matter in what scale the drawing is made.
This is a great saving of labour, which is very much facilitated if, as often
is the case, old maps and drawings are to be made use of.
In using the curve scale it will sometimes happen that the curve to be
ascertained does not exactly meet the line drawn on the scale, but will fall
between two lines. In this case the smaller division can, as the radii are
marked progressively by 0'5 cm., be easily estimated by eye after a little
practice.
For example, the curve of the radius of 1,110 meters, at a proportionate
scale of ^ 5 1 6 6 ., lies between 88 5 and 89 * of the curve scale, and amounts to
nearly 88 -9.
As, however, in most cases, round numbers, without fractions, are chosen
for the radii, the radius can always be determined with the greatest accuracy,
109 3 a. Ellipsometer.
Before the eyepiece of the glass, a double refracting prism is made to turn
until a wire, moving perpendicularly to the principal section of the prism.
passes through the two intersecting points of the two reflections of the ellipse.
An index shows at the moment the position of the prism.
Graphometer of Botti.
The Royal Institute of " Studii Superiorly Florence.
III. MEASUREMENT OF AREA. *
316. Amsler's Flanimeter, for calculating with perfect
accuracy the areas of plans, maps, or other plane surfaces, in
square inches and metrical measure. Elliott Brothers.
317. Folarplanimeter. Ott and Coradi, Kcmpten, Baviera.
By means of the polarplanimeter the superficial contents of any kind of
figures drawn on paper, no matter what their outline may be, can be ascer^
tained by mere tracing more exactly and quickly than by any other method.
The inventors of this instrument are respectively J. Amsler, Schaffhausen,
and Ch. Starke, Vienna. Ott and Coradi's construction is a combination
of both, embracing the excellences of each. It differs from Amsler's instru-
ment by the pole (axis) of the instrument not being formed by an inserted
point of a needle, but by a steel ball embedded in a metal cylinder, thus
78 SEC. 3. MEASUREMENT.
giving it a firmer position ; and, moreover, by the axis of the roller being
lodged in a horizontal frame, and the dividing circle of the roller as well as
the indicating wheel being free at the top, thereby affording much easier and
more accurate reading than Amsler's instrument. This arrangement has the
advantage that for simple calculation the zero point of the roller can be placed
exactly on the zero point of the vernier, when the tracing pencil is at the
commencement of the figure. The weight can be separated from the instru-
ment, by withdrawing the bolt, and placed in the case by itself. The runner
carrying the axis of the polar arm can be moved along the whole length of the
quadrangular bar, by which means at every longitudinal scale desired a
round number can be obtained for the value of the vernier unit (for example,
scale 1 * 500 vernier unit, 2 square meters, or scale 1 1440 vernier unit, 5 square
fathoms). The tracing bar is divided into \ mm., and the runner sliding on
the same carries on one side a vernier, on the other an index. For adjustment
with the index, the most usual or specially desired longitudinal scales are
marked with lines on the bar ; by means of the vernier and the divisions on the
bar, proportions of measure not previously given can be easily inserted and
noted down ; in the same manner, in the case of plans which have been drawn
on shrunk paper, the area can be retained in its actual size by a corre-
sponding movement of the runner, and the position of the vernier noted down
for a certain amount of shrinking.
318. Planimeter, divided on a glass plate.
F. W. Breithaupt and Son, Cassel.
The planimeter consists of a network marked on a glass plate for a certain
scale of the meter measure.
319. Wetli's Planimeter.
Physiological Institute of the University of Halle (Prof.
Bernstein, Director).
The planimeter is fitted together by placing the six-toothed movement into
the centre of the divided disc, whilst the central point of the small glass disc
moves at the other end in the screw of the ring encircling the divided disc.
Next, the slide with the large glass disc is placed on the three-railed track
in such a manner that the horizontal glass disc comes underneath the smaller
vertical one ; the latter is then, by means of the screw which is fixed on the
ring, regulated in such a manner that it is easily carried along with the hori-
zontal disc by friction.
The pointer moving on the same axis with the divided disc indicates the
superficial contents of the figure in square millimeters. The small toothed
wheel records every 1,000 square millimeters of the surface.
IV. MEASUREMENT OF VOLUME.
STANDARD MEASURES.
319a. Casts of a Collection of Roman Measures to hold
liquids. Archaeological Museum, Madrid.
The originals, of alabaster, are preserved at the Archaological Museum of
Madrid. They were discovered at the end of the last century in the Torre del
Mar, Province of Malaga, Spain.
IV. VOLUME. 79
322a. Series of Standard Measures of Capacity, in
copper, with glass discs, from the centilitre to the double
decalitre. (11 measures.)
Messrs. Collot Brothers, Boulevard de Montrouge, Paris.
324. The Standard Pint, popularly known as " The Stirling
Jug." The Smith Institute, Stirling.
This measure was entrusted to the town by Act of (the Scottish) Parlia-
ment, in the year 1437. Sometime previous to 1745 it had been borrowed
by a coppersmith for the purpose of making others, and as he joined the
insurgents in " 45 " it was lost sight of. On his not returning, his effects were
sold, with the exception of a few that were thrown into a garret as rubbish ;
among these, in 1752, the Stirling Jug was found, after some years of patient
and unwearied search (by Rev. A. Bryce, of Kirknewton). It is made of
brass, and is in the shape of a hollow truncated cone, weighing 14 Ibs. 10 oz.
1 dr. 18 grs. Scottish troy. Diam. of mouth 4.17 English in., of the bottom
5-25 in., and depth 6 in. On the front, near the mouth, is a shield in relief,
bearing a lion rampant, the Scottish national arms, near the bottom is ano-
ther, bearing an ape passant gardant, supposed to be the arms of the foreign
maker.
324a. Russian Standard Measures of Capacity (Vedro,
V., \ V., T \J- V., T ^ V.). Siemens and Halske, Berlin.
These measures, made of bronze, have a coni-
cal shape, newly adopted in Russia, for standard
and trade measures of capacity. In these mea-
sures the inner diameter, A B, of the bottom
is equal to an inner side, A C, and double
diameter, C D, of the orifice. By very sim- /
pie contrivance, such trade measures might /
be verified, approximately, by (linear) mea- / jj
surement of A B, A C, and C D.
325. Set of Standard Measures for Alcohol, conical
shaped, in order to diminish the possibility of evaporation of the
liquid. Siemens and Halske, Berlin.
322. Measures of Capacity, according to natural principles.
Hans Baumgartner, Basle.
WATER METERS.
321. Schmid's New Water Meter. A. Schmid, Zurich.
This meter consists of two of Schmid's patent hydraulic motors, coupled
at right angles, and enclosed in a water-tight casing. They are set in motion
by the force of the fluid they have to measure. At each revolution a volume
equal to the contents of four cylinders must pass. The pressure required to
keep tight the oscillating surfaces of the cylinders is furnished by the
difference of pressure at inlet and outlet, which is thus self-regulating. The
80 SEC. 3. MEASUREMENT.
meter is also kept in motion by the difference of pressure. The frictional
resistance is the same with all pressures of the fluid under measurement, and,
according to the size of the meter, is represented by a water head of 3 to
16 ft. The different parts of the meter are constructed of materials not
liable to chemical influence.
The chief advantages of this meter are :
1. The velocity of the engine is exactly in proportion to the quantity
flowing through the meter.
2. According to the most careful experiments, the error, if any, does not
exceed 1 per cent.
321a. Siemens' and Adamson's Patent Water Meter.
Guest and Chrimes, Rotherham.
This meter has a great resemblance to the motive-power machine known as
Barker's Mill. The water passes down through a funnel into the measuring
drum, and in passing outward through the curvilinear channels of the 'same
causes it to revolve, delivering a certain quantity of water at each revolution
of the drum, and this is indicated by worm wheel and gearing, in gallons, feet,
or any other units required, on a dial plate properly divided and prepared
for the purpose.
The meter is exhibited in section, so that the internal arrangements and its
action can be seen. This meter has been extensively used for upwards of 20
years.
32 lb. Half-inch Patent Water Meter, for the water supply
for domestic and trade purposes on the constant supply system.
J. Tylor and Sons, London.
326. Water-meter, for cold water, for 26 mm. width of
tube. Dreyer, Rosenkranz, and Droop, Hanover.
327. Water-meter, for domestic use.
Dreyer, Rosenkranz, and Droop, Hanover.
331. Model of a Gas Meter of ancient construction, with
glass sides.
School for Industry, Halle (Dr. Kohlmann, Director).
329. Apparatus for determining the capacity of Car-
tridge-cases as far as 20 cub. mm. A. Bonsack, Berlin.
330. New Volumeter, consisting of A. Sauer's burette,
a second glass piece, stands and tubes.
(Compare Fresenius, " Zeitschrift fur analytische Chemie," xiv.
heft. 3 and 4).
Berggewerkschafts-kasse, Bochum, Dr. Heintzmann.
V. MASS. 81
V. MEASUREMENT OF MASS.
A. BALANCES.
333. Balance, with double column, 20-inch beam, fitted with
steel knife edges working on agate planes, to carry 5 Ibs. in each
pan, and turn distinctly with '01 grain. Fitted with apparatus
for moving sliding weight without opening glass case. As made
for the Warden of Standards, for comparison of standard weights.
L. Oertling.
334. Balance, with double column, very light beam, 10 inches
long, fitted with agate knife edges and agate planes, to carry
30 grains in each pan, and turn distinctly with 001 grain, with
apparatus for moving sliding weight. L. Oertling.
335. Balance, with 14-inch beam, fitted with agate knife
edges and agate planes, to carry 1,500 grains in each pan, and
turn distinctly with *001 grain. L. Oertling.
336. Balance, with 16-inch beam, fitted with agate knife
edges and agate planes, to carry 2 ibs. in each pan, and turn
distinctly with 02 grain. L. Oertliny.
337. Balance, with triangular beam, 6J inches long, fitted
with agate knife edges and agate planes, to carry 3,000 grains, and
turn distinctly with 01 grain. L. Oertliny.
338. Balance, with beam 6 inches long, fitted with agate
knife edges and agate planes, to carry 2,000 grains in each pan,,
and turn distinctly with '02 grain. L. Oertling.
339. Portable Assay Balance, with 6-inch beam, to carry
30 grains in each pan, and turn distinctly with '001 grain.
L. Oertling.
34:0. Balance, constructed by H. Qlland, of Utrecht, to
weigh bodies up to 40 kilogrammes.
Prof. Dr. P. L. Rijke, Leyden.
This instrument is furnished with a double system of " fourchettes,"
directed by a rod 6 m. long. A difference of 1 in the pointer corre-
sponded to a difference in weight of
9 5 m. gr. when the weight was 20 kilogrammes.
10-5 50
13-8 73
With weights of about 50 kilogrammes, in a series of experiments under
favourable conditions, between each of which the balance was set at rest,
numbers not differing in the average by more than 0'03 were obtained.
When conditions were less favourable, the differences amounted to 0'26, and'
only reached 0> 94 when the conditions were altogether unfavourable.
40075. F
82 SEC. 3. MEASUKEMENT.
341. Analytical Balance, charge up to 500 grammes in
each pan ; sensible to -^ part of a milligramme with its full charge.
Beckers Sons, West Zeedyk, Rotterdam.
This balance is furnished with agate knife edges, and all bearings rest on agate
planes ; it has a rest for pans and beam, and apparatus with adjustable shelf
for taking specific gravities. The beam is divided in -J- parts of a milligramme.
Sets of weights from 500 grammes down to 1 milligramme. Three riders.
342. Analytical Balance, on plan suggested by Professor
Dittmar, Andersonian University, Glasgow, for a charge up to
100 grammes in each pan.
Beckers Sons, West Zeedyk, Rotterdam.
This instrument shows a new method for displacing the centre of gravity of
the beam, and for weighing up to 110 milligrammes by means of riders. The
two riders form a part of the balance, with plunger for displacing exactly
10 grammes of water at 15 C. for taking specific gravities of liquids. Sets
of weights.
343. Balance, with drawer and eccentric for lifting, movable
pans, set screws and level, charge up to 1^ kilos, in each pan,
sensible for 20 milligrammes with its full charge.
Beckers Sons, West Zeedyk, Rotterdam.
344. Balance, charge up to 1 kilo, in each pan, sensible for
20 milligrammes with its full charge.
Beckers Sons, West Zeedyk, Rotterdam.
344a. New description of Balance of Precision, designed
by M. Mendeleef, Professor of the University of St. Petersburgh,
and constructed by Oertling. It is more particularly described
in Appendix 10 to the Ninth Annual Report of the Warden of the
Standards. H. W. Chisholm.
The peculiarity of this balance is that it has very short arms, and thus
occupies very little room, and by its more rapid motion time is saved in weigh-
ings, whilst it gives results quite as 'accurate as those given by balances of
precision with arms of greater length as ordinarily used.
Though constructed to carry a kilogram in each pan, the total length of
the beam of this balance is less than 4f inches, whilst it is intended to give
results within one tenth of a milligram. The balance beam to carry a kilogram
is ordinarily 20 inches in length.
It can be used as a vacuum balance, as well as for weighings in air.
344b. Balance of Precision for minute weighings of 10
grains and under in each pan, constructed by Oertling.
H. W. Chisholm.
The beam is made as light as possible, and unusually so. The pans and
suspending wire are of aluminium. The balance works upon fine points.
A single action lowers the support of the beam and the supports of the
pans.
348-9. Frerich's analytical Balance, capable of carrying
2,000 grnis. with riders and *a set of gramme weights.
F. Sartorius, Gottingen.
V. MASS. 83
350. Analytical Balance, capable of carrying 500 grms., and
a set of gramme weights. F. Sartorius, Gottingen.
351. Analytical Balance, capable of carrying 200 grms.,
with a set of gramme weights. F. Sartorius, Gottingen.
352. Frerich's Analytical Balance, with contrivance for
weighing by means of torsion. F. Sartorius, Gottingen.
353. Pair of Russian Scales. Bennct Woodcraft, F.R.S.
354. Test Balance capable of carrying 20 grammes in each
scale. Edouard Sacre, Brussels.
The bearings are taken off the knife edges when the balance is at rest. With
20 grammes the balance is affected by the 750th part of a milligramme.
With 2 grammes it is affected by the 7,000th part of a milligramme.
354a. Model Balance, with 'two columns, specially intended
for verifying the standard kilogram weights, mounting and tongue
of aluminium bronze, tires and scales of aluminium, riders,
carriage for shifting the weights from one scale to the other,
rests for four weights, rules for the use of small sliding weights
replacing the divisional series of the gramme, such as the deci-
gramme, centigramme, milligramme, 10th of milligramme, hand
of aluminium with double dial, parallel mirror for reading the
oscillations at a distance, spherical level, two " Baudin " ther-
mometers.
Messrs. Collot Brothers, Boulevard de Montrouge, Paris.
354b. Model Balance, with two columns, charge 300 grammes
range, for chemical analysis, mounted on cast-iron tripod, mount-
ing and tongue of bronze, platina tires, riders showing tenths
of the milligramme, spherical level.
Messrs. Collot Brothers, Boulevard de Montr ouge, Paris.
357. Printing Beam for Weighing Machine, admitting of
the registration of each weighing. M. Chameroy, Paris.
This method of checking is applicable to all weighing machines of the
nature of the steelyard. It would be found useful at custom houses, depdts,
markets, railway stations, works, and other similar places.
Its advantages are :
1. The affording of a record, by means of a printed impression on a special
ticket, of the exact amount of the weight as determined by the machine itself.
2. The facilitating of the reading of the weights, either on the ticket or on
the scale beam.
3. The preservation of an exact record^ of weighings, the authenticity of
which is thus ensured.
358. Physical Balance, weighing up to five kilogrammes.
Hugo Schickert, Dresden.
F2
84 SEC. 3. MEASUREMENT.
359. Physical Balance, weighing up to 200 grammes.
Hugo Schickcrt, Dresden.
363. Fine Assay Balance for weighing 20 grammes, turning
with I/ 100 nig. G. Westphal, Celle.
364. Large Balance for determining the specific gravity of
liquids. G. Westphal, Celle.
365. Large Balance used in the Manufacture of Sugar.
G. Westphal, Celle.
366. Small Balance for determining the specific gravity of
liquids. G. Westphal, Celle.
367. Pharmaceutical Balance, for simple chemical opera-
tions. G. Westphal, Celle.
370. Balance for chemical and physical purposes.
C. Staudinger and Co. (F. W. von Gehreri), Giessen.
Balance of the exhibitors' construction ; capacity of weighing, one kilo-
gramme on each scale ; sensitive at this weight, to 0-4 milligr. The balance is
made of one piece of wrought (not cast) brass, and gilded. The centre and
terminating knife edges are of steel, and all supports of hard stone. The
weight of the beam with knife edges is = 793 grammes ; deflexion of the beam at
1 kilogr. weight on each scale = 0' 14 mm. ; at 1-500 kilo. weight=0'02S mm. ;
at 2-000 kil. weight = 0-042 mm.; at 3-000 kil. = 0*070 mm. A permanent
deflexion has not been observed at such a weight.
375. Ten Plates of Bock Crystal for Balances.
Hermann Stern, Oberstein.
376. Cheinico-physical Balance, executed by Ch. Jung,
in G iessen.
Collection of Physical Instruments of the University of
Giessen (Prof. Dr. Buff).
By shortening as much as possible the beam these scales offer the ad-
vantage of great sensitiveness and sufficient rigidity to weigh accurately from
250 grammes to -- milligrammes.
377. Analytical Balance, executed by Stollenreuther.
University of Munich.
379. Standard Weights in Glass, executed by Stollen-
reuther. University of Munich.
381. Model of a Balance for determining the quality of
grain, constructed according to the directions of the Imperial Ger-
man Commission for Standard Weights and Measures, with a
corn measure of 1 liter capacity. Reinhold Lohmann, Berlin.
The manner of adjusting the several parts, as well as the successive series
of applications of the same, is illustrated and facilitated by an explanation,
with sectional and cross-sectional drawings, accompanying the model.
V. MASS. 85
The practical employment and use of the apparatus for scientific and
technical industries, in the first instance, and next for the solution of national-
economical problems, will be demonstrated by two continuous memoirs,
published by the Imperial German Commission on Normal Weights and
Measures.
381a. Corn Balance, in box for showing the per-centage
in value of corn by weight as a means of fixing the price for pur-
chase or sale. L. Casella.
382. Model of a Centesimal Weighing Machine, with
glass platform. Dr. Kohlmann, Halle.
384. Model of a Decimal Weighing Machine, with glass
platform.
Physical Institute of the University of Halle (Prof.
Knoblauch, Director).
386. Beam Balance with equal arms, sensibility 1 : 200,000.
Kleemann, Mechanical Engineer, Halle.
390. Beam Balance, for educational purposes.
Alex. Bernstein and Co., Berlin.
The beam, for educational purposes, has contrivances for demonstrating
the different peculiarities of a scales-beam, or balance, namely, displacement
of the centre of gravity, lifting and grinding of the principal bearings, unequal
lengths of levers, non- parallelism of the knife edges, and position of one ter-
minal knife edge out of the level of the two other knife edges.
388. Small Decimal Balance, for educational purposes.
Alex. Bernstein and Co., Berlin.
The decimal balance for instruction in schools has on each prism a scale,
so that the influence of the weight on each prism can be shown by itself.
389. Analytical Balance.
Alex. Bernstein and Co., Berlin.
This analytical balance is capable of carrying 500 grammes, and when
fully weighted has a sensitiveness of -^ mgr. ; it has a perforated gilded
brass beam with axes of agate and pans with arrangement for releasing all
knife-edges, stop balance with pencil, and riders.
389a. New Balance for a Laboratory, carrying three
kilogrammes in each pan, and turning with five milligrammes.
Dcleuil, Paris.
When it is not in use, the beam is supported free of the knife edge, as in
other accurate balances ; vessels 25 centimetres in diameter can be placed on
the pans, also vessels with long necks, and flasks of 1-2 litres capacity. By
the aid of the second pan, the specific gravity of very bulky bodies can be
obtained.
389b. Balance in mahogany case.
Universitdts Laboratorium, Berlin,
86 SEC. 3. MEASUREMENT.
390a. Self-Acting Balance for Galvanic-plastic pur-
poses. Alex. Bernstein and Co., Berlin.
The balance for galvano-plastical purposes is so constructed that the con-
duction is interrupted automatically as soon as a deposit of a certain weight
has been obtained.
391. Balance for Blow-pipe Experiments, in a case,
with weights. Alex. Bernstein and Co., Berlin.
The scales are for blow-pipe experiments; they have steel axes, and
agate planes, two horn pans, two pairs of small gilded bowls, one bowl
with hook for the determination of specific gravities, and a set of weights from
1 gr. to 1 centigr. of silver ; from 1 centigr. to 1 milligr. of aluminium, and
the fraction milligr. of quills.
392. Gold Assay Balance.
Alex. Bernstein and Co., Berlin.
The gold-alloy scales have a carrying capacity of 5 grammes, and are
provided with bearings of agate, and indicate, when fully weighted, ^- milligr.
378. Balance for Weighing in Vacuo, on von Jolly's
principle. University of Munich.
392a. Bullion Scales. The property of the Conservatoire
des Arts et Metiers, 1866 ; constructed by Baron Seguier.
The late Baron Seguier, Membre de Tlnstitut.
419a. Spring Balance, with arrangement for suspending the
lever and the scales on steel springs.
Physical Institute of the University of Halle (Prof.
Knoblauch, Director).
428. Von Jolly's Spring-balance. University of Munich.
B. STEELYARDS.
332. Roman Steelyard or Stater a, of bronze. It was
found in the year 1855, during building operations at Watermoor,
a suburb of Cirencester, Gloucestershire.
Professor A. H. Church.
The beam, which is nearly 17 inches long, may be reversed, and it is con-
sequently divided along both its upper and under edges. When the fulcrum
nearer the head of the beam is employed objects can be weighed more than
twice as heavy as those which can be accommodated when the beam is sus-
pended by the other hook. To the head of the beam is attached a chain,
branching below into two parts, each terminated in bold hooks adapted for
grasping soft and bulky articles. This steelyard is a very good example of
its kind. The locality which furnished it was the site of the Roman city of
Corinium or Durocornovium, which has yielded an immense number of Roman
remains, many of which are preserved in the local museum.
V. MASS. 87
383. Model of a Roman Balance, with sliding weight of
To grammes, and stand.
Physical Institute of the University of Halle (Professor
Knoblauch, Director).
C. WEIGHTS.
346. Five Standard Weights derived from the polar stand-
ard of length. Prof' Hcnnessy, F.R.S.
One of these weights is equivalent at 15 centigrade to a cube of distilled
water whose side is the one hundred millionth part of the earth's polar
axis. The others are submultiples of this weight, and the Astern is
suggested in connexion with the polar standard proposed. See " Essay on a
Uniform System of Weights, Measures, and Coins of All Nations," by Pro-
fessor Henuessy.
346a. Series of Massive Copper Weights, standards of
I gramme up to 20 kilogrammes, with subdivisions in platina.
II Necessaire " for inspector of weights and measures on his rounds,
weighing about 10 kilos., and containing every requisite for testing
scales, of weights, measures of capacity, and of length, and
apparatus for stamping.
Messrs. Collot Brothers, Boulevard de Montrouge, Paris.
346b. Ancient French Standard Weight of the city of
Rouen, of brass, in the form of a series of cup weights in a
closed box of ornamental shape, weighing altogether 8 Ibs. of the
old poids de marc de Charlemagne. Presented to the Stan< lards
Department in 1869 by Colonel Le Contens, Viscount of Jersey.
H. W. Chisholm.
346c. Weight, wrought iron, ornamented with arabesques,
flowers, and masks. Made for the old Mint at Madrid in the 17th
century by the iron-master Salinas.
Archaeological Museum, Madrid.
360. Physical Weights. Hugo Schickert, Dresden.
361. Eight Sets of Weights, for analytical purposes.
G. Westphal, Celle.
The first of these weighs from 1 kilogramme downwards, the second from
500 grammes downwards, the third from 100 grammes, the fourth, fifth, and
sixth from 50 grammes, the seventh from 10 grammes, and the eighth from
5 grammes downwards.
362. Standard Weights. Each weight consists of one piece
of solid metal adjusted by the gilding process.
G. Westphal, Celle.
These consist of a 1 kilogramme weight, a set of weights weighing from
1 kilogramme downwards, and a set of standard weights with pin adjustment
weighing from 500 grammes downwards.
362a. Box of Weights, containing two kilos, and fractions of
a kilo. Deleuil, Paris.
88 SEC. 3. MEASUREMENT.
362a. Case of Weights and Measures. T. Oertling.
'Containing
Set of weights from 1 kilogramme to 1 milligramme.
Set of weights from 50 grammes to 1 milligramme.
Set of weights from 1,000 grains to -^ grain.
Set of weights for assaying silver, 1,000=1 gramme, in
circular ivory box.
Sets of weights of rock crystal (one spherical set), from 50
grammes.
Set of measures from \ litre down.
Dikes' hydrometer, as supplied to the Honourable Board of
Inland Revenue.
Bates' saccharometer, as supplied to the Honourable Board
of Inland Revenue.
Set of petroleometers for testing liquids of 650 to 900
specific gravity.
262b. Iridio-Platinum Standard Kilogram.
Johnson, Matthcy, and Co.
323. Standard Weights, according to natural principles.
Hans Baumgartner, Basle.
374. Sets of Weights and single Weights from 1 kilo-
gramme, made of rock-crystal ; amongst them some which have
been examined and marked with an index error by the Imperial
Commission for regulating Standard Weights and Measures at
Berlin. Hermann Stern, Oberstcin.
The weights, as well as the measures of quartz or rock-crystal, were
many years ago recognised as the best and most correct ; but no one has, up
to this time, executed them in such a manner as to afford institutes an op-
portunity of procuring them ; which want has now been supplied by the
exhibitor.
The other objects of agate are such as are produced by the Oberstein-Idar
grinding and polishing mill, and can be employed in different kinds of
machinery.
374a. Series of Spherical Standard Weights in Quartz,
from 1 kilogramme to 1 milligramme. A. Hilger.
374b. Standard Kilogramme Weight, quartz sphere, on
brass stand. A. Hilger.
374c. Standard Kilogramme Weight, of guaranteed value
1-0000019 kilo. A. Hilger.
387. Set of Pharmaceutical Weights from O'Ol grammes
to 200 grammes (19 pieces).
Kleemann, Mechanical Engineer, Halle.
Representation of the Weights and Measures used in
the time of Henry VII., as well as the mode of punishment of
fraudulent traders, copied from a painting on panel of the period
(doubtless official). Gardner Collection.
V. MASS. 89
D. INSTRUMENTS FOR DETERMINING SPECIFIC GRAVITY.
347. Tangential Balance for measuring the density of
liquids and solids by the angle of inclination, read on a divided
circle to two minutes, thus giving the third decimal of specific
gravity ; made by Oertling, of London.
Prof. Carl Wenzel Zenger, Prayue.
355. Hydrostatic Balance, by Ramsden; with Weights,
by Robinson, presented to the Royal Society by Lady Banks.
Royal Society.
368. Xylometer (cylindrical form), with brass cylinder.
Zimmer Brothers, Stuttgart.
369. Xylometer of Glass, prismatic form.
Zimmer Brothers, Stuttgart.
These instruments are chiefly used in the management of forests, and for
agricultural purposes.
They are employed for exact scientific examinations, especially for the
cubing of irregularly-shaped pieces of wood, and for determining the specific
gravity of wood.
Discs of wood which have been split out from the heart in the direction of
the pith rays, and therefore contain proportionate parts of all veins of wood,
can be quickly and exactly examined.
With both apparatus it is possible to read on the scale accurately down to
5 cub. centimeter (5 grammes water).
(See " Holzmessekunst," by Prof. Dr. Baur, Hohenheim.)
425. Hydrostatic Apparatus for ascertaining the specific
gravity of woods.
Prof. Dr. Nordlinger, Hohenheim, Wurttemberg.
372. Densimeter of Major Bode's construction, for determin-
ing the specific gravity of all sorts of powder.
A. and R. Hahn, Cassel.
The densimeter is the only existing instrument with which the specific
weight of all sorts of gunpowder (prismatic powder, powder-cakes, fine and
coarse grained powder, &c,), can be easily determined, in quantities of 50 to
250 grammes, with the most perfect accuracy.
It is constructed by Major Bode.
This apparatus consists of a reservoir with bolt, two gutta-percha tubes, and
a clamp.
1 . The reservoir is formed by a steel capsule, with lid fitting air tight.
By means of the bolt the lid of the steel capsule can be screwed fast on
this.
The contents of the reservoir are so measured in the clear that a prismatic
powder grain can be easily placed in it.
Lid and steel capsule are vaulted, in order to accelerate the exhaustion of
the air by pumping.
In the steel capsule in the upper part and in the lid in the lower
part, there is an air-tight cock. The reservoir communicates with these
90 SEC. 3. MEASUREMENT.
cocks by means of two channels, which, for fine-grained powder, are shut off
by a steel tinplate filter, the holes of which.have a width of 0'3 mm. The two
tubes, 1 and 2, are screwed air-tight on the plugs of the two cocks 1 and 2.
At the upper ends of both tubes funnels of glass are squeezed in for more
conveniently filling and emptying the mercury. The shorter tube, No. 1, of
about 600 mm. length, carries in the centre a glass-tube, about 200 mm. long,
divided into niillims, and can, just above this tube, be closed air-tight by
means of a screw cramp. The interior diameter of the tube No. I is about
9 mm., whilst that of tube No. 2, which is about 2,500 mm. long, measures
only about 5 mm. The gutta-percha tubes are spun over on the outside.
Reservoir and tube 1 are fastened in a wooden frame ; funnel 2 is in a
wooden- lining.
This precaution has been taken for the reason that the temperature of the
mercury and of the apparatus should be altered as little as possible during the
operation by the warmth of the hands. By means of two strings, which run
over rollers fastened in the ceiling of the room, funnel 1 and funnel 2 can be
pulled up or down at pleasure.
The auxiliary apparatus further required :
1. A thermometer, by means of which, previous to, during, and after the
filling in of the mercury, the temperature of the same will be ascertained.
2. A fine pair of scales indicating to 0*001 grammes, with a carrying
capacity of 6 kilos, (each scale 3 kilos.)
3. A barometer for determining the pressure of the atmosphere at the
place of operation.
4. A wooden scale, 1 m. long, with a steel point, and a slide for exactly
measuring the difference in the levels of the mercury meniscus in the two
tubes 1 and 2.
Theory of the Densimeter.
Let the weight of the reservoir, with the tubes screwed off, but inclusive
of the connecting piece screwing the capsule and the lid together, = R
grammes. After the reservoir has been exhausted, and filled with mercury,
let its weight at temperature t of the chemically pure mercury =T grammes.
Consequently the contents of the reservoir filled bythe mercury amount to
rp *D
cub. centim.
13-59(1 -0-00018 fr
If now P grammes of powder be placed in the reservoir, and the air exhausted
and the remaining space filled with mercury, the whole will weigh, at
temperature t, only T' grammes, hence if Y is the volume of the P grammes
powder, at t temperature,
T-T' + P
13-59 (1-0-00018 <)
consequently the specific gravity of the powder to be examined
* =spec ifi c g*y-r"*(*_-^"q-
The following examples will serve as illustration :
The specific gravity of chemically pure mercury amounts at
Gels. = 13-59; 10 Cels.= 13'5 n 19 Gels. = 13-55 ; 27 Cels.= 13'53
5Cels.= 13-58 ; 15 Cels. = 13'56 23 Cels. = 13'54.
V. MASS. 91
Example 1.
T=the reservoir filled with mercury weighs at 19 Cels.= 1091-6
K = the empty reservoir - = 329*6
Q = T li. Consequently mercury 762'0'grammes,
Consequently contents of the reservoir at 19 Cels.
T-R 762-0
= 13-59 (l-< 0-0018) = 13T5 ==56>236 Cub " Centim "
If now 60 grammes (= P) gunpowder is placed in the reservoir, and the
remaining space filled with mercury, we obtain
611-6 grammes ( = T t )
Reservoir empty =329 -6
60 grammes powder = 60-0
= 389-6 deducted,
remains Q = 222.0 grammes weight of the mercury filling the intervening
space, occupying at 19 Cels.
1 = 2^=16-444 CUD. centiin.
13'55
Consequently volume of the 60 grammes powder= 56-236 16*444
V= 39*792 cuh. centims.
p
S y = specific weight of the 60 grammes gunpowder
1.J07
39-792
Example 2.
If a powder prism weighs 42-0 grammes at 190 C. and weight of reservoir,
powder prism and mercury = 808-4 grammes.
Reservoir empty 329-6
42 grammes powder 42-0
371-6
consequently of 808-4
371-6 deducted,
= 436-8 grammes weight of mercury,
or - - = 32-236 cuh. centim. occupied hy these 436'8 grammes.
13*55
Consequently volume of the 42 grammes weighing powder prism =56-236
32-236 = 24-0 cub. centim.
Thus, specific weight of the powder prism= _I_ = 1-75
24-0
General Formula.
S _P_ F P _ __ Q
V I-I 1 T-R or -13-59(1-^0-0018),
13-59(1- t 0-0018)
g = P [13-59 (l-< 0-0018)] Since Q 1 = T' - R . - P
T-R-Qi . '
g _ P 13-59 (l-t 0-0018)
T-T' + P
92 SEC. 3. MEASUREMENT.
The extension of the examples 1 and 2, therefore, is essentially facilitated :
Example 1.
Given P= 60 gr. t= 19 C., consequently 13-59 (1 19 0-0318) = 13'53
T=1091-6 grammes, T' = 61 1-6 grammes.
Example 2.
Given P = 42 grammes <=190 C.,
consequently specific weight of mercury =13*55.
T= 1091-6 T'= 808-4
Because the expansion coefficient of the reservoir made of steel is different
for changing temperatures from that of the mercury, it will be necessary for
determining once for all empirically the weights of Tn for +0, +5, 10, 15,
20, 25, 30, 35 Gels., to calculate the required cubical contents of the reser-
voir = Vn, to interpolate them graphically, and to embody them from degree
to degree in a table.
DIRECTIONS FOR USE OF THE DENSIMETER.
The temperature of the mercury is determined and noted before, after, and
during the period of operation. For that purpose it is advisable to employ a
thermometer composed of a very fine glass tube, which admits of being
inserted in the gutta-percha tube No. 1, which has been filled up to the
aperture of the funnel.
The mercury in funnel 1 will show, on account of the friction and con-
sequent heating, 13 more heat than that in funnel 2. This difference is,
however, equalised in a very short time.
During the operation the apparatus must only be touched on the wooden lining,
in order to avoid as much as possible any variations in the temperature which
may be caused by the warmth of the hands. The powder to be tested must
be of nearly the same temperature as the mercury to be employed, for which
purpose it will be best to keep both before the testing operation for several
hours in the same room. The reading of the barometer which indicates the
pressure of the atmospheric air must be noted down.
The two tubes 1 and 2 are screwed air-tight to the reservoir, the two cocks
are opened, and the apparatus fastened in the wooden frame with vertical
position of the tube No. 1.
Thereupon the funnel T" is lifted to the level of T' (upon +760 mm.), and
chemically pure mercury poured into the funnel T", until both funnels are
filled with mercury to a height of about 20 mm. The mercury will then stand
760mm. high above the ( + 0) point of the reservoir; consequently the
pressure upon the highest point of the reservoir will be altogether two atmo-
spheres (1 atmosph. pressure corresponding in the mean to 7-fi.O mm. mercury.
Under this pressure the air in the reservoir will for the greatest part be
already forced up, and in fact in the direction towards funnel 1.
Now the cramp screw-piece is attached below the funnel 1, and above the
glass tube in the centre of the hose 1 filled with mercury, and the latter shut off
v. MASS. 93
air-tight at a height of about + 600 mm. Then funnel 2 is sunk to about
1,000 mm. below the zero point of the reservoir. The mercury level will
thereupon sink below the reservoir. In case reservoir and hose 1 were
already exhausted of air, the difference of the level of both the mercury
menisci will be exactly as much as indicated by the barometer, otherwise the
difference will be smaller. All the mercury then flows back from the reser-
voir, &c. into the funnel 2, for which reason the same must have a sufficiently
large capacity, and must be lowered carefully, not too quickly. Cock
No. 1 is then shut, funnel No. 2 lifted above the zero point of the reservoir,
and the latter, which in the most unfavourable case will contain only extremely
rarified air, filled by the same ; then cock 1 is opened, and the cramp at the
hose No. 1, so that the mercury in the funnel No. 1 can rise again. This
exhausting of the air is repeated a second time if necessary.
For testing whether the reservoir is entirely or sufficiently exhausted of air,
funnel 2 is sunk so far until its mercury level has reached about 400 mm.
below the zero point of the reservoir. Now occurs a Toricelli's vacuum in
hose 1, and the mercury meniscus is seen in the glass tube.
If there were still air in hose 1, the level-difference in the hoses 1 and 2 will
be smaller than the height indicated by the barometer for the day in milli-
meters. In this case the operation mentioned before is repeated. In all cases
at a position of funnel 2 at about 440 mm., the difference of the level of
both the mercury menisci will be, at the utmost, smaller by 2 3 mm. than
the indication of the barometer for the day. If the difference in the variation
of the levels should show itself equal to the height of the barometer, which
may be easily ascertained by the scale, by adjusting the slider fastened at
the height indicated by barometer at the upper meniscus in the glass tube ;
the pressure at the upper part of the reservoir will then be
1 atmosph. air pressure 1 =
1 atmosph. mercury pressure J
consequently the reservoir is exhausted of air.
But in order to employ a further powerfully-acting means for exhausting
the air, BO far as this should not have be'en accomplished already, the
funnel 2 is lifted as high as possible up to about 2, 760=1,900 mm., thereby
the very small quantity of air still present will be forced into the hose 1
under 2* + 1 =3* atmospheric pressure, and will ascend either towards the
hose 1, or occupy only a small and practically insignificant place, of O'OOl to
O'COOl cub. cent, by shutting off the cocks 1 and 2.
The raising and lowering of hose 1 and 2 is performed by pulling or
slackening the cords running over the rollers fastened into the ceiling of
the room.
It may now be supposed that the air is completely exhausted from the
reservoir, and that its vacuum is completely filled with mercury. At all
events the hydrostatic air pump of to 3' 5 atmosph. pressure, attached to the
apparatus in the simplest manner possible, will act much more powerfully
than any other air pump.
Finally, the two cocks 1 and 2 in the mercury are shut off, the temperature
of the latter being determined, the two hoses 1 and 2, which have previously
been carefully emptied, are unscrewed, the reservoir cleaned of the mercury
globules sticking to it (especially in the parts of the screw and the interior
channel-openings of the cocks), and the weight of the reservoir, including
bolt, determined with mercury.
94 SEC. 3. MEASUREMENT.
DETERMINATION OF THE SPECIFIC WEIGHT OF THE POWDER TO BE
TESTED.
The prisms or pieces of cake, or the coarse or fine-grained powder to be
tested, are accurately weighed on a scale.
The powder prisms of 25 mm. height, 40 mm. measured across the edges,
35 mm. on two sides, with channels each of 4-2 4 f mm. wide, or one chan-
nel 10 mm. wide, weigh, as a rule, at a specific weight of 1 '6 to 1'8, from 36
to 44 grammes.
Of grained powder so much is weighed that the steel lid can be easily fixed
on the reservoir, and fastened with the bolt, consequently about 50 grammes
in case of a small reservoir with about 76 cub. cent, capacity, or 200 gr. in
case of a larger reservoir of about 217 226 cub. cent, capacity. The
quantity of powder weighed is filled into the reservoir ; this is then closed,
the two hoses 1 and 2 are screwed on, and the operation is thereupon
proceeded with as detailed in the preceding explanations.
It must be observed that the operation is very simple and expeditious,
excluding every personal error, so that, consequently, the method, being
based on scientific principles, is a thoroughly rational one.
It should cause no surprise if the operations 1 and 2 must be repeated several
times, when the powder has been filled in, in order to raise the difference of
the level of the two mercury columns to the same height as the position of
the barometer, as the large capacities of the coal of the powder for absorbing
air is a notorious fact, and as also the moisture contained in the powder is
to a very great extent evaporated in the form of aqueous vapour, or ejected
by hydrostatic pressure and tension.
373. Mercurial Powder Balance, Major Bode's con-
struction, for determining the specific gravity of prismatic and
coarse-grained gunpowders. A. and R. Hahn, Cassel.
The mercurial powder scale replaces the alcohol or so-called " volumetrical
analysis method," and by means of this instrument the specific weight of
the different sorts of powder, prismatic, powder-cake, and coarse-grained
can be exactly determined with quantities of 40 to 50 grammes.
380. Balance for Weighing in Vacuo.
Paul Bunge, Hamburg.
The vacuum scale is a duplicate of a similar scale made by the exhibitor
for the Physiological Institute at Kiel. For facilitating exhaustion it has
been enclosed in a small receiver of 5 inches diameter and 10 inches in
height, which was only possible by the exhibitor's system of employing a
short beam. This is 69 millimeters long, and Avith a load of 50 gr. the
balance turns with -$ mgr.
The use of the scales is as follows : After the body which is to be weighed
in dried air or in a vacuum has been placed on the scales, and the exhaustion
or the desiccation has been effected, the scale can be arrested and released
by turning three studs fixed in the bottom plate. All weights of 20 gr. to
0-01 gr. can be placed on or lifted off the pan. Lastly, a rider can be tra-
versed the whole length of a beam in the line of the axis.
VI. VELOCITY. 95
VI. MEASUREMENT OF VELOCITY.
A. LOGS AND CURRENT METERS.
393. Patent Log, by Massey. For measuring speed at sea ;
in use in II. M. Navy.
Hydrograpldc Department of the Admiralty.
394. Patent Log, by Walker. For measuring speed at sea.
Hydrograpldc Department of the Admiralty.
394a. New Ship's Log. Benjamin Theophilus Moore*
In this log a revolving cylinder, furnished with screw blades, is placed
behind a tube, the front portion of which terminates in a solid pointed head.
The cylinder turns upon a spindle, in bearings inside the tube. Within the
revolving cylinder is a water-tight tube of glass containing the recording
mechanism. This tube is drawn out for the purpose of reading the dials.
The log line is attached near the centre of gravity of the whole instrument,
by which means the log is made to run horizontally, and below the surface of
the water, and as steadily as an arrow in the air.
The mechanism, being entirely protected from contact with sea water,
works smoothly, and cannot get out of order.
The glass tube is itself protected from any injury by the manner in which
it is contained within the revolving cylinder.
This log will indicate any distance, from one-tenth of a cable to one
thousand miles, with great accuracy.
394b. Massey's Patent Ship's Log. E. Massey.
Massey's Patent Frictionless Sounding Log.
E. Massey.
394c. Massey's Frictionless Propeller Conical End
Log. E. Massey.
394d. Massey's Patent Self-registering Ship's Logs.
L. P. Casella.
These logs are constructed on the rotating system devised by E. Massey,
and have registers and mile indices, to show distance run during the time the
log is overboard towing astern of ship.
394e. Reynold's Patent Pendent Log.
J. Cohen $ Co.
This log is composed of two parts ; first, the rotating log itself, and second,
the apparatus for registering the distance run while the log is overboard.
398. Ramsten's Patent Ship's Log. Elliott Brothers.
396. Current Meter, for measuring the velocity of currents
in rivers at different depths. Elliott Brothers.
An endless screw on a spindle turns two wheels at the same time, the one
recording every revolution of the blades by moving one division ; the other
indicating every complete revolution of the former.
96 SEC. 3. MEASUREMENT.
397. Bevy's Current Meter, constructed for measuring the
velocity of currents in larger rivers. Elliott Brothers.
The spherical boss is so determined that it will displace just as much water
as will balance the weight of all the parts which are fixed to the spindle, so
as to reduce friction to a minimum. Although the apparatus is covered
with glass, it has to be filled, before using it, with pure water to establish
similarity of pressure inside and outside. After every experiment the water
is removed and the spindle thoroughly dried. This form of current meter
was used by Mr. Bevy in the survey of the Parana and Uruguay rivers.
39 7a. Darcy-Pitot Gauge or Current Meter, for deter-
mining the velocity of streams of water. Prof- W. C. Unto in.
The velocity is obtained by a single measurement, and no time observation
is required. Used in Darcy and Bazin's researches on the flow of water in
pipes and canals.
399. Water Meter, based on the principle of measuring the
volume of water by recording its speed. J. A. Mutter, C.E.
This water meter consists principally of an air and water-tight chamber or
vessel, wherein moves a float, carrying two magnets of equal power, and fixed
with their dissimilar poles in juxtaposition to each other : the whole combina-
tion of the float and its spindle, together with the magnets, is made as near as
possible equal in density or specific gravity to the water. The water in pacing
through this measuring vessel is forced to take a rotary motion, by means of
a screen or a tongue, being a metal piece, put at a certain distance from the
inlet opening, and parallel with and lying along the inner circumference of
the measuring vessel. The top cover of the measuring vessel is p-operly
dished out, so a& to allow of two small soft iron armatures, fixed to a thin
metal arm or needle, to be brought outside the vessel, as near as can be to
the poles of the magnets inside; the metal arm or needle is fixed to a light
spindle, carrying an archimedean screw, which further gears with the regis-
tering parts of the apparatus. It is evident that the water in passing through
the measuring vessel, or rather alongside the same, communicates its motion
to the water inside the measuring vessel, which motion is also communicated to
the float and magnets, and lastly to the needle and worm spindle and further
gearing. It is plain that this meter really registers the true velocity of the
water, and taking, moreover, into consideration the lightness of its different
parts and the transmission of the speed of the float by means of magnets, it
will be found to be a very correct and sensitive meter, of simple and durable
construction.
399a. Current Meter, with electrical tell-tale apparatus',
according to Amsler's latest construction. (See description.)
Polytechnic School, Aix-la-Cliapelle, O. Intzc.
If the instrument makes 100 revolutions the electric current will be closed
by a contact, and the chime work will be kept in motion during some revolu-
tions of the instrument ; it will not be necessary, therefore, in measuring the
velocity in water-courses, to pull the instrument out of the water, but only to
note the time which passes from one signal to the other. By experiments it
must be ascertained what velocities of the current of the water correspond
to certain intervals of time between the electric signals.
400. Patent Electric Velocimeter, invented by Francis
Pastor elli, arranged for water currents, and for ascertaining the
speed of vessels. It consists of three parts. Francis Pastorelli.
VI. VELOCITY. 97
1. Four hemispherical cups are fixed to the end of four strong metal arms
that radiate at right angles from a central boss, mounted on a horizontal axis
at right angles to a framework of metal, or other material, BO that they may
freely revolve when placed iu the water. The horizontal axis has fixed to
it a point or piece of platina ; upon this work pressing points or surfaces,
which can he made of any form, circular or otherwise ; each revolution of the
axis causes a contact to be made.
2. The same receiving instrument, as used for the mining instrument, No.
.3388.
3. A Leclanche battery, as used for the mining instrument.
The receiving instrument can be placed in any convenient position on
board.
N.B. No. 1. This part of the instrument is intended to be fixed at any
desirable and convenient part of the vessel, or it may be arranged to throw
overboard ; under such conditions it will give more accurate indications than
the logs now in use, for it is not affected like them in their motion by depth,
or the increasing density of water ; assuming that corrections be applied for
force and direction of currents, with respect to the course or line of motion,
the errors would probably not be found to exceed 5 per cent.
402. Apparatus for indicating the Speed of a Ship by the
aid of Electricity. Be a net Woodcraft, F.R.S.
4O9. Hhysimeter, without frictioual parts, for measuring
the speed of water or other liquids whether in pipes or open
channels. Alfred E. Fletcher, Liverpool.
4O9a. Current Meter.
Benjamin Thcophilus Moore, M.A.
This instrument will measure the velocity of running water at any depth
below the surface, with accuracy and facility.
The frame is formed of thin brass bars united in front to a solid ogival
head, and terminating, in the opposite direction, iu a double vane or tail. It
is suspended in water by a cord attached to a stirrup.
The frame supports a hollow cylinder which is provided with six screw
blades, and is free to revolve upon fine pivots at its extremities. This cylinder
contains a water-tight glass tube within which is a simple train of mechanism
to record the number of revolutions made by the cylinder. This train of
mechanism is suspended in such a manner, that it remains at rest while the
cylinder revolves, and the dials which record the number of revolutions are
seen through the glass without opening the cylinder. When the instrument
is suspended iu running water by a cord attached to the stirrup, the frame
immediately takes up a position in which the axis of the revolving cylinder is
parallel to the direction of the stream. The cylinder is set in motion, and
stopped, at known instants, while under water, by means of a spring operated
upon by a light cord.
For use in very deep water a simple automatic starting and stopping
apparatus is placed inside the water-tight compartment of the cylinder, which
operates in such a way that while the instrument is descending or ascending
in water, the mechanism does not record the revolutions of the cylinder, but
only while it is at the depth at which the velocity is required. In this case
the* spring is removed and one cord only is used.
409b. Deep Sea Current Indicator.
Benjamin Theophilus Moore, M.A.
This instrument is intended to be used for the purpose of ascertaining the
direction of submarine currents.
40075. G
98 SEC. 3, MEASUREMENT.
It consists mainly of a water-tight globular shell of gun metal, pointed in
one direction, and terminating in the other in a long double vane, and is
carried by two pivots on a stirrup. Within the shell is a brass box,
suspended by girnballs in the manner of a ship's chronometer, and containing
a magnet with a graduated ring, and a train of clockwork. When the instru-
ment is lowered into deep water, its principal axis takes the direction of the
current, while the magnet settles itself in the magnetic meridian. After the
magnet and the instrument have taken up their respective positions, the
clockwork suddenly fixes the magnet at a known time. The instrument is
then drawn up out of the water and opened, when the fixed magnet shows
the direction, or bearing, of the current below.
This bearing is shown directly by the instrument when it is suspended from
a fixed platform, or from a ship at anchor, or otherwise at rest: When the
ship is in motion the instrument is to be used in combination with the deep
sea current meter, by which means the velocity and direction of the submarine
current can be determined simultaneously by a simple geometrical con-
struction.
409c. Recorder for Indicating Speed, Pressure, &c.
W. H. Bailey and Co.
B. ANEMOMETERS.
408. Anemometer, without frictional parts, suited to measure
the speed of air or gases, even when highly heated, or when
contaminated with smoke or corrosive vapours. Used by H.M.
Inspectors of Alkali Works. Alfred E. Fletcher, Liverpool.
41O. Lowne's Portable Air Meter, originally introduced
by Casella. JR. M. Lowne.
The indications of this instrument are obtained by means of a light fan
which communicates motion to indicating wheels ; the dial of the instrument
is placed at right angles to the fan, and is supported by three pillars on a base,
which also carries the tube containing the fan. The works are extremely
sensitive, the first centres running in jewels, and the indicating parts can be
thrown in or out of gear with the fan.
41Oa. Lowne's Patent Magnetic Air Meter, especially
adapted for measuring currents of air, gases, and fluids in positions
where delicate instruments would be subject to corrosion.
R. M. Lowne.
The peculiarity of this instrument is, that the registering works are en-
closed in an air-tight chamber, the connexion of the revolving fans with the
works being made through a sheet of brass by magnetism. The fans carry a
small bar magnet, and the first wheel of the indicating mechanism carries a
piece of soft iron, so that when the fans revolve outside the plate of brass the
soft iron revolves within by attraction and thereby moves the works.
41Ob. Lowne's Patent Colliery Air Meter, constructed
expressly for use in mines. R. M. Lowne.
The external aspect and form of this instrument is that of the well known
" Biram's Anemometer." The improvements consist of. 1st, a strong, light,
;aud anti-corrosive fan ; 2nd, a large clear dial ; 3rd, the indicating parts ~are
perfectly protected from dust and smoke ; and 4th, a lever is placed in a con-
venient position to enable the observer to throw the indicating wheels in or
out of gear with the fan.
VI. VELOCITY. 99
410c. Lowne's Patent Magnetic Anemometer and
Current Meter, for measurement of velocity of currents of air,
gas, and fluids. R. M. Lowne.
In this instrument the registering works are enclosed in an air-tight cham-
ber, the connexion of the revolving fans with the works being made through
a sheet of brass by magnetism. This instrument is mounted on gymbals,
with direction vane for use on board ship.
41Od. Lowne's Patent Ventilation Anemometer, origi-
nally introduced by Stanley. R. M. Lowne.
This instrument measures the air by means of a fan wheel placed in a clear
opening, without any obstruction from the registering apparatus, which is in a
separate chamber on the same plane as the fans, so that the instrument is quite
flat for the pocket ; the whole of the works are of extreme sensitiveness, and
the axes of the fans run in jewels, the indicating hands give the current that
passes the fans in feet (after correction), and a lever above the dial throws the
registering works in or out of gear with the fans.
410e. Mining Anemometer, for showing the velocity of cur-
rents in mines. Elliott Brothers.
410f. Biram's Anemometer. Improved for Coal Mines.
Francis Pastorelli.
It consists of a broad brass ring; fixed to it is a metal frame which carries
three divided circles ; in the interior and centre of the ring is a spindle
which carries eight vanes ; on one end is an endless screw ; this works a series
of wheels, which give motion to the hands on the dials, which record the
distance travelled by the air current every foot up to 100, 1,000, and 10,000
feet.
41Og. Dickinson's Anemometer.
Joseph Casartelli, Manchester.
This anemometer consists of a disc, or plate, made of light material, sus-
pended in a frame on delicate centres, having a balance weight attached to
the top of the fan. To one side of the frame is fixed on pivots a quadrant
opening out at right angles to the fan, and on it is marked the velocity of
the current in feet per minute, as indicated by the angular rise of the fan upon
which the current impinges. The advantage of the instrument consists in
the fact that it requires no timing as required by every other instrument, and
from actual experiment it is found as accurate as the most delicate instrument.
410h. Improved Biram's Anemometer.
Joseph Casartelli.
The improvement in this instrument consists in the fan being made of light
material, thus greatly diminishing the friction, and rendering it a delicate and
useful instrument.
41Oi. Biram's Patent Anemometer for ascertaining the
current of air in mines, air flues, &c. John Davis and Son.
This anemometer registers up to 1,000 feet. At the bottom there is a tube
in which a stick may be inserted, so that the experimenter can stand at a
distance from the instrument, otherwise the current of air would be deflected
by the body of the experimenter.
The vanes may at will be disconnected from the indices by means of a stud
at the side, thus rendering the process of timing more simple and exact.
G 2
100 SEC. 3. MEASUREMENT.
410k. Biram's Patent Anemometer for ascertaining the
current of air in mines, air flues, &c. John Davis and Son.
The 4" anemometer indicates up to 10 million feet. The size and angle of
the vanes are calculated from theory and corrected by experiment, each
instrument being corrected separately.
The registering apparatus consists in the 4 in. new anemometer of six small
circles, marked respectively X, C, M, X M, C M, and M, the divisions on
which denote units of the denominations of the respective circles ; in other
words, the X index in one revolution passes over its ten divisions and registers
10 x 10 or 100 ft. ; the C index in the same way 1,000 ft. ; and so on up to
10,000,000 ft.; so that an observer has only to record the position of the
several indices at the first observation (by writing the lowest of the two figures
on the respective circles between which the index points in their proper order),
and deduct the amount; from their position at their second observation, to as-
certain the velocity of the air which has passed during the interval ; this mul-
tiplied by the area in feet of the passage where the instrument is placed, will
show the number of cubic feet which has passed during the same period.
The novelty in this anemometer is in its extreme portability and substantial
workmanship ; it is supplied with a lever which disconnects, at will, the vanes
from the indices, thus rendering the process of timing more simple.
414. Edelmann's Anemometer with galvanic register.
M. Tli. Edelmann, Munich.
416. Anemometer for determining the velocity of the air,
and other gaseous currents in pipes and air passages.
Moritz Gerstenhofer, Freiberg.
C. CHRONOGRAPHS.
4O1. Apparatus for measuring the velocity of projectiles,
and capable of recording several measurements on one and the
same trajectory and of the same projectile.
Antoine Joseph Gerard, Liege.
403. Ballistic Chronoscope, with t\vo pendulums, for ascer-
taining the speed of a projectile at any point of its trajectory, by
measuring the time of flight of a portion of the trajectory ; also
for measuring portions of time between one tenth of a second and
25 seconds. Lieutenant- General Leurs, Brussels.
404. Electric Chronograph, for measuring the initial velo-
city of projectiles. Le Boulenge, Liege.
405. Electric Clepsydra, for measuring the time of flight
of projectiles. Le Bouletige, Liege.
405a. Electro-Ballistic Apparatus, for determining the
velocity of a projectile, with description of experiments and addi-
tional apparatus. M. Navez, Paris.
406. Electric Chronograph for the measurement of minute
portions of time, &c., &c. Lieut. H. Watkin, R.A.
This instrument consists of two upright cylinders resting on a base of wood ;
between them, suspended by an electro-magnet, is a weight with projecting
arms. The cylinders being connected with the secondary circuit of'an indue-
VI. VELOCITY. 101
tion coil, the circuit is complete with the exception of the small spaces on
either side of the weight. When taking velocities of shot, the primary
circuit is led through screens, constructed so that the current is broken and
immediately made again during the passage of the shot. The gun being
fired, the weight begins to descend ; the shot in passing the first screen causes
a spark to flash from one cylinder to the other through the weight which
having been previously smoked registers by a white spot the position of the
weight at that instant. As the weight continues to descend the same result
is obtained at the next screen, and so on. Adjacent to the cylinder is a time
scale divided into thousandths of a second, subdivided by a vernier of novel
construction into hundred thousandths of a second, by which the absolute
time taken by the shot between the screens is easily read off. For other uses
to which the instrument may be applied, see Royal Artillery Institution Papers.
407. Clock-Chronograph, contrived for the purpose of
measuring the time occupied by projectiles in passing over a
succession of equal spaces, with a view to determine accurately
the resistance of the air to their motion. Rev. F. Bashforth.
If the fly-wheel be spun by hand, and the markers be brought down,
they will trace two uniform spirals on the cylinder ; each marker is, however,
under the control of an electro-magnet. When the galvanic current is inter-
rupted, a record is made by the corresponding marker being suddenly drawn
aside. The circuit of the lower electro-magnet is interrupted once a second
by a clock beating half-seconds, which gives a scale of time. The circuit of
the upper electro-magnet passes along the tops of all the screens, as is
shown in the case of one screen. When one or more threads are broken
in any screen, a record is made on the cylinder. Thus, when an experi-
ment is to be made, the fly-wheel is spun briskly by hand, the markers
are brought down, and the gun is fired. The times of passing the screens are
recorded on one spiral, opposite a scale of time on the other. This instru-
ment was used in making all the experiments referred to in " Reports on
" Experiments made with the Bashforth Chronograph to determine the
" Resistance of the Air to the Motion of Projectiles, 1865-1870," published
by authority. Generally 10 screens were placed at intervals of 150 feet, but
in the experiments with the WhitAvorth gun (p. 162), 16 screens were placed
at intervals of 75 feet ; some of these records are shown. For a full descrip-
tion of the chronograph, see Proceedings of the Royal Artillery Institution,
Woolwich, for 1866, which description is also published separately.
407a. Chronograph for projectile experiments with the
recording apparatus of Deprez. Diimoulin fromcnt, Paris.
407b. Electric Chronograph. Dr. Werner Siemens.
This instrument, which was described in the year 1845 in Pogg. Ann.
(Bd. 66, p. 435), serves for the measurement of high velocities, especially
those of projectiles both along the barrel and in their further flight, and also
that of electricity.
It is based on the circumstance that an electric spark leaves a sharp mark
on polished steel, and that this mark can easily be discovered when the cylinder
has been previously blackened. The cylinder is turned rapidly by clock-
work, and each hundredth revolution is marked by the stroke of a small bell.
By means of a regulator the rapidity of rotation is so arranged that the
stroke of the bell coincides exactly with the beat of a second pendulum ; the
reading is made with a microscope with cross wires, the clockwork being
stopped. The graduation of the micrometer head gives 0-0001 of a revolu-
tion of the cylinder or millionths of a second if the cylinder rotates 100 times
a second.
102 SEC. 3. MEASUREMENT.
The measurement of the velocity of projectiles is effected by the passage of
an electric spark at the moment when the projectile touches an insulated wire
which reaches to the inside of the gun, and thus is free from retardation
caused by the inertia of matter or magnetism.
The same apparatus can be used for the measurement of the velocity of
electricity in suspended wires.
The complete apparatus comprises a Leydeu jar, induction coil, commutator,
gun barrel, chronograph, and two batteries.
407c. Recording Cylinder, with original marks by which
the speed of electricity in iron wires has been measured.
Dr. Werner Siemens.
Those marks which are surrounded by a halo or circle indicate the com-
mencement of the discharge, the successive series of small marks has been
formed by the electricity which has traversed the conductor ; the angular
distance between the first-mentioned mark and the first point of the series
gives the measurement of the speed of electricity. By measurement of the
time which the electricity requires to pass through lines of various lengths,
the electrostatic retardation, which is proportional to the square of the length
of the line, has been eliminated. By these researches it has been shown
that electricity is transmitted in conductors with a constant velocity which is
independent of the static retardation, and which for iron amounts to about
230,000 kilometres per second.
(See Monatsberichte der Kgl. Pr. Acad. der Wissenschaften, 6 Dec. 1875.)
411. Complete Apparatus for measuring the Velocity
of Projectiles in the bore of a gun, and for measuring the speed
of electricity. Siemens and Halske.
412. Vibration Chronograph, for measuring the time of
descent on an inclined plane, executed according to Beetz, by
M. Th. Edelmann, at Munich. (A description accompanies the
object.) Prof. Dr. Beetz, Munich.
413. Edelmann's Apparatus for the descent of a fall-
ing Body accessory to Beetz's chronograph.
M. Th. Edelmann, Munich.
413a. Chrono-Gonioxneter, with magnifier.
Le Vicomte Duprat, Consul- General of Portugal.
D. STROPHOMEJERS.
44. Counters and Speed Indicators.
T. R. Harding and Son.
(a.) Counters with reciprocating motion, as applied to marine and
stationary engines.
Counters with rotary motion, suitable for shafting, printing, and other
machinery.
Small counters with rotary motion applicable to spinning machinery and
various other purposes.
Pocket counters for ascertaining the speed per minute of spindles or quick
running machinery up to 10,000 revolutions per minute.
(6.) Counters actuated by pneumatic and electric apparatus at a distance
from the motion to be indicated.
(c.) Speed indicators, showing by the height of a column of mercury the
actual speed, at any moment, of engines and other machinery.
VI. VELOCITY. 103
44a. Mercurial Indicator and Counter.
T. R. Harding and Son.
The above instrument is a combination of Harding's integrating counter
and Brown's patent indicator, for which T. R. Harding and Son are sole
licensees in Great Britain.
The mercurial indicator shows the speed per minute of the shaft above
it ; the counter records AaZ/'the number of revolutions of the same shaft.
The principle of the mercurial indicator is very simple. The tubular arms
of the rotating U tube are connected with the central glass tube, and when
the instrument is at rest the mercury settles to a level in the glass tube and
arrives at the zero of the scale. When the instrument is rotated, the mercury,
owing to the centrifugal tendency, rises in the arms and sinks ill the central
tube to a greater or less extent according to the speed.
These indicators are of great importance for marine, stationary, and loco-
motive engines, as well as for various kinds of machinery.
By means of the counter and a watch, the accuracy of the mercurial
indicator can at any time be verified.
47. *' The Motometer," a machine to indicate the number
of revolutions made per minute, or other portion ,of time, by a
steam engine or revolving shaft, or any body having intermittent
motion, so that by simple inspection of a dial the rate of speed may
be seen. ff. Faija.
This instrument is constructed so as to indicate by a positive motion direct
from the engine or other moving body to which it is attached, and is of
purely mechanical construction independent of all centrifugal and other
forces of an indirect nature. The indication is consequently absolute and not
comparative.
The instrument is made in various forms to suit differences of speed, from
the slow stroke of a pumping engine to the high speed of a locomotive, &c.
The skeleton machine exhibited is suitable to indicate the ordinary speed
of a marine or stationary engine, while the one attached to the shafting is
adapted for very high speeds.
395. Hearson's Patent Strophometer or Revolution
Indicator, an instrument for showing at a glance, by the position
of a pointer on a graduated dial, the number of revolutions per
minute an engine is at the time making. Elliott Brothers.
395a. Working Model of Revolution Indicator, for
engines and machinery, by J. Wimshurst. J. F. Planner*/.
415. Mercurial Gyrometer, or " orbit meter."
Royal Polytechnic Academy {Prof. Reuleaux, Director},
Berlin.
The instrument indicates directly the angular velocity of an axle, shaft,
&c., in figures showing the rotations per minute. The reading takes place
on an alcohol column, which shows on one side a millimeter scale, and on
the other the rotation numbers. The instrument is so arranged that the
scale of the rotations has uniform graduation.
532b. Reuleaux's Ball-Gyrometer.
H. ffddicke, Engineer, Demmin, Pomerania.
The object of the instrument is to indicate the rotations made per minute
by any rotating body brought into connexion with the same. The number
104 SEC. 3. MEASUREMENT.
indicated will be read off a dial. As a peculiarity it may be mentioned that
the scale of the dial shows a uniform division, although the position of
the balancing balls moving the pointing hand depends according to a
complicated law on the velocity of the rotation of the spindle.
The motion is worked by means of straps and pulley, and can, as a matter
of course (on vessels, &c.), be effected by a fixed connexion with a shaft-
movement.
The winch-handle, however, will enable the spectator to put the instrument
in motion by the hand.
The accuracy of the indications of the instrument will be augmented if the
pointing hand is turned off a little with the finger in the direction of the pro-
gressive numbers, and then allows it to jerk back freely.
A forcible turning of the pointing hand in the opposite direction, toward O,
is not allowed.
41 5a. Revolution Indicator, to show the rate at which
machinery is working. Frederick Guthrie.
From the machinery an up-and-down motion is communicated to the piston
of a pneumatic forcing pump. The compressed air escapes through a fine
opening, and also exercises pressure on oil, water, or mercury, in a vessel
provided with a manometer tube. The height of the liquid in the tube
measures the rate at which the pump and machinery are working.
488 d. Drawings of a Simple Counter, and of a Registering
Counter.
(Sec Report of Baron Seguier to the Society of Encouragement,
1844.) M. Winnerel, Paris.
VII. MEASUREMENT OF MOMENTUM.
417. Model of the Ballistic Pendulum, erected in the
Royal Arsenal in 1814, and transferred to the Royal Military
Repository in 1836. Weight, 7,740 Ibs. Centre of gravity below
centre of suspension 10'97 ft.; centre of oscillation below centre
of suspension 1 1 88 ft. Scale Jth. Major M. L. Taylor, R.A.
418. Navez Electro-Ballistic Apparatus.
Major M. L. Taylor, R.A.
41 8a. Discussion on Electro-Ballistic Apparatus.
419. Model of Ballistic and Gun Pendulum, as erected
at Shoeburyness in 1858. Oscillating system of gun pendulum,
weighs 37 Ibs. 10-5 oz. ; that of the block pendulum weighs
31 Ibs. 8-25 oz. Scale, Jth. Major M. L. Taylor, R.A.
VIII. MEASUREMENT OF FORCE.
42 la. Attraction Meter. An instrument for measuring
horizontal attraction. j) Tt Siemens.
vni. FORCE. 105
This instrument consists of two horizontal tubes of wrought iron, ter-
minating at each end in a horizontal tube of cast iron. The first-named
horizontal tubes are partiall}* closed at their extremities, and communicate
with the transverse tubes below their horizontal mid-section. The transverse
tubes communicate also by means of a horizontal glass tube of 2 millims.
diameter at a superior level to the former.
The whole apparatus being mounted upon three levelling screws is filled
to the level of the half diameter of the transverse tubes with mercury, which
mercury also fills the whole of the longitudinal connecting tubes ; the upper
halvc-s of the cast -iron transverse tubes and the glass connecting tube are
filled with alcohol, comprising, however, a small bubble of air, which can be
made to occupy a central position in the glass tube b} r raising or lowering
the levelling screws.
If a weighty object is approached to either extremity of the connecting
tube, an attractive influence will be exercised upon the mercury, tending to
a rise of level in the reservoir near at hand, at the expense of the more
distant reservoir ; and this disturbance of level between the two reservoirs
must exercise a corresponding effect upon the index of air in the horizontal
glass tube, moving it away from the source of attraction. The amount of
this movement must be proportional to the attractive force thus exercised.
Variations of temperature have no effect upon this instrument, because the
liquids contained on either side of the bubble of air are precisely the same
in amount ; and the total expansion of the liquids is compensated for by
open stand tubes rising up from the centre of the connecting tubes through
which the apparatus can be easily tilled.
It is suggested that an instrument of this description may be employed
usefully for measuring and recording the attractive influences of the sun and
moon which give rise to the tides.
The instrument, which is of simple construction and not liable to derange-
ment from any cause, would have to be placed upon a solid foundation with
its connecting tube pointing east and \vest, records being taken either by
noting the position of the index upon the graduated scale below, or by means
of a self-recording photographic arrangement.
42 Ib. Bathometer. An instrument for measuring the depth
of the sea without the use of the sounding line. Dr. Siemens.
The total gravitation of the earth, as measured on its normal surface, is
composed of the separate attractions of all its parts, and the attractive
influence of each equal volume varies directly as its density, and inversely as
the square of its distance from the point of measurement.
The density of sea water being about i-026, and that of the solid con-
stituents composing the crust of the earth about 2'763 (this being the mean
density of mountain limestone, granite, basalt, slate, and sandstone), it
follows that an intervening depth of sea water must exercise a sensible
influence upon total gravitation if measured on the surface of the sea.
The bathometer consists essentially of a vertical column of mercury con-
tained in a steel tube having cup-like extensions at both extremities, so as to
increase the terminal area of the mercury. The lower cup is closed by means
of a corrugated diaphragm of steel plate, and the weight of the column of
mercury is balanced in the centre of the diaphragm by the elastic force derived
from carefully tempered spiral steel springs of the same length as the column
of mercury.
One of the peculiarities of this mechanical arrangement is, that it is para-
thermal, the diminishing elastic force of the springs with rise of tempera-
ture being compensated by a similar decrease of pressure of the mercury
106 SEC. 3. MEASUREMENT,
column, which decrease depends upon the proportions given to the areas of
the steel tube and its cup-like extensions.
The instrument is suspended a short distance above its centre of gravity in
a universal joint, in order to cause it to retain its vertical position, notwith-
standing the motion of the vessel, and vertical oscillations of the mercury are
almost entirely prevented by a local contraction of the mercury column to a
very small orifice. The reading of the instrument is effected by means of a
glass tube on the top, which connects the upper surface of the mercury with a
liquid of less density. In this is enclosed an air bubble, whose position on a
scale indicates the depth of water below the instrument.
Variations of atmospheric pressure have no effect upon the reading of this
instrument ; but a correction has to be made for variations of atmospheric
density as affecting the relative weight of the mercury column, which correc-
tion might be avoided, however, by excluding the atmosphere from both the
upper and lower surface of the mercury, and connecting the extremities of
the column. The only necessary correction is that for the effects of latitude,
which may be calculated as depths in fathoms, and tabulated for use with the
instrument.
The readings of the instrument have been checked by actual soundings
taken by means of Sir William Thomson's steel wire sounding apparatus ;
and the comparable results agree in all cases as closely as could be expected,
considering that the sounding line gives the depth immediately below the
vessel, whereas the bathometer gives the mean depth taken over a certain
area, depending for extent upon the depth itself.
It is thought that the bathometer may render useful service to the mariner in
warning him of changes of depth long before reaching dangerous ground ;
and the position of a vessel, when no astronomical observations can be taken,
may be ascertained by means of the instrument, provided the contour lines of
equal depths of oceanic basins were accurately laid down.
42 Ic. Graphical Bathometer , after von Jolly.
University of Munich.
42 Id. Gravimeter. An instrument for the measurement of
the variations of the earth's attractive force, invented by J. A.
Broun, F.R.S., and constructed from his drawings by Dr. C. F.
Miiller, of Stuttgart. J. Allan Broun, F.R.S.
The instrument consists of a weight suspended by two gold wires ; a single
wire fixed to the top of the weight and passing through its centre carries a
cylindrical lever ; when the lever is turned through 360 at the normal (say
southern) station, the torsion of the single wire thus produced carries the
weight round through an angle of 90. The forces then in equilibrium are,
the torsion force of the single wire and the attraction of the earth on the
weight, Avhich, as the two wires are no longer vertical, has been slightly raised
and seeks to attain its lowest point.
On proceeding from a southern to a more northerly station the earth's
attraction increases ; the amount of this increase may be measured in two
ways :
1st. The lever will require to be turned through more than 360 in order to
carry the weight to the height due to turning it through 90. (Had the station
been more southerly the lever would be turned through less than 360.) The
difference of the angle from 360 measures the increase (or diminution) of
weight.
2nd. By removing a small portion of the weight, equal to that due to the
increased attraction of the earth, the weight can be turned through exactly
VIII. FORCE. 107
90 by rotating the lever through ,360, as at the normal station. (On pro-
ceeding south weight has to be added.)
The following are the instrumental arrangements in order to make these
observations :
The weight has on each of three sides, at its base, a vertical mirror
silvered, not quicksilvered) ; the middle mirror makes an angle of exactly
90 with the other two. The lever also carries a vertical mirror, which when
there is no torsion in the suspension wire is immediately below and in the
same vertical plane with the middle mirror of the weight. A telescope,
having a glass scale at the focus of the eye-piece, is adjusted so that images
of the scale can be seen (one higher than the other) reflected from the middle
mirror of the weight and the lever mirror. When both of these mirrors arc
exactly in the same plane, the middle division on the scale seen directly with
the eye-piece, coincides with the same division in the two reflected images.
By a wheel and pinion (with endless screw and clamp for delicate movement)
placed below the instrument, a polished agate point can be made to act on a
similar agate point fixed to the lever, so as to turn the latter through any angle.
When turned through 360 the middle scale division again agrees with the
image from the lever mirror. If the image reflected from one of the side
mirrors of the weight does not agree also, the lever is turned through a greater
(or lesser) angle than 360, till this agreement is obtained ; the difference of
the angle through which the lever has been turned from 360 is obtained from
the scale reading, as seen on the lever mirror.
The following apparatus is employed for very small increases or diminutions
of the weight. Suspended to and vertically below the lever is a carefully
calibrated glass wire (1 millimetre diameter), which enters a glass tube fixed
below the instrument. At the lower end of this tube is a cistern containing
a liquid (distilled water, or as at present, chemically pure glycerine). This
liquid can be forced into the glass tube by a screw and piston (as in some
barometer cisterns). The liquid is then raised till such a diminution of weight
is produced by the immersion of the glass wire as to bring the mirror of the
weight through exactly 90, when the lever is turned through 360. The
length of glass wire immersed is read, by a micrometer microscope and scale,
to a thousandth of a millimeter.
Though finely polished agate points have been employed for turning the
lever so as to diminish the friction, there is an additional apparatus to ensure
that vertical friction has no effect on the observation at last. The lever
contains a magnet ; and two bar magnets, with rack-work adjustments for
height, are placed one on each side of the instrument, so that by a pinion and
rack movement they can be approached to the lever magnet till their force is
exactly equal to the torsion force of the single wire, and the agate points are
no longer in contact.
The instrument is made to serve for latitudes differing about 10 or 15,
but an auxiliary apparatus carries five platinum rings, which can be lowered
upon the weight, so as to make the instrument serve from the equator to the
poles, and to any height in the atmosphere.
There are special appliances for portability, by one of which the weight is
fixed ; another fixes the lever ; so that strain is removed from the suspension
wires> and the suspended pails cannot be shaken from their places. Levels,
a thermometer, and other details fit the instrument for the most accurate
observations. The suspension wires are fixed at their ends in a special
manner, so that the fixed points cannot vary. All the suspended apparatus is
electro-gilt.
42 Id. Photograph of Automatic Bathometer.
A. Gerard, Lie ye*
108 SEC. 3. MEASUREMENT.
In this instrument a lever of the second order supports a glass cylinder
containing 100 grammes of mercury by means of a spiral spring attached to
its extremity. The variation of the weight of the mercury, due to a change
in the altitude of the point of observation, produces a corresponding variation
in the length of the spring ; this is rendered apparent by means of a pointer
30 centimeters in length, worked by a watch chain passing round a pulley on
the axis of the pointer and attached to the lever.
42 le. Photograph of Pendulum of Altitude.
A. Gerard, Liege.
The pendulum consists of a glass rod mounted on knife edges ; the bob is
a cylinder of mercury attached to the glass rod by a spiral spring, thus
affording a perceptible variation in time of oscillation, due to variations of
gravity.
42 5 a. Drawing of a Registering Statical Gauge for
Pressure in Guns. System of W. Paschkiewitsh.
Captain W. Paschhiewitsh, St. Petersburg.
2828. Dynamic Anemometer for obtaining the horizontal
and vertical pressure of air in motion, upon inclined surfaces of
different forms and angles. Manufactured by John Browning.
The Council of the Aeronautical Society of Great Britain.
This instrument is intended simultaneously to determine the component
parts i.e., how much pressure is due to the horizontal, and how much to
the vertical of a current of air when directed against planes of different
areas, and of different forms, at angles varying from 15 to 90. The experi-
ments are tabulated in the Aeronautical Society's Keport for the year 1871
(Hamilton and Co.).
426a. Machine for measuring the slipping between hard
surfaces rolling in contact. Prof. Osborne Reynolds.
This machine was constructed for the purpose of verifying the conclusions
of the exhibitor respecting rolling friction, and the existence of a certain
amount of slipping between two smooth surfaces of different curvature, or diffe-
rent hardness, when the one rolls on the other under pressure. It has also been
used to measure the slipping between the surfaces, when the one is driving
the other against various resistances and at various speeds, as well as the
wear of the surfaces.
The large rolling surface is of cast-iron, supported so that it can rotate
freely, but otherwise rigidly fixed. For the smaller surface various materials
have been used, that exhibited being of steel ; this cylinder is supported so
that while its axis is always parallel to that of the larger cylinder, it can
be pressed against the latter with various degrees of pressure by means
of a lever acting through friction rollers. Arrangements are made for
recording the number of revolutions of both cylinders ; and connected with
"both spindles are driving pulleys and friction breaks on Appold's system, by
means of which the force to be transmitted can be regulated.
An amount of slipping of not more than the one hundred thousandth part
of the distance rolled can be measured with this machine.
The machine was constructed in Owen's College by Mr. Foster.
IX. WORK. 109
IX. MEASUREMENT OF WORK.
429. Dynamometer, graduated up to 100 kilogrammes by
intervals of 200 grammes, and showing dynams in kilogrammetres
up to 981, each interval measuring two dynams nearly in absolute
measure. P r f> Hennessy, Dublin.
430. Dynamometer graduated up to 10 kilogrammes, and
giving absolute dynams in kilogrammetres up to 98, each interval
measuring nearly one dynam in absolute measure.
Prof. Hcnnessy, Dublin.
Dynamometers similar to these are are employed at the Royal College of
Science. Dublin, as referred to in the College Directory for 1876-77, page 17.
" The dyuam or unit of force commonly employed throughout the course is
one kilogramme moving through one metre in one second of time."
430a. Photograph of Electrodynamometer. Made by
Professor H. A. Rowland, Johns Hopkins University, Baltimore,
on the model of that of the British Association.
Cavendish Laboratory, Cambridge.
431. Drawing of a Dynamometrical Apparatus, con-
structed in 1844 by the exhibitor, to measure the real horse-power
of steam-boats. Prof. Daniel Colladon, Geneva.
This apparatus, approved by the Academie des Sciences in 1843, was, in
the same year, adopted in the IJoyal Dockyard at Woolwich.
644. Surface Spring Indicator.
H. Hadicke, Demmin, Pomerania.
The indicator was constructed by the exhibitor, and executed from his
drawings by Messrs. Blanche and Co., in Merseburg. The piston has been
replaced by a surface spring, and the construction aims at
1. Avoiding the friction of the piston of the indicators hitherto in use.
2. Avoiding the slackness of the piston.
3. Avoiding the points of the diagram of machines in rapid motion
produced by the mechanical momentum of the piston.
432. Richard's Patent Steam Engine Indicator, with
Darke's Patent Detent and Cord Adjuster. Elliott Brothers.
By means of the detent, the paper cylinder is instantaneously set in motion
or stopped by the movement of the pencil arm, as it is being applied or with-
drawn, giving great facilities for taking a number of consecutive diagrams,
also rendering its application to oscillating engines much more convenient.
433. Cooper's Patent Slide Valve Indicator. An in-
strument for ascertaining the relative position between the piston
and slide valve of an engine at different points of the stroke.
Elliott Brothers,
1 1 SEC. 3. MEASUREMENT.
434. Flexion Pandynamometer. An instrument designed
to determine the work done by a stearn engine, by means of the
flexion of the beam. G. A. Him.
On the upper edge of the beam is a rigid wooden bar of the same length,
resting in the centre on a fork which prevents it from swerving, fastened to
one end of the beam with an iron rod, and free at the other end. To this
extremity is attached an inelastic cord, which passes round a pulley, fixed
at the head of the beam, and is carried thence towards the centre, where it is
wound round the axis of a very light needle.
It is evident, from this arrangement, that when the beam moves in either
direction, the end of the wooden bar which remains rigid approaches to or
recedes from the head of the beam. The cord consequently winds itself
round, or unwinds itself from, the axis of the needle, and the deviation of the
latter indicates the degree of flexion of the beam, multiplied if desired. At
the end of the needle is fixed a pencil, which works on a small board placed
above the beam. This pencil, at each double stroke of the piston, traces a
closed curve, of which the ordinates indicate the successive degrees of flexion
of the beam during the work. To determine, once for all, the degree of
flexion corresponding to a given load, the crank of the fly-wheel should be
fixed at the dead point, and steam at a known pressure should be introduced
into the cylinder.
435. Torsion Pandynamometer. This instrument is de-
signed to measure the power supplied by an engine to a factory,
by means of the torsion of the shafting through which the motive
power is transmitted. G. A. Him.
At the extremities of one length of the shafting are keyed two toothed
wheels of equal diameter, which gear, one directly and the other by an inter-
mediate wheel, into two smaller pinions. These pinions gear into the four
bevelled wheels of an ordinary differential movement. The two intermediate
wheels of this movement are loose on a shaft, which is prolonged in a vertical
direction, and made of a light steel rod. The result of this arrangement is,
that if the shaft twists, this rod deviates, and forms with a vertical line an
angle proportionate to the torsion to which the shaft is subjected. At the
upper and free extremity of the steel rod is seciyed, by means of a hinge, a
horizontal very light wooden bar, carrying at its extremity a roller, to which
is attached a recording apparatus. This roller, when the shaft is at rest, lies
in the centre of a wooden disc covered with paper, and revolving uniformly
on a vertical axis.
So soon as the steel rod deviates from a vertical line, in consequence of the
torsion of the driving shafting, the roller leaves the centre of the disc, and
begins to revolve. The turns registered by the recording apparatus are exactly
proportional to the torsion of the shafting.
The mean torsion of the shafting being thus known for a clay's work, two
parallel levers, placed in contrary directions, are securely fixed at the extre-
mities beyond the two toothed wheels, and the free extremities of the
levers, so as to determine the deviation caused in the vertical bar by a given
weight.
Simple proportion then gives the resistance, corresponding to the mean
angle obtained during a day's work, and it becomes easy to determine the
mechanical work which corresponds to this angle.
X. ANGLES. Ill
435b. Dynamometer Waggon, for marking and registering
the tractive power, and the distances travelled.
Eastern Railway of France Company, Paris.
436. Theoretical Pressure Diagram for calculating the
mechanical work in a steam cylinder.
H. Hadickc, Demmin, Pommerania.
X. MEASUREMENT OF ANGLES.
437. lO-inch Protractor, by Ramsden. Royal Society.
438. Clinometer of Precision, employed in 1865 by Pro-
fessor Piazzi Smyth in the interior of the Great Pyramid.
Prof. Piazzi Smyth.
This instrument was made to order by T. Cooke and Sons, of York, in 1864,
at the cost of Andrew Coventry, Esq., of Edinburgh, for measuring the
interior slopes of the Great Pyramid. When thus used it was further
mounted on a deep wooden beam, 120 inches long, armed with feet of gun
metal.
The angle measuring portion of the instrument is a complete circle, pro-
Tided with three pairs of opposite verniers, each reading to 10" in order to
eliminate errors of division as well as eccentricity, and the whole circle can
be moved and clamped on its centre so as to repeat any required angle all
round the circumference. On the voyage to Egypt a thermometer broke
inside the box, and the mercury tarnished the divided rim in parts. The
Pyramid angles thus obtained were printed in Vol. II. of " Life and Work
at the Great Pyramid," by Professor Piazzi Smyth, in 1867.
439. Smaller Clinometer of Precision, with improved
mounting, readers, and level. Prof. Piazzi Smyth.
This instrument was made to order by E. E. Sang, of Edinburgh, in 1869,
and intended for measuring Great Pyramid angles of slope. It carries its
own footbar, 25 inches long, has improved readers and illuminators, and a
chloroform level, as being more quick and frictionless than either ether or
alcohol. The circle can be rotated and clamped on its own centre for due repe-
tition of the angles round the circumference ; the verniers read to 1', and there
are supplementary verniers for investigating errors of division.
435a. Method of ascertaining Angles of Torsion by means
of instruments constructed by Professor Wischnegradski.
Laboratory of Mechanics, Technological Institute, St.
Petersburg.
This is composed of a support fixed with two horizontal screws in the
given section of the beam subjected to torsion. This support carries a
horizontal axle, upon which is fixed an arc, bearing the teeth, whose pitch
measures an angle of 2,440 seconds. This arc gears with an endless screw, the
head of which bears a circle divided into 244 equal parts, and furnished
with a fixed decimal vernier ; the arc also carries a very sensitive level, placed
at the beginning of the experiment in a horizontal position.
1J2 SEC. 3. MEASUREMENT,
The angle of torsion between the two given sections of the beam is calcu-
lated by two instruments exactly similar. The deformation of the twisted
beam causes an inclination of the levels of both instruments ; they are re-
stored to their original position by means of the endless screws, and then is
effected the reading of the angles described by the arcs of the two instru-
ments. The difference between these angles is the angle of torsion required.
In the Laboratory of Mechanics of the Technological Institute of St.
Petersburg the well-known apparatus of Wohler is used for the torsion
of trees, the photograph of which, taken together with the instruments for
measuring the angles of torsion, is exhibited. For demonstrating how to use
the instruments, a provisional apparatus is exhibited, wherewith the torsion
of the beam is effected by means of a simple lever.
442. Clinometers, devised by the Rev. Professor
Hen slow, one of which was used by Dr. Hooker in his
Himalayan journeys. J. I). Hooker, M.D., P.JR.S.
442a. Three Clinometers. G. W. Strawson.
443. Protractor, with scale, vernier, and magnifying glass.
Reads to 1 min. Prof. Baron von Feilitzsch, Greifswald.
443b. Instrument for the Measurement of Angles.
Dr. Fr. Holler, Selbo Drontheim, Norway.
440-1. Drawings and Photographs of Dividing Ma-
chinery. Messrs. Trougliton Simms.
Fig. 1. General view of dividing machine.
A. The circular table with racked circumference containing 4,320 teeth,
each tooth, therefore, equal to five minutes of arc.
B. The screw by which movement is communicated to Table A.
C. A ratchet wheel attached to the screw shaft.
D. A crank arm which during one half of a revolution gives a forward
movement to the screw ; during the remaining part of its revolution
the screw is at rest. The axis which carries the crank arm has a
bevelled wheel upon it, serving to communicate motion to the
cutting apparatus.
E. The cutting frame.
F. A cam to give movement to the dividing knife or other tool by which
the division is made.
The apparatus is so arranged that the division may be cut whilst
the circular table is at rest, the tool being lifted by a second earn (not
well seen in the drawing) when the table is in motion.
Fig. 2. Plan of cutting apparatus showing the relation it bears to the
circular table and screw.
Fig. 3. Section of table and axis.
Fig. 4. Drawings of cams and cutting frame, the cam " h " for lifting the
tool (just seen in Fig. 1) is here shown.
XI. TIME.
XLMEASUREMENT OF TIME.
Copy of the Drawing representing the first idea of the
Application of the Pendulum to the Clock ; dictated by
Galileo, then blind, to his son Vincenzo and his disciple Viviani.
Elucidated on the original of the Galilean manuscripts in the
Biblioteca Palatina.
The Royal Institute of ^ -Studii Super iori," Florence.
40075.
114 SEC. 3. MEASUREMENT.
In an account which he gave Prince Leopoldo de' Medici, Viviani, after
having described Galileo's experiments on the pendulum, and the way in
which he applied it to the measurement of time, continues thus : " But as
ff Galileo was most liberal in communicating his inexhaustible speculations,
" it frequently happened that the uses and newly discovered properties of
" his pendulum, spreading little by little, fell into the hands of persons who
" adopted them for their own ends or inserted them in publications, and
" by artfully passing in silence over the name of their true author, made
" such use of them that it was believed at least by those who knew nothing
" of the origin of the discoveries that the writers were the real authors of
" them. He next speaks of the observations of the ' Stelle Medicee,' of the
" tables relating to them prepared by the Padre Renieri, of the offering made
" by Galileo to the States General of Holland of his method for determining
" longitudes by means of the eclipses of Jupiter's satellites, and of Galileo's
" determination to send his son Viucenzo and the aforesaid Padre to Holland,
" since he himself, being old and blind, was unable to travel thither." He
then continues : " While, therefore, Padre Renieri was employed on the
" composition of the tables, Galileo gave himself up to meditations on his
" time-measurer; and I remember, one day in the year 1641, when I lived
" near him in the Villa d'Arcetri, that the idea struck him that it would be
" possible to adapt the pendulum to clocks with weights or springs, and
" make use of it instead of the usual regulator, hoping that the perfectly
" equable and natural motion of the pendulum would correct all the defects
" in the mechanism of the clocks. But as his blindness deprived him of the
" power of making plans and models of the designs he had formed in his
" mind, his son Vincenzo having arrived one day at Arcctri, from Florence,
" Galileo confided his ideas to him, and many times afterwards did they
" reason over the matter, and at last settled upon the method which is
" shown in the accompanying draAving, and then set to work' at once
in order practically to overcome those difficulties which for the most part
it is impossible to foresee. But Sig. Viucenzo intended to construct the
instrument with his own hand, in order that by this means the secret
of the invention should not be reported by the artificers before it had
been presented to His Serene Highness the Grand Duke, his master, and
to the States General (to be used for observing the longitude), but he
put off the execution of his work so frequently that a few months later
Galileo, the author of all these admirable inventions, fell sick, and on the
8th of January 1641, ' ab Incarnazione ' according to the Roman style, he
died ; and consequently Sig. Vincenzo's energies so cooled down that it
was not until the month of April 1649 that he actually began to make the
present clock upon the idea explained to him by his father Galileo. He
then managed to obtain the services of a young man who is yet living
named Donienico Balestri, a locksmith who had had some experience in
making large wall clocks, and he made him construct the iron frame, the
wheels and arbors, but the tooth-cutting and the remainder of the work he
executed with his own hands, constructing on the highest wheel called the
scape wheel (tacche) 12 teeth with as many pins (pironi} spaced between
the teeth, and with a pinion of six leaves on the same arbor, and another
wheel of 90 teeth which moves the above-mentioned. He then fixed on
one side of the support which is at right angles to the frame the detent
(scatfo) which rests on the scape wheel, and on the other side he fixed the
pendulum, which was made of an iron wire screwed at the lower extremity
for the attachment of a ball of lead, so that it could be lengthened or
shortened for regulating. When this much had been done Sig. Vincenzo
wished me (as one who was in the secret of this invention and who inde i
had urged him on to complete it) to see, by way of trial, the combine 0.
XI. TIME. 115
" working of the weight and the pendulum. I observed the mechanism in.
" operation more than once, and his workman was likewise present. When
" the pendulum was at rest it prevented the descent of the weight, but when
" it was raised and then let go, in passing beyond the perpendicular, Avith
" the longer of the two arms attached to the pivot of the pendulum, it raised
" the detent which fits into the scape wheel, which wheel drawn by the weight
" in rotating with its higher part moving towards the pendulum, pressed with
" one of its pallets on the other shorter arm, and gave it, at the beginning of
" its return, an impulse sufficient to cause it to swing to the height from
" which it had started, so that when it fell back naturally, and had passed
" the perpendicular, it returned once more to lift the detent, and immediately
" the scape wheel was set in motion and gave a fresh impulse to the pen-
" dulum, thus, the swinging of the pendulum was rendered continuous until
" the weight had reached the ground. We examined the operation together,
" connected with which, however, many difficulties arose ; but Sig. Vincenzo
" did not doubt but that he would be able to overcome them all, indeed he
" fancied that he would be able to apply the pendulum to clocks in a different
" manner and by means of other inventions ; but since he had got so far, he
" wished to finish it on this plan, as the drawing shows it, with the addition
" of hands to show the hours and even the minutes. For this purpose he set
" to work to cut another cog-wheel. But whilst engaged on this work to which
"' lie was unaccustomed, he was overtaken by a very acute attack of fever, and
" was obliged to leave it unfinished at this point, and on the 22nd day of his
" illness, 011 the 16th of May 1649, all his thoughts and aspirations, together
" with this most exact measurer of time, were for ever lost to him. He,
" their author, passed away to measure (let us hope) in the enjoyment of the
" Divine Essence, the incomprehensible moments of Eternity."
Dodecahedron, with eleven solar watches, made in Florence-
in 1587. The Royal Institute of u Studii Superiori" Florence.
Horizontal Solar Watch.
The Royal Institute of " Studii Superiori" Florence.
Horizontal Watch, at the latitude of 43 44', made by
Cammillo della Volpaja, Florentine, in the second hah 5 of the 16th
century. The Royal Institute of " Studii Superiori" Florence.
Vertical Watch, of boxwood, at the latitude of 43 30' r
made in Florence in 1590 by Girolamo della Volpaja.
The Royal Institute of " Studii Superiori" Florence.
Night Watch, at the latitude of 43 30', made in Florence in.
1568 by Girolamo della Volpaja.
The Royal Institute of" Studii Superiori" Florence*
483. Universal Dial, made in 1616 for Prince Charles.
The Royal United Service Institution.
Presented to the United Service Museum, in 1832, by Captain W. H.
Smyth, R.N., K.F.M., F.K.S., &c., &c.
485. Universal Dial, in use about 160 years ago.
The Royal United Service Institution*
Presented to the United Service Museum in 1838, by His Royal Highness
the Duke of Sussex.
H 2
116 SEC. 3. MEASUREMENT.
484. Timekeeper, which was twice carried out by Captain
Cook. The Royal United Service Institution.
This timekeeper is thus spoken of in Cook's Voyage to the Pacific, 1776,
Vol. I., p. 4 : "I had likewise in my possession the same watch or time-
" keeper which I had in iny last voyage, and which had performed its part
" so well. It was a copy of Mr. Harrison's, constructed by Mr. Kendall."
This watch was taken out again by Captain Bligh, 1787, and when the
crew of the " Bounty " mutinied it was carried by the mutineers to Pitcairn's
Island. In 1808 it was sold by Adams to an American, Mr. Mayo Fletcher,
who sold it in Chili, and in 1840 it was purchased for fifty guineas by Sir
Thomas Herbert. It was repaired and rated at Valparaiso, and taken by Sir
Thomas to China, and brought home in the " Blenheim" in 1843, having kept
a fair rate with the other chronometers for the space of three years.
Presented to the institution by Admiral Sir Thomas Herbert, K.C.B.
484a. Two Hour Glasses. These were used in Spanish
men-of-war at the beginning of the last century.
Ministry of Marine ', Madrid.
484b. Chronometer, the fifth made by the English maker
Arnold. It was used on board one of the Spanish ships at the
battle, of Trafalgar. Ministry of Marine ', Madrid.
491. Ancient Striking Clock.
H. M. Commissioners of Patents.
This clock is of Swiss manufacture, and supposed to have been made in the
year 1348. It was obtained from Dover Castle, and had never been removed
from there till the year 1872. It is interesting from the fact of its having the
verge escapement, which was used many years before the pendulum.
444. Clock Dial. The hours, six only, are indicated by
perforated Roman letters. The hand or pointer is formed of a
revolving disc, painted in oil, with the subject of Aurora and
the Hours ; it must have gone round four times in 24 hours.
The dial is fitted in the original carved door of the clock.
Italian. 17th century. Rev. J. C. Jackson.
445. Clock, in the shape of an orb of silver-gilt, covered
with silver filigree, suspended from a ring which is surmounted
by a cupid. The base of black marble is ornamented with
beads enriched with silver-gilt filigree, enamels, and precious
stones. German (Hamburg). Dated 1685.
Rev. J. C. Jackson.
446. Clock, in gilt ormolu case, engraved with figures of
soldiers and festoons of flowers and fruit. It has a single hand,
and strikes the hours. The present pendulum has been sub-
stituted for the old bob. English. Early 17th century.
Rev. J. C. Jackson.
XI. TIME. 117
462. Model of a Clock with four Faces, to be worked
by water. Major M. L. Taylor, R.A.
463. Sir W. Congreve's Clock, in which the action of
the pendulum is replaced by the motion of a small steel ball on an
inclined plane, which it descends in 30 seconds.
Major M. L. Taylor, R.A*
486. Month Equation Clock, with double pendulum and
dead-beat escapement by Quire, showing minutes and seconds both
sidereal and mean time, also sun fast or slow, and containing an
annual almanack, mentioned in Cooke & Maule's account of
Greenwich Hospital in 1789. Royal Naval College, Greenwich.
447. Two Chronometers, by Arnold. Royal Society.
These chronometers were taken round the world by Captain Cook.
447a. Chronometer, with Glass Balance Spring.
E. Dent and Co.
This is the invention and handiwork of the late Frederick Dent, of the Strand
and Royal Exchange, and the only specimen in existence. The spring requires
far less compensation for any given change of temperature than a steel spring
would, and the balance, which is composed of a glass disc, is compensated by
the two small compensation laminae mounted upon it.
448. Explanation of the principles of action of the Com-
pensation Balance, with four models showing the various
stages of construction. James Poole ? Co.
*' Cut open " for action of heat and cold ; ordinary construction without
auxiliary, in rough state from casting.
450. Silver Pocket Chronometer. James Poole $ Co.
451. Diagrams and Models of the method of winding and
setting watches without a key. James Poole fy Co.
452. Keyless Watch, complete, with fuzee.
James Poole fy Co.
452a. Dipleidoscope with Telescope. M. Littz, Paris.
453. Keyless Watch, complete, with centre seconds and
going barrel. James Poole $ Co.
454. Ship Chronometer (2 day), complete.
James Poole fy Co.
455. Ship Chronometer (2 day). Movement reversed, to
show workmanship. James Poole fy Co.
456. Chronometer Movement (2 day), as received from
the factories in Lancashire. James Poole ty Co.
456a. Six Chronometers with rates froni the Geneva Obser-
vatory, stating records of trials of the years 1875 and 1876.
H. R. Ekegren, Geneva.
118 SEC. 3. MEASUREMENT.
No. 16,175, gold, open face, 21 lines, keyless.
No. 16,873, 18
No. 16,144, Chronographs, 19 lines, keyless.
No. 16,534, hunter, 21 lines, keyless.
No. 16,576, 19
No. 16,525, 18
457. Regulator Clock, filled with the Exhibitor's new patent
gravity escapement, having no upward locking, and which cannot
trip or slip teeth. Alfred John Higham.
On the escape wheel there are two sets of teeth, one set longer than the
other ; the teeth of each set are arranged, and the pallets are formed and
placed, so that the shorter set of teeth only is used, except in case of tam-
pering or other disturbance, when the longer set comes into action. This
secondary locking entirely prevents irregularity in the clock rate, but the clock
can be allowed to " run," if it is desired to be so set to time, by removing two
extra stops which are adjustable. The action of the escapement is ordinarily
exactly the same as that of the gravity escapements invented by Mr. Denison
(Sir Edmund Beckett, Bart.), and the secondary locking can be applied to
those escapements. For further description, see the Horological Journal,
April 1876.
458. Regulator, with improved gravity escapement on the
Bloxamic principle, as arranged and patented by Mr. Higham ;
founded on the old pin- wheel escapement, and fitted with a gal-
vanic interrupter for chronographical and other astronomical
purposes. Charles Frodsham $ Co.
459. Marine Chronometer, fitted with a galvanic inter-
rupter for chronographical and other astronomical purposes.
Charles Frodsham fy Co.
459a. Two-day Marine Chronometer, fitted complete for
ship's use. Charles Frodsham.
460. Apparatus for demonstrating the application of the
pendulum to the clock, at the same time serving for audibly indi-
cating the minutes.
The Secondary Government School, Assen (Netherlands).
This apparatus is constructed by C. H. Van der Heydeu, watchmaker, at
Assen (Netherlands), in conjunction with Dr. A. Van Hasselt, teacher at
the school for middle-class education, Assen. Price about 4/. The escape-
ment may be pulled forward so as to allow the wheel to turn freely. In this
manner it may be demonstrated, that clockwork without a pendulum will
acquire an accelerated motion.
The escapement must be kept in a forward position, until the weight has
reached the ground.
The apparatus, as it audibly indicates the minutes, may also be used for
experiments to demonstrate the laws of the pendulum, the laws of hydro-
dynamics, &c.
460a. Wheat stone's Motor Magneto-Electric Clock
(in teak case). The British Telegraph Manufactory, Limited.
XI. TIME. 119
460b. Wheatstone's 'Sympathetic Magneto-Electric
Clocks (4). The British Telegraph Manufactory, Limited.
46Oc. 18-inch Wheatstone's Sympathetic Magneto-
Electric Clock.
The British Telegraph Manufactory, Limited.
461. New System of Electric Clocks.
Prof. Osnaghi, Imperial Central Meteorological Institute,
Vienna.
In these electric clocks the uncertainty of the action of the greater number
of electric pointers has been avoided by causing the electric current to flow
with almost unabated force, as if there were no other clocks present. This
is attained by giving the electro-magnets double coils of very unequal
resistance. The spirals with great resistance serve for the attraction of the
needle from a distance ; the spirals with little resistance for retaining the
already attracted needle. With every clock there is also a wire coil for the
general return current, through which the electric current can circulate until
the attraction of the needle is complete, when its course is diverted by certain
mechanism, and is forced to pass over to the next clock.
464. Model of a Protomotive Clock.
The Committee, Royal Museum, Peel Park, Salford.
An apparatus consisting of a dial with hour and minute hands, and a gutta-
percha tube 100 feet in length, the object of which apparatus is to demonstrate
how a number of such dials in distant situations may be made, by means of a
column of air at natural pressure, to indicate the same time as the clock with
which they are connected. Invented and made by the late liichard Roberts,
C.E., Manchester, about the year 1848.
465. Ley's Compensating Pendulum. Henry W. Ley.
An inexpensive pendulum compensation is to be obtained by the employ-
ment of zinc and flint glass.
466. Ley's Entirely Detached Gravity Escapement.
Henry W. Ley.
The object of this escapement is to cut off absolutely from the pendulum
the clock train with its variations, so that there may be nothing whatever to
disturb the arc of vibration. The arrangement of the escapement shown in
the Figs, permits the motions of the various parts to be clearly followed.
The scape wheel has six long teeth A, Figs. 1, 2, 3, and 4, by means of
which it is " locked," and six " impulse " pins B near its arbor. The arbor
carries a fly, not drawn. The pendulum receives its impulse at each alternate
beat ; at the beats from right to left in the Figures. The parts of the escape-
ment are : (1), a pallet C; (2), a lever D, having the same axis as C, and
resting normally against a fixed stop, from which it can lift, but below which
it cannot fall ; (it is in its normal position in Figs. 1, 3, and 4) ; (3), an arm
E, of which one end can turn on a pin in D, and the other end, which is free,
is lifted by the impulse pins, and rests on them successively ; (it is resting
on an impulse pin in Fig. 1) ; (4), a first detent F, against which C sets
when at the top of its lift; (C is thus set against F in Fig. 1); (5), a
second detent G ; and (6), set on a spring, a stop H, against which the scape
wheel locks.
120
SEC. 3. MEASUREMENT.
Fig. 1 The pallet against
the first detent.
Fig. 2. At the end of the pendulum
swing to the right.
The action of the escapement is as follows : Suppose (as represented in
Fig. 1) the scape wheel to be locked and that C has been lifted from its lowest
position through an angle a + ft to the top of its lift. Suppose also that
the pendulum is moving to the right from the end of its swing at the left.
First, a slot or a pin in the pendulum rod (a pin is supposed here for sim-
plicity sake, and the path of the pin is shown by the dotted curve in each
Fig.) lifts G, idly, which falls back to its normal position, that of Fig. 1,
immediately the pin has passed ; then the rod itself, towards the end of its
swing to the right, impinges against a "beat" pin c in C, and, still rising,
carries C with it through a further angle 7. In rising through 7, C takes
up D, and the free end of E, which was resting on the impulse pin by which
it was lifted, is carried clear of that pin (now see Fig. 2), and drops on to
B 1 , the^ impulse pin next below, depressing F in its drop, and afterwards
holding F down (see E and F in same Fig.). The pendulum now returns,
from right to left, and C with D falls back through 7, D being arrested at the
fixed stop ; the free end of its arm E still resting on B 1 , and still holding F
down. The pendulum continuing its descent, C falls back through B (the
detent F being out of the way), as far as the detent G (here see Fig. 3),
where it stops. In this fall through /3, C gives the impulse. The pendulum
now moves on by itself, until presently the pin in its rod once more lifts
G ; not, however, idly now, but releasing C, which falling back further through
a to its lowest position (shown in Fig. 4), unlocks the scape wheel from
H. The position of II with respect to that part of C which acts upon it is
XI. TIME.
121
Fig. 3. The pallet against
the second detent.
Fig. 4. The pallet at its
lowest position.
shown in plan in Figs 3a and 4a ; in Fig. 3a just before, and in Fig. 4a just
after the unlocking of the scape wheel. The pendulum having lifted G,
continues its swing to the extreme left, whence it was supposed started.
The scape wheel, free to move, lifts C and also E, the detent F, which is
weighted so as to rise of itself, following E's motion, and being in position
to hold C when the lifting is done, which is the case just before the next long
tooth of the scape wheel coming round and setting against H (which returned
to its normal position as C in lifting cleared it), the parts are again as
represented in Fig. 1.
Such being the action, it is evident that the escapement is not only a
detached one in the sense in which all properly so-called gravity escapements
are so, that is, the pendulum is free from the scape wheel between the un-
lockings, but that the detachment is entire, seeing that the pendulum is never
in connexion icith the clock -train at all, being out of the way for the unlock"
ings, as well as between whiles. There is therefore nothing whatever to
affect its rate.
The pressure of the scape wheel against the stop by which it is locked
varies. This variation, however, is altogether apart from the pendulum, as
unlocking is the work of the pallet.
In the arrangement drawn the impulse is not given across the line of
centres ; it can, however, be so given ; and other modifications of the escape-
ment as here arranged can be made within the limits of its principles of
action, which are (1.) that the lifted pallet shall be held independently of any
variations in the lift, and (2) that the unlocking shall be apart from the
pendulum.
122 SEC. 3. MEASUKEMENT.
46 6a. Jamin's Compensator. M. Lutz, Paris.
466b. Diagram representing the Great Westminster
Clock. E* Dent and Co.
This is by far the largest and most powerful clock in the world. The clock
frame is 15 feet 6 in. long, and 4 feet 10 in. wide. The escapement is the
double three-legged gravity, and the pendulum which controls it weighs
685 Ibs., is 14 feet 5 in. long, and vibrates once in two seconds. Its compen-
sation is effected by zinc and iron tubes. The dials, four in number, are 22|-
feet in diameter, and the bell on which it strikes, " Big Ben," weighs nearly
14 tons.
463c. Diagrams representing the New Standard Clock
of the Royal Observatory, Greenwich. E. Dent and Co.
One of these is a view of the back of the movement of the Greenwich
clock, showing the escapement, the galvanic contact springs, and the contri-
vances invented by Sir George Airy for altering the compensation of the
pendulum and for altering the rate of the clock without stopping it. The
other diagram shoAvs the barometric compensation.
466d. Collection of Compensation Balances.
E. Dent and Co.
No. 1. An early form of balrffice. Steel connexions are fastened near the
root of the rims of a plain brass balance ; the expansion or contraction of these
being less than that of the central brass arm, the rims are by any change of
temperature tilted towards or away from the axis of motion.
No. 2. An eariy form of balance. Loops formed of brass melted on to
steel are fastened upon each side of the axis of motion, in consequence of the
greater expansion or contraction of the brass, these open or close with the
change of temperature, and drag in or thrust out the small brass weights, to
which they are attached by wires.
No. 3. An early form of balance. The riuis are of brass melted upon steel,
the brass being outwards ; with any change of temperature the rims open or
close.
No. 4. An early form of balance. A flat steel bar has soldered to its
extremities underneath pieces of brass ; the ends of the steel bar carry uprights
bearing weights upon their summits, the brass pieces underneath having a
different rate of expansion to the steel, bend it either upwards or downwards,
and tilt the uprights carrying the weights towards or away from the axis of
motion.
No. 5. A balance of similar design, but having brass melted upon the
steel, instead of merely being soldered to its extremities.
No. 6. A balance of modern design, similar in its action to No. 5.
In order to obtain perfect compensation, it is found that for an increase of
temperature the compensation weights must advance more rapidly towards
the axis of motion, than for the same decrease of temperature they would
recede from it. This peculiarity necessitates what is called secondary com-
pensation. The following balances have been introduced to obviate this
error :
No. 7. Compensation pieces formed of brass melted upon steel receive such
curves, that with any increase of temperature the compensation weights move
towards the axis of motion more directly than they recede from it with any
decrease of temperature. (Dent's balance.)
XI. TIME. 123
No. 8. A compensation bar is formed, as in No. 5, by brass being melted
upon steel, and this bending upwards or downwards, with any change of
temperature, tilts the weights carried by the staples towards or away from
the axis of motion. But the staples are themselves compensation pieces, and
they lift the weights higher with any increase, and depress them with any
decrease of temperature, and in this manner increase the rate at which
they approach the axis of motion, and diminish the rate at which they recede
from it. (Dent's patent balance.)
No. 9. A balance of nearly the same form as No. 6, but the section of its
rim is somewhat in the shape of a prism ; the form of the rim offers less re-
sistance to the motion of the compensation weight inward than outward.
(Dent's registered balance.)
No. 10. A balance similar to No. 5 is mounted upon the arm of a balance
similar to No. 6. With any increase of temperature, the first balance can
assist the second, but with any decrease of temperature its motion is checked.
The whole combination, therefore, is more effective in the heat than in the
cold. (Glover's form.)
No. 11. An experimental balance, contrived for the purpose of removing
weight from the centre, both with an increase and decrease of temperature.
(Wetherill's form.)
No. 12. An auxiliary compensation is added to a balance similar in form
to No. 6. The auxiliary consists of two double compensation pieces, and the
effect is to carry weight towards the axis of motion, both for an increase and
decrease of temperature. The effect of the main compensation weights is
therefore increased in the heat and diminished in the cold. (Dent's balance.)
No. 13. A balance of similar design to No. 8, but arranged so that tho
secondary compensation can be altered with greater facility. (Dent's
balance.)
No. 14. A balance having the same general operation as No. 8, but the
effect is obtained by straight bars only. The secondary compensation can
also be altered without inconveniently disturbing the main compensation, and
both without producing any great alteration in the time of the chronometer.
(Dent's balance.)
467. Drawings of Compensation Balances, Escape-
ments, and other appliances connected with the construction of
Clocks and Watches. The British Horological Institute.
Lever Escape Wheel.
Lever Escapement.
Double Roller Lever Escapement.
Two Pin Lever Escapement.
Chronometer Escapement.
Duplex Escapement.
Club Tooth Lever Escapement.
Verge Escapement.
Horizontal Escapement.
Double Roller Lever Escapement with Compensation Balance.
Marine Chronometer Escapement.
Compensation Adjustment by Sir G. B. Airy, Astronomer Royal,
1875.
Double Three-legged Gravity Escapement as used in the West-
minster Great Clock.
124 SEC. 3. MEASUREMENT.
Dead Beat Clock Escapement.
Pin Wheel Clock Escapement.
Zinc and Steel Compensation Pendulum as used in the West-
minster Great Clock.
467a. Compensation Balance arranged in Two Groups.
GROUP I. Earnshaw's balance with circular rim (1795), and
modifications thereof to the present time.
Earnshaw's balance.
Modification of do.
Do. do.
Do. do., with extra adjusting screws.
Do. do., with screws for weights.
Do. do. do. do.
Do. do., with screws for more minute adjust-
ment.
Do. do. do. do. do.
Do. do., with double weights.
Do. do., with variation of weights.
Do. do., with auxiliary by Molyneux.
Do. do., do. do.
Modification of Molyneux's auxiliary.
Eifle's mercurial auxiliary:
Poole's auxiliary.
Example of recent auxiliary.
Do. do. do.
Do. do. do.
Compensation adjustment by the Astronomer Royal (Sir
G. B. Airy).
GROUP II. Balances of a form distinct from Earnshaw's, from
Hardy (1805) to the present time.
Hardy's balance.
Arnold's do.
Dent's do.
Balance with laminated arm and rim.
Hartnup's balance.
Do. do. cup.
Modification of Hartnup's balance.
Kullberg's flat rim balance.
Do. double-flat rim balance.
Cole's balance.
The British Horological Institute.
468. Enlarged Model of Compensation Watch Balance.
The British Horological Institute.
469. Ordinary Marine Chronometer Compensation
Balance. The British Horological Institute.
XI. TIME. . 125
471. Models (ten) of Compensation Balances, showing
various attempts to overcome what is known as the " Error " of the
ordinary Compensation Balance, by the late Thomas Hewitt.
The British Horological Institute.
472. Marine Chronometer by Earnshaw.
The British Horological Institute.
473. Marine Chronometer with Mudge's Escapement.
The British Horological Institute.
474. Grossmann's Micrometer.
The British Horological Institute.
475. Model of " Ferguson's Paradox."
The British Horological Institute.
476. Model of Cole's Resilient Escapement.
The British Horological Institute.
477. Callipering Engine, by the late Richard Roberts.
The British Horological Institute.
478. Models of English and French Repeating Motions
for Watches. The British Horological Institute.
479. Watch Movement.
The British Horological Institute.
480. Marine Chronometer Movement.
The British Horological Institute.
481. Collection of Watch and Chronometer Balance
Springs. The British Horological Institute.
482. Map showing allowance of time to be made for velocity
of sound as applied to the Westminster Clock Bell.
The British Horological Institute.
482a. Working Model, for educational purposes, of
a Chronometer Escapement, with a 6-inch compensation
balance. Ignaz Herrmann.
482b. Working Model, for educational purposes, of
a Lever Watch Escapement. Ignaz Herrmann.
Working Model, for educational purposes, of a Hori-
zontal Watch Escapement. Ignaz Herrmann.
Model for demonstrating the law of the compensation balance
or of any vibrating or rotating body. Ignaz Herrmann.
An arm carrying movable weights revolves about a vertical axis under the
action of a spring. The time taken for the spring to run down is propor-
tional to the square root of the distance of the weights from the axis.
126 SEC. 3. MEASUREMENT.
434a. Eight-day Marine Chronometer.
Parkinson fy Frodsham.
484b. Eight- day Marine Chronometer.
Parkinson Sf Frodsham.
484c. Chronometer, used by Captain Parry in the year
1819. Parkinson fy Frodsham.
This chronometer, used by Captain Parry in his voyage to the Polar Sea
in 1819, was specially compensated for extreme cold. Others of a similar
character were recently made for the Arctic Expedition under Captain Nares ;
also for Dr. Livingstone's Central African Expedition, the latter being com-
pensated for a higher range of temperature.
487. Pendulum Clock for marking the time according to
the time system of nature, thus forming the standard of a system
of measurement including time and space together, with decimal
subdivisions. The pendulum measures space by its length, and
time by its period of oscillation.
Hans Raumgartner, Basle, Switzerland.
The pendulum has the exact length of a longitudinal uuit of natural
measure, that is to say, of the one hundred thousandth part of a degree, of
which 540 go to a meridian, and measures the natural second, or the one
hundred thousandth part of a mean day.
487a. Pendulum. Professor Dr. A. Krucger, Helsingfors.
A barometer tube of about 350 mm length is attached to the pendulum rod
in the plane of swinging ; a little quantity of dry air is introduced in the upper
part of the tube: height of the mercury column about 150 mm . The rising
and falling of the mercury, depending on the variations of atmospherical
pressure, will affect the length of the pendulum and the clock-rate. It will
be very easy to calculate the distance from its centre, at which the tube is to
be attached ; then the barometrical variation in the clock -rate will be com-
pensated. A pendulum of this construction has been used with success at
the Helsingfors Observatory since 1866. See Astrononiische Nachrichten,
Vol. 62, No. 1482.
488. Clepshydral Escapement.
Prof. W. II. Miller, M.A., F.R.S.
By means of the fountain bottle of Berzelius, or Gay-Lussac's syphon
washing bottle, or any similar contrivance, a current of water is directed
into a capsule, from which it is transferred by a syphon to the mouth of an
inverted syphon partly filled with fine sand, one leg being rather more than
twice as long as the other. The upper end of the short leg is stopped with
a cork, in which is inserted a. short syphon about 0'29 inch (8 mm ) in diameter.
A compensated pendulum carrying near its upper end at a distance of 5-5
inches (140 ram ) an inverted funnel about 0-63 inches (IG" 11 --) long, 0'27
inches (7 mm ) wide at its base, and about 0-04 inches (l mm ) at the upper end.
The lower end of the upper syphon is supported at about 0-12 inch (3 mm )
above the top of the funnel carried by the pendulum when at rest. A tube of
about 0'08 inches (2 mnl ) in diameter, and 0'4 inches (10 mra ) long, is
supported with its upper end about 0- 12 inches (3 mm ) below the lower end
of the funnel at rest.
XI. TIME. 127
The pendulum being made to vibrate through a small arc before reaching
the upper syphon takes up a drop, and on arriving near its lowest point
delivers a drop to be carried off. The time is thus measured without allowing
the pendulum to come in contact with any solid body except the agate plane
on which it is supported.
The drop given off by the lower tube at the end of every two seconds, may
be used to record every alternate second of time by means of a timepiece
having a very light pendulum timed in accordance with the pendulum the
water clock.
No attempt has been made to exhibit the mechanism for counting the
seconds.
48 8a. Model of Compensation Balance, applicable to
watches and chronometers. (With a drawing.)
M. Winner -cl, Paris.
488b. Model of Escapement, applicable to the model
clock at the Paris Observatory. (With a drawing.)
M. lYinnerel, Paris.
488c. Model of Escapement, with simplified suspension,
applicable to clocks. (With a drawing.)
M. Winner el) Paris.
483e. Two Movements for Chronometers, one eight days
and one two days. Victor Kullbcrg.
489. Standing Pendulum Clock, in black wooden box with
silvered dial. Professor Buys-Ballot. Utrecht.
This is one of the first clocks made after Huygen's principle (i.e., provided
with cyeloidal pendulum). This peculiarity may be seen by opening the
door.
490. Two Conical Pendulum Clocks, for determining short
time intervals. Professor Buys-Ballot, Utrecht.
Each of these clocks is contained in a truncated wooden column covered
by a circular brass plate, by lifting which the dial may be seen. The foremost
part of the box can be removed to put the pendulum in motion, the spring
being woundup. In this condition only one hand moves. By pressing on the
button at the foremost part of the dial, the two other hands move until the
finger is withdrawn. In this manner very short lapses of time can be
measured. The instruments must be placed accurately horizontal. These two
specimens were used by Moll and van Beelt on the heath near Amersfoort
for determining the velocity of sound. They are constructed for the decimal
division of time, and indicate the ten millionth part of a day (24 hours).
491a. Very curious Timepiece, designed by Mudge.
E. Dent and Co.
The escapement is a true remoutoire ; two small pendulum springs are
wound up at every beat of the scape wheel, and these give impulse to the
balance. The balance is controlled by two pendulum springs, one above and
the other beneath it ; the first of these receives the action of the " compen-
" sation curb," the second is for ordinary regulation. TJie action of the
}28 SEC. 3. MEASUKEMENT.
Ji compensation curb " is analogous to the ordinary regulation by curb pins,
but the curb pins are advanced backwards or forwards along the spring by
the operation of the compensation pieces, which, being constructed of brass
melted upon steel, bend at every change of temperature. The whole time-
piece has been designed and got up with a surprising degree of refinement.
492. Working Model of Chronometer Escapement, with
two inch scape wheel. Philip John Butler.
493. Small Electric Pendulum. Striking seconds on
a bell, and thus capable of being used for astronomical studies.
Antoine Joseph Gerard, Liege.
494. Book containing plans of instruments, apparatus, and
machines. Antoine Joseph Gerard, Liege.
49 9a. Chronometrical Regulator, for putting in motion a
registering cylinder. Mr. Yvon Villarceau.
This system of regulator, the theory of which is due to Mr. Yvon Villarceau,
is represented by the model included among the objects exhibited by M. L.
Breguet.
500. Edelmann's Seconds Pendulum, with galvanic
attachment. M. Th. Edelmann, Munich.
501. Chronometric Comparateur, an instrument of coinci-
dences, for determining the difference of time between two distant-
clocks. M. Redier.
5Ola. Collection of Steel and Electro-gilded Pendu-
lum Springs. E. Dent and Co.
502. Clock employed in the Pantheon Experiment by M. L.
Foucault. Conservatoire des Arts et Metiers, Paris.
502a. Different applications of Metal Tubes of elliptical
section to instruments for measuring pressure, temperature,
weight, speed, and time.
1. Manometer for steam, air, or water pressure.
2. Barometer. Counterpoised barometer.
3. Thermometer.
4. Tacheometer, or speed indicator.
5. Balance for light and heavy weights.
6. Clock with pneumatic motor.
M. Eugene Bourdon, Paris.
502 a. Motor Clock and case, with two electric dials,
batteries, and fittings. T. Cooke $ Sons.
503. Electric Apparatus by M. Foucault, for keeping up
continuously the motion of the clock.
Conservatoire des Arts et Metiers, Paris.
XI. TIME. 129
503a. Marine Chronometers for ships' use. Manufactured
by Victor Kullberg, Liverpool Road, London, N.
South Kensington Museum.
503b. Two-day Chronometer, fitted complete. Two move-
ments reversed, to show the compensation balances.
South Kensington Museum.
503d. Chronometer and case 011 stand with glass shade.
The Royal Observatory, Greenwich.
509. Marine Chronometer, regulated at sidereal time, used
by the Scientific Commission of Noumea in observing the transit
of Venus. Messrs. Tondola and Co., Paris.
510. Marine Chronometer, suitable for distributing the
hour in quarter minutes to an unlimited number of electric
receivers, going for one year without being wound up. (System
applied for more than three years with complete success.)
Messrs. Tondola and Co., Paris.
511. Marine Chronometer, regulated to mean time. Speci-
men of ordinary construction. Messrs. Tondola and Co., Paris.
512. Geographical Clock, with revolving planisphere j
showing the time, longitude, and latitude, of all parts of the globe.
Messrs. Tondola and Co., Paris.
513. Astronomical Pendulum Clock.
W. Brooking, Hamburg.
514. Wheel-work of Clock. W. Brooking, Hamburg.
515. Astronomical Pendulum Clock with mercury com-
pensation pendulum. Th. Knoblich, Hamburg.
517. Chronometer-escapement, model.
Th. Knoblich, Hamburg.
518. Anchor-escapement, model.
Th. Knoblich, Hamburg.
519. Pendulum Clock belonging to the tide-gauge of Mr.
Reitz. Th. Knoblich, Hamburg.
519a. Clock worked by Water-power. T. Hankey.
520. Astronomical Pendulum Clock.
F. Dencker, Hamburg.
The Jiirgens compensation pendulum system has an isochronous sus-
pension spring, determined by calculation. It is, contrary to the formerly con-
structed repose pendulum, executed with sufficient stability. Not only is the
expansion coefficient of the separate bars exactly determined by the pyrometer,
40075. I
130 SEC. 3. MEASUREMENT.
but likewise the whole pendulum is directly controlled in the pyrometer. The
pyrometer employed is of quite a novel construction ; the observation takes
place in a liquid, without contact, under two micrometer microscopes. As
the observation through the microscope requires water of perfectly equable
temperature, the uniform^ of its temperature is ensured ; the bars likewise
must be quite homogeneous, as otherwise a bending of them will take place
by a change of the temperature, whereby the terminal ends will move out of
the range of vision. With regard to compound pendulums, the centre of
gravity is to be found by means of a balance the point of flexion of the spring
of which is known to the exhibitor, and then the point of oscillation by cal-
culation ; in a quite homogeneous and uniformly strong spring it is exactly in
the centre. By means of a bar, which is adjusted exactly to the length of the
pendulum,* the point of oscillation can be exactly fixed in the pyrometer, and
the whole pendulum examined with regard to extension and stability. The
working of the clock affords a check upon the accuracy of the measurement ;
if no error be made, the pendulum thus adjusted and fitted to a clock will
exactly vibrate seconds.
521. Model Escapement. F. Denckcr, Hamburg.
An anchor escapement, enlarged tenfold, with an impulse derived from
the chronometer and acting like the same from fork upon balance. This
requires no oil. The straight lines of the fork and the release stone
render a quite exact execution possible, and consequently an effect which
almost equals the direct impulse from wheel upon balance, without detracting
from the great insensibility of the anchor escapement. The lifting which
it is desired to give to the balance in this case is determined only by tbe
length of the fork, independent of the length of the lever. Arranged for
quarter seconds, it will be very useful for determining the time on journeys
and on sea. The last seconds are regulated by a curb, permitting only
little motion, but being securely guided by means of a screw. The last regu-
lation by the balance screws always disturbs the equilibrium of the balance,
and effects thereby a doubling of the errors at the change of the position.
The flat spiral spring has an inner and an external curve.
522. Gold Watch. F. Dencker, Hamburg.
The pocket watch has been executed exactly according to this model in
the exhibitor's establishment at Geneva. It is provided with a flat spiral
spring hardened in fire according to his invention. Up to the present time
no flat spiral springs hardened in fire are employed, as far as the exhibitor
knows.
523. Watch with spindle without spiral spring ; constructed
in the East in the first half of last century, indicating month, day,
and hour in Arabic figures. (JRemariable for its age and origin.)
Property of H.H. Prince Pless, Fiirstenstein.
The Breslau Committee.
V
523a. Watch, thickness of a crown piece, made for the late
Sir C. Wheatstone bv Mr. A. Stroh.
* The extension of the parts to be employed being known, a pendulum can be deter-
mined by calculations which swings in exactly one second.
131
SECTION 4, KINEMATICS, STATICS, AND
DYNAMICS.
WEST GALLEKY, GROUND FLOOR, ROOM K.
I. SPECIAL COLLECTIONS.
COLLECTION OF APPARATUS USED BY 'SGRAVESANDE TO ILLUS-
TRATE HIS PHYSICAL RESEARCHES.
524. 'sGravesande's Apparatus to demonstrate the
Laws of Centrifugal Force.
Professor Dr. P. L. Rijke, Ley den.
(See 'sGravesande's "Physices Elementa Mathematica," 3rd edition, Vol.
I., p. 153.)
525. 'sGravesande's Apparatus to demonstrate the
Theory of the Wedge.
Professor Dr. P. L. Rijke, Ley den.
526. 'sGravesande's Apparatus, to show, by means of a
pendulum furnished with weights and springs, that the same
quantity of Mechanical Work produces the same quantity of
Vis Viva.
Professor Dr. P. L. Rijke, Ley den.
527. 'sGravesande's Apparatus to demonstrate the Laws
of Falling Bodies.
Professor Dr. P. L. Rijke, Ley den.
528. 'sGravesande's Apparatus for Parabolic Motion.
Professor Dr. P. L. Rijke, Leyden.
I 2
132 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
COLLECTION OF KINEMATIC MODELS, EXHIBITED BY THE KONIGL.
GEWERBE-AKADEMIE, BERLIN, PROF. KETILEAUX, DIRECTOR.
The models in this collection are connected throughout with Professor
Reuleaux's treatment of the theory of machines. Their nature will be found
fully discussed in his " Theoretische Kinematik " (Vieweg und Sohn). The
English edition of this work (Maciniilan), translated and edited by Professor
Alexander B. W. Kennedy, C.E., of University College, London, was pub-
lished in June. The English names of the mechanisms here given are those
used by Professor Kennedy in his translation.
551. I. Fairs of Kinematic Elements.
(a.) LOWER PAIRS.
1. Turning or cylinder pair, R+ R- or C + C~.
2. Sliding or prism pair, P+ P-.
3. Twisting or screw pair, S+ S~.
552. Fairs of Kinematic Elements.
(b.) HIGHER PAIRS.
4. Equilateral duangle in equil. triangle.
These models of the higher pairs of elements can be inverted ;
that is, the movable element can be fixed, and the fixed element
made movable. The centroids are shown in thick black or red
lines ; the roulettes, or point-paths, in thinner lines.
5. Expanded duangle in equil. triangle.
6. Equilateral curve-triangle in square.
7. Equilateral curve- triangle in rhombus.
8. Expanded isosceles curve-triangle (90) in square.
9. Expanded equilateral curve-triangle (90) in rhombus.
10. Regular curve-pentagon in square.
11. Symmetrical curve-pentagon in square.
553. II. Conic Axoids, with corresponding Spheric
Roulettes and Profiles.
12. Spheric epicycloid.
Katio 1 : 3.
13. Spheric cycloid.
A full cone rolling upon a plane cone (1:3).
14. Spheric hypocycloid.
A full cone rolling in an open one (2:1).
15. Spheric hypocycloid.
Ratio 1:3.
16. Spheric pericycloid.
The curve upon the rolling cone passes always through the de-
scribing point of the fixed one.
I. SPECIAL COLLECTIONS. 133
17. Spheric involute.
Katio 1:3.
18. Spheric involute.
Ratio 8:9 ; the curve in red is a curtate involute.
1 9. Apparatus for describing spheric cycloids.
Describes, among other curves, those here exhibited.
554. III. Simple Kinematic Chains and Mechanisms.
20. Quadric cylindric-crank chain.
21. Slider-crank chain.
22. Quadric conic-crank chain.
23. Reduced slider-crank chain.
The link c omitted.
24. Reduced slider-crank chain.
Links a and c omitted.
25. Reduced conic-crank chain.
The link c omitted.
26. Quadric crank chain with slot and sector.
27. Single crossed slide chain.
28. Double crossed slide chain.
29. Simple spur-wheel chain.
30. Simple spur-wheel chain with annular wheel.
31. Endless screw.
32. Stand for carrying the above models when in use.
555. IV. Crank Trains.
33. Double slider-crank.
34. Slider-crank.
With ceutroids.
35. Slider-crank.
With centroids.
36. Double slider-crank.
With centroids. (The centroids are here Cardan's circles.)
37. Slider-crank.
38. Skew double slider-crank.
39. Double slider-crank with curved slide.
40. Double slider-crank with skew slide.
41. Lever-crank.
42. Double slider-crank with curved slide.
With pin expansion.
43. Slider-crank.
Link b is here a disc.
44. Slider-crank.
With adjustable connecting rod.
45. Slider-crank.
With adjustable cross-head.
134 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
46. Slider-crank.
In the form of a marine engine.
47. Slider- crank.
Slotted link gear.
48. Slider-crank.
Double slide gear.
49. Slider-crank (Norman Wheeler).
Three-fold.
50. Slider-crank, with pin expansion, 2 within 1.
51. Slider-crank, with pin expansion, 1 within 2.
52. Slider-crank, with pin expansion, 3 within 2.
53. Slider-crank, with pin expansion, 2 within 3.
54. Slider-crank, with pin expansion, 2 within 3.
Annular expansion.
55. Slider-crank, with pin expansion, 1 within 2 within 3.
56. Slider-crank, with pin expansion, 3 within 2 within 1.
57. Slider-crank, with pin expansion.
Adjustable stroke.
58. Swinging block (slider-crank).
59. Turning block (slider -crank).
60. Skew (turning) cross block.
61. Turning block (slider-crank).
With pin expansion (can be used also as a turning slider-crank).
62. Turning block (slider-crank).
With reduced centroids.
63. Double crank (drag-link coupling).
With reduced centroids.
64. Turning block (slider-crank), Redtenbacher's "Maskirte
Kurbelschleife."
Quick return motion ; the stroke is adjustable.
65. Swinging slider-crank.
650. Swinging double slider.
66. Swinging skew double slider.
67. Conic crank-train.
68. Isosceles double-crank (Galloway).
Mean velocity, ratio 1:2.
69. Isosceles double- crank (Galloway).
Mean velocity, ratio 1:2; arrangement for crossing dead points,
by Eeuleaux.
70. Anti-parallel cranks (Reuleaux).
Special arrangement for crossing dead points.
71. Anti-parallel cranks (Reuleaux).
With centroids, which are ellipses.
72. Anti-parallel cranks (Reuleaux).
With centroids, which are ellipses and hyperbola.
I. SPECIAL COLLECTIONS. 135
73. Double parallel crank train, used as a coupling.
For transmitting uniform rotation.
74. Double parallel crank train, used as a coupling (Reuleaux).
For transmitting uniform rotation.
75. Crank train for transmitting uniform rotation (Heilrnann).
76. Crank train for transmitting uniform rotation (Bohm).
77. Differential crank train (Romer).
Numbers of teeth, 56 and 56, with apparatus for tracing diagrams.
78. Differential crank train (Romer).
Numbers of teeth, 56 and 57, with apparatus for tracing diagrams.
79. Differential crank train (Romer).
Numbers of teeth, 30 and 90, with apparatus for tracing diagrams.
80. Hooke's joint.
81. Universal joint (Blees).
82. Universal joint (Polhein).
83. Universal joint (Reuleaux).
84. Universal joint (Klein).
85. Universal joint (Klein).
Simplified by Reuleaux.
86. Double Hooke's joint.
The velocity ratio here can be made constant.
556. TV ft. Mechanisms for describing Straight Lines
(exactly or approximately).
87. Roberts triangle, " parallel motion."
88. Triangle motion, inverted, by Reuleaux.
89. Elliptic linkwork (Nehrlich), 3rd form, inverted.
90. Elliptic linkwork (Nehrlich), 3rd form, inverted.
91. Hypocycloidal linkwork.
92. Hypocycloidal linkwork, inverted, by Reuleaux.
93. Epicycloidal linkwork, Reuleaux.
94. Elliptic linkwork, inverted.
With the whole motion.
95. TchebischefFs linkwork.
Arranged so that it can be inverted.
96. Conchoidal linkwork, 1st form.
97. Conchoidal linkwork, 3rd form (Reichenbach).
98. Conchoidal linkwork, 3rd form (Reuleaux).
99. Lemniscoidal linkwork, 1st form (Watt).
100. Lemniscoidal linkwork, 2nd and 3rd forms.
101. Lemniscoidal linkwork, 1st form, inverted (Reuleaux).
102. Lemniscoidal linkwork, 2nd and 3rd forms.
Steam engine model with Watt's planet wheels.
103. Sector mechanism (Reuleaux).
Involute.
136 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
104. Sector mechanism (Reuleaux).
Cycloid.
105. Sector mechanism (Reuleaux).
Cycloid.
106. Cartwright's mechanism.
107. Mandsley's mechanism.
108. TchebischefPs mechanism.
109. Harvey's mechanism.
110. Harvey's mechanism.
111. Pantograph.
With elliptic Imkwork, 1st form.
112. Pantograph.
With prism guide.
113. Semi-pantograph.
With prism guide.
114. Semi-pantograph.
Steam engine model.
115. Rhombic linkwork.
557. V. Apparatus for describing Curves.
116. Ellipsograph.
117. Ellipsograph, by Slaby, on Haman and HempePs system.
Describes also cycloids. Dr. Slaby's construction contains very
essential improvements.
118. Elliptic chuck (Leonardo da Vinci).
119. Elliptic chuck (Delnest).
120. Sinoid and cardioid tracing gear.
121. Curve tracing apparatus.
122. Curve tracing apparatus.
123. Mechanism for describing Lissajous' figures.
Describes also ellipses.
124. Hastie's conoid gear.
125. Tricentric gear.
Tor the construction of three-grooved taps, &c.
126. (Form-) copying machine.
127. Rose-engine.
128. Rose-engine.
129. Rose-engine.
130. Rose-engine, special form.
558. VI Parallel or Translating Trains.
131. Parallel ruler.
Single and double.
132. Parallel ruler.
With crossed bars.
I. SPECIAL COLLECTIONS. 137
133. Complete lever parallel train.
Weighing machine, of Roberval.
134. Incomplete lever parallel train.
Weighing machine, of Milward.
135. Incomplete lever parallel train.
Weighing machine, of Farcot.
] 36. Incomplete lever parallel train.
Weighing machine, of Schwilgue.
559. VII. Compound Parallel Trains.
137. Feathering paddle-wheel, of Buchanan.
A combination of trains similar to parallel rulers. The floats
remain always vertical.
138. Feathering paddle-wheel, of Oldham.
The floats rotate about their axes as the wheel revolves.
139. Feathering paddle-wheel, of Morgan.
With eccentric ring.
560. VIII. Higher Couplings.
140. Uhlhorn's coupling.
141. Oldham's coupling.
142. Reuleaux's grooved disc coupling.
143. Kochlin's cylindric coupling.
144. Schiirinann's cylindric coupling.
145. Conic coupling.
146. Pouyer-Quertier's coupling.
561. IX. Toothed-wheel Trains.
147. Spur wheels (point-paths used for profiles).
148. Returning spur-wheel train.
149. Returning spur-wheel train, with annular wheel.
150. Returning spur-wheel train, with annular wheel.
151. Returning spur-wheel train, with two annular wheels.
152. Returning spur-wheel train, with two annular wheels.
153. Returning spur-wheel train, with intermediate wheel.
154. Returning spur-wheel train, with intermediate wheel.
Keuleaux's so-called halving spur-wheel train.
1 55. Returning spur-wheel train.
With Marlborough wheel.
156. Spur-wheel train.
The centroids are Cardan's circles.
157. Beylich's universal wheels.
Pin-wheels."
158. Cylindric friction wheels.
Held by axial pressure.
138 SEC. 4. KINEMATICS, STATICS, AND DYNAAIICS.
159. Screw wheels.
Working as spur-wheels.
160. Screw wheels.
Screw wheel and rack.
161. Bevel wheels.
Plane- (face-) wheel and full wheel.
162. Mangle-wheel train.
Automatic reversal.
163. Mangle-wheel train.
164. Mangle- wheel train.
With internal teeth.
165. Whitworth's feeding gear for drills.
The drill is under a constant pressure.
166. Re versing gear, claw coupling.
With bevel wheels.
167. Reversing gear, bevel wheels.
168. Reversing gear, returning wheel gear.
By Reuleaux.
169. Reversing gear, Sellers' arrangement.
Open and crossed belts.
170. Reversing gear, with three pulleys.
171. Face-wheel and runner (Rupp).
172. Speed changing gear (Sellers).
For lathes.
173. Speed changing gear with double pulleys.
174. Reversing and disengaging train (radial).
Wheels of 103 and 53 teeth respectively.
175. Reversing and disengaging train (Fairbairn's).
1 76. Reversing and disengaging train (Brown's) ;
177. Engaging and disengaging train (Plait's).
178. Engaging and disengaging train (Curtis').
Globoid Gearing.
179. Globoid screw wheels ; spheric screw and wheel.
Reuleaux.
180. Globoid ring, screw, and wheel.
Reuleaux.
181. Skew globoid ring, conic screw and tooth.
Reuleaux.
182. Globoid ring, cone, and wheel.
Used by Stephenson in locomotive reversing gear,
183. Crossed globoid ring, screw, and tooth.
Reuleaux.
184. Crossed globoid ring, screw, and tooth.
Reuleaux.
I. SPECIAL COLLECTIONS. 139
185. Globoid screw aud screw wheel.
Endless screw.
186. Globoid screw.
Applied in horse gins ; velocity ratio 1 : 12.
Parallel Wheels.
187. Parallel wheels with 24 teeth.
Reuleaux. The teeth are revolutes.
188. Parallel wheels with 6 teeth.
Reuleaux. Would work also with 3 teeth. The teeth are ping.
189. Parallel wheels with 5 teeth.
Reuleaux. One wheel annular.
190. Parallel wheels with 24 (pin) teeth. -
Reuleaux. The parallelism is destroyed by displacing the axes.
Planet Wheel Chains.
191. Planet wheel chain.
192. Planet wheel chain, a==oo .
With excanching wheels.
193. Planet wheel chain, a=&=oo .
194. Planet wheel chain, with annular wheel.
195. Planet wheel chain, b=c=<x> .
196. Hyperboloidal endless screw.
562. X. Belt-trains.
197. Eeturning belt- train.
Shows the alteration of velocity due to the slipping of the belt.
198. Skew belt- train.
Acts in one direction only.
199. Belt-train with crossed guide pullies.
The necessary tension is given to the belt at the instant it is thrown
into gear.
563. XI. Slider-cam Trains.
200. Sinoidic cams. Cardioids.
Open cam with roller, pair-closure.
201. Sinoidic cams. Cardioids.
With second disc and centroid.
202. Sinoidic cams. Cardioids.
Pair-closure.
203. Sinoidic cams. Polar sinoid.
With centroid.
204. Sinoidic cams. Polar sinoid.
With centroid.
140 SEC. 4. KINEMATICS, STATICS, AXD DYNAMICS.
205. Cams with discontinuous profiles. Curve-triangle in skew-
curved slot.
With centroid.
206. Cams with discontinuous profiles. Equilateral curve-quad-
rangle.
With centroid.
207. Cams with discontinuous profiles. Equilateral curve-penta-
gon in straight slot.
208. Cams with discontinuous profiles. Equilateral curve-penta-
gon in adjustable slot.
Both parts are adjustable.
209. Cams with discontinuous profiles. Curved disc in curved
slot.
Both parts are adjustable.
210. Cams with discontinuous profiles. Curved disc.
For the motion of a slide valve.
211. Cams with discontinuous profiles. Disc with looped slot.
With shuttle, used in printing presses.
212. Slider-cam, two-lobed cylindric sinoid.
Force-closure.
213. Slider-cam.
Force-closure.
214. Slider-cam, cylindric sinoid.
21 5. Screw reversing train of Whitworth.
216. Steering gear of Scott and Sinclair.
217. Steering gear of Steel (Greenock).
218. Steering gear of Me William.
219. Steering gear of Reed.
220. Steering gear of Rogers.
221. Steering gear of Reuleaux.
222. Boring machine.
223. Boring machine (Stehelin).
224. Boring machine (Reuleaux).
225. Differential screws.
226. Differential screws, with wheel train.
227. Double screw train (Napier).
Self-acting return.
228. Cam reversing train (Girard).
For governors.
229. Leading screw with disengaging gear.
With self-acting disengagement.
230. Screw disengagement (Whitworth).
With pallet action.
231. Screw heckling machine (Houldsworth).
I. SPECIAL COLLECTIONS. 141
564. XII. Hatchet Trains.
232. Click train.
With two external and one internal clicks.
233. Centrifugal click train.
If rapid rotation occur, the centrifugal force throws out the click.
234. Silent click train.
235. Pinching click train.
236. Click train of Wilbers.
237. Ratchet train of Langen.
Used in gas engines.
238. Turning ratchet gear (Maltese cross wheel).
239. Turning ratchet gear (incomplete cross wheel).
240. Turning ratchet gear (spur wheel).
241. Ratchet train.
With automatic disengagement.
242. Ratchet train, with pin teeth.
With automatic disengagement.
243. Ratchet train (Reed).
With automatic disengagement and fall.
244. Ratchet train, with fast click.
245. Single acting ratchet train.
The direction of motion can he altered.
246. Double acting ratchet train.
247. Reversing ratchet train (Francis).
Used for governors.
248. Dividing machine (Nasmyth).
249. Lagarousse ratchet gear.
With eccentric.
250. Crown wheel ratchet train.
251. Tooth ratchet train, with double acting free click.
Model illustrating action of a force pump.
252. Escapement train (Mudge).
Can he held in the stand, No. 32.
253. Throttle click train.
Illustrates the action of the throttle valve.
254. Ratchet train, with pinching clicks.
255. Ratchet train, with several clicks.
256. Ratchet train, with free clicks.
Directing gear can be added so as to illustrate the action of
steam engine.
257. Ratchet train, with fast clicks.
258. Ratchet train, with Farcy's director.
259. Ratchet train, with Watt's director.
Watt's automatic valve gear.
142 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
260. Double acting ratchet gear.
261. Ratchet train, with cataract director (Hoffmann).
262. Double acting ratchet gear.
(Reuleaux.) Shows that the steam engine is a ratchet train. The
model can be worked with various forms of directing gear ; it stands
upon a large mahogany frame with columns.
263. Apparatus for using with Nos. 244 to 254 : Column with
fly wheel and two connecting rods.
Escapements.
264. Graham's anchor escapement.
265. Escapement of Reuleaux.
266. Pin escapement of Lepaute.
267. Escapement of Denison.
With three-toothed escape wheel.
268. Gravity escapement of Denison (1860).
As in the clock at the Houses of Parliament.
269. Gravity escapement of Denison.
270. Spindle escapement.
271. Cylinder escapement.
272. Anchor escapement.
273. Chronometer escapement of Jiirgensen.
564a. XIII. Chamber-crank Gears and Chamber-
wheel Trains.
274. Chamber-crank gear, Simpson and Shipton.
Steam engine.
275. Chamber-crank gear, Bahrens, Napier, Bompard.
Steam engine.
276. Chamber-crank gear, Wedding, Cochrane.
Ventilator.
277. Chamber- crank gear, Ramelli.
Pump.
278. Chamber-crank gear, Beale.
Gas exhauster.
279. Chamber-crank gear, Cochrane.
Steam engine.
280. Chamber-crank gear, Pattinson.
Pump.
281. Chamber-crank gear, Minari, Stocker.
Steam engine and pump.
282. Chamber-crank gear, Ramey.
'*' jSteam engine and pump, with elliptic wheels.
283. Chamber-crank gear, Lemielle.
Ventilator.
284. Chamber-crank gear, Cochrane.
Steam engine.
II. ELEMENTARY ILLUSTRATIONS. 143
285. Conic crank gear, Davies.
Steam engine.
286. Parallel crank gear, Galloway.
Steam engine.
287. Chamber-wheel train, Pappenheim.
Pump.
288. Chamber-wheel train, Fabry.
Ventilator for mines.
289. Chamber-wheel train, Fabry.
290. Chamber-wheel train, Root.
Blower.
291. Chamber-wheel train, Root.
Blower.
292. Chamber-wheel train, Payton.
Water-meter.
293. Chamber-wheel train, Evrard.
Pump.
294. Chamber-wheel train, Repsold, Lecocq.
Pump.
295. Chamber-wheel train, Dart, Behrens.
Pump.
296. Chamber-wheel train, Ganahl, Eve.
297. Chamber-wheel train, with three wheels.
298. Screw-wheel chamber train, Revillion.
Ventilator.
564b. Kinematic Compasses with Three Branches,
designed by Reuleaux.
Royal Academy of Industry, Berlin, Director, Prof. F.
Reuleaux.
By means of this instrument it is easy when the orbs of two points of a
system are given, to find all the other curves of the same system.
(See Reuleaux's " Kinematik," s. 24, and following.)
The third branch of these compasses may be altered longitudinally, and is,
besides, provided with a joint, so that entirely obtuse angular triangles
(amblygons) as well as entirely acute-angled triangles (oxygons) can be
taken by the compasses, for which the three-branched compasses of older
construction were not adopted.
These compasses were manufactured by J. Kern, mechanical instrument
maker, at Aarau, Switzerland, by order of the exhibitor.
II. ELEMENTARY ILLUSTRATIONS.
528a. Parallelogram of Forces.
Dr. G. Krebs, Frankfort-on-the- Maine.
528b. Inclined Plane.
Dr. G, Krebs, Frankfort-on-the- Maine.
144 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
528c. Inclined Plane, constructed by Professor Dr. Bertram,
Councillor of the Board of Education. Ferdinand Ernecke, Berlin.
The inclined plane is represented by tv?o parallel iron rods, which can be
placed at any angle with the horizontal bar.
Three distances can be measured as follows :
1. The length of the inclined plane, that is to say, the distance from the
joint to the perpendicular iron support bar, which maintains the plane in its
proper position.
2. The base, that is to say, the horizontal distance from the joint to the
support bar ; this is read on the horizontal pedestal.
3. The height, that is to say, the perpendicular from the terminal point of
the first distance to a horizontal line drawn through the joint ; this is read
on the support bar, the zero point of which is situated on a level with the
joint.
The weight on the inclined plane can be balanced in two different ways :
either parallel to the inclined plane, or in a horizontal direction. The
carriage of the roller can be turned, and the pulling string can, therefore,
be placed parallel to the inclined planes or horizontally. The double division
on the slotted support bar serves for observing the horizontal position of the
string.
At every experiment the weight carriage, that is, the two-wheeled axle
with its scale, is balanced with the scale which is suspended on the string.
This is effected by tare weights. Then the weight and the power of traction,
that is to say, the weights which are balancing each other in the weight scale
and the traction scale, are adjusted by means of the measured distances.
1. If the string remains parallel to the inclined plane, then the weight is
to the traction in the proportion of the length of the inclined plane to the
height.
For example, if the length be 80 and the height 40, then 20 grammes in the
weight scale will be balanced by 10 grammes in the traction scale.
2. If the string remains horizontal, then the weight is to the traction in
the proportion of the base of the inclined plane to the height.
For example, if the base be 40 and the height 40, then 4 grammes in the
weight scale will be balanced by 20 grammes in the traction scale.
In order to make the difference in the two cases intelligible, such positions
in the inclined plane are advantageous in which the three distances are indi-
cated by round numbers, such as height, 20 ; length, 29 ; base, 21. The weight
20 in the traction scale balances with the string in a horizontal position,
the weight 21 ; and with the string parallel the weight 29 will be balanced.
With the height 30 and the base 40 the length will be 50, and 30 grammes in
the traction scale will balance 50 grammes in the weight scale with a parallel
direction, whilst the weight required in a horizontal direction will amount to
40 grammes.
52 Sd. Parallelogram of Forces, constructed by Professor
Bertram. Ferdinand Ernecke, Berlin.
Apparatus for demonstrating the theorem of the parallelogram of forces.
^ If two adjacent sides of a parallelogram represent in magnitude and direc-
tion two forces acting at a point, the diagonal through the point will represent
their resultant in magnitude and direction.
This theorem is illustrated by the apparatus. The angular point of the
parallelogram is the (white) peg, over which a ring has been placed, on
which are fastened the three cords ; the magnitude of the forces is deter-
mined by the weights in the pans, the directions pass along the three rails
of which the one, AB, which is fixed, vertically ; the second AC, and the
III. PRINCIPLES OF MECHANISM. 145
third, AE, movable around the peg A, always move in the diagonal of the
parallelogram BADE, produced. The greatest of the forces is always taken
in the direction of AB, and determined as equal to 100, and the value of
the two others is read on the graduations of the lines BG and AF.
If, for example, the parallelogram is placed so that the lines are respec-
tively AB = 100, BF = 70, AF = 80, the ring in that case will poise freely
without coining into contact with the peg, if the weights in the pans amount
respectively to 100, 70, 80 grammes; the weights of the pans, of course, must
be adjusted previously by tare weights.
528e. Centrifugal Apparatus, complete.
Ferdinand Ernecke, Berlin.
529. Drawing. Experimental demonstration of the theory
of the parallelogram of forces and velocities, used by the exhibitor
since 1835. Professor Daniel Colladon, Geneva.
Two small pulleys are placed at some distance from each other on the edge
of a table. Ou the opposite edge, held by the hand, is a small ball of the
size of a musket ball, to which are attached, by one of their extremities, two
helical springs of fine brass wire ; the other extremity of these two springs
is drawn parallel to the plane of the table by cords passing over the pulleys,
and themselves stretched by the weights P and P'. The table being sprinkled
with sand or seeds, two lines are traced upon it, marking in direction and in-
tensity the tensions of the two springs which draw the ball, which are equal
to the weights P and P'. On discharging the ball it traces on the table a
straight line, which is in the direction of the diagonal of the parallelogram of
the forces P and P' of the two springs.
111. PRINCIPLES OF MECHANISM.
529a. Models (14) of the various Link-works for effecting
the exact rectilinear motion of a point, commonly known as
" parallel motions." A. B. Kempe, B.A.
Selected from a number described by the exhibitor in a paper published in
the "Proceedings of the Royal Society," No. 163, 1875, and entitled, " On
" a General Method of producing exact Rectilinear Motion by Linkwork,"
which points out the common principle on which the linkworks depend.
The points which have rectilinear motion are denoted by stars.
529b. The Sylvester-Kempe Parallel-Motion. Model of
a link work for effecting the exact rectilinear motion of a point.
A. B. Kempe, B.A.
Discovered simultaneously by Professor Sylvester and the exhibitor in
1875. The main portion of the apparatus consists of a linkwork of four bent
rods called a " Quadruplane," which is such that four points, one on each rod,
always lie at the angles of a parallelogram of constant area and angles. Two
of the points consequently are situate at such distances from a third that the
one distance is the inverse of the other. One of the points being fixed,
another is made by means of a link to move in a circle passing through the
fixed point, the other then describes a straight line. If the bent rods are
made straight, the four points lie in a straight line, and the parallel motion
becomes that of Mr. Hart.
40075. K
146 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
52 9d. Model of a Link-work, by which two rods may be made
to rotate about the same axle with equal velocities in contrary
directions. A. B. Kempe, B.A.
This and the following linkwork are described by the exhibitor in the
" Messenger of Mathematics," No. 44, 1874.
529e. Model of a Linkwork, by which rods may be made to
rotate about the same axis with velocities proportional to 1, 2,
3, &c. The linkwork can also be used to divide angles into a
number of equal parts. A. B. Kempe, B.A.
529g. Model of a Parallel Ruler. A. B. Kempe, B.A.
In this ruler the upper bar is constrained to move vertically up and down,
and has no lateral motion.
52 9i. Link Motion. William Howe, Chesterfield.
The sketch was made by W. Howe, in August 1842, which was the first
sketch of the shifting link motion. The small rough wooden model was begun
by William Howe, in or about 1 838, at the Vulcan Foundry, near Warrington,
Lancashire, where the sectional cylinder, piston, valve, and foundation frame
were made, but this was not for the purpose of applying the link motion, but
a tappet motion. When the sketch referred to above was made, the link
motion was applied to that model, and all the parts of the old model that
could be brought in were used. The model of the twin bar link was designed
in 1848 by William Howe, and made by Mr. William Usher, who was on a
visit to William Howe at the time.
529j. Model of Mechanism invented by a pupil of the
Royal School of Mines of Madrid, Dr. Horacio Bentabol, to ascer-
tain the direct line of a given point by means of linkage.
Royal School of Mines, Madrid.
A memoir by the author accompanies this model, in which all the necessary
details are given.
76c. Instrument, with joint, which makes its upper part
movable in a horizontal plane.
Professor Tchebichef, University of St. Petersburg.
76d. Model of joint, which directly transforms a reciprocating
into a circular motion.
Professor Tchebichef, University of St. Petersburg.
530. Drawing and Model of a connecting motion between
two shafts turning in reverse directions. Charles Bourdon.
530a. Pour Models, for the description of tooth -profiles, and
lines of contact.
Royal Rhenish Westphalian Polytechnic School, Aix-la-
Chapelle.
No. 1 illustrates the construction of general toothing, according to Reu-
leaux's method.
IV. PENDULUMS AND GYROSCOPES. 147
No. 2 shows that by the describing point of a string which runs over two
rollers, two evolutes constantly coining in contact are traced relatively to
them, which for this reason are tooth-profiles correctly working together.
As the same profiles are described when the axes are removed from or
brought nearer to each other, it follows that evolute-wheels may alter the
distance of their axes, preserving, notwithstanding, correct contact.
The circles " K" and " K 1 " cut off from the " contact line" a 6, the
contact space PP.
No. 3 shows that at the cycloid toothing, the " contact space " consists of
the curves (segments) cut off from the head circles, and that every normal
placed on the tooth-profile in the common point of contact of two teeth always
passes through the point of contact of the two dividing circles.
No. 4 evolves spontaneously the circumferential line of the smallest possible
space between the profiles.
53Ob. Model of Weston's Differential Pulley, with
weights complete.
Polytechnic School at Halle, Director Kohlmann.
IV. PENDULUMS AND GYROSCOPES.
531. Gyroscope. A mechanical contrivance to exhibit the
phenomena of rotation, and to show experiments on the deviation
of spherical projectiles. Elliott Brothers.
532. Foucatilt's Gyroscope. Ordinary model.
Geneva Association for the Construction of Scientific In-
struments.
532a. Gyroscope, by Foucault. College of France, Paris.
532c. Electric Gyroscopes. G. Trouve, Paris.
Illustrating trials concerning the maintenance by means of electricity of the
motion of the " Foucault " gyroscope. (Solution of the problem of gyroscopy,
laid before the inventor by M. Foucault in 1864.)
533. Polytrope. A gyroscope mounted on circles so as to
prove the laws of combined rotations about several axes. It may
be used to determine the meridian or the latitude of a place, and
to show the rotation of the earth on its axis, and for other
experiments. The Council of King's College, London.
534. " Soldier Experiment." Model designed to demon -
strate the relative effects of revolution and of rotation, separate or
combined, by the movements of soldiers. Henry Perigal.
535. Compass Experiment, demonstrating that a mag-
netised needle does, but an unmagnetised needle does not, maintain
its parallelism while revolving in a circle. Henry Perigal.
148 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
536. Gyroscope, demonstrating the effects of revolution and
of rotation, the two ways of turning round. Henry Perigal.
537. Gyroscope, demonstrating that revolution alone will
account for our always seeing the same face of the moon.
Henry Perigal.
538. Selenoscope, to demonstrate the kinematic effects of
the three hypotheses of the moon's motion, as a satellite of the
earth. Henry Perigal.
539. Kinescopes, illustrating the laws of compound circular
motion, by ocular demonstrations of their representative curves,
shown by bright beads revolving with great rapidity.
Henry Perigal.
539a. Pendulum Apparatus, for the graphic representation
of the combination of rectangular and non-rectangular vibrations,
with illustrative plates.
Institute for Physical Science of the University of Halle,
Professor Knoblauch.
An apparatus for the graphical representation of two simultaneous oscilla-
tions inclined to each other.
To a table are fastened the bearings of two pendulums, the oscillation-
planes of which are permitted to change their angle of inclination. One of
these pendulums transmits its motion to a horizontal bridge, the other to a
writing pen which moves exactly above the bridge. The oscillatory directions
of the bridge and the writing pen are the directions of the combined. velo-
cities. The curve the pin traces on the oscillatory bridge is to be con-
sidered as the trajectory of a point moving on a plane at rest under the
simultaneous oscillations of the pin and the bridge.
This trajectory is recorded either by the motion of a steel pin over a piece
of sooted paper, or on white paper by a narrow-pointed glass tube filled with
aniline ink.
If the weights on the pendulums are displaced the proportion of their
oscillatory movements is altered ; every difference of phase is obtained by
an appropriate choice of the time, one pendulum beginning to move after the
other. In this way the apparatus produces the greatest variety of geome-
trical figures.
The traces accompanying the apparatus may serve as specimens, which
were drawn by the apparatus.
A more exact and scientific explanation is to be found in the " Zeitschrift
" fur die gesammten Naturwissenschaften von Dr. C. Giebel," Bd. XIV.,
October 1875.
The apparatus has been designed by P. Schcenemann in the Royal Semi-
nary of Dr. Knoblauch, Professor of Physics at the University of Halle, and
has been executed for the physical science cabinet of the University by
Kleemann, mechanical engineer (Halle, Mauergasse 6).
539b. Compensation Pendulum.
Rohrbeck and Ltthme, Berlin.
V. VIBRATIONS AND WAVES.
149
539c. Tisley's Compound Pendulum Apparatus, for
combining two rectangular harmonic vibrations producing figures
known as Lissajous' curves. See Report of the British Associa-
tion 1873 ; Engineering, Feb. 6, 1874 ; also " Sound," 2nd ed.,
Tyndall. Tisley and Spiller.
539d. Donkin's Karmono graph, for compounding two
parallel harmonic motions.
See Proceedings, Royal Society, 1874.
Tisley and Spiller.
V. VIBRATIONS AND WAVES.
54O. Apparatus for the Composition of two parallel
simple vibrations. Dr. F. G. Groneman, Groningen.
1. Principle. If the point C moves with constant velocity on the circum-
ference of the circle HCG, it is known that its pro-
jection B upon the diameter GH performs a motion,
which is called a simple vibration.
If to this variable point B a string is fixed, which
is passed over the pulley D, and from this hangs
down to E, so that BD + DE is the constant length of
the string, it is easy to see that the point E will per-
form the same motion as B.
If this string is not attached to B, but to the
moving point C itself, E will have a motion which is
not strictly, but nearly that of B, the difference re-
sulting from the difference of the .two variable lines
BD and CD. This difference can be diminished to
any degree, by increasing the distance between the
pulley and the centre A.
2. Two discs of the same diameter are placed in the
same vertical plane, and can turn round horizontal
axes, one of which has a handle. The motion of the
first disc is communicated to the second by means
of crown wheels and cog wheels. One of the latter
can be fixed at any point of its axis, so that it may
be made to gear with each of the six crown wheels of
the second disc. By this arrangement the ratio of the
velocity of the second disc to that of the first can be
made successively equal to 1, i, , f, , &. For
changing this velocity, or for changing the difference
of the phases, when the velocities of the discs are
the same, the washer at the end of the axis of the
second disc must be a little loosened, and this axis
pushed forward.
3. The discs have one knob each. If the distance of the knob of the first
disc from the centre is called 1 , that of the knob of the second disc can
be made successively 1, ^, or -$. From the knobs proceed two strings,
which pass through the pulleys on the top of the instrument, and are
attached to the hooks A and B (Fig. 2).
150
SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
Fig. 2.
It is easy to understand that these hooks, when
" the handle is turned, perform two simple vibra-
tions, the one being invariable, the other variable,
in amplitude, phase, and velocity.
4. From A and B proceed two strings, passing
through the pulleys C and E, and fixed in F and H.
These pulleys have strictly the same motions as
A and B, but reduced in the ratio one half. A
third string proceeds from A to B, passing through
D. At any moment the displacement of D will
be the sum of the displacements of A and B, re-
duced one half. Its motion is therefore the resul-
tant of the displacements of C and E.
The motions of the three pulleys are shown
by the little white balls, placed on the front of
the instrument.
5. With this apparatus an infinite number of combinations can be demon-
strated, of which the following are examples :
. Two vibrations of the same amplitude and velocity, no difference of
phase. The middle ball has double the amplitude.
b. The same, the difference of phase being 180. The motion of the
middle ball is nearly zero. The deviation that will appear results
from the difference in the length of BD and CD (Fig. 1).
c. Combinations of a tone with one of its harmonics 2 and 3 with its
quint , or its quart , as well as when they are of the same intensity
or not (theory of the timbre).
d. Combinations of two tones of the same intensity, with the interval if-,
showing the origin of beats.
541. Apparatus, of a new form, to illustrate Wave Motion.
C. J. Woodward.
This apparatus consists of a series of balls suspended from a horizontal
beam by strings. These balls rest against a series of partitions in a wedge-
shaped horizontal trough, which can be raised and depressed parallel to itself.
The box, being drawn on one side in the plane in which the balls hang and
then slowly depressed, the balls will be successively liberated, and a wave,
similar to that of the sound wave, produced. If the beam be drawn aside
prior to depressing the box, the balls will rest against one side of the trough
and can be liberated in succession, causing them to oscillate in a plane at
right angles to the beam, a vibration being produced similar to that of plane
polarized light.
1576f. Wheatstone Wave Machine.
The British Telegraph Manufactory, Limited.
541a. Wheatstone's Apparatus, for illustrating the com-
position of rectangular vibrations.
The Council of King's College, London.
542. Drawings of new Apparatus for demonstrating the
composition of Vibrations. Dr. Leopold Pfaundler, Innsbruck.
Plate I. Two blackened glass discs are each placed on a separate horizontal
axis one before the other, in such a manner that the transparent curves
apparently cut in their periphery, intersect each other nearly at right angles.
A reflection of light is produced thereby, which, at the revolution of the discs,
V. VIBRATIONS AND WAVES. 151
will generate figures such as are caused by the complex effect of the vibra-
tions acting at right angles upon one another. By a simple mechanical con-
trivance the velocity of the rotary motion of each of the discs can be regulated
according to equally simple relative relations, by which the figures of the
different intervals are produced. By varying the tension of the strings more or
less, an alteration in these places will be achieved. By changing one or the
other of these discs, and replacing it by another with a different curve, the
figures observed by Dr. Helmholtz, on oscillating strings with the vibration
microscope, will be obtained, instead of those of Lissajous.
Plate II. Two thin rods of steel are fastened by screws at the two
oblique corners of a strong bar of iron in such a manner that their further ends,
one reaching above the other, vibrate vertically the one upon the other. To
these ends small metal plates with incised slits are attached in a parallel
position. The reflection of light produced by the intersection of these slits
will show Lissajous' figures. A movable weight regulates the intervals.
B, the well known tuning-fork apparatus with mirrors is simplified by the
tuning-fork being replaced by steel springs which are inserted in suitable
movable wooden columns.
Plate III. Apparatus for simplified demonstration.
A. ramified tuning-fork.
The same produces a sound composed of two tones, and marks the corre-
sponding musical note direct on a smoked glass plate.
J3, resonator with monometrical flame without membrane.
A conical shaped Resonator, which is held with the large opening down-
wards and is filled from the top with illuminating gas, which is allowed to escape
through a small tube attached, and then ignited. The flame will react on the
tones in the usual manner.
C, an igneous Kaleidophon.
Mr. Tollinger has shown that by fastening with wax a glimmering candle to
the end of a prismatic steel spring, a very admirable demonstration for large
audiences of this well-known experiment can be produced.
542 a. Apparatus for combining waves in one plane. The
resultant shown is that of two sets of waves (superposed) that
differ by half a wave-length. Chas. Brooke, F.R.S.
542b. Apparatus for combining waves in two planes per-
pendicular to each other. The resultant shown is a right-handed
elliptic helix. Chas. Brooke, F.R.S.
1229e. Apparatus for showing the longitudinal vibrations of
a row of particles, (1) stationary, and (2) progressive.
Chas. Brooke, F.R.S.
The vibrations shown are those constituting the first harmonic subdivision
of a pipe closed at one end.
543. Stationary Liquid Wave Apparatus and Sector
Pendulum. Frederick Guthrie.
When such a system of stationary waves is formed in a deep cylindrical
trough that the centre rises and falls as the edge falls or rises, the undu-
lation is synchronous with a pendulum whose length is equal to the radius of
the trough ; and the accelerations of motion of the wave and pendulum are
identical.
152 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
544. Wheatstone's Wave Apparatus. A complete in-
strument, showing plane, circular, and elliptical waves, the pheno-
mena of interference, &c. Elliott Brothers.
544a. Apparatus to illustrate Wave Motion.
Rohrbeck and Lwkme 9 Berlin.
544b. Apparatus to illustrate Waves and Nodal Vibra-
tions of a row of Mutually Influencing Particles.
Sir William Thomson*
Each particle has only one degree of freedom, and is influenced by a force
depending only on the relative positions of itself and of its next neighbours
on each side. The shorter the wave-length the smaller the velocity of
propagation of the wave.
The apparatus consists of a series of light rods loaded at each end, and
strung transversely on two threads which form, a bifilar suspension placed
equidistant from the centre of gravity of each rod. The distance between
the threads at any point is inversely proportional to the square root of the
tension at that point.
545. Illustrations of Vortex Motion. Nos. 1 and 2 are
vibrations ; Nos. 3-5 steady motion. (Proceedings of Royal
Society of Edinburgh, 1 November 1875.) Sir William Thomson.
Series of 11 successive figures of a simple vortex ring, performing violent
transverse vibrations of the first fundamental mode.
No. 2. Series of 1 1 successive figures of a simple vortex ring performing
violent transverse vibrations of the second fundamental mode.
In Nos. 3-6 the motion is analogous to that of screw propellers backing,
the vortex core being in each instance as it were the edge circumference
of the screw propeller.
No. 3. Two-bladed screw.
No. 4. Three-bladed screw.
No. 5. Four-bladed screw.
No. 6. Trefoil knot described in Sir W. Thomson's papers on Vortex
Motion (Transactions of Royal Society of Edinburgh for 1857 and 1858), and
figured on the back of the " Unseen Universe," by Professors P. G. Tait and
Balfour Stewart.
VI. FALLING BODIES AND PROJECTILES.
546. Drawing of a new Apparatus for demonstrating the
lateral deflection of rotating conical projectiles. %\
Dr. Leopold Pfaundler, Innsbruck.
The conical projectile A turns within the horizontal frame B on its own
horizontal axis, and can be put in rotation by pulling off the reel the string
attached to a. Fastened, on the outside of the frame, on two little hooks, b, //>
whose line of communication is perpendicular to the axis of rotation and passes
through the centre of gravity of the entire body, are two threads, which join
further up, and whose combined continuation is attached to a hook in the
ceiling.
At the back there is a steering vane C with a counter-weight D, attached
in such a manner that according to the position in which it is placed the line
VI. FALLING BODIES AND PROJECTILES. 153
of the resultant of the atmospheric resistance will pass either ahove or below
the centre of gravity of the projectile, without, however, altering the position
of the centre of gravity itself. The vane can be turned on its axis, or be
removed and replaced by a double vane C 1 with the two flat surfaces placed at
right angles to each other.
The following experiments can be made with this apparatus :
1. Stability of the Axis of Rotation.
The apparatus is put in motion to swing in a curve of five meters length by
taking hold of the vane and pulling it backwards, and then allowing it to drop.
If the projectile does not rotate, it easily turns over and will deviate from its
course by very slight causes ; if it rotates, it will remain parallel with its axis.
The vane must be given a neutral position in regard to the atmospheric
resistance.
2. Lateral Motion.
The apparatus is made to rotate to the right by the vane C being placed in
an upward position, when the point in flying forwards will revolve to the right.
If the direction of the rotation, or the position of the vane, be altered to the
opposite course or direction, the point will revolve towards the left. If both
are changed, the rotation will keep in the direction to the right.
3. Lateral Deflection.
The single vane C is replaced by the double vaue C 1 , the flat surfaces of
which being placed in a vertical and horizontal position, the proceeding then
is the same as described before.
Instead of the lateral motion, a parallel lateral deflection will be the result.
The latter experiment corresponds to the actual motion of the projectiles.
The greater degree of velocity being equalized by the larger surface of the vane
exposed to the atmospheric resistance.
682. Rotation Apparatus for determining the effect
of Atmospheric Resistance on bodies of different shapes,
particularly on projectiles. Constructed by Theodor Baumann,
junior, Mechanical Engineer, Berlin.
Professor Dr. E. E. Kummer, Berlin.
(See " Abhandl. der Konigl. Akademider Wissenschaften in Berlin,
1875 "; " Uber die Wirkung des Luftwiderstandes," by E. E. Kummer.)
547. Simple and Inexpensive Form of IVTorin's
Machine for demonstrating the law of falling bodies. It can be
made by an ordinary carpenter, at a moderate price, made by the
exhibitor. Dr. Stone.
548. Apparatus by General Morin for the experimental
demonstration of the laws of falling bodies.
M. Digeon, Paris.
549. Attwood's Machine with water clock attached.
The Council of the Yorkshire College of Science, Leeds.
The time is measured by a water clock, the orifice of which can be opened by
means of a lever moving under the influence of an electro-magnet. The weights
are supported by a thread grasped by a pair of iron pincers, which are kept shut
by a spring, but can be opened by means of another electro-magnet included in
the same circuit as that attached to the water clock, so that the water begins
154 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS.
to flow and the weights to fall simultaneously. Another metal piece can be
screwed on to the instrument. One of the binding screws with which it is
furnished is insulated from it by a plate of ebonite pierced with a metallic
rod in connexion with the binding screw, and on which rests one extremity
of a lever in electric communication with the rest of the piece. This
piece being included in the circuit the current cannot pass when the lever is
raised, and the water clock is stopped as soon as this is effected by the falling
weight.
549a. Attwood's Machine, with friction rollers and electro-
magnetical release. Ferdinand Ernecke, Berlin.
549b. Attwood's Machine, with penduluni attached.
Rohrbeck and Luhme, Berlin.
VII. FRICTION.
550. Apparatus for determining the Friction between
Water and Air.
Professor Viktor von Lang, Vienna University.
The above consists of a heavy stand with one fixed and three movable
arms. The fixed arm bears a short glass tube, from which water is made
to flow in a continuous vein. A crosspiece of four glass tubes is united, air-
tight, by its longest arm to the water-delivering tube ; the opposite arm is
directed downwards, and closed by a caoutchouc mouthpiece passing over
the " aspirating tube." This latter is supported by the two lowest arms of
the stand, the remaining fourth arm securing the crosspiece. The vein of
water passing through the " aspirating tube " moves the air, the quantity
of which is determined by the motion of a soap lamina in the " measuring
tube." This tube is joined to one of the horizontal arms of the crosspiece,
the fourth arm bearing a water manometer.
550a. Machine for the Examination and Measurement
of the Sliding Friction caused by the Motion and the Variable
Velocity on Kails. Constructed by ^Herr Jung, University of
Giessen.
This machine includes :
a. A board, with hooks for attaching a scale by means of a
cord running on a roller, for the purpose of measuring
the friction.
b. Two pairs of iron and brass rails, to be fixed to this board.
c. Three pairs of wooden rollers.
d. A pair of iron rollers.
e. A pair of brass rollers.
Physical Science Institute of the University of Giessen,
Professor Dr. Bujff.
This apparatus was originally used for measuring sliding friction. It is at
the same time a convenient appliance for demonstrating the friction of the
steam engine on the railway line.
res, from Book described under No. 599,
155
SECTION 5. MOLECULAR PHYSICS.
WEST GALLERY, UPPER FLOOR ROOM Q
I. SPECIAL COLLECTIONS.
Hydrostamm (Hydrometer), with ballast of mercury, for
liquids lighter than water. The Accademia del Cimento.
Hydrostamm (Hydrometer), with ballast of shots, for
liquids heavier than water. The Accademia del Cimento.
The Hydrometer, No. 20, was probably used for determining the specific
gravity of precious stones ; by observing to what degree it was immersed
without the precious stone, and with the precious stone placed upon the little
metallic disc, suspended by the three little chains. This is also a fitting place
to draw attention to the so-called " Palla d' Oncia " (ounce ball), of the
Grand Duke Ferdinand, u glass globe which displaces very nearly an ounce
of water. On the stem several rings were placed in order to make it sink,
and then by the number of these rings, it was known what the specific gravity
of the liquid was into which it had been immersed.
Besides the Hydrometer, No. 21, for determining simultaneously the tem-
perature and the corresponding specific gravity, other ones of the Accademia
del Cimento, which are true thermometers, having in addition the scale of
graduation of hydrometers.
Hydrostamn (Hydrometer), with a small metallic balance,
the first idea of Nicholson's areometer.
The Accademia del Cimento.
Photograph of the Hydrostamm (Hydrometer), enclosing
a thermometer. The Accademia del Cimento.
Ball of Metal, filled with water, and prepared by the Accade-
mia del Cimento to serve in the experiments for the compression
of water. The Accademia del Cimento.
Ball of Metal, still containing some water that served for the
experiments of the Accademia del Cimento on the compression
of water. The Accademia del Cimento.
Among the many experiments made by the Accademia del Cimento for
the compression of water, either Jby means of rarefied air, by the pressure of
mercury, or by the force of percussion, the last one which was carried out
with a ball of very thin silver, has attracted the most universal attention.
When beaten with a hammer, the water " sweated through all the pores of the
" metal, like quicksilver spouting through some skin in which it was being
" squeezed."
156 SEC. 5. MOLECULAR PHYSICS.
Two Tubes of Torricelli, one of which ends in a sphere.
They served him for his experiments on atmospherical pressure
in 1644. The Accademia del Cimento.
Galileo, by condensing air, had demonstrated its weight, and in his
dialogue on the resistance of solids, he says of water, that in suction pumps,
it does not rise higher than about 18 braccia, leaving the space above empty.
Torricelli, pondering over this fact, was led to think of what would happen,
if, in the place of water, mercury, which is so much heavier, were used ; for
he argued that by its means there would be much greater ease in obtaining a
vacuum, in a much shorter space than that necessary for water. He then
made a long glass tube of the length of about two braccia, which terminated
at one end in a' ball, likewise of glass, and remained open at the other;
through this aperture he proposed to fill the tube and the ball completely
with mercury ; and then holding it with his finger, and turning it upside-
down, submerge the orifice of the tube below the level of more mercury in a
large vessel ; and that being done, take away his finger and open the tube,
thinking that the quicksilver would detach itself from the ball, and having
glided down and remained suspended according to the various calculations, at
about the height of 1 ^ braccia, would in all probability leave a vacuum in the
ball above and in part of the tube. He communicated this thought to his
great friend Viviani, who, most anxious to see the result, agreed to the
experiment, which he himself carried out, and was hence the first, about a
year after Galileo's death, to see Torricelli's ingenious idea confirmed by the
fact. He hastened to his friend, who, most joyful at the news of this
evidence, was all the more persuaded that the weight of the air was really
that which was in equilibrium with the column of water or mercury. Indeed,
being asked by Viviani what would have happened if the experiment had
been made in closed space, Torricelli, after having reflected for a short time,
answered, the same thing ; since the air is already compressed in it. This
most important discovejy was communicated by the author himself to Ricci
in Rome, and by Ricci to Sig. de Verdus, who, in his turn, made Padre
Merseune acquainted with it, from whom Pascal learnt it, and made it famous,
as everyone knows, in his celebrated Puy-de-D6me experiment. Torricelli
himself in a letter to Ricci, observes ; " that it would be possible, by means
' of his instrument, to ascertain when the air was lighter or heavier ; and
that it might be the case that air, which is most heavy upon the surface
' of the earth, becomes more and more light and pure as we rise higher and
' higher to the tops of the loftiest mountains." And Carlo Beriguardi in his
' Circolo Pisano," published in 1643, says; "that the tube of quicksilver
" leaves more space empty, when placed at the top of a tower or of a
" mountain, than at the foot."
STANDARDS OF THE HYDROMETERS AND THERMOMETERS USED
BY GOVERNMENT OFFICERS IN HOLLAND.
Exhibited by Dr. J. W. Gunning, Professor of Chemistry at the
" Athenaeum illustre" Amsterdam.
579. General Hydrometer (No. 1), with open stem and
variable weight. Every degree has a bulk equal to -^ of the part
of the hydrometer below zero. When this instrument, having the
arbitrary weight = W grammes, marks a degrees in a liquid, the
I. SPECIAL COLLECTIONS. 157
apparent specific gravity of that liquid at the observed tempe-
rature will be -
580. Instruments (Nos. 2 and 3) for ascertaining the strength
of alcoholic liquors. The degrees are the same as in No. 1, but the
weight is not variable, and the zero is the immersion point at
15 C. in a liquid, of which the specific gravity at that temperature
is equal to the specific gravity of pure water at 4 C. Tables are
added, those of Professor von Baumhauer (1863), used in Holland ;
those of the exhibitor (1873), used in the colonies. The latter are
based on the researches of MendekjefF. Phil. Mag. (4) XXIX.
395.)
581. Hydrometer (No. 4), for liquids of a specific gravity
greater than 1. The construction is the same as in Nos. 2 and 3.
The Beaume scale is added. Used for solutions of salts and sugar
juices.
582. Hydrometers (Nos. 5 and 6), for ascertaining the
specific gravity of seed oils and of petroleum, allowing immediate
application of correction for temperatures above or below 15 C.
(For description see Scheik. Bijdragen door J. W. Gunning,
Amsterdam, 1867.31.)
583. Densimeters (Nos. 7, 8, and 9), with flat stems. The
zero is the same as in Nos. 2 and 3.
584. Hydrometer (No. 10), for preparing a liquid having at
15 C. the specific gravity of pure water at 4 C. The instrument
is made in the following manner : Through the open stem shots
are introduced till the instrument floats at the mark on the stem in
pure water of 15 C. The weight of the instrument is then
increased in the ratio 0-99915 : 1, in consequence of which it floats
at the same mark at 15 C. in a liquid having at that temperature
the specific gravity of pure water at 4 C.
585. Trough for comparing Hydrometers.
Thermometers. The instruments have the Celsius' scale.
By their mode of construction they possess the following advan-
tages : (1.) They may be turned upside down and shaken in any
manner without breaking the column of mercury. (2.) Though
newly made, the zero is not subject to displacement.
The former advantage is obtained by filling the tube and the
upper space with perfectly dry air, free from dust, as highly com-
pressed as possible.
The latter advantage is secured by placing the bulbs of the
newly made' thermometers in a bath of paraffin, heated slowly to
100 C. and then 'allowed to cool slowly and in succession sixty to
a hundred times.
158 SEC. 5. MOLECULAR PHYSICS.
II. AIR PUMPS AND PNEUMATIC APPARATUS.
597. Air Pump, by Otto von Guericke, with stand.
Professor Dr. Lepsius, Berlin.
606. Otto von Guericke's Air Pump.
" Collegium Carolinum" Polytechnic School at Bruns-
wick, Professor Dr. If. Weber.
The earliest trustworthy information respecting Otto von Guericke's original
apparatus is contained in a list of the physico-chemical apparatus of the
Collegium Carolinum, at Brunswick, of the year 1816. In this list it is stated
that this apparatus was obtained from the legacy left by Aulic Councillor
.Beireis, in Helmstedt. According to a special ordinance of His High-
ness Frederick Wilhelm, Duke of Brunswick, dated 8th October 1814, the
collection of physical, mathematical, and astronomical instruments acquired
from the legacy left by Beireis, physician in ordinary, at Helmstedt, was
exhibited in the rooms, and by a later ordinance dated 9th March 1815 incor-
porated with the collections of the ducal Collegium Carolinum. The air-pump has
been preserved unaltered, with the exception of the lever and the piston attached
to it, the former having been replaced by a new one of the same construction,
and the latter by a wooden one, in the year 1864. The pump has been described
and faithfully represented by a drawing in a work published by Otto von
Guericke, entitled " Ottonis de Guericke Experimenta nova (ut vocantur)
Magdeburgica de vacuo spatio Ainstelodani," 1672, cap. IV. p. 75, Tab. VI.,
in which work he also (p. 122) successfully refuted the assertion of Augustus
Hauptmannus, doctor of medicine, in his " Berg-be-deneken, anno 1658,
Lipsiae," " that it would not be possible to either angel or devil to
bring about a vacuum." This work is in the possession of the ducal library,
at Wolfenbiittel. But, previous to this air-pump, Otto von Guericke had con-
structed one more simple, consisting of only one cylinder and a piston, which
is said to be in the library at Berlin (see No. 597). The difficulty, however,
connected with the motion of the piston, the resistance of the air against the
free piston being so great that it required two strong men to pull it out re-
peatedly, p. 75, induced him to contrive their second improved construction.
The receiver stand at present in use was unknown to Otto von Guericke.
In order to produce a vacuum, he employed a hollow copper ball with stop-
cock,* which was placed in the axis of the barrel. It was exhausted, and
screwed on to other vessels, which, by the repetition of the process, were also
exhausted. The pail of tin-plate attached to the lower end of the barrel,
as well as the copper bowl fastened to the upper end of the barrel, were filled
with water or oil, in order to effect a greater tightness.
607. Two large Magdeburg Hemispheres of copper.
Professor Dr. H. Weber, Brunswick.
The two large hemispheres of copper are those of which Otto von Guericke
states, in page 104, Tab. XI., that after their exhaustion they could not be
separated by the united strength of 16 horses. They have a diameter, as
mentioned in the work alluded to above, of nearly f Magdeburg ells, or,
according to a second more exact statement, 0'67 Magdeburg ells.
* This ball (page 88, Tab. VIII.), as well as a pair of still larger Magdeburg hemi-
spheres, nearly an ell, Magdeburg measure, in diameter, which 24 horses had not the
power to separate (page 105), and, lastly, a copper boiler with inserted piston, which,
when the air below the same was withdrawn, 50 men were not able to lift or to pull up
(page 109, Tab. XIV.), are likewise enumerated in the list, but are no longer to be
found.
[To face page 158.]
Otto von Guericke's Air Pump, and Magdeburg Hemispheres, described under
Nos. 606 and 607.
<*'*!
IV Li **
[To face page 159.J
VACUO SPATIO
Title-page of Book described under JNb. 599.
II. AIK PUMPS, ETC. 159
608. Two smaller Magdeburg Hemispheres of brass.
Professor Dr. H. Weber, Brunswick.
The two smaller hemispheres of brass were used for experiments with
weights (page 106, Tab. XII., of Otto von Guericke's " experimentanova").
598. Two Magdeburg Hemispheres.
Professor Dr. Lepsius, Berlin.
599. " Ottonis de Guericke Experimenta nova (ut
vocantur Magdeburgica) de Vacuo spatio." Primum a R. P.
Gaspare Schotto e Societate Jesu et Herbipolitanae Academiae
Matheseos Professore : nunc vero ab ipso Auctore perfectius
edita, variisque aliis Experimentis aucta. Quibus accesserunt
simul certa quaedam de Aeris Pondere circa Terram, de Virtutibus
mundanis, et Systemate mundi planetario, sicut et de Stellis fixis,
ac Spatio illo immenso quod tarn intra quam extra eas funditur.
Amstelodami apud Joannem Janssonium a Waesberge, Anno
1672. Cum Privilegio S. Caes. Majestatis.
Professor Dr. Lepsius, Berlin.
587. Air Pump, with double barrel (1662), by Boyle.
Royal Society.
622. Diagram of Von Guericke's Air Pump. Invented
1654. A. Galletly, Edinburgh.
It consisted of a globe of copper, with a stopcock, to which a pump was
fitted.
The pump-barrel was entirely immersed in water to render it air-tight.
This was the earliest of all air-pumps.
623. Diagram of the First English Air Pump, constructed
in 1658-59 by Hooke and Boyle, but mainly by the former.
A. Galletly, Edinburgh.
As shown in the diagram, it had a single barrel, in which was a piston
worked by a rack and pinion. In working it the valve G of the cylinder was
shut, while the stopcock L of the receiver was open, during the descent of
the piston. When the piston was driven home, L was shut and G kept
open. In this air-pump a vacuum was produced slowly, and was imperfect
at best.
624. Diagram of the Second English Air Pump, con-
structed by Boyle and Hooke in 1667.
A. Galletly, Edinburgh.
The piston was worked by a rack and pinion like the first English air-pump,
but in this one the barrel was kept under water to keep the leather of the
piston always wet.
The piston had an aperture at F and a stop-cock at I, which were worked
as in the first English air-pump.
625. Diagram of Fapin's Air Pump. 1676.
A. Galletly, Edinburgh.
The diagram represents only the working parts of the instrument, without
the frame supporting them. This air-pump had the great advantage over
160 SEC. 0. MOLECULAR PHYSICS.
earlier forms of having two barrels, in which case, as the air becomes
exhausted, the resistance which it offers to the ascent of one piston is nearly
balanced by the force with which it compels the other to descend. This air-
pump was worked by moving the feet alternately up and down in stirrups.
626. Diagram of Hauksbee's Air Pump. 1703-9.
A. Galletly, Edinburgh.
This instrument, like Papin's, had two barrels, but the stirrup arrangement
and pulley are replaced by racks on the piston rods, and a pinion moved by a
handle, as in the modern double-barrelled air-pump. These diagrams 622-
626 were made to illustrate a paper on the early history of the air-pump, pub-
lished in the New Philosophical Journal, April 1849, by the late Dr. George
Wilson of Edinburgh.
687. Diagram of Torricellian Vacuum. 1644.
A. Galletly, Edinburgh.
603. Air Pump, by J. van Musschenbroek, and two Magde-
burg hemispheres.
The Royal Museum, Cassel, Dr. Pindcr, Director.
1. Air-pump, with obliquely placed cylinder, on Seng uercl' 's system.
This air-pump is, perhaps, the oldest of the kind existing, with a " four
way" stop-cock. It was constructed in the year 1786, by Jan van Mus-
schenbroek, in Leyclen, and bears the Musschenbroek arms, namely, the
" Oosterche lamp," and the crossed keys ; the armorial bearings of the city of
Leyden. The invention of the four way stop-cock notoriously originated
with Sengucrd, who, from the year 1675-1724, was a professor at Leyden.
The air-pump, preserved in the Physical Science Cabinet of that town, which,
according to the inscription, was constructed by Samuel Musschenbroek, in
the year 1675, and which has a four way stop-cock, is there considered
to be the first of the kind, but could not at first have been provided
with this adaptation since it was invented at a later date. This appliance
must have been adapted to it only at a later period. Senyuerd first described
this kind of cock in the second edition of his " Pbilosophia Naturalis,"
which was published at Leyden in the year 1685. In his work, " Rationis
atque Experimentise Connubium," which was published at Rotterdam in the
year 1715, he states that he made the invention in 1675, and that in 1679
he had the air-pump executed by a skilful artizan. That this artizan was
Samuel Musschenbroek is proved by a notice in the handwriting of Petrus van
Musschenbroek, which he wrote in a copy of his work entitled, " Beginselen
der Naturkunde." HoAvever, Senguerd, in the first edition of his work,
' Philosophia Naturalis," which appeared in 1680, and of which a copy is in
the possession of the Library of the University at Utrecht, makes no men-
tion at this time of the cock, but gives an illustration of an air-pump of the
original construction of Otto von Guericke. That the air-pump was con-
structed is plain, from a record of Offenbach's, describing the " Laboratoriuin
Physicum " of the University of Leyden, dated the 19th January 1711 :
" In the centre stood an elevated table. Upon this table there stood an
" * Antlia pneumatica ' of considerable size, of Samuel Musschenbroek' s old
" invention, inclined with a ' cista ' to put water in." Although the words
" from the invention of Sam. Musschenbroek " may also have reference to
the air-pump, which is still preserved in the Physical Science Cabinet at
Leyden, yet the description does not tally with it, inasmuch as its cylinder
is perpendicular, and stands next to an elevated table which carries the
plate, and is consequently united with it in one apparatus. It is possible
that Uffenbach, who was not an adept in that science, was only induced to make
II. AIR PUMPS, ETC. 161
use of the above-mentioned expression on seeing the arms of the firm of 5. v.
Musschenbroek. But how it happened that he did not see the other air-pump,
since he mentions a third air-pump, of Boyle's construction, still in existence,
is rather obscure, as De Voider, Sengucrd's predecessor in the professorship of
physics at Leyden, who himself laid the foundation of the establishment of
the Physical Science Cabinet at Leyden, must have worked in the same labo-
ratory. " There are given here (in the laboratory), as we were assured,"
continues Uffenbach in his narratives, " ' Lectiones publicae ' four times a week
" by M. Senguerd; De Voider, however, it was stated, has had larger
" audiences, as he was more artful (' curieuser ') in his experiments."
Senguerd did not deliver these lectures until after De Volder's retirement,
in 1705. De Voider died in 1709, and it is possible that the air-pump was
at that time in course of reconstruction, Scngucrd's air-pump, therefore,
as it is not to be found in the Physical Science Cabinet at Leyden, must,
in all probability, have been private property ; and it is possible that, like
many old instruments, it is still somewhere in private possession in Holland.
So long, however, as it is not discovered, the Cassel Museum may lay
claim to the distinction of having in its possession the air-pump with
the oldest four-way stop-cock. For although Senguerd had his air-pump
made in 1679, the description of it did not appear until 1685, when it
excited much attention. Christian Wolff, in 1718, had one constructed
exactly according to the same pattern, by Leupold at Leipsic, which may
still be seen in the Physical Science Cabinet of the University at Marburg.
It is very singular that Musschenbroek, in his manifold writings, never as
much as mentions Senguerd's air-pump. That, of course, this omission can-
not be construed into an argument against the priority of Senquerd is plain
from the subsequent remarks in the above-mentioned autograph notice, in
which it is stated that "in the year 1679 Senguerd and the same Samuel
" Musschenbroek had under consideration air-pumps of another kind, which
" were afterwards improved by my father, Jan van Musschenbroek, and by
" my brother " ("in den jaare 1679 heeft de Heer Senguerd met dienzelven
" Samuel Musschenbroek lucht pompen van een anderen aart bedagt, welke
" geduurig naderhand door inynen vader Jan van Musschenbroek, als door
" mynen broeder verbeterd zyn.") It seems as if family partiality had in-
fluenced him.
The air-pump is accompanied by two powerful Magdeburg hemispheres
with which the experiments of Otto von Guericke, of the Kegensburg Diet,
were repeated at Cassel.
604. Compression Machine, for throwing bombs.
The Royal Museum, Cassel ; Dr. Finder, Director.
This is one of the most ancient instruments in the possession of the
Cassel Museum. On the 16th November 1709, von Uffenbach saw it in the
Art Museum of Landgrave Karl. It was to serve for the purpose " of throw-
" ing lighted grenades through the air to a distance of more than 100 yards,
" with the usual effect." At that time some of its former defects had just
been repaired. " Twelve grenades can be thrown one after another with great
" rapidity. But, because the air is continually diminishing, the last, as may
" be easily conceived, do not go as far as the others." This instrument,
which acts on the principle of an air-gun, the brass ball carrying a funnel
upon which the grenades were placed, and by which also red hot shots could
be thrown without any danger to the men serving it, is of historical interest,
as it is a surviving witness of the joint labours of Papin and the Landgrave
Karl, and it even transports us to the midst of that catastrophe which put an
end to Papin's activity. It was a similar machine, with which Papin con-
templated throwing bomb shells by means of steam, which exploded in his
40075. L
162 SEC. O. MOLECULAK PHYSICS.
laboratory. i! The other and greatest misfortune was that, having undertaken
to shoot the same with steam as with pOM'der, he might have provided a
weapon of great destructive power. The machine prepared for that pur-
pose, however, exploded, not only demolishing a great part of the labora-
tory, and mortally wounding several men (one among whom had his jaw-
bone carried away), but Landgrave Karl himself, who is a very curious
lord, intent upon seeing and examining everything minutely, might have
been hit, and have lost his life, had not His Highness been accidentally de-
tained by other affairs and come to the laboratory later. On this occasion
Papin was dismissed from his service."
614. Air Pump with two Barrels. The first pump of the
kind ever constructed. It is an exhausting and a condensing
pump, and was made for King George III. in 1761.
The Council of King \s College, London.
618. The Abbe NoUet's Air Pump.
Conservatoire des Arts et Metiers, Paris.
586. Hand Pump, Regnault's System improved.
Geneva Association for the Construction of Scientific In-
struments.
Exhausting and forcing hand pump. The hand pump, constantly used in
laboratories, has now attained a satisfactory practical shape, from which not
much deviation is possible. Its general proportions are determined by the
consideration of how best use can be made of muscular power, with simpli-
city and facility of carriage of the apparatus. Silken valves, as being too
perishable, are excluded and replaced by cones of metal and leather. All the
movable parts, piston and valves, are equally accessible. ' Three cocks effect
the complete cutting off of all communication between the pump and the
exhaust and the compression receivers, as well as restore direct com-
munication, either between both or one of these and the atmosphere. If
rarefaction is required in the compressing vessel, or vice versa, Without dis-
turbing the tubes of communication, the relative position of the valves must
be inverted, which may be done in a few minutes, or else a change cock
must be joined to the pump.
For effecting all communication between the pump and its receivers, a
screw flush joint is always used, which is very safe, and can be fitted to
tubes made of india-rubber, copper, or lead. This avoids the deterioration of
the india-rubber, which is unavoidable on account of the constant action of
fastening the joints, especially as it is rarely that a thoroughly air-tight joint
can be made with india-rubber alone.
588. SprengePs Mercury Pump.
Prof. Dr. R. A. Mees, Director of the Physical Labora-
tory of the University of Groningen.
This instrument differs from all others (1) in the numerous curvatures of
the tube through which the mercury falls. These augment the exhausting
power of the pump, while the air bubbles, which are carried away with the
mercury, and which, when near vacuum, are so minute that they remain
hanging on the walls of the tubes before coming down, assemble in the curva-
tures, until their size is so far augmented that they are carried away by the
falling mercury. (2) The instrument is provided with a peculiar stop-cock
with two perforations, whereby the flowing of the mercury is regulated and
II. AIR PUMPS, ETC. 1(33
the acquired vacuum preserved. To effect this, the stop-cock is furnished
with two iron rings, which float on the mercury, and, falling with it, close the
opening of the stop-cock. By means of the second perforation of the stop-
cock the instrument can he joined to an ordinary air pump, and the operation
abridged by a partial exhaustion of the air. To produce a more complete
vacuum than can be obtained by an ordinary air pump, the stop-cock is turned
half round, and, when the vessel surrounding- the stop-cock is filled with
mercury, the Sprengel pump begins to act.
589. Aspirator, moved by clockwork with sulphuric acid ;
U tube for determining accurately the amount of moisture in the
atmosphere by the use of the balance. Dr. Andrews, F.R.S.
The amount of moisture at different periods of the day, or the average
amount in 24 hours, may be determined with great precision by means of this
arrangement, which the exhibitor proposed many years ago for use in meteor'
ological observatories, instead of the present defective methods.
590. Spirator. Designed to get a constant current and
known volume of air driven or drawn over a body. .
Frederick Guthrie.
The principle resembles that of " Tantalus' cup." A constant current of
water enters a flask, and (1) drives out its own volume of air through a
mercury trap ; (2) when the flask is filled up to a certain point, a siphon acts,
and, in emptying the flask, draws air in from another tube.
590a. Apparatus for collecting Gases without exercising
upon them either pressure or rarefaction. George Gore, F.R.S.
612. Apparatus for Air Pump. An air-gun supported
by two vertical mahogany pillars and cross-bar, by means of which
it may be adjusted to any angle.
The Council of King's College, London.
613. Apparatus for Air Pump. Metal condenser with
glass ends, large enough to take a pair of four-inch Magdeburg
hemispheres with fittings, and a metal lever to which weights may
be attached to measure the pressure of the air, either when com-
pressed or at its ordinary pressure.
The Council of King's College, London.
592. Drawing of Mercurial Air Pump (1872).
J. P. Joule, D.C.L., F.R.S.
By alternately lifting and. lowering the bulb attached to the flexible tube,
the air being dried by the admission of sulphuric acid through a glass valve
at the upper part of the perpendicular tube, a very excellent vacuum may be
obtained in a short time.
592a. Sprengel's Mercurial Air Pump, improved form.
E. Cetti $ Co.
592b. Modification of Sprengel's Air Pump, with air-
trap and means of supplying sulphuric acid, in order to clean out
the fall tube while the pump is in use. Prof. H. McLeod.
L 2
164 SEC. 5. MOLECULAR PHYSICS.
593. Mercury Air Pump. Dr. H. Geissler, Bonn.
594. Photograph of an Air Pump, the exhibitor's con-
struction (in frame).
C. Staudinger and Co., F. W. von Gehren, Giessen.
This air-pump has a double-acting barrel of 10 cm. diameter and 32 cm.
in height. The motion of the piston is effected by the rotation of a fly-wheel
in one direction.
595. Hydro-dynamical Air Pump.
Baron Dr. von Feilitzsch, Professor at the University of
Greifswald.
An ordinary air-pump receiver communicates with a tube through which
mercury is passed with great rapidity in such a manner as to flow in
through a small aperture and to flow out again through a wide opening.
A vacuum will thus be produced under the receiver.
596. Mercury Air Pump, with valve, on Mitscherlich's
system. Prof. Dr. Mitscherlich, Miinden, Hanover.
(See " Poggend Ann. der Chem. und Phys.," vol. 150, p. 420.)
600. Air Pump. Charles Gustavus Pinzger, Breslau.
This air-pump is provided w r ith a double acting piston, and so arranged that
it can be used as an exhausting and as a compressing pump. In the former
case the barrel is placed in a diagonal position, and the pump provided with
glass plate and stop-cock, but if the plate with the cock be screwed off, and
the hose-screw attached to the wooden stand screwed on, and the barrel
detached from its support and placed perpendicularly, the pump can in that
case be used as a compression pump. Plate with cock are meanwhile
screwed again on the wooden stand. The cock below the barrel, by reason of
its parallel position, effects with this the connexion between barrel and plate,
and in its upward position, the communication between barrel and the external
air ; and, lastly, in its downward position, the communication between the
plate and the external air.
601. Mercury Air Pump, on Professor von Jolly's system,
Prof, von Jolly, Munich.
This air-pump has been described by G. Jolly in Carl's Repertorium, 1865.
As regards the alterations which have since taken place, and which have been
introduced in the apparatus exhibited, a special description has been added
to the object.
602. Apparatus for Demonstrating Marietta's and
Dalton's Law.
Prof. Baron Dr. von Feilitzsch, University of Greifswald.
This apparatus enables the laws in question to be demonstrated when the
pressure is above or below that of the atmosphere. A glass tube open at the
upper end, and a glass gauge tube, which can be closed at the upper end by
ft stop-cock, communicate by means of a long gutta-percha tube, and can be
displaced on a vertical scale. These are partly filled with mercury, the
latter tube containing the gas to be tested, or the combination of gases and
II. AIR PUMPS, ETC. 165
vapours, when by raising or lowering of the first tube, the level of the mer-
cury can be changed as required, and the resulting volume of gas observed.
The apparatus can be easily adapted to all kinds of experiments, at
pressures either above or below that of the atmosphere.
605. Suction Pump, on an iron stand.
Ferdinand Ernecke, Berlin.
605a. Suction Apparatus. Two small pieces of apparatus
to illustrate the deficiency of pressure attending a high velocity
in a stream of air. Lord Rayleigh.
By blowing through the electrotyped copper tube a suction of 6 inches of
mercury may be realised at the narrow part.
In the second arrangement the novelty consists in the cap at the end of the
brass tube, by which the efficiency is increased.
609. Double Cylinder Air Pump, with Babinet's stop-cock,
cylinder 170 mm. high, 60 mm. wide, with manometer and glass
plate of 200 mrn. diameter, on a mahogany board, with the
following auxiliary apparatus :
1. Pair of Magdeburg hemispheres of glass.
2. Electric egg, consisting of two parts, with arrangement
for carbon points.
3. Double mill.
4. Balloon, with bell.
5. Balloon, for the gravity of the air.
6. Fountain.
7. Quicksilver.
8. Ring.
9. Dasimeter.
10. Falling tube.
11. Heron's ball.
Warmbrunn, Quilitz, and Co., Berlin.
610. Apparatus for Lighting, on the system of Dobereiner,
with contrivance for drying the gas.
Warmbrunn, Quilitz, and Co., Berlin.
61Oa. Water Vacuum Pump, invented by H. Sprengel in
1863. Hermann Sprengel.
610b. Air Pump and two receivers, by Staudinger, Giessen.
Chemical Laboratory, University of Berlin; Prof. A.
TV. Hofmann, Director.
611. Water Pump, either for exhausting or for compressing
air. Joseph Conquet.
This apparatus can be used either in place of an air pump, or in place of
bellows. Water at a pressure of two atmospheres is required for working it.
166 SEC. 5. MOLECULAR PHYSICS.
615. Electrical Apparatus belonging to Air Pump.
Vertical cylinder electrical machine with two leather rubbers.
The apparatus is so constructed that the cylinder may be enclosed
in a large glass receiver, which can be exhausted.
The Council of King's College, London.
616. Large Air Pump, arranged for producing the ordinary
vacuum or a dry vacuum of a millimetre of mercury, and also for
producing ice. M. Carre, Paris.
616a. Small Air Pump, also capable of being transformed
at will into a eompressionpuinp. M. Carre,, Paris.
617. Apparatus for producing ice by vacuum and sulphuric
acid. M. Carre, Paris.
619. Hydraulic Press of Copper and Glass (for demon-
stration). Luizard, Paris.
620. Apparatus for Compression. Luizard, Paris.
62Oa. Model of an Air Compressor, which may also be
used as a water meter. M. Eugene Bourdon, Paris.
621. Air Pump for Double Exhaustion (Babinet's prin-
ciple). . Luizard, Paris.
62 la. Model of Pneumatic Machine.
M. Loiseau, jun., Paris.
627. Pick's Spring Manometer. Weber, Wurzburg.
63O. Air Pump, made by Spencer & Sons, Dublin.
Prof. W. F. Barrett.
This air pump has no valves between the barrels and the receiver, hence
it is free from regurgitations of air, and is capable of making a vacuum nearly
equal to that obtained by means of Sprengel's air pump. The ends of the
pistons and barrels are conical, and, when they are in contact, no cavities
remain. All the air in the barrels is therefore expelled at each stroke of the
piston ; the effect is the same when it is highly rarefied. The horizontal
portions of the pump admit of the barrel being brought into close connexion
with the plate, and leaves the valves accessible for cleaning or repairs.
63Oa. Single Barrel Air Pump. James How and Co.
630b. Air-pump on Babinet's system. Dr. Stone.
680a. Improved Portable Spireometer. E. Cetii fy Co.
IV. CONDENSATION ANT> SOLUTION OF GASES. 167
in. OSMOSE, DIALYSIS AND DIFFUSION.
631. Electric differential Osmometer. Engelmann.
Prof. Engelmann, Utrecht.
Two glass vessels of quadrangular section, possessing in the plane ground
surfaces facing each other a round aperture 30 mm. diameter, and each con-
taining an electrode ; a platinum disc 30 mm. diameter. Between the two
vessels the cell is placed, a plane parallel plate of ebonite, furnished with a
transverse perforation 30 mm. diameter, communicating with a short brass
top, upon which a rise-tube, manometer, etc. can be screwed. The mem-
branes or porous plates, whose electric osmotic permeability is to be compared,
are placed between the cell and the glass vessels, the whole being secured by
two brass vices. Both vessels and the cell are now filled with the same fluid.
Inelastic partitions, such as clay plates, must, in order to prevent breakage
and leakage, be provided, on each side, with an elastic ring (india-rubber or
bladder).
Thin, \ery pliable, membranes, e.g. skin of a frog, are secured between sieve-
like perforated plates of ebonite to prevent bending.
The apparatus is used to demonstrate :
1st, the fact of electric osmosis.
2nd, the specific influence of the membrane ; the rise and fall of the fluid
in the cell shows which of the two membranes possesses the greater electric
osmotic permeability. On removing one of the partitions, the apparatus
becomes an ordinary osmometer.
(Onder/oekingen gedaan in het physiologisch laboratorium der Utrechteche
Hoogeschool. Derde Keeks, II., 1873, p. 365, etc.)
632. Osmometer, illustrating the transpiration of gases
through capillary tubes. Prof. IV. F. Barrett.
This is an apparatus constructed under the direction of Professor Sullivan
for illustrating the law of the transpiration of gases. The diaphragm is
made of a number of short lengths of capillary tubes.
IV. CONDENSATION AND SOLUTION OF GASES.
633. Addams' Apparatus, for condensing and solidifying
carbonic acid. William Sykes Ward.
634. Apparatus used in 1857 for Liquefying Ice by
Pressure at temperatures below 65 C.
Prof. Mousson, Zurich.
A small cylindrical chamber, hollowed out of a strong piece of steel, is
filled with water containing a movable metallic index. When the water is
frozen, the chamber is closed by means of a soft copper cone, subject to the
action of a strong screw. The apparatus is then reversed. The chamber
merges into a long, slightly widening cone of soft copper, on which a short
steel rod presses by means of a powerful screw-nut acting on the principal
piece, and a double lever a metre in length. If the chamber be opened, after
the pressure is removed, the index is found to have been carried over to the
other end, as a proof that the ice has been reduced to a liquid state. Soft
copper is the only means of closing under excessive pressures.
The experiment can be successfully made at 18 C.
168 SEC: o. MOLECULAR PHYSICS.
635. Original Model of the Fluid Vein of Messrs. Pon-
celct and Lescros. Conservatoire des Arts ct Metiers, Paris.
636. Original Thilorier Apparatus for liquefying carbonic
acid, 1857. Conservatoire des Arts et Metiers, Paris.
637. Apparatus for the demonstration of Boyle and Mar-
riotte's law to a class. Prof. W. F. Barrett.
The mercury contained in the upper iron reserroir can be admitted to
the tube through an aperture closed by a valve that is moved by pulling the
string. The eye is kept level with the air chamber. Equalk}' of pressure
with the atmosphere is readily obtained by means of the stopper closing
the lower bent tube or air chamber.
638. Compression Pump and Receiver. An apparatus
for the liquefaction and solidification of gases.
H. Lloyd, Trinity College, Dublin.
640. Apparatus employed in the researches of Dr. Andrews
on the continuity of the gaseous and liquid states of matter, and
on the properties of matter at high pressures and varied tempera-
tures. Dr. Andrews, F.R.S.
This apparatus consists of two cold-drawn copper tubes of great strength,
communicating by a horizontal passage, and having massive end-pieces above
and below, firmly bolted on with leather washers interposed, so as to be able
to resist any pressure. The upper end-pieces are traversed by fine glass tubes,
the junction between the glass and metal being made tight by a peculiar
system of conical packing. The exposed parts of the glass tubes have a
capillary bore, and, if sufficiently fine, will bear a pressure of 500 atmospheres
or more without bursting. One of the tubes contains air or hydrogen, and
serves as a manometer, the other contains the gas or liquid to be examined.
The lower end-pieces carry well packed steel screws, which produce the pres-
sure by compressing the water with which the apparatus is filled. The tem-
perature of the air or hydrogen in the manometer, and that of the gas or
liquid under examination, can be varied at pleasure by enclosing the glass
tubes in outer cylinders of glass, or, where accurate readings are required, in
rectangular vessels with plate-glass sides. With this apparatus, accurate
measurements can be made to 500 atmospheres, or even higher pressures, and,
with a slight modification, at any temperature which glass will bear without
softening.
641. Single Apparatus, adapted to exhibit the properties of
gases and liquids under different conditions of pressure and tempe-
rature, but without measuring the pressures employed.
Dr. Andreivs, F.R. S.
This apparatus is similar in construction to the compound form last
described.
641 a. Original Apparatus, by Despretz, by the help of
which he proved the difference, shown by gases, in relation to the
law of Marriotte. The Faculty of Sciences, Paris.
V. IIYDKOAIETEKS. 169
641b. Original Apparatus, by Gay Lussac, for ascer-
taining the elastic force of gases and vapours.
Polytechnic School, Paris.
641 c. Apparatus, by M. Dumas, for illustrating tlie density
of vapours. Conservatoire des Arts et Metiers, Paris.
642. Sulphurous Acid Tube, to exhibit the flickering stria3
which occur, from slight changes of pressure, near the critical point
of temperature. Dr. Andrews, F.R.S.
643. Model, constructed by Professor J. Thomson, to illustrate
the results of the experiments by which Dr. Andrews first es-
tablished the continuity of the gaseous and liquid states of matter.
Dr. Andrews, F.R.S.
V. HYDROMETERS.
644a. Regnault's Apparatus for estimating the specific
gravity of solid bodies.
Golaz, 24, Hue des Fosses, St. Jacques, Paris.
645. Compensation Salinometer.
H. Hadicke, Demmin, Pomerania.
The compensation salinometer is an areometer especially constructed for
measuring the saliferous contents of sea water, or of the water in steam
boilers, the readings of which are independent of the temperature of the
respective fluids. The dimensions of the same have been so calculated that
the increase of the volume of the instrument effected by the expansion of all
its constituent materials (i.e., aluminum, or iron and mercury) will avoid
the deeper immersion which in the instruments of the ordinary construction
would take place in consequence of an increase of the temperature of the fluids.
646. Apparatus for measuring the Density of Liquids.
Prof. Dr. Bohn, Aschajfenburg.
647. Apparatus for determining Vapour Density, on
Dr. French's system. F. Sartorius, Gottingcn.
648. Oleometer. An instrument for ascertaining the density
of oils. Dring and Page.
649. Small Sykes's Hydrometer. Dring and Fage.
650. Barktrometer. Used by tanners for ascertaining the
density of bark liquor. Dring and Fage.
The indication of the steam in degrees, and true specific gravity at 60 F. ;
the sliding rule accompanying the instrument enables indications at higher or
lower temperature to be reduced to the equivalent at 60 F.
t,
170 SEC. 5. MOLECULAR PHYSICS.
651. Small Barktrometer. Dring and Page.
The same in principle as the larger one, but it is not capable of indicating
over so wide a range of specific gravities.
652. Salinometer, used on steam vessels to ascertain the
amount of salt in the water in the boiler. Dring and Page.
On the stem of the instrument are the words " limit " and " blow." " Limit "
indicates the maximum amount of salt in the water that can be used with
safety, and " blow " when it is necessary to blow off a portion of the water iu
the boiler through there being too much salt in solution.
653. Atkins' Saccharometer. (Obsolete.)
Dring and Fagc.
654. Tour-weight Hydrometer on Sykes's principle.
(Obsolete.) Dring and Fage.
The stem is divided into 20 parts, and a part again divided into 2 parts,
each of which is equal to one-half per cent. The sliding rule accompanying
this instrument gives the equivalents of other hydrometers of the same
period. About 1817.
656. Sykes's (Revenue) Hydrometer. For ascertaining
the proof-strength of spirits. Dring and Fage.
The instrument, used by the Kevenue in collecting the duty on spirits, was
first established under Act of Parliament in the year 1 8 1 6 ; by this Act also proof
spirit (which forms the basis of estimation in this instrument, as all strengths
are indicated by their relation to this point) received a particular definition as
that which weighed twelve-thirteenths of an equal bulk of distilled water at a
temperature of 51 Fah. The stem of the instrument is divided into 10 parts,
and each part again into subdivisions, \A hich, with the nine weights (each
of which is a multiple of the divisions of the stem), enables the instrument
to measure all gravities from 67 over proof to just past distilled water at
60 Fah. The tables which accompany this instrument were compiled from
..the experiments of Gilpin, who carried them out with such accuracy that no
error has ever been detected. The range of temperature given is from 30 to
80 Fah. These tables having been found inconvenient for use in hot climates,
in the year 1851, Messrs. Dring and Fage compiled an extension from 80 to
100, which meets all requirements for high temperatures.
657. Clark's Export Hydrometer (obsolete). Used for
ascertaining the strength of spirits in the various stages of manu-
facture. Dring and Fage.
The instrument used for determining the strength of spirituous liquors prior
to the introduction of Sykes's hydrometer. It was the first of its kind
established under Act of Parliament, and to which any definite kind of cor-
rection for temperature was applied. It is constructed to show the number of
gallons of water, plus or minus, necessary to reduce to proof strength a sample
of spirits under trial, and was only used for spirits in the various stages of
manufacture.
658. Clark's Import Hydrometer (obsolete). Formerly
used for ascertaining the strength of spirits imported.
Dring and Fage.
V. HYDROMETERS. 1 7 1
The same in principle and construction as the one for export, only having
nine extra or intermediate weights, called per cent, weights. This class of
instrument was only used for determining the strength of spirits imported,
and was adjusted slightly in favour of the importer.
659. Set of Six Twaddell's Hydrometers. Used for
ascertaining the density of a solution ; principally used in trades
for which no special instrument of the kind is constructed.
Dring and Fage.
The divisions on these instruments are so placed as to indicate equal dif-
ferences of specific gravity. The specific gravity of a fluid is found from the
indication of this scale by multiplying by 5, cutting off 3 decimal places,
and prefixing unity.
659a. Hydrometer by Fordyce. Royal Society.
659b. Hicks's Patent Hydrometers, Urinometers,
Salinometers, &c. Hicks.
These instruments have the scales and figures divided in black on a white
enamel stem, thus avoiding all errors from shifting of scale, as with paper ;
alteration of form, as with vulcanite ; or corrosion, as with metal.
65 la. Tan Tester, for ascertaining the exact quantity of
tannic acid in any substance by passing it through a piece of hide.
Thomas Christy and Co.
The solution having been gauged by a tannometer before being tested and
after it has passed through the hide, the difference gives the exact value of any
tannic matter, and a merchant knowing the price of oak bark can calculate
the value at once of the substance he has tested.
655. Specific Gravity Instruments, for testing liquids
from 650 to 900 sp. gr. L. Oertling.
659a. Fahrenheit's Metal Hydrometer.
The Physical Science Laboratory of the Technological
Institute, St. Petersburg.
The theory of this instrument has been described and illustrated by an
example by E. Lenz, Academician, in the " Bulletin physico-mathematique
de 1'Academie des Sciences," Vol. XV., 1857.
660. Thermo-Dilatometer, by Baudin, showing by dilata-
tion the per-centage strength of alcohol, from distilled water to
absolute alcohol 100. M. Baudin, Paris.
661. Thermo-Dilatometer, by Baudin, showing by dilata-
tion the alcoholic strength of wines and other liquids, from 10 to
20 per cent.
(The last two instruments are the property of the " Conservatoire
des Arts et Metiers.") M. Baudin, Paris.
662. Dring and Fage Saccharometer, for ascertaining
the density of brewers' worts. Dring and Fage.
172 SEC. 5. MOLECULAR PHYSICS.
Used for determining the density (in pounds weight) of a barrel of wort,
of 36 imperial gallons, in excess of the same quantity of distilled water at a
temperature of 60 Fah. The rule accompanying the instrument shows the
weight of the residuum if a barrel of wort were evaporated to dryness ; also
the amount of proof spirit to be obtained, and the specific gravity.
This instrument was the joint invention of Messrs. Dring and Fage, and
perfected by the valuable experiments and calculation of Drs. Hope Coventry
and Thomson.
663. Quin's Saccharonieter. (Obsolete.)
Dring and Fage,
664. Dring and Fage Still, for ascertaining the original
specific gravity of a wort from a sample of beer. Dring and Fage.
Used by the Excise and Customs when making the allowance for drawback
on export beer.
664a. Apparatus by Bakowitsch for te sting Alcohols and
Saccharine Matter in Liqueurs ; likewise for ascertaining the
fatness of butter, and for testing water.
R. Nippe, St. Petersburg.
665. Apparatus for determining the Specific Gravity
of bodies, inclusive of a thermometer.
Ch. F. Geissler $ Son, Berlin.
671. Piknometer. Dr. H. Geissler, Bonn.
671a. Fiknometer 9 for ascertaining the specific weight of
small quantities of liquid, with thermometer attached.
IV. Haak, Neuhaus, Thiiringcn.
672. Two Sets of Areometers. Dr. H. Geissler, Bonn.
672b. Micromanometer.
Royal Mining Academy, Freiburg.
672c. Drawing of Apparatus for measuring low pres-
sures of Gas. Prof. H. McLeod.
The pressure is measured by compressing a known volume of the gas into
a smaller space, and measuring the pressure under the new conditions. By
dividing the pressure thus found by the ratio between the original volume and
the reduced volume, the original pressure is obtained. See Proc. Phys. Soc.
i. 30.
673. Manometer for Minute Observations, used by A. de
la Rive in all his latest researches concerning the propagation of
electricity in rarefied gases.
De la Rive Collection, the property of Messrs. Soret,
Perrot, and Sarasin, Geneva.
This instrument, constructed by the Geneva Association for the Construc-
tion of Scientific Instruments, consists of two glass tubes dipped in a common
mercury trough, of which one is a simple barometric tube serving as a point
of comparison, the other communicating on its top with the quantity of rarefied
V. HYDROMETEKS. 173
gas by means of a pipe adjusted in the setting of the apparatus. The pressure,
that is, the difference between the two mercury columns, is read by means of
a small cathetometer, of which the inillirnetric graduation is turned towards
the tubes and the lamp which lights them both. This graduation is reflected
in the telescope by means of a total reflecting prism placed before the objective.
Thus the level is at once read, and a micrometrical division placed at the focus
of the eye-piece shows the ^ of the millimetre.
673a. Delicate Pressure Gauge. E. A. Cowper.
The very light pressure required to produce a current through stoves can
be shown by the delicate pressure gauge (enclosed in a mahogany case),
which has a thin diaphragm exactly one square foot in area, and has a light
lever and weights to cause it to bear the pressure brought on its surface,
so that the whole pressure of the air on one square foot is exactly weighed
with ease. As small a pressure as one hundredth of an inch of water can be
measured.
673b. Multiplying Manometer, for measuring the force of
the draught in chimneys and stoves, as well as for the pressure
of gas. Dr. K. List, If a gen, Westphalia.
This apparatus was first constructed by the exhibitor in 1862 for the
purpose of meeting the desire of several blast-furnace proprietors resident
at Hagen, who wished to be able to measure more accurately the pressure
of the blast in their furnaces than was possible with the ordinary manometer,
consisting of a curved glass tube, as is mentioned in the description given in
the " Zeitschrift des Vereins deutscher Ingenieure," (Journal of the Society of
German Engineers) of 1863, vol. vii, p. 493. It consists essentially of a
long narrow horizontal and two wider vertical glass tubes, the latter of which
are filled to about half their length, and the first up to a long air-bubble,
with coloured petroleum. If a suction is effected on one of the vertical tubes,
the air-bubble contained in the horizontal tube must, if the vertical tube has
a diameter n times as large as the horizontal tube, traverse a distance in
the horizontal tube ri 2 times as large as the liquid rises or falls, as the
case may be, in the vertical tube ; the sensibility, therefore, can be increased
71^
at pleasure. The space which the index travels is - times as large as the
difference in the respective heights of the liquid in the two vertical columns.
The apparatus has been constructed for some years by the exhibitor
himself ; the scale indicating in water-millimeters the difference of pressure
,vas prepared by him in the manner described in the Journal of the Society
of German Engineers. The apparatus has answered well everywhere. It
has been recommended for measuring the pressure of gas by authorities such
as Schiele in Frankfort-on-the-Maine and Schilling at Munich.
673c. Level Manometer, by Gallaud. M. Breguet, Paris.
673d. Two-fold Control Manometer.
C. D. Gabler, Hamburg.
1. The advantage here consists in two independent manometers, acting
under quite similar conditions, being combined in one case, whereby not only
a greater guarantee of control is obtained, but by the close proximity of the
two scales the simultaneous reading of the divisions is facilitated. The
upright position of the tubes prevents the collection of impurities out of the
174 SEC. 5. MOLECULAR 'PHYSICS.
water, as the latter flows freely away after use. The instrument may be con-
nected by a simple screw arrangement with the boiler.
673e. Four-fold Control Manometer.
C. D. Gabler, Hamburg.
This manometer, consisting of two manometers of the above construction,
combined one with the other, offers the greatest possible safety in controlling ;
because, if only two-fold action be required, the one pair of manometers
can be shut off by closing the stopcock, and may thus be used as reserve or
control of the manometer thence used. The connexion with the boiler
flange is performed by means of the accompanying two thumb nut-screws.
673f. Control Manometer, showing the inner construction.
C. D. Gdbler, Hamburg.
Shows the extremely simple construction of the inner mechanism of the
manometers described above.
674. Alcoholometer, consisting of two cylinders of ebonite
and brass, keyed together. G. Recknagel, Kaiser si autern.
This instrument is not liable to break, and answers all requirements of
accuracy in reading.
675. Areometer of ebonite and brass, with adjustable cylinder.
G. JRecknagel, Kaiser slautern.
This not being liable to be broken can be used for educational purposes as
well as for practical application.
The level upper terminal plate is adapted for the addition of small weights
by means of which the value of the divisions can be demonstrated. The
instrument, moreover, is arranged with a cylindrical slide, Avhich can be
extended to the double volume of the divided spindle. If the scale is over-
run, the slide is to be pulled out a volume more, and the scale is then again
at disposal for use.
Eor instruction and practice the most suitable is the uniform scale of the
Gay Lussac areometer. As, however, there is space for four scales, the
others can be arranged for direct indication of specific weights, or, like the
present models, for alcoholometry.
676. Areometer Case, containing three standard areometer-
cylinders, for determining the specific gravity of all kinds of
liquids, with indicator scale fused into them. W. Zorn, Berlin.
677. Areometer. The indicator scale is not fused into the
glass, but fastened only with sealing-wax. W. Zorn, Berlin.
Each of these areometer-cases contains three glass spindles, which, loaded
at the top in a similar manner to Nicholson's metal spindles, with weights,
indicate with the greatest accuracy the specific weight of all liquids.
The liquid to be tested must be brought to a temperature of 15 Celsius ; if
one of the spindles is inserted in the liquid, so many weights must be placed
on the glass plate as are required to make the spindle sink as far as the black
mark on the milk-white glass line iu the neck of the spindle.
The lightest spindle embraces all liquids from 0'650 to 1,000; if this
has been used, 0-650 must be added to the weight placed on the spindle. If
the medium (1,000) spindle has been employed, 1,000 must be added to the
weight, and at the heaviest (1,400) spindle, 1,400 must be added to the weight
placed on the same. The sum obtained will give the specific weight of the
liquids with an accuracy extending a little over the third decimal.
V. HYDROMETER < . 175
The proof of the correctness is simple ; it is only necessary to have a good
pair of scales and some distilled water :
650 weight = spindle 650 ;
spindle 0-650 +350 weight = spindle 1,000;
. spindle 1,000 + 400 weight = spindle 1,400.
The construction of these areometers is new. Eor many years the exhibitor
had constructed similar areometers, consisting, however, of two spindles only,
which were very much liked, under the name of Wittstock's areometer,
on account of their accuracy ; but it was too fragile, owing to the light
spindle (there being but two of them) having to carry too much weight.
Moreover, the late Privy Councillor, Dr. Wittstock (apothecary to the Royal
Court at Berlin), had devised a peculiar proportionate weight to the same,
from which the spindles had derived their name, but which is now no longer
in use.
The areometers constructed by the exhibitor, the normal weight of which
has been recommended by Mr. Hirsch, apothecary, at Giessen, and which
corresponds to the gram scale, have the following advantages, compared with
other similar instruments :
They can be easily tested as to their accuracy (as shown before) ; they
will not be affected by the liquids ; they can be easily cleaned, and will
sink slowly and imiformly in any liquid, and are not surpassed, nor even
equalled, by most similar instruments, in respect of accuracy.
One of the exhibited areometer-cases contains three spindles, which are
perfectly equal in point of accuracy with those in the second case. The
milky glass lines at the neck are, however, fastened only with sealing-wax,
which, in case of great carelessness, may dissolve, although persons of ex-
perience have used these spindles for years without injury; besides, every
particle of sealing-wax can be easily supplied as soon as any defect has been
noticed. But, in order to avoid this, the milky glass lines on the three
spindles in the second case have been melted together with the glass
plate.
Besides the weights, there are added to the two cases a cylinder for
weighing the liquids, a pair of forceps for placing the weights, and a thermo-
meter for determining the temperature of the liquids, which latter is adapted
in its form and the strength of the glass to be used as a stirring rod.
The exactness of the indications of Zorn's spindles affords also the advant-
age of testing the correctness of other liquid scales, such as Tralles, Baume,
and others made on a scientific basis.
679. Alcoholometer.
Siemens Brothers and Co., Charlottenburg.
An apparatus for measuring simultaneously the quantity of spirit flowing
through it, and the per-centage of proof spirit contained in that spirit. The
quantity is measured by a revolving drum imparting motion to a counter
under the control of a hydrometer containing spirit such as is the average
production of the still. The measurement is unaffected either by the velocity
at which the spirit enters or by the friction of the bearings of the spindles of
the drum.
679a. Metallic Alcoholometer, on Tralles's principle.
VV. Gloukhoff, St. Petersburg.
The metallic alcoholometer, with additional weights, newly adapted by the
Russian Government, is made on the principle of Sykes's hydrometer, but its
scale is adapted to the system of Tralles, legalized in Russia.
176 SEC. 5. MOLECULAR PHYSICS,
VI. MISCELLANEOUS.
680. Apparatus, serving to illustrate the Mechanical
Effect of the Expansion of Liquids. T. A. Snyders, Delft.
Consisting of gun-barrels closed by a lead plate 3 millimetres thick, which
is retained by a perforated screw-plug. The expansion of the liquid causes
a cylinder of lead to be forced out through the aperture of the plug.
681. Apparatus, constructed by Leschot and Thury, to
suppress Friction by the interposition of a stratum of air.
Geneva Association for the Construction of Scientific In-
struments.
The apparatus is composed of two plates, superposed, and perfectly
adjusted, between which is introduced air or gas under pressure. The air,
spreading from the centre between the two plates, exerts upon these a total
pressure measured by its elastic force multiplied by the extent of the surfaces
brought into apparent contact. When this pressure equals or exceeds the
weight of the plate acted upon, it supports the plate, and the friction is re-
duced to its smallest limits.
683. Two Apparatus for measuring the Transpira-
tion of Air at different Temperatures.
Dr. 0. E. Meyer, University of Breslau.
(Described in "Poggend Ann., 1873," vol. 148, p. 203.)
634. Apparatus to illustrate to a large audience the fact
that the pressure exerted by a curved liquid film increases
with the curvature. The Yorkshire College of Science.
The apparatus consists of a glass tube communicating with two others,
each of which is furnished with a stop-cock. Bubbles of different diameters
are blown at the ends of the tubes, one stop-cock being closed while the other
is open, and then communication with the outer air being cut off, and the
cocks both opened, the smaller bubble is seen to diminish and the larger one
to increase, thus proving that the air inside the smaller bubble was the more
compressed. The tubes are bent, so as to bring their extremities close
together, and the experiment can be shown to a large audience by throwing a
magnified image of the bubbles on a screen.
685. Apparatus for demonstrating Leidenfrost's phe-
nomenon of drops. Dr. J. Hoogewerff, Rotterdam.
This apparatus was constructed by Mr. Kellenbach, curator of the Batavian
Society, Rotterdam, and belonging to the academy of plastic arts and tech-
nical sciences at Rotterdam. The apparatus is used as follows : a Grove
pile is connected with the instrument, a galvanometer being placed on the
conducting wire, and the copper tray or platinum capsule into which the
drops of water have been put, are heated by means of a gas lamp. Every
time Leidenfrost'B experiment is repeated, no current is indicated by the gal-
vanometer, contact having been interrupted by the layer of steam ; when on
the contrary the water, the surface of which is in contact with the copper
wire, comes into immediate contact again with the metallic surface of the
tray or capsule, the galvanometer distinctly indicates the current.
VI. MISCELLANEOUS. 177
686. Apparatus for determining the Tension of the Vapours
of different liquids at the boiling point. Prof. W. F. Barrett.
This is a useful and strong form of the usual apparatus. The liquids
whose tensions are to be measured are inserted in the barometer tubes,
and either steam or the vapour of some liquid having a lower boiling point,
such as alcohol, is sent through the larger tubes.
670. Parabolic Diagram of the relation between tension
and volume of the saturated steam.
H. Hadicke, Demmin, Pomerania.
The area of this parabolic tension diagram shows that it is justifiable to
replace the area of Mariotte's oder Pambour-Navier's tension-lines of the
saturated steam by a parabola. This method gives for the ratio of the mean
pressure (p ~) on one side of the piston to the absolute pressure at the
commencement (p), and the cut off (e) the elementary formula : Po^p ^
0- ) 2 (4 ;>+!), or
4p+l
(See " Practical Tables and Rules for Steam Engines," by H. Haedicke
Kiel, 1871.)
687a. Independent Bed Plate for Pneumatic Machines.
Geneva Association for the Construction of Scientific In-
struments.
This plate is made entirely of cast-iron, as well as its stand, so as not to
become damaged in experiments where mercury is employed.
4C075.
178
SECTION 6. SOUND.
WEST GALLERY, UPPER FLOOR, ROOM ,'
I.SOURCES.
688. Apparatus used by M. Rijke to cause a tube to emit
sounds when wire gauze placed in its interior is heated.
Prof. Dr. P. L. Rijke, Ley den.
689. Whistles for .producing shrill notes, within and beyond
the limits of ordinary audition. Francis Galton, F.R.S.
These whistles were designed for testing the limits of the power of men and
animals of hearing very shrill notes. The plugs that close the whistles can
be screwed up and down, and the length of the whistle can be ascertained
by the attached graduations, whence the number of vibrations per second
may be calculated. The whistles are of three forms : (1) a small cylindrical
tube, which gives a pure note, but of small power ; (2) a flat, wide and narrow
whistle, of which the plug is a broad thin plate of metal ; (3) an instrument
which is externally a cjdinder of 2 inches in diameter, but of which the
effective part is merely an annulus ; the plug of this is a cylindrical sheet of
brass ; it gives a powerful note, but not a pure one.
690. Brass Tube to sound the constant proper tone of the
mouth, characterising the vocal sound.
Prof. Donders, Utrecht.
This consists of a brass tube terminating in a broad slit at one end and at
the other end in an india-rubber tube to be placed, on a blower (" souffleur ").
(Bonders.) The blast, directed by the slit on the borders of the lips, sounds
during the time a vocal sound is sung in different tones, the constant
proper tone of the mouth characterising the vocal sound. (Compare Bonders,
Uber die Natur der Vocale,.Holl. Beit, zur Nat. u. Heilk. 1846.)
691. Set of Vowel Forks and Resonance Globes.
Frederick Guthrie.
692. Set of Organ Pipes. Frederick Guthrie.
693. Set of Tuning Porks. Frederick Guthrie.
926o. Acoustical Instrument, illustrating harmony and
discord. S. F. Pichler.
This instrument is constructed to demonstrate the relations between
musical sounds. By its means, harmony and discord, gravity and acuteness
of pitch, beats, waves, and amplitude of notes, may be rendered visible as well
as audible.
I. SOURCES. 179
T~>vo metallic vibrators, each with a small speculum, are fixed at right
angles to each other, and sounds are produced by a current of air acting on
one or both of them at pleasure. The perpendicular vibrator is tuned to a
given note, and the horizontal vibrator is fitted with a mechanical arrangement,
whereby its pitch can be graduated to any degree of nicety within the compass
of two octaves. An apparatus is also provided with a means of concentrating
a pencil of light upon the speculum of the perpendicular vibrator, whence it
is reflected to the speculum of the horizontal vibrator. For educational pur-
poses, artificial light may be used, which can bo further reflected and magni-
fied upon a screen so as to be visible to a number of spectators.
When musical sounds are produced by the vibrations, various luminous
geometrical figures are formed on the horizontal speculum, which, being thence
thrown on the screen give the curves described by the pencil of light, by the
single or joint action of the vibrators, and the form and motion of such figures
demonstrate the exact relation to each other of the musical notes produced.
Sounds which harmonise to the ear, produce regular figures to the eye, as for
example, segments of the circle, ellipses, ovals, or straight lines, and if the
amplitude of each vibrator be equal, these luminous figures will appear on the
speculum or screen with an apparent steadiness. If the sounds do not
harmonise, the figures are confused, unsteady, and complicated.
The mathematical relations of musical notes can also be demonstrated by
this instrument ; regular simple forms being produced by combinations of
those notes which result from vibrations bearing a definite numerical ratio
to each other, while irregular and unsteady figures are caused by notes which
have no such ratios.
This apparatus has advantages over those in which tuning forks are used
for a like purpose; (L) In being able to prolong the effects to any period
desired by the operator ; and (2.) In its capability of representing combina-
tions and graduations otherwise unattainable.
694. Photograph of a Chemical Harmonica of glass for
gas-flames, with eight pipes (major-scale from d l to d 2 inclusive),
with double regulating cocks, and key-board for playing.
With a copy of a few melodies executed on the same for two
and three voices.
Prof. J. Joseph Oppel, Frank fort-on-the-Maine.
The glass tubes can be turned by means of metal mountings, and can be
adjusted according to the height of the flames, which being regulated by the
taps, and the acoustic effect of the major and minor accords (particularly
when carefully tuned) are astonishing.
695. Diapason Tuning Fork. F. Ernecke, Berlin.
695a. Diapason of 200 double vibrations, arranged for
continuous action. T. Hawksley.
695b. Model of a Scientific and Musical Instrument
called the Pyrophone, invented by the exhibitor, composed of
a series of glass tubes of different lengths and dimensions, in which
gas jets, when ignited and moved by a very simple apparatus,
produce the most perfect musical notes, and establish the new
scientific principle of the " interference ' : of melodious flames.
Frederic Kastner, 43, Rue de Clichy, Paris.
M 2
180 SEC. 6. SOUND.
Thu profit pyrophone, which this model represents, has three octaves like
those of a piano, and is composed of a series of glass tubes, similar to organ
pipes, of different lengths and dimensions, in which gas jets burn. A very
simple mechanism causes each key to communicate with the corresponding
supply pipe of the flames in the glass tubes. On pressing the keys, the
flames separate and the sound is produced as soon as the little jets in each
tube are separated from each other ; when re-united and becoming one flame,
the sound immediately ceases.
In this instrument it is shown that when two or more flames are introduced
in a tube they vibrate in unison, and produce a musical sound when they are
placed one-third the length of the tube, and a new law has been demon-
strated, as an application of which an instrument which approaches the human
voice more nearly than any yet made has been constructed.
A contrivance opens and shuts like the fingers of a hand, at the extremities
of each of which a small jet of gas is lighted. When the fingers are separated,
the sound is produced ; when they are closed or approach each other, the
sound ceases, and the numerous jets become one silent flame.
The new principle is as follows : "If two or more flames of a certain size
" be introduced into a tube made of glass or other material, and if they be
M so placed that they reach to the third part of the tube's height (measured
" from the base), the flames \vill vibrate in unison. This phenomenon con-
" tinues as long as the flames remain apart, but as soon as they are united the
a sound ceases."
The pyrophone gives sonorous and penetrating tones, and may be con-
structed from one octave to a most extended compass, and for the cabinets
de physique, with one, two, three, or more notes to show the principle of the
" interference " of singing flames. The exhibitor has also invented a gaselier
(lustre chantanC), lighted by electricity, which can be placed in the centre of
a room, and by unseen electric wires be made to produce powerful and
melodious sounds, and on which any kind of music can be performed.
696. Tube for Singing Flames, according to Schaff-
gotsch's system. Albrecht, Tubingen.
697. Set of Glass Tubes for illustrating singing flames,
with paper sliders for adjusting the pitch of any tube.
Prof. W. F. Barrett.
The only novelty here is the paper sliders, which enable the pitch of the
note to be readily adjusted, and were originally suggested by the exhibitor.
697a. Stand and Burner for Sensitive Flames.
Prof. W. F. Barrett.
The sensitive flame is an illustration of resonance. The vibrations accepted
by the flame are those which the flame itself would emit when roaring. A
flame to be sensitive must be brought to the verge of roaring by a proper
adjustment of pressure on the gas supply. The flame is then in unstable
equilibrium, and a feeble sympathetic vibration will then produce the same
effect on the flame as a slight increase in the gas pressure.
The flame to be extremely sensitive must be fed with gas which flows
smoothly and freely to the orifice. A bell gas holder is far better than a gas
bag for obtaining the necessary pressure. The gas cocks must be fully open
and the pressure adjusted by altering the weights on the gasholder' The
stand shown allows the gas to flow smoothly, and the best burner is a steatite
" jet photometer " burner carefully enlarged till it gives the tallest possible
I. SOURCES. 181
flame under a pressure just short of roaring. Such a flaine with good gas
can be had 2 feet high, shrinking down under the influence of a sound to less
ih;:n one half this height. With similar burners and pressures the quality
of different specimens of coal gas is accurately determined by the degree of
sensitiveness of the flame. See Phil. Mag., March and April 1867.
697b. Suitable source of Sound for experiments with
Sensitive Flames. Prof. W. F. Barrett.
This is simply a loud ticking watch enclosed in a padded case with a
movable cover, and mounted on a sliding stand.
697c. Practical application of Sensitive Flames.
Prof. W. F. Barrett^
By using a suitable burner a sensitive flame can be made to spread out
sideways into a fish-tail flame under the influence of sound. Under such con-
ditions the flame can be made to touch a compound metallic ribbon, which
curves by unequal expansion, closes an electric circuit, and rings an electric
bell. An arrangement of this kind could be adapted to detect burglars, or
to act as a self-recording phonoscope. First exhibited by Prof. Barrett at
the Koyal Dublin Society, January 1868.
698. Set of Resonant Tubes. Prof. IV. F. Barrett.
By suddenly and successively withdrawing the stopper, the resonance of
the air within the series of tubes will give the notes of the common chord.
699. Apparatus for experiments with singing gas flames.
Yeates $ Sons.
The above, consisting of glass tubes of similar size, with the assistance of
a revolving mirror, will illustrate most of the phenomena of interference,
harmony, &c.
700. Inferior Limits of Audibility. An apparatus to
show the lowest number of vibrations that will produce sound.
Elliott Brothers*
701. Sir Charles Wheatstonc's Resonating Tubs.
W. Groves,
By moving a piston up and down, and thus diminishing or enlarging the
resonator, a perfect two-octave scale of aliquot parts may be produced from a
spring, which would othenvise sound but one note. The scale may thus be
played as rapidly as by the fingers upon a pianoforte. Set the spring in
vibration by a twang with the forefinger of the left hand, and draw the piston
with the right hand.
701 a. Sir Charles Wheatstone's original " Magic
Lyre,'* for rendering vibrations audible at a distance through
wires. Robert Saline.
704. Set of five Steel Tuning-forks on a new system.
Dr. Stone.
182 SEC. 6. SOUND.
II. MEASUREMENT.
705a. Apparatus, by M. Regnault, for ascertaining the velocity
of sound. College of France, Paris.
706. Acoustic Apparatus, for ascertaining the velocity of
transmissio of sound through water, used in 1826 on the Lake of
Geneva at i distance of 13,487 metres, and subsequently in 1841
at a distance of 35,000 metres.
Prof. Daniel Colladon, Geneva.
This apparatus was used in 1826 and 1841, during a series of experiments
upon the transmission of sound through water, and upon the direct measure-
ment of the velocity of sound in the water of the Lake of Geneva.
Memoires de 1' Academic des Sciences de 1'Institut de France, savants
etrangers, sciences mathematiques et physiques, vol. 5, p. 267 and following
pages. Comptes-rendus de 1'Institut, vol. 13, p. 439, seance 23rd August
1841.
N.B. With this instrument it is possible in calm weather to hear, at the
distance of more than a hundred kilometres, the blows struck upon a bell
of about half a ton weight immersed in the water, which may thus be used
as a submarine telegraph, or for transmitting signals in foggy weather.
715. M. lie Houx's Apparatus, for determining the velo-
city of sound. Conservatoire des Arts et Metiers, Paris.
707. Apparatus for registering Tuning-fork Vibra-
tions. Prof. L. von Babo, Freiburg, Brcisgau.
707a. Original Apparatus, by Duliamel, for registering
vibrations. Polytechnic School, Paris.
708. Helmholtz' Double Siren.
H. Lloyd, Trinity College, Dublin.
705. Revolving Drum, for determining pitch of note.
Frederick Guthric.
The styles attached to two vibrating forks mark sinuosities on the blackened
surface of the drum when it turns and advances on its screw axis. The
pitch of the notes is thus compared.
709. Double Siren, such as was employed by Professor
H 17 in his researches on sound.
Frederick Guthrie.
710. Siren, of card-board, with four circles of holes, 64, 80,
96, and 128, giving major chord. Made by Yeates and Sons.
Prof. W. F. Barrett.
The above is provided with an air-chest and four keys, so that any or all
the circles of holes can be made to sound at pleasure.
711. Siren, an instrument for showing the number of
vibrations corresponding to a given note. Elliott Brothers.
III. ANALYSIS AND SYNTHESIS. 183
712. Savart's Toothed Wheels. A set of wheels, of
different sizes and numbers of teeth, to produce a succession of
notes. Elliott Brothers.
713. Sonometer, with sound-post on the principle of the
violin. Also adapted for passing the galvanic current through
strained wires. Dr. Stone.
714. Metronome, invented by Francis Wollaston.
G. H. Wollaston.
716. Phonometer. Prof. Lucae, Berlin.
The phonometer, " speech- measure," is intended to determine accurately the
intensity of speech, that is to say, the pressure of expiration employed in
speaking.
The apparatus consists of a short metal tube, one end of which expands
in the shape of a funnel to a kind of mouth-piece, the rim of which is coated
with india-rubba. The other end of the tube is attached to a contact
lever oscillating in an axis, the lower section of which is formed by a round
aluminium plate, which closes the tube when the lever is in a vertical
position and in repose, whilst the upper end of the contact lever, terminating
in a point, indicates on a quadrant the oscillations of the pendulum. By any
word which is spoken into the mouth-piece, the plate will be pressed outwards
according to the pressure of the air employed. When speaking is discon-
tinued a;spiral spring attached to the axis has the effect of suspending the
action of the lever at the maximum of the motion transmitted to it, and its
inclination can be read on the quadrant. The practical use of the instrument
in the first instance is, to determine when speaking in a loud or a low voice
the relative intensity of one and the same word, or, rather, the preponderating
sound prominent in the word uttered, and imparting to it the greatest colour.
This object the apparatus perfectly accomplishes, since the force of utterance
is proportional to the density of the air effected in the tube. The apparatus
consequently affords, among other things, a more exact test of hearing with
persons slow of hearing than has been the case hitherto with ordinary
speaking.
716a. Phonoptometre, by M. Lissajous.
M. J. Duboscq, Paris.
716b. Experimental Windchests, for measuring the effect
of heat on reeds. Dr. Stone.
III. ANALYSIS AND SYNTHESIS.
717. Series of Chladni's Figures. Frederick Guthric.
Sand being scattered on a square brass plate, clamped in the middle
and horizontal, the plate is bowed at various points of its edge, while
various other points are touched with the ringer. The sand is accumulated
in the lines of least motion or nodal lines. Gummed paper is then pressed
upon the figures so formed.
184 SEC. 6. SOUND.
718. Five Wire Figures for representing Lissajous'
Figures. Prof. Buys-Ballot, Utrecht.
On a horizontal wooden rod are placed five figures of wire, so bent that
their shadows or lens images form the figures of Lissajous. Each interval
has its own wire figure, and the changes produced by various phase-
differences are shown by turning the figures round their vertical axes.
719. Wooden Board for constructing Lissajous 9
Figures. Prof. Buys-Ballot, Utrecht*
The instrument consists of a white-painted wooden board, on which a
circle is traced. Horizontal and vertical lines cut the circle in points
corresponding to the angles of a regular inscribed icosagon. At the inter-
section of each pair of lines a hole is made in the board for fixing pins, which
can be joined by threads for showing the figure. Along one of the hori-
zontal and vertical sides of the board two rods can be fixed, provided with
ciphers corresponding with the horizontal and vertical lines. Each of
these lines may be figured to represent the phase of a vibrating particle either
by sound or light for each twentieth part of a vertical and horizontal
direction.
For instance, the figure exhibited by the interference of two notes of the
same pitch is constructed in the following manner: The horizontal rod
indicates the vertical chords on which the particle is at a supposed moment
by a horizontal vibration, then the perpendicular rod indicates in the same
manner the horizontal on which it would be at the same moment by a
vertical vibration. By fixing pins at the intersections of those chords
indicated by the same ciphers, and joining them by a thread, the desired
figure originated by both motions is obtained.
If the oscillations differ in phase, another rod not beginning with the same
cipher, but with another differing as many twentieth parts of the oscillation
as required is found.
If the two interfering notes are not of the same pitch, but one figure is the
octave of the other, for the higher note a difference of phase double as great
as for the other is taken, and so on.
719a. Tonophant, a simple arrangement for showing Lissa-
jous' Figures. Sec Phil. Mag., Sept. 1868.
Prof. W. F. 'Barrett.
719b. Apparatus for exhibiting the combination of
rectangular Vibrations, made by Yeates & Son, Dublin.
Prof. W. F. Barrett.
By turning the handle the two mirrors have a vibratory motion imparted
to them in planes at right angles to each other ; the relative rate of vibration
of the mirrors can be adjusted by a simple mechanical contrivance. A beam
of light reflected from one mirror to the other and projected on a screen thus
enables a large audience to see the whole of Lissajous' figures.
1576a. Wheatstone Kaleidophone.
The British Telegraph Manufactory, Limited.
1576b. Wheatstone Kaleidophone.
The British Telegraph Manufactory, Limited.
720. Melde's Universal Kaleidophon.
Ferdinand Suss, Marburg*
(See Poggendorffs Annalen, vol. 114, p. 117.)
III. ANALYSIS AND SYNTHESIS. 185
This apparatus is too well known already to require in this place a
more detailed description as regards its capabilities. It will therefore be
necessary to give only a short explanation of the reading indications on the
Lamellae, and to refer, as to all specialities respecting this apparatus, to
Prof. Melde's publications. Poggendorff's Annalen, Vol. CXIV., page 117,
" Lehre von den Schwingungs-Curven," by Dr. Franz Melde, p. 25.
The great Lamella has on each side a line as a mark, and on its upper end
the figures I. and II. ; the smaller Lamellae have the same figures I. and II.,
and on each side three lines.
If the great Lamella is placed upon the mark of side I., and the small
Lamella on the line of side I., with the indication ^, then the vibrations of
both Lamellae to each other are as 1 : 4. The indications of side II. naturally
correspond to the mark of side II. on the great Lamella.
The Lamella with the little mirror is used when the curves are to be shown
to a whole audience, for which purpose the apparatus ought to be so placed
that the rays of the sun, or electric light, falling on the mirror are thrown
either on the ceiling or on the wall of the room.
The round bars serve for the production of oscillating curves of two ellip-
tical vibrations.
Finally, it is to be observed that the apparatus may be used equally well
for fixing the vibration curves, for which purpose a phonautograph is em-
ployed, the cylinder of which is covered with a paper, as smooth as possible,
on which soot is lightly scattered.
A small piece of the top of a feather fastened with wax upon one of the
smaller Lamellae will be sufficient to describe the curves. In this case, the
oscillating surfaces ought to be parallel.
721. Atlas, belonging to the same, illustrative of the theory
of oscillation curves, by Dr. F. Melde.
Ferdinand Suss, Marburg.
722. Melde's Tuning-fork Apparatus for producing
stationary waves on a thread.
(See Poggendorff's Amialen, vol. 109, p. 193 ; and vol. Ill,
p. 513.) Ferdinand Suss, Marburg.
In Poggendorff's Annalen, Vol. CIX., p. 193, and Vol. CXI., p. 513, a de-
tailed description is given of this apparatus, and of several experiments made
with it ; also an account of the theory of the oscillation curves (" Lehre von
" den Schwingungscurven "), by Dr. Franz Melde, p. 94.
By means of the small sliding rod of glass which is screwed into one of
the prongs of the fork, and rubbed with wet fingers, the tuning-fork is
brought into a state of vibration. (The small glass rod, owing to its fragility,
must be inserted reversely into the wooden frame, when not used, so that only
the brass neck of it is visible.) On the lower part of the tuning-fork there is a
peg for tuning, which takes up one end of the thread, and serves for stretching
it. From this point the thread passes through the neck of the other prong
of the fork to a clamp admitting of adjustment to any point of the bar, which
is about a meter in length, and thus allows of any length of the thread up to
this limit. In order to read the length of the thread, there is on one of the
narrow sides of the bar a division indicating half centimeters.
The tuning-fork can be turned about its vertical axis in such a way that its
surface of oscillation falls in a parallel line with the longitudinal direction of
the thread, perpendicular to it, or at any other selected angle.
The bar can be turned about a horizontal axis, and arrested in any desired
186 SEC. 6. SOUND.
position by means of the set screw fixed at the back, so that the thread makes
any desired angle with the longitudinal axis of the tuning-fork.
It requires but little practice to effect such a tension of the thread that the
required number of waves always appears.
723. Melde's Apparatus for the Combination of Two
Thread- vibrations.
(See Melde's Lehre von den Schwingungscurven, p. 99.)
Ferdinand Suss, Marburg.
723a. Melde's Apparatus for the production of Oscilla-
tion Curves of two Rectilinear Vibrations on a Strained
Thread. Ferdinand Suss, Marburg.
The apparatus consists of two principal parts, one of which is a Lamella,
oscillating vertically, fastened on a pedestal, and which is set in oscillation
by an electro -magnet. The Lamella itself forms the interference. The
other part consists also of a Lamella, which is brought into vibration by an
electro-magnet, and the surface of vibration of which can be placed at any
desired angle to that of the first Lamella.
In order to put the apparatus in motion for experiments both parts must be
firmly fastened, either to a long, or on two separate solid tables, at such a
distance (about 8-12 feet) from each other that the thread when strained
measures 3 to 3'5 meters in length. (The thread can, of course, be shortened
at pleasure, or replaced by one a few meters longer; but for class experiments
the length stated appeared to be most practical.) The thread is fastened to
Lamella I., and passed through the hole in Lamella II. towards the peg by
which the correct tension is effected.
The white points on the (red) thread serve for facilitating the better obser-
vation of the curves, and, in order to render them more prominent, the black
screen is placed behind the oscillating thread. The screen has on one side
small holes, which are hinged in the hooks of the frame of Lamella I. ; when
the screen is expanded, the foot of it is screwed firmly by a vice-pin to the
opposite table.
Two (large-sized) chrome elements, the strength of which may be easily
regulated, will serve best as electro-motors. In the present case two chrome
elements were employed, each with tw r o carbon plates, and a zinc plate, of
18 cm. in height, and 6 cm. in width, joined together one behind the other.
When newly charged, it was only necessary to dip the zinc plate from 1 to
1'5 cm. into the acid, in order to obtain the requisite strength of electric
current. Both elements and the wire spirals of both magnets are, of course,
united to form one circuit. As already observed, Lamella I. serves at the
same time for interference, for which purpose an attachment screw is fixed at
its reverse end, which is intended to be connected with the Avire leading to the
battery. To the attachment screw, which is in connexion with the mercury
bowl, a wire is fastened, which is to be connected with the first attachment
screw of the wire spirals, if the proportion of the numbers of the vibrations of the
two Lamellae are from 1:1 to 1:2 (accord, octave). If Lamella II. is to
perform three or four vibrations in the same tune in which Lamella I. makes
only one vibration, then only one wire spindle of Lamella I. is set in motion
by fastening the wire coming from the mercury bowl in the centre attach-
ment screw. The current must always be so powerful that the interference,
whose rough displacement is effected by raising and lowering the platinum
pin, and the more minute displacement by turning the mercurj 7 bowl, can be so
placed that the shutting off of the current is effected as quickly as possible,
as upon this the purity of the figures chiefly depends.
III. ANALYSIS AND SYNTHESIS. 187
The intensity of the vibrations on Lamella I. is regulated by raising and
lowering the electro-magnet, which is kept in its position by a set screw,
and on Lamella II. by screwing in and out the iron cores, and by the shifting
the whole magnet.
With a powerful current the vibrations will be most regular when the
magnet is entirely moved back, and the cores are screwed so closely to the
Lamella that the contact just ceases.
Lamella I. has only one mark on which it always remains accurately
adjusted. If it is required that it should oscillate uniformly with Lamella II.
1 a 1
the latter is moved to the back, marked with the annotation j and upon
the spot marked with x the weight is placed with the annotation i. If the
weight is removed further from Lamella II. the oscillations of the two La-
mellae are as 1:2. If Lamella II. is moved to the mark indicated by
I a I
2 the oscillations of both Lamella are as 1:3 (S fifth of the octave).
By placing the weight with the annotation ^ upon the spct indicated with x
on Lamella I. the oscillations are as 1 : 4 (double octaves).
The two smaller weights of different size serve for the more exact regula-
tion in case great changes in the temperature, or simultaneous oscillation of
either one or the other of the tables, should be of injurious influence.
Lamella II., as has been observed at the commencement, can be turned
about an horizontal axis, so that its vibrations can be adjusted either rectanr
gularly, parallel, or in any angle whatever to Lamella I. In case it is neces-
sary to ease and screw fast the hexagonal nut, the key is added for the purpose.
The small key is for unscrewing and fastening the screws which fix the
Lamella.
724. Melde's Wave Apparatus, for showing the produc-
tion of Ghladni's figures of sound, according to the theory of
Wheatstone.
(See Poggendorff's "Annalen, Jubelband, p. 101, and the
accompanying description.) Ferdinand Suss, Marburg.
This apparatus has been more particularly described by Professor Melde, in
Poggendorff's Armalen, Jubelband, page 101.
The present apparatus is distinguished by several differences from that de-
scribed in the above-mentioned work, by which the manipulation is consider-
ably facilitated, but before entering into this, it must be mentioned that in the
construction of this apparatus it was kept in view that two systems of waves
of equal length and equa intensity pass swiftly through a square plate.
The upper system of waves is formed of 33 rows of 17 pins each, which
together make two wave lengths. The saddle upon which the pins are
placed corresponds to a length of 1 5 of wave lengths ; it has on two sides
(above and below) wave-systems, which in so far differ from one another, as
the one is like a system of two mountains with one valley in the middle, and
the other like two valleys intersected by a mountain. On the longitudinal
sides of this saddle rectangular zinc plates have been screwed, which are pro-
vided with divisions for adjusting the desired phases.
O denotes the centre position (middle between mountain and valley). The
lines marked on the black board correspond to the waves formed by the pins.
The longitudinal line serves as index upon which the lines of the saddle are
indicated.
When the saddle has been adjusted in the desired position, the board is
lifted by the handles fastened on the sides as far as possible perpendicularly
188 SEC. 6. SOUND.
so high, that the wires running parallel under the board catch into the hooks,
and so prevent the board from descending.
In order to let the board and the saddle down again, a slight pressure with
the thumb on the pegs protruding from the board next to the handles, while
holding the bandies themselves firmly in their position, will be sufficient to
prevent the too rapid, or sideways, sliding down of the board.
Finally, it is to be observed, that this apparatus can also very well replace
Eisenrohr's Interference Apparatus in so far as two waves will be sufficient';
it would only be necessary to add a number of bars, or if entire surfaces are
desired, some saddles, the waves of which are of different and certain lengths.
Great care is required by placing the one part of the apparatus upon the
other.
725. Wave Disc, by Professor J. Miiller.
J. Wilhclm Albert, Frankfort-on-the- Maine.
The wave-disc by Prof. Dr. Joh. Mutter, Freiburg (Breisgau), is an
adaptation of the well-known stereoscopic disc (Phenakistoscope, or Wunder-
scheibe), for demonstrating the wave undulation. The eight drawings are
for the purpose of illustrating the water, rope, sound, and air waves, in CDvered
as well as in open pipes.
See " Lehrbuch der Physik," VII. Edit. Vol. I., 155).
726. Telephon, on Reis' system, for the reproduction of
sounds by galvanism.
J. Wilhclm Albert, Frankfort-on-the- Maine.
The telephon is based 011 the experiments of Wertheim and others re-
garding galvanic sounds. Philipp Reis, at Friedrichsdorf, made use of these
with a view of reproducing by means of galvanic action the musical sound;
produced by singing (or by pipes, &c. played upon), by employing an elastic
membrane and an interference apparatus constructed by him.
(See Jahresbericht des physikalischen Vereins zu Frankfurt a Main.
Jahrgang 1860-61 ; also, "Muller's Lehrbuch der Physik, VII. edit. Vol. II.,
135.
727. Crank Apparatus, for showing the production of pro-
gressive waves in water, &c.
Prof. J. Joseph Oppct, Frankfort-on-the- Maine.
The rotating liquid molecules are represented by white wooden balls on
a black background, and are all put into motion by a crank attached at the
back.
The whole shows two wave lengths.
728. Cylinder Apparatus, for showing directly and com-
paratively, progressive and stationary waves of sound, and the
essential difference between them.
Prof. J. Joseph Oppel, Franhfort-on-tlie- Maine.
Contains H corresponding wave lengths on both cylinders. Other
drawings likewise, for example, with different wave lengths (for illustrating
the musical intervals, &c.), can be mounted on the cylinders, which are of a
somewhat conical shape.
729. Two Wave Discs of paste-board for stroboscopic
illustration of a progressive and a stationary (water) wave.
Prof. J. Joseph Oppel, Frankfort-on-the-Maine.
IV. INTERFERENCE. 189
Would be best fastened to a rotatory apparatus such as are used for
colour spindles, &c., and placed in front of a mirror. All waves, with the
exception of a horizontal one, should be covered by a black screen.
730. Brass Tube, with Gas-burner, for Intonation.
(Compare Poggendorff's Annalen, vol. 129, 1866.)
Albrccht, Tubingen.
731. Rotating Mirror, movable towards all sides.
Albrecht, Tubingen.
This mirror has not yet been described, but several specimens have already
been executed by Mr. Albrccht. That position of the mirror in which its
normal forms a moderate angle with the rotatory axis, is peculiarly adapted
to change the reflected image of the sonorous flame into a beautiful elliptical
crown.
731a. Barlow's Logograph, an instrument for recording
pneumatic effects of speech, showing the consonant actions and
the vibratory effects accompanying vowel sounds.
W. H. Barlow, F.R.S.
731b. Apparatus for Synthesis of Vowel Sounds.
Prof. Clifton, F.R.S.
732. Apparatus for the projection on the screen of the
curves produced by the combination of rectangular vibrations.
Yeates fy Sons.
787a. Electro-Diapasons, showing the composition of vibra-
tory movements by producing fixed acoustic figures.
M. Mercadicr, Paris.
IV. INTERFERENCE.
733. Apparatus for demonstrating, by the aid of flames, the
interference of two musical sounds.
Prof. Dr. R. A. Mees, Director of the Physical Labora-
tory of the University of Groningen.
The apparatus consists of two curved movable cross tubes, narrowed at
one end ; their narrow openings, being near each other, are tightly fixed in a
longer tube, also ending in a narrow opening ; this is placed close to a strong
flame, and also a very small flame, which can be seen in a rotating mirror. A
small movable burner for this small flame is attached to the apparatus. When
a sound-wave proceeds from the opening of tbe instrument, the strong flame
diminishes abruptly in length and begins to roar, while the small flame rapidly
vibrates, its motion being visible in the rotating mirror. The open ends of the
two curved tubes can be placed before the mouths of two unisonant organ
pipes, or above two different segments of a vibrating plate. When only one
of the pipes is sounded, the flames show the vibrations, but, when both pipes
are sounded, there is no agitation of the flames, the two sound-waves counter-
acting each other. When the two openings are above segments of the plate,
which are in the same phase of vibration, the flame is agitated, but, when they
are above segments in the opposite phase, the flame remains at rest.
190 SEC. 6. SOUND.
734, Apparatus, of simple character, for demonstrating by the
aid of flames the interference of two musical sounds.
Prof. Dr. R. A. Mees, Director of the Physical Labora-
tory of the University of Groidngen.
This apparatus is designed for the same purpose as that last described, but
is of more simple construction.
735. Quincke's Interference Tube, to demonstrate by the
action of a flame the diminution and increase of sound by inter-
ference.
Prof. Dr. R. A. Mees, Director of the Physical Labora-
tory of the University of Groningcn.
This apparatus is furnished with a supplementary brass tube having a
narrow opening. It can be used with the same flames as those provided for
the instruments last described.
735a. Interference Apparatus, by Jamin.
M. J. Duboscq, Paris.
735b. Interference Apparatus. Prof. W. F. Barrett.
This is a circular modification of the usual trombone apparatus. When
used with a pitch pipe, the extinction of the sound is made evident to a large
audience, the two resonant columns being rendered in opposite phases by
adjustment of the movable circular tube Phil. Mag., Aug. 1874.
V. ABSORPTION, REFLECTION, AND REFRACTION.
736. Apparatus for showing Approach caused by
Vibration. Frederick Guthrie.
A suspended card or mass of cotton wool, or an air ball floating in water,
approaches a resonant fork ; and the latter, when free to move, is also urged
towards neighbouring matter.
737. Apparatus for showing the Expansion of Gases
by Sound. Frederick Guthrie.
One prong of a tuning fork is enclosed, air-tight, in a glass tube provided
with a capillary exit tube, in which water stands at a certain height. On
bowing the free prong of the fork the water level is seen to fall about a quarter
of an inch.
738. Apparatus for the Reflection of Sound by heated
air and vapours. Prof* Tyndall, F.R.S.
Sound of high pitch from a vibrating reed is passed through a long rectan-
gular chamber, and caused to agitate a sensitive flame. Air, saturated with the
vapour of a volatile liquid, is gently driven through six narrow openings into
the chamber, at right angles to the direction of the sound. The atmosphere
within the chamber is thus immediately rendered heterogeneous, and the
sound waves being reflected, the agitated flame is rapidly stilled. The removal
of the heterogeneous medium instantly restores the flame to its former
agitation.
VII. MUSICAL INSTRUMENTS. 191
For the action of heated air, the rectangular chamber is turned upside
down upon its support, and the heated air from six gas jets allowed to stream
in through six narrow openings across the sound waves. The air thus
rendered heterogeneous has the effect of immediately rendering the sensitive
flame quiescent. Phil. Trans., 1874.
739. Diagrams and Apparatus illustrating the reflection
and refraction of sound-bearing waves, as exhibited to a class by-
means of a sensitive flame. Prof. W. F. Barrett.
The arrangement shows a suitable source of sound, a good form of gas
pillar for yielding a tranquil flow of gas to the burner, and the best shape
and size of steatite burner for the flame, together with a useful form of gas--
holder for giving steady pressure of gas larger than that usually given by the
street mains.
These experiments \vere first shown by the exhibitor in connexion with a
paper read by him before the Royal Dublin Society in Jan. 1868. See
Quarterly Journal of Science, Jan. 1870.
VI. RESONATORS.
740. Resonator of adjustable pitch. Lord Rayleigh
Resonator, whose pitch can be rapidly adjusted to the various notes of a
harmonic scale A';> , a[? , e;> , a't? , e". The smallest hole is made first and
adjusted until the resonator responds a[> . The second hole is then made and
adjusted, until, with both holes open, the note is dj . Similarly with three holes
the note is a'^ , and with four holes e". When the note Aj? is sounded on the
piano or harmonium, and the resonator is suitably fingered, the various
overtones are heard with great distinctness, and the phenomenon is more
marked than usual in consequence of the contrast afforded by the rapid
transition.
740a. Sonorous Tubes, by Dulong.
Polytechnic School, Paris*
741. Six Resonators of glazed cardboard, for the sounds:
c' (256 vibrations), e 7 (320 vibrations), g' (384 vibrations),
c"(512 vibrations), e" (640 vibrations), g" (768 vibrations).
Gustav Schubring, Erfurt.
VII. MUSICAL INSTRUMENTS.
742. Enharmonic Harmonium, with generalised key-
board ; 84 keys in each octave ; compass, 4-| octaves.
R. H. M. Bosanquct.
This instrument is tuned according to the division of the octave into 53
equal intervals, a system sensibly identical with a system of perfect fifths.
192 SEC. 6. SOUND.
References. Proceedings Royal Soc. XXIII. 390.
Philosophical Magazine, XLVIII. 507, L. 1G4.
Proceedings of the Musical Association, 1874-5.
Novello's Dictionary of Musical Terms, Article Tempera-
ment.
Ellis's Helrnholtz, pp. 602-699.
Elementary Treatise on Temperament ; Macmillan, 1S76.
742a. General Thompson's Enharmonic Organ. Built
by Messrs. Robson, London, 1856. John Curwcn.
It is an improvement upon a similar instrument he exhibited in Hyde Park,
in 1851, which also was an improvement on the first organ built for him in 1S34.
It is capable of being played in 21 keys, with their minors of the same tonic.
The organ is fully described in General Thompson's pamphlet, " The prin-
" ciples and practice of just intonation with a view to the abolition of tempera-
<: rnent." Effingham Wilson, Royal Exchange. On the middle finger-board
the keys of C, G, D, A, E, B, with their minors, can be played perfectly ; on
the lowest finger-board there can be played, besides the keys of C and G,
those of F, B ! ? , acute Eb , acute Ab , and D 1 ? . The lingering is mainly the
same as in other instruments. The red shows the principal key tone of the
board. The black shows the fourth and sixth of that scale, as well as the
grave second, with which they make a true chord. The white shows the
fifth and seventh of the scale, as well as the acute second of the same scale,
with which they accord truly. The small oblong quarrils and the flutals
(finger ke}'s of a flute) are always a komma shriller or deeper than the digital
in which they are embedded. The buttons are always a diatonic semitone
deeper or shriller than the adjacent digital. The serrated edges are for the
blind.
742b. Harmonium, with double key-board.
M. Gueroult, Paris.
This instrument, of which the two key-boards are tuned in fifths, has a
comma at fi interval one from the other, which serves to verify the theories
of musicians and natural philosophers upon the melodic or harmonic gamut.
743. Patent Double Trumpet, called Bi-Clairon.
Franz Hirschberg, Breslau.
The double trumpet (Bi-Clairon), constructed by the exhibitor, is described
by him equally as an interesting and practical invention. As the instrument
consists of two bell-mouths of different measure and construction, into which
the air can be admitted or from which excluded at pleasure through the valve,
it has been rendered possible to produce by the same two kinds of sounds,
which, according to their sonorous colour, are equal to at one time the bugle
horn, at another to the piston (or, also, to the cornet and the trumpet). The
instrument is particularly adapted for being used in concerts, inasmuch as by
the different sonorous colours more, " light and shade," consequently more
variation, is imparted to the execution, and, therefore, no band of musicians
should be without it. In a weak orchestral band, in which both bugle horn
and piston (respectively cornet and trumpet) are not always represented, this
instrument supplies the place of both. Its pitch is high C with B, and A low,
and is so constructed that the smaller bell-mouth can be screwed off, in which
case the instrument can be used as a common bugle horn (or cornet).
744. Model of the Action of Grand Pianofortes.
Messrs. Erard.
VII. MUSICAL INSTRUMENTS. 193
745. Molineux's Patent Self-acting Escapement and
Check Repeater Action for upright Pianofortes. It com-
bines extreme simplicity, a firm and elastic touch, with freedom
from friction and great durability. Thomas Molineux.
746. The first of the now generally adopted obliquely
strung upright Pianofortes, patented Robert Wornum, of
the firm of Wilkinson & Wornum, in 1811.
Messrs. Wornum fy Sons.
The large factory in Oxford Street, in which this instrument was made, is
shown by an engraving within the lid. This factory was burnt down in
October 1812, and the partnership was then dissolved. In the folloAving year
Robert Wornum made the first successful " Cottage " pianoforte, with vertical
stringing, to which he gave the name of " The Harmonic Pianoforte." He
accomplished this by discarding entirely the use of brass wires, and adopting
the closely-spun copper-covered strings in their stead.
747. Model of the Elastic Tie Action for the Piccolo
Pianoforte, invented and patented by Robert Wornum in 1826.
Messrs. Wornum $- Sons.
The principles of this mechanism are very generally adopted in France and
Germany, as well as in England.
748. Model of Robert Wornum's method of returning
the hammer, in his down-striking Action for Horizontal Grand
and Square Pianofortes, patented in 1842.
Messrs. Woj'num $ Sons.
This action greatly economises the cost of manufacture. The usual actions
are up-striking.
749. Model of Alfred Nicholson Wornum's new Patent
Action for Grand Pianofortes (1875), in which the heads of the
hammers are reversed, and now face the wrest plank, this being
effected by an entirely new method. Messrs. Wormim Sons.
By this invention longer strings may be used, relatively to the external
dimensions of the case, than in an instrument of the ordinary construction.
750. Model of the action of Ancient Great Hydraulic
Organ, from Mr. Chappell's description of the instrument.
Dr. Stone.
750a. Model of a Keyboard for an Organ.
Colin Broun.
751. Marimba or Balafo, from South-eastern Africa.
Modern. Given by Captain J. Stuart.
South Kensington Muscuui.
The instrument has twelve slabs of a sonorous wood, beneath which are
fastened, by means of a dark-coloured cement, twelve gourds, to increase the
sound. In each gourd are two holes, one of which is at the top, and the
40075. N
194 SEC. 6. SOUKD.
other at the side. The latter is covered with a delicate film, to promote
the sonorousness. Several African travellers have noticed this curious
acoustic contrivance. Du Chaillu says that the film consists of the skin of a
spider ; Livingstone mentions spiders' web being applied to instruments of
this kind used by certain native tribes in Southern Africa. The marimba is
a favourite instrument of the negroes as well as of the Kafirs.
752. Glass Harmonica. Modern. Made by E. Pohl, in
Bohemia. South Kensington Museum.
The glass harmonica consists of a series of glass bells, which are affixed in
regular order to an iron spindle lying horizontally in a case, and which by
simple machinery are set in motion by the feet. The sound is produced by
the performer moistening his fingers and pressing them on the bells while
these are rotating.
753. Sol-Pa Harmonicon, invented by Miss Glover. In-
tended as an assistance in learning singing, and the theory of
music. South Kensington Museum.
754. Organ Pipes, a selection in illustration of their manu-
facture, showing the middle C pipe of each stop. H. Speechly.
755. Chromatic Harmonium, peculiarly constructed key-
board, " showing the twenty-four progressions. The common
method is seen at the back of the instrument in connexion with the
keys." Mrs. Read.
756. Chromatic Pianoforte, peculiarly constructed key-
board, in which the keys are distinguished by different colours.
Intended to facilitate the playing in the different major and minor
keys. Mrs. Read.
757. Models of several Ancient Egyptian Pipes, the
originals of which are in the Egyptian Museum at Turin or in the
British Museum. Those from Turin are copied in brass, and
those from the British Museum in cane.
W. Chappell, F.S.A.
The original pipes were found in Egyptian tombs, some examples being as
old as the fourth or fifth dynasty of Egypt. They were played upon by
means of a cut, or split, piece of reed, or of straw, inserted in the end, as was
usual with ancient shepherds' pipes, and much in the manner of the modern
hautboy, or bagpipe, reeds. Parts of the ancient reed or straw remain within
one of the pipes in the British Museum, and another at Turin. Usually a
fresh long piece of reed or straw was laid in the tomb by the side of the pipe,
and it may be assumed that the object was to supply the dead man with a
stock of those perishable inciters of tone, in order that he might play con-
tinuously upon his pipe when he awoke. Examples of the straws or reeds, so
deposited, are included in the Museum at Leyden and in the British Museum.
The pipes selected for copying were those which varied in length and in the
number of finger holes, so as to obtain varieties of pitch, and varieties of the
prehistoric scales. Through the kind assistance of Dr. W. H. Stone, himself
an accomplished player upon reed instruments, the following have been
ascertained.
VII. MUSICAL INSTRUMENTS. 195
1. Pipe from Turin 14| inches long, with six finger holes. Scale
-
This is the scale of E major, but only extending to six notes. It lacks the
addition of D jf and E to complete the octave. The fundamental note, or tone
of the whole pipe, was not obtained.
2. The longest pipe from Turin, 23f inches, but with only three holes.
The scale is
This forms a Diatessaron, or Fourth, from B-flat to E-flat, therefore one note
below our C D E F in pitch. In order to obtain the notes from this pipe, it
was found necessary to lower the reed into the pipe, as in the drone of a
bagpipe. It extends three inches down the tube.
3. A pipe in the British Museum, copied in cane. It has four holes, and is
8f inches in length. The scale is a Diatessaron, or Fourth, exactly one note
above the last, but with an F sharp added to it at the top. Possibly this
F sharp may have been intended for a G to make a Fifth ; or as F sharp to
lead into the key of G upon a treble pipe.
4. Also from the British Museum, copied in cane. It has four finger holes,
and the entire length is 10 1 inches. This pipe has a hole bored through it
near the mouth end. It would have been absolutely impossible to produce
sound from the pipe if this hole had been left open. It may therefore be
assumed that it was once covered with thin bladder, such as that of a fish.
The intention of placing bladder there would have been to give a tremulous-
ness to the tone of the pipe so as to assimilate it to the human voice. The
old English pipe called the Recorder, referred to by Shakespeare in Hamlet,
and in A Midsummer Night's Dream was of the same kind, and differed in
no other respect from the English flute, both being blown at the end. It
is curious to find that such an appreciation of the difference of tone that might
be produced has been anticipated by the ancient Egyptians. A film of gutta
percha is now tied over the hole. The scale is
This is a peculiar scale, a pentaphonic major scale, such as is popularly
entitled the Scotch scale. It is suitable for playing tunes upon the black
keys of the pianoforte.
It is remarkable that no one of these pipes gives any indication of* a minor
key, and they seem therefore to be older than the introduction of the minor
N 2
196 SEC. 6. SOUND.
"scale, inherited by us from the Greeks, by the junction of two tetrachords.
For this an astronomical or theological reason is assigned, that, as there were but
seven planets (according to ancient supposition), and seven days in the week,
or quarter of the lunar month, &c., &o there should be but' seven notes in-
stead of eight in a musical octave. Therefore a scale of two tetrachords,
each of four notes, was reduced to seven, through uniting them by one note
common to both. Hence the intervals of our BCD E E F G A.
757a. Indian Vina, with resonating gourds.
IV. Chappcll, F.S.A.
757b. Patent Comma Trumpet, producing approximately
correct intonation, by means of a valve, which raises the pitch the
interval of a comma. H. Bassett.
757c. Marimba from Angola, on the principle of the musical
box. IT. Bassett.
757d. Wooden Trumpet from Angola, made from the root
of a tree. H. Bassett.
757f. Double Bass, with heavily covered fourth string, going
clown to C C 0. Dr. Stone.
758. Series of Acoustic Models. M. Lancelot, Paris.
759. Savart Violin.
Conservatoire des Arts et Metiers, Paris.
759a. A new Orchestral Musical Bass Instrument, with
concertina fingering, full tone, and expressive for part and solo
performance. S. F. Pichler.
759b. Acoustical Instrument, illustrating Harmony
and Discord. S. F. Pichler.
759c. Violin fitted with Tension Bars. Dr. Stone.
759d. Viol d'amore, illustrating the principle of consonating
springs. Dr. Stone.
759e. Tenor Bassoon, or Altp Fagotto. Dr. Stone.
VIII. SPECIAL COLLECTIONS.
DETAILED LIST OF INSTRUMENTS MANUFACTURED BY
M. LANCELOT OF PARIS.
Exhibited by Augustc Bel S> Co., London.
760. Eight Pieces of Wood, giving a scale.
761. Mouth of a Flute Pipe, showing the inside of the
air-chamber.
VIII. SPECIAL COLLECTIONS. 197
762. Wertheim's Apparatus.
763. Pipe with glass side, and membrane.
764. Pipe carrying a slide, enabling holes of different sizes
and shapes to be opened in the same situation.
765. Four Pipes, all containing the same mass of air, ona
cylindrical, one cubical, one tetrahedral, one spherical.
766. Three Pipes containing the same mass of air, one pris-
matic, one in the shape of a right cone, one in that of an inverted
cone.
767. Mons. Bourbouze's Pipe with glass side, bearing
three membranes, with mirror, one placed at the node of the first
sound, the two others at the two nodes of the second sound.
768. Six Plates, five of different woods, one of brass.
769. Two Plat Bods of brass for transverse vibrations.
Support for fixing these.
7 7O. Sonometer on Mons. Barbereau's principle.
771. Circular Membranes, with varied tensions.
772. Two Tuning Forks on resonance box, to give four
beats a second.
773. Two Tuning Forks, mounted between the poles of
electromagnets, with contact-breaker.
774. Duhamel's Vibroscope.
775. Apparatus for transmi;
juids.
776. Instrument for showing the quality of vowel-sounds.
775. Apparatus for transmission of vibrations through
liquids.
Various Scientific Instruments illustrating the Phenomena of
Sound, invented and made by the late John Henry Grics-
bacli.
'777. Monochord, with apparatus for printing and regis-
tering the vibrations of strings, with a view to ascertaining the
number of vibrations per second.
778. Phonometer, by means of which the equally tempered
12 fixed sounds in the octave may be produced.
779. Monochord, giving the positions of the Nodal Points
in vibrating strings.
198 SEC. 6. SOUND.
780. Mono chord, which affords the means of measuring
the 200th part of an inch, with a view to ascertaining the number
of vibrations given by that length of string.
781. Apparatus for producing musical sounds, mainly con-
sisting of notched wheels of different diameters, which, being
set in motion at a given speed, and duly prepared pieces of card-
board brought in contact with their teeth, produce the notes of
the common chord ; the number of notches in the wheels corre-
sponding with that of the vibrations required to produce those
notes.
782. Apparatus for showing the relative positions of the
vibrations of two strings or tubes under the operation of altering
the ratios; the strings first tuned to coincidence as unisons,
the ratios then altered by lowering the pitch of one of the strings,
as from 81 lo 80, 82 to 80, or any other numbers within the
scale of the apparatus.
783. Set of Flute Pipes, w T ith bellows attached, some of
which have too high sounds to be heard singly, but which together
give the resultant tone.
784. Large Set of Coloured Diagrams for illustrating
lectures on sound.
784a. Collection of Tuning Forks.
One tuned to Handel pitch.
Two in a box.
Two normal diapason.
One tuned to Big Ben.
One C. 528.
784b. Paper printed by J. H. Griesbach to Handel's
pitch, and one to the true diapason.
785. Collection of Acoustic Apparatus.
George Appunn and Sons, Hanau.
785a. Three Acoustic Wind-Chest Tables. These three
tables are required for placing all the following apparatus :
George Appunn and Sons.
I Overtone Apparatus, consisting of 64 lingual tones, the first 64 part
-2
tones of the fundamental or key tone (primary sound) C =32 vibrations in
a second with reed pipes.
VIII. SPECIAL COLLECTIONS. 199
2. The same Apparatus, consisting of 32 lingual tones, the 32 part tones of
-2
the fundamental tone C =32 vibrations.
On the overtone apparatus there result quite plainly the corresponding
difference-tones of all phases that may be chosen at pleasure ; also, up to a
certain point, the corresponding resultant tones. By means of this overtone
apparatus not only the waves and the quality of the sound can be demon-
strated, but likewise the different degrees of harmony of the various musical
proportions (rhythm), and of poly-accords in different keys and transpositions.
The latter, in particular, in combination with the tone limit apparatus for low
tones, mentioned hereafter.
3. Tonometer, consisting of 65 lingual tones; every subsequent tone higher
by 4 vibrations (waves) than the previous one, from c = 256 to c = 512
vibrations in a second ; with reed pipes.
4. Tonometer, consisting of 33 tones ; each succeeding tone being 4 vibra-
tions higher than the preceding one, from c = 128 to c = 256 vibrations in
the second.
(Note. By the number of vibrations given, double vibrations (waves) ar
always to be understood.)
5. Tone-limit Apparatus, for low (pitch) tones ; consisting of 57 lingual
tones, with reed pipes, from c = 128 vibrations downwards to 8 vibrations in a
second, namely, from c= 128 to C- 1 = 64, every subsequent tone in the de-
scending scale lower by 4 vibrations than the next preceding tones from
C- 1 = 64 to C~ 2 = 32, each two vibrations lower, and, lastly, from C- 2 = 32
vibrations downwards, each one vibration lower as far as 8 vibrations.
6. Tone-limit Apparatus, for high (pitch) tones ; consisting of 31 small
tuning-forks, the diatonic Durton scale c; d; e; f; g; a; h; c;
24 : 27 : 30 : 32 : 36 . 40 : 45 : 48.
through 4| octaves, namely, from c 5v = 2048 vibrations (double) to e viii = 40,960
double vibrations, with two bows.
In order to be able to observe, and to perceive better and more distinctly
with the tone-limit apparatus for high tones (tuning-fork apparatus of 31
tuning forks), the ascending scale up to the highest pitch, it will be advisable
to intonate with two bows the scales in octaves, one after the other, and thus
to sound every tone with its octave simultaneously or one directly after
the other.
7. Two large Gedact Pipes (stopped mouth pipes), whose pitch can be
lowered an octave, with small wind chest and wind trunk, for illustrating the
interference, waves, resultant tones, &c.
a. Two smaller Gedact Pipes, with small wind chest and wind trunk, for the
same purpose.
b. Very powerful-sounding Lingual (reed) Pipe, accompanied by a large
number of overtones, with bell-mouth : C~ r2 = 32 vibrations in a
second.
c. Twenty-nine Resonators to the same, from the 4th to the 32nd overtone.
(The resonators are conical, and made of zinc.)
d. Reed pipe, with bell-mouth, C~ 1 = 64 vibrations.
e. Four open and four stopped Labral Pipes, with small wind chest and
valves, producing the C major accord : c : e : g \ c.
8:10:12:16
f. Accord Heed Pipe, producing the C major accord c : e : y : c : e : g : c
(The two apparatus e and/ are for demonstrating the quality of sound.)
200 SEC. 6. SOUND.
786. Stand of Apparatus illustrating the progress of
CEolian Principles. J. Baillie Hamilton.
1. Primitive JEolian types.
The rod.
The bow.
The harp.
2. Modern CEolian harp.
3. Wind concentrated upon a string, and applied to its entire
length. By Professor Robinson.
4. Wind applied to a portion of the string, as by Wheatstone,
Green, Isoard, &c.
5. Further modifications of the same.
6. Use of a free-reed. By Pape. The connexion with the
string being effected by a silk thread.
7. Julian's mode. A metal string flattened into a tongue at the
part where the wind impinges.
8. Farmer's mode. A reed-tongue substituted for the flattened
portion.
9. Farmer and Hamilton's mode. A rigid connexion between
reed-tongue and string allows the reed to be used as in reed-
organs.
SUBSEQUENT INVESTIGATIONS BY HAMILTON IN CONJUNCTION
WITH HERMANN SMITH.
10. Improved string-organ note, in which a sympathetic re-
sistance is offered to the string, the vibration transmitted to the
soundboard, and constancy of pitch preserved by a spring -bow.
The reed tone is modified by a tube, and the connexion effected
through the tube by a " purse," the latter suggested by Hermann
Smith.
11. Further modification by Hamilton. The necessity for the
" purse " abolished by setting both reed and string inside the
register. The economy of space effected by Hamilton's spiral
spring, and the use of a short metal spring-bow.
12. Application of these improvements for use in a wind-
viol. Also a conical string, invented by Hamilton, for obviating the
following difficulties peculiar to reeds and strings in combination.
a. The difficulty caused by the string breaking into segments,
owing to the constraint on the reed, and the scarcity of
notes obtainable.
b. By the irregularity of intervals which, in a cylindrical string,
are crowded together near the reed, and are far apart when
remote from it.
c. By the irregularity of tone in different portions of the string's
length. When an ordinary string is used in short lengths
the reed's motion is confined, and the tone is consequently
VIII. SPECIAL COLLECTIONS. 201
pure ; as the string lengthens, the tone becomes loose and
coarse.
(I. By the reducing of the string's bulk by stretching when
tuned, as the reed remains constant the intervals would
be changed when the string is thus attenuated.
The conical string meets these difficulties thus,
. The bulk of the string lies in the part used for playing upon,
and thus no intervals are wasted.
b. The bulk is increased where the intervals would otherwise
be wider.
c. The increasing bulk controls the reed equally at all points.
d. If tuned from the smaller end the string does not become
attenuated, as more bulk is brought over the other bridge.
13. Apparatus for studying the relative amount of tone con-
tributed through the string.
a. By the action of a soundboard and bridge.
b. By the reciprocal action of a spring-bow.
The spring-bow can also be rendered rigid, and the tone is then
due merely to the constraining effect of the string on the reed's
motion.
14. JEoliau effects produced by percussion. For investigating
the causes of the JEolian tone.
15. Apparatus investigating the most effective modes of
a. Constraint upon a reed.
b. Transmission to a soundboard.
An intermediate mass is here used for transmission.
16. Apparatus showing how far quality of tone can be now
affected by reaction from the soundboard. By placing a weight
on different parts of the soundboard any quality of tone can be
produced.
17. Further modifications for reducing these principles to
practical use by altering the relation of levers and spring resis-
tance, und substituting for the intermediate mass the structure
of the register, which, as in No. 18, is itself the conductor to the
soundboard.
18. Register embodying the foregoing improvements into a
form for practical use, and illustrating the different forms of
constraint applicable to reeds.
19. A new form of vibrator applicable to all solid bodies as
well as to columns of air. Invented by James Baillie Hamilton,
April 1876.
20. 21, 22. Apparatus for studying the laws of strings combined
with reeds.
202 SEC. 6. SOUND.
IX. EDUCATIONAL.
787. Apparatus for illustrating lectures. Auguste Bel $ Co.
788. Graphical Representations of Musical Scales, on
paste-board. Gustav Schubring, Erfurt.
The logarithms of the numbers of vibrations and their differences where
first recognised by Euler (Leonhard Euler, tentamen novae theoriae musicae,
1739). These logarithms were at a later period used by Opelt ( " Natur der
" Musik," 1834, "Theorie der Musik") for the graphical representation of
musical scales. Herbart, likewise, has employed them in his psychological
speculations, and, lastly, Prof. Drobisch (Leipsic) has extensively applied
them in his calculations of the musical intervals (Abhandlungen der furstlieh
Jablonowskischen Gesellschaft, 1846).
The exhibited plates are especially intended to illustrate the musical scale
calculations of Prof. Helmholtz ; they agree in their annotations with those
employed in the older edition of the " Lehre von der Tonenipfindungen "
(Part III., sections 15 and 16). A reconstruction of these plates, according
to the annotations used in the new edition, is in course of execution.
789. Model for the Higher Tones.
Gustav Schubring, Erfurt.
Prof. Mach (Prague) has made use of the high-tone scales, drawn according
to logarithmic scales, in order to produce a model for the high-scale tones.
By means of the same not only can the higher tones of any sound be ascer-
tained directly, but the higher tones of several sounds can also be compared
with one another, and the theory of the musical consonance and dissonance
advanced by Prof. Helmholtz can be demonstrated in the most excellent
manner.
Prof. Mach's model had a length of three octaves, and contained the high
tones according to the tempered free-balancing scale.
The model exhibited is more than four octaves long, and contains the high
tones in the pure (natural) key.
789a. Model, similar to the two preceding, but not on paste-
board. Gustav Schubring, Erfurt.
790. Sir Charles Wheatstone's Mechanical Illustration
of the Vibration of Strings or Bods.
The Council of King's College, London.
203
SECTION 7. LIGHT.
WEST GALLERY, UPPER FLOOR, ROOM (q
DETERMINATION VELOCITY.
791. Original Apparatus, by M. Fizeau, for measuring
the velocity of light. Polytechnic School, Paris.
792. Apparatus, by M. Foucault, for measuring the velocity
of light. Polytechnic School, Paris.
I. DISTRIBUTORS.
a. LENSES.
794. Burning Glass (German), made probably by Count
von Tschirnhausen in the 18th century. The property of Prince
Pless Furstenstein. The Breslau Committee.
798. Early Stereoscope, made by the late Sir David
Brewster, the inventor of this instrument. John Maclauchlan.
798a. Early Stereoscopic Pictures, prior to the applica-
tion of photography. From the collection of the late Sir C.
Wheatstone. Robert Sabine.
798b. Early Stereoscopic Pictures. Daguerreotypes of
1. Biot; 2, Bequerel ; 3, Foucault, from the collection of the late
Sir C. Wheatstone. Robert Sabine.
798c. Seven Earliest designs for the Stereoscope
printed in black and white. From the collection of the late Sir
C, Wheatstone. Robert Sabine.
798d. Early Stereoscopic Pictures. Two Daguerreotypes
of Faraday, from the collection of the late Sir C. Wheatstone.
Robert Sabine.
799. Double Opera Glass. An early example, probably
made in Holland about 1700. Soiith Kensington Museum.
801. Binocular Pield Glasses, Nos. 17, 29, 37.
Voigtlander and Son (Chevalier von Voigtldndcr\ Bruns-
wick.
204 SEC. 7. LIGHT.
804. Telescope, No. 14.
Voigtldnder and Son ( Chevalier von Voigtlander), Bruns-
wick.
807. Iceland Spar Ball, for showing double axis.
A. Hilgcr.
810. Series of Metrical Glasses. The dioptric unit
is a lens of one metre focus ; the lens 0'50 to two metres
focus is a semi-dioptric value of the unit ; the lens 2 to 50
focus is a dioptric value of double the unit. The same rule
applies to all the other lenses in the collection. M. Cretes, Paris.
810a. Globe made of Spar. M. Lutz, Paris.
811. Early form of Stereoscope.
The Council of Kings College, London*
812. Early form of Stereoscope.
The Council of King's College, London.
812a. Polistereoscope. Apparatus which serves as tele-
stereoscope, pseudoscope, iconoscope, &c., &c.
Augustus Rigid, Professor of Natural Philosophy, Royal
Technical Institute, Bologna (Italy}.
This apparatus consists of two plane mirrors, one of which (on the left in
the figures) can turn about an horizontal and a vertical axis ; the other
mirror, besides these movements, can be fixed at different distances from the
former. The eyes must be applied at two cylindrical tubes fixed to a dia-
phragm, which can take different positions. One of the eyes sees directly the
objects, while the other sees the sameobject but apparently in a different position.
This virtual position can be determined by forming the image of the eye, given
by the left mirror, and afterwards the image of the point so determined in
relation to the other mirror. If objects not too near are observed the illusion
succeeds equally, though the image in the eye which sees by reflection is
smaller than the other. According to the inclination which is given to the
mirrors, it is possible to make any determinate point of the observed objects
appear in the true position.
Fig. 1. If the apparatus be placed as in Figure 1, it produces the effect of
the telestereoscopc.
Fig. 2. Placed as in Figure 2, it acts as a pseudoscope. According to the
distance between the mirror, diminution or augmentation of relief can be
obtained, together with the inversion of relief. Some curious effects (which
cannot be obtained with a Wheatstone's pseudoscope) are observed by looking
at rotating geometrical solids, constructed with metallic wire, or by looking
at these solids while the observer moves round them.
Fig. 3. With the apparatus placed as in Figure 3, the effects of an icono-
scope are obtained. A very narrow mirror is substituted for the large mirror.
Fig. 4. In Fig. 4 the apparatus is placed so that the ej-es see the objects as
if they were in a same plane perpendicular to the right line which joins the
eyes ; the relief in objects made with vertical wires then disappears. If the
diaphragm which bears the two tubes is kept fixed, and the instrument turned
slowly round the left tube, very curious apparent motions occur in the objects
under observation.
For the mathematical theory of this apparatus, see the " Nuovo Cimento,"
2 d ser. t. xiv.
I. DISTRIBUTORS. 205
813. Jewel Lens (Ruby) of -^ inch focus. Made by An-
drew Pritchard, at the suggestion of Sir David Brewster.
, (See Brewster's " Optics/' 1831, p. 337.) John Spiller, F.C.S.
813a. Vertical Apparatus for Projections.
M. J. Duboscq, Paris.
813b. Projecting Apparatus, for all phenomena of double
refraction and polarization. M. J. Duboscq, Paris.
813c. Support, with Reflector, by Fresnel.
M. J. Duboscq, Paris.
~b. LANTERNS, CAMERAS, &c.
814. Oxy-hydrogen Lantern, of new form, suitable for
lecturers. C. J. Woodward.
The lantern is mounted on a " Willis's stool," so that supports of various
kinds may readily be attached. The body of the lantern is swung between
two uprights, and can be clamped so as to send a beam of light at any angle ;
this, combined with a rotatory motion in a horizontal plane, enables the
lecturer to direct a beam in any required direction. A rod carries lenses and
a mirror when it is required to throw the light vertically upwards on an object,
as, e.g., for cohesion figures.
816. Camera Obscura. An early example, said to have
belonged to Sir Joshua Reynolds. South Kensington Museum.
This camera when closed has the form of a large folio leather-bound book.
It is recorded to have been given by Sir Joshua Reynolds to Lady Yates, by
whose great grand-daughter, Mrs. J. R. Harrison, it was, in May 1875,
presented to the Museum.
81 6a. Camera, by Colonel Laussedat. M. Lutz, Paris.
816d. Camera Lucida, invented and used by Dr. W. H.
Wollaston. G. H. Wollaston.
816g. Camera Lucida, with slight magnifying power.
A. Nachety Paris.
816h. Camera for Landscapes, by M. Govi.
A. Nachet, Paris.
8161. Camera Lucida, invented and used by Dr. W. H.
Wollaston. > G. If. Wollaston.
816j. Wollaston's original periscopic Camera Lucida.
Sec Tilloch, xxvii. (1807), p. 343 ; Phil. Trans., 1812, p. 370.
Wollaston Collection, Cavendish Laboratory, Cambridge.
816k. Wollaston's Camera Lucida adapted to Tele-
scope.
Wollaston Collection, Cavendish Laboratory, Cambridge.
206 SEC. 7. LIGHT.
817. Improved Electric Lamp and Lantern for Lecturer's
use. John Browning.
- The lamp is automatic, the carbon poles being drawn asunder in proportion
to the strength of the battery power used ; this is effected by drawing iron
rods into a hollow coil of insulated copper wire. The lantern has two nozzles,
one intended for exhibiting screen experiments in spectrum analysis, polari-
sation, refraction, reflection, diffraction, &c., the other for exhibiting diagrams
on the same screen, without altering the arrangement of the apparatus for
physical experiments.
818. Lithographs for the Stereoscope, from drawings
by J. Muller, Hessemer, Oppel, Nell.
J. Wilhelm Albert, Frankfort-on- Maine.
The coloured drawing marked with A (upon grey cardboard) is the
original made by the late Prof. Miiller. Images 2, 3, and 4 serve for a
stereoscope without glass. The other images refer to stereometrical, astro-
nomical, and optical subjects (colour combinations). Some images appear,
by a slight -change of position, in IOAV or high relief.
819. Edelmann's Spectral Lamp, for the projection of
spectra, with printed description. M. Ph. Edelmann, Munich.
821. Duboscq's Lantern. To be used in connexion with
the following apparatus :
1. Top with illuminating lens ; is to be employed with spectral
slit and polariscope.
2. Spectral slit ; can be regulated by means of a fine screw.
3. Stand with convex lens; serves for the projection of the
rays in spectrum experiments.
4. Two hollow prisms.
o. Prism plate for two prisms, arranged for being turned and
put higher or lower.
6. Stand with holder for a prism ; can be regulated.
7. Polariscope.
8. Lens system, with four-inch illuminating lenses and achro-
matic objective ; serves for the projection of photographic and
other images of about 3 inches in diameter.
9. Microscope. This can be screwed to the end of the preceding
system of lenses, after the objective has been removed.
10. Regulator for producing electric light.
11. Hydro-oxygen gas lamp.
A. Kriiss, Hamburg.
Apparatus for the use of Lecturers, to show sketches,
drawings of instruments, anatomical preparations, &c., by means
of hydro-oxygen illumination, arranged for the projection of
opaque objects. A. Kriiss, Hamburg.
8 2 la. Photogenic Lantern. M. J. Duboscq, Paris.
II. SELECTORS. 207
822. Double demonstrating Oxy-hydrogen Lantern,
with triple condensers, consisting of two 10-inch plano-convex
lenses, and a 7-inch meniscus, next to the source of light. The
last lens is made to slide backward and forward between guides,
so as to increase or diminish the cone of rays, and enable large or
small diagrams or pictures to be exhibited without material
distortion. Dr. Stone.
823. Magnesium Lamp, provided with brass cylinders and
reflector. A. Hcrbst, Berlin.
824. Brewster's Patent Kaleidoscope (with case). The
original form of the instrument made by Bate, of London, in the
year 1815. (Position of the reflectors capable of adjustment,
non-central eye piece, and rotating terminal disc, or box contain-
ing the coloured glass.) John Spiller, F.C.S.
II. SELECTORS.
a. SPECTROSCOPES, PRISMS, &c.
825. Photographic and Spectre-photographic Speci*
mens and Apparatus of Sir John Herschel and Sir William
Herschel. Prof. A. S. Herschel.
1 . Original fragments and complete photographs on glass with chloride of
silver of the forty foot telescope at Slough. Produced in 1839 bj" Sir John
Herschel, as a new modification of the process of Daguerre. Paper wrapper
of the specimens inscribed in autograph by Sir John Herschel with the above
description of the plates.
2. Prismatic apparatus designed and used in researches on the photo-
graphic action of the different rays of the spectrum, by Sir John Herschel,
Slough, 1839. Original description, and notes of experiments with the
instrument extracted from MS. journal. Specimens of photographed spectra
obtained with the instrument by Sir John Herschel, at Collingwood, in 1859.
3. Heliostatic mirror (used by fixing outside to aperture in a window
shutter, and turning screws by hand inside to direct the sun's rays horizon-
tally or in a required direction) . Glass prism to receive and bend downwards
the reflected ray to a table on which thermometers were exposed to action of
the different rays of its spectrum. Constructed and used (with other ap-
paratus not preserved) by Sir William Herschel, in experiments on thermal
radiation in the solar spectrum, described in the Philosophical Transactions,
1800-1801.
A plate of light blue cobalt glass, mounted on cardboard diaphragm pierced
with an eye-hole ; used with the prismatic photographing apparatus to exa-
mine test papers submitted to the solar spectrum (before sensitizing), and to
mark with pencil on the test paper the exact position of a certain yellow colour
of the spectrum. When the paper had been thus fixed and marked, the sen-
sitive solution to be tested, if not already present in the paper, was applied to
its exposed surface with a brush, and the time of exposure and intensity of
the direct sunlight was at the same time recorded. Two small card-leaves
have, for the purpose of examination, been attached to the cardboard dia-
208 SEC. 7. LIGHT.
phragm, by closing which upon the glass, the " fiducial " yellow ray trans-
mitted by blue cobalt glass will be observed with the accompanying eyepiece
of a small pocket spectroscope placed with the plate. Through the narrow
slit left between them the selective absorption of the glass can easily be
distinguished if white light is examined through it, and spectroscopically
analysed by means of the dispersion of the prisms.
825a. Fluorescent Eyepiece, by M. Soret, for adaptation
to the Spectroscope.
Geneva Association for the Construction of Scientific In-
struments.
It consists of a plate made of a fluorescent and transparent substance
(uranium glass or different liquids contained between two glass plates), which
is placed in the focus of the objective of the spectroscope. The ultra-purple
spectrum projected upon this plate becomes visible, and is observed through
an eyepiece which is movable upon the axis of the observing telescope.
A very intense light is necessary. (For description of this apparatus, see
Poggeudorffs Annalen, 1274. Jubelband, p. 407; Archives des Sciences
physiques et naturelles, 1874, vol. 41, p. 338 ; and 1875, vol. 54, p. 255.)
82 5a. Combination of Three Prisms of different dis-
persive power, giving by one combination deviation without dis-
persion, and by another dispersion without deviation. Formerly
the property of Dr. Priestley. Mrs. Parkes.
82 5b. Apparatus used by Sir C. Wheatstone in his early
researches in Spectrum Analysis. Robert Sabine.
82 5c. Arrangement of Apparatus for Experiments on
the Assay of Gold Alloys, by means of the Spectroscope,
in the manner suggested by Mr. Lockyer.
W. Chandler Roberts, F.R.S.
The apparatus consists of:
(1.) An induction coil, capable of giving a 10-inch spark in air, which is
provided with a Foucault contact breaker in order that the spark may be
perfectly continuous.
(2.) A frame on which the portions of metal under examination can be so
arranged as to be easily brought in succession under a fixed pole of alumi-
nium. Accompanying this frame is a fixed microscope provided with cross
wires in the ^eyepiece, and the table bearing the assay pieces can be adjusted
by a micrometer screw, so that the image of the apex of each assay piece can
be brought to coincide with the cross wires, thus ensuring that the striking
distance remains constant.
(3.) A lens to throw an image of the spark on the slit of
(4.) A large spectroscope in which the spectra of the alloys are examined.
It is provided with a micrometer, the wire of which is horizontal and moves
in a vertical plane.
When a spark from the induction coil (the two terminals of which are also
connected with the coatings of a Leyden jar) passes between the aluminium
pole and one of the alloys, an atmosphere of the vapours of gold and copper
is formed round the lower pole which does not extend to the upper pole, and
therefore in the spectrum observed the lines due to these metals will not cross
the field of view. Mr. Lockyer observed, that, when all other conditions
remain the same, if the composition of the alloy be slightly altered, the relative
II. SELECTORS. 209
heights and intensities of the lines of the two metals vary. For these com-
parisons the gold line having a wave length of 5,230 tenth-metres, and the
copper line 5,217, are the most convenient. If a series of known alloys vary-
ing slightly in composition is examined, a curve may be constructed, the ordi-
nates of Avhich represent the ordinary assays, and the abscissae the micrometer
readings for the points at which the above two lines are equally bright, and
then, theoretically, if an unknown alloy of about the same composition be
examined, this curve enables us to determine its exact composition when the
micrometer reading is known.
In practice, however, it is found necessary to vary the striking distaace
with the composition, and the amount of this variation is still under investi-
gation.
826. Spectroscope for determining the smallest displace-
ment of spectral lines, and for measuring the velocity of motion of
the object. Professor Carl Wenzel Zengcr, Prague.
This new instrument gives double images, two spectra produced by an
additional prism of quartz or calcspar, giving two dark lines in parallel
directions, e.g., the D. line, and of constant distance, if there be no motion
towards or from the luminous body. The motion of heavenly bodies pro-
ducing, therefore, the displacement of both D lines, and an accurate micro-
meter measuring it, gives the amount of velocity.
827. Hermann's Haematoscope, for examination and
demonstration of absorption bands in fluids by the spectroscope.
, Professor Dr. L. Hermann, Zurich.
The fluid is poured into the little chamber, and the thickness of the layer
is regulated by sliding the inner tube until the bands appear.
828. The Collection of Prisms of crown and flint glass used
in the construction of refractors and spectroscopes by Steinheil and
Merz at Munich, and by Hofmann at Paris, whose refractive
indices for 50 lines in the solar spectrum were determined by
Prof. Van der Willigen. Teylcr Foundation, Haarlem.
Steinheil No. I. flint, No. II. flint, No. III. crown glass.
Merz No. I. and No. II. both of the same heaviest flint, No. III. crown,
No. IV. crown, No. V. and No. Va. both of the same ordinary flint glass.
Ilofmann No. I. heavy flint glass.
See " Archives du Musee Teyler, " Vol. I. p. 31, 64 and 205, and Vol. II.
p. 183.
See the chemical composition of crown Steiuheil No. III., and Merz
No. IV., and of flint : Steinheil No. II., Merz No. I. and No. II., and
No. V. and No. Va., and Hofmann No. I., given by the late Prof. P. J. van
Kerckhoff, ' Archives du Musee Teyler," Vol. III. p. 117.
Steinheil No. II. and No. III., Merz No. I. and No. II., No. IV. and
No. V. and No. Va., and Hofmann No. I. are accompanied by parallelepipeds
and plates of the same glass and by pieces or powder for chemical analysis.
829. Powerful Spectroscope, with Browning's automatic
action, for adjusting the prisms to the minimum angle of deviation
of the ray under examination. John Browning.
In this instrument the ray can be made lo pass four times through the six
prisms, and a dispersive power of 24 prisms thus obtained can be used, or
4007..
-T
210 SEC. 7. LIGHT.
that of any lesser number of prisms at pleasure. The instrument is fitted
with a new reflecting bright line micrometer ; when measuring with this
contrivance no light is visible in the field of view, but the wires of the
micrometer are seen faintly illuminated.
830. Universal Spectroscope, with Browning's automatic
action, giving a dispersive power of from 2 to 12 prisms.
John Browning,
791. Rotating Tube Holder, a contrivance for containing
a number of Ffliicker's tubes, and obtaining their spectra suc-
cessively without loss of time. John Browning.
792. Rotating Metal Holder, suggested by Mr. Lockyer,
for holding specimens of all the principal metals, and obtaining
their spectra successively, or for the purposes of comparison.
John Browning.
831. Direct-vision Spectroscope, with apparatus for
registering observations.
Geneva Association for the Construction of Scientific In-
struments.
This direct-vision spectroscope is distinguished from others of the same
description, in that the distance of the lines of the spectrum is measured, not,
by the superposition of the spectrum upon an illuminated micrometric scale,
but by measuring the angle formed by the e}-epiece in moving the cross
wires of the telescope from one line to the other, and then comparing it with
that formed by the telescope when directed successively to two lines of known
distance. A tangent screw effects the angular displacement of the telescope ;
this screw is graduated on the head to read angular displacements of less
than 20 seconds. A recorder, formed of a movable pencil which acts upon
a counter, serves to make series of observations in the dark. The collimator
telescope possesses also an angular motion, which serves to bring any portion
whatever of the spectrum to the centre of the field of view.
832. General Apparatus for Spectroscopy, Polari-
sation, Reflexion, Refraction, and for various experiments
in Fluorescence.
Geneva Association for the Construction of Scientific In-
struments.
This apparatus has been constructed with the object of carrying out, with
one and the same instrument, all, or nearly all, experiments in spectroscopy,
rotatory polarisation, reflection, and refraction. The divided circle is mov-
able around an axis, and serves to bring the rays of light at any angle upon
the eyepiece of the line of collimation. For experiments in spectroscopy, a
table of one, three, or six prisms may be set up. The prisms are raised above
the divided circle sufficiently to allow of their being heated from below if
required. For determination of the line of collimation suitable arrangements
have been provided, and for experiments in polarisation, eyepieces fitted with
divided circles and nicols ; a Babinet compensator may also be adapted to them.
The first apparatus of this kind was constructed for the use of Professor
Wiedernann, of the University of Leipzig.
II. SELECTORS. 211
833. Large Spectroscope, according to Meyerstein's system
for determining the relations of refraction and dispersion of diffe-
rent media, with contrivance for polarisation.
Schmidt and Haensch, Berlin.
834. Smaller Spectroscope, of the exhibitors' own con-
struction. Schmidt and Haensch, Berlin.
835. Spectroscope, according to Abbe's system, with divi-
ded circle of 20 cm. diameter, repeating circle, and micrometer
apparatus for determining the dispersion. Also a hollow prism
with metal body. Carl Zeiss, Jena.
The spectroscope has only one telescope, which serves at the same time
for collimation and observation. The adjustment brings about automatically
the minimum deviation for every ray. The measurement of the refracting
angle and that of the deviation takes place without change in the instrument.
The determination of the dispersion is effected, independently of ascertaining
the absolute refractive index of one colour, by micrometric measurement.
836. Two Prisms of Glass, for observing the dispersion
of coloured liquids ; constructed by Steinheil, of Munich.
Prof. Kundt, Strassburg.
The refracting edge of the hollow prisms is so sharp that they show the
dispersion of even highly coloured liquids.
837. Spectroscope, with five-inch circle, according to Dr.
Meyerstein's system, for measuring the refraction and dispersion
of different media, for chemical and optical analysis, as well as for
all kiuds of goniometrical measurements.
There are belonging to this :
a. Small circle with pivot and plate.
b. Telescope with stand.
c. Slit tube (Spaltrohre).
d. Scale tube.
e. Crystal stand.
/. Prism.
Aug. Becker (Dr. Meyer steirfs Astronomical and Physical
Workshops}^ Gottingen.
The telescopes, when required, are screwed on to the places marked
" Fernrohre," " Spaltrohre," &c. The small circle is put into the middle of the
larger one. To determine the refracting angle of a prism, the telescope is
attached to that part of the instrument which is marked " Zur Bestinmung,
&c.," it is left here for all goniometric measurements, but the smaller circle is
removed and the crystal-holder put into its place.
838. Spectroscope, of the latest construction, according to
Dr. Meyerstein's system, arranged for the relations of refraction
and dispersion of different media, for the reflection of polarised
light at the free surface of liquids, as well as for the reflection of
solid bodies, for all kinds of goniometrical measurements, and for
chemical and optical analysis.
O 2
212 SEC. 7. LIGHT.
There are belonging to this :
a. Small circle with plate.
b. Two telescopes.
c. Two slit-tubes (Spaltrohre).
d. Scale- tube.
e. Babinet's compensator.
f. Two weights for balancing telescope and slit in a vertical
position.
g. Crystal stand.
h. Flint-glass prism.
Aug. Becker (Dr. Meyer stein* t Astronomical and Physical
Workshops], Gb'ttingen.
For attaching the telescopes, collimators, &c., the same rules apply as
in the previous case. The larger telescope and collimator serve for deter-
mining the refraction and the refracting angle ; the small tubes are for the
polarisation. Determination of refraction and of refracting angles are
effected as with the larger instrument, except that the telescope is put into
the place of the micrometric tube. Solid bodies, when submitted to polarisa-
tion, are fixed with some wax against the plate which is put up in the black
dish. When liquids are to be investigated, the small circle with its clamps is
entirely removed, the screw, which maintains the principal circle in horizontal
position, taken out, and the instrument turned down until the main circle
stands vertically, when it is fixed again by the screw. For ah 1 polarisation
experiments a JBabinet compensator is fixed by means of the two screws
upon the bearer of the telescope.
839. Hollow Prism, according to Dr. Meyerstein, which is
used for optical analysis with the spectroscope.
Aug. Becker (Dr. Meyer stein's Astronomical and Physical
Workshops), Gottingen.
840. Rigid Spectroscope by Browning, constructed for
Mr. Gassiot on the design of Dr. Balfour Stewart, with the view
of determining whether the position of the D lines of the spectrum
is constant, whilst the co-efficient of terrestrial gravity is made to
vary. Kew Committee of the Royal Society.
It is described in the Proceedings of the Royal Society, Vol. XIV., p. 320.
Observations were made by it from 1866-1869, on board IT.M.S. "Nassau,"
during a voyage to and from the South Pacific, and subsequently at the Kew
Observatory until 1872, the results of which are not yet published.
It consists of a train of three prisms, the last of \vhich is silvered on one
side, so as to return the light which falls upon it. Close to the slit another
prism is placed, which reflects the rays on their way back into a micrometer,
by which the position of the D lines is measured."
841. Vierordt Spectroscope, adapted for the measure-
ment of absorption spectra and for quantitative chemical analysis.
Schmidt and Haensch, Berlin.
This apparatus is described in Vierordt's work on the " Application of the
Spectroscope to the Photometry of Absorption Spectra, and in Quantitative
" Chemical Analysis." Tubingen, 1873.
II. SELECTORS. 213
843. Mitscherlich's Stand for use in the spectroscopic
examination of coloured flames.
Prof. A. Mitscherlich, Miindtn.
843a. Direct-vision Spectroscope of gre.it dispersive
power, provided with a specially constructed micrometer for mea-
suring intervals between lines to '0001 in. A. Hilger.
843b. Two powerful Direct-vision Spectroscopes, 7 in.
in length. A. Hilger.
844. Pocket Spectroscope, showing sodium line in a
simple burning candle, of great use in chemical and meteorological
observations. A. Hilger.
845. Hilger's Pocket Spectroscope, showing all the prin-
cipal Fraunhofer lines, dividing D easily with nickel line between;
when on sun, a sliding slit with division adjustable to position,
besides a limb in front of eyepiece. A. Hilger.
846. Pocket Spectroscope of the simplest and cheapest
kind. A. Hilger.
847. Rhomboid of Iceland Spar. . /. Hilger.
Iceland Spar Prism of 60, 1-J. in. surfaces, single re-
fracting. A. Hilger.
Spar Prism, 1| in. surfaces. A. Hilger.
Flint Prism, 1 J- in. surfaces. A. Hilger.
Flint Prism, 1 in. surface. A. Hilger.
Two Half Prisms, 1 in. surface. A. Hilger.
Lateral Flint Prism, If in x 3 in. A. Hilger.
Three compound Direct-vision Prisms, one of a new
form receiving light at right angles. A. Hilger.
Four compound Prisms without colour. A. Hilger.
Two dull Glass Prisms for photometric use. A. Hilger.
Nicol Prisms for polarisation. A. Hilger.
Double Image Prism. A. Hilger.
Parallel Plane Glass Plate, surface 3 in. x 2^ in.
A. Hilger.
848. Nicol and a Double Image Prism. A. Hilger.
848a. Large Prism of 60, with perfectly worked surfaces
3 in. bv 3| in. of the finest Thalium glass, on brass stand.
A. Hilger.
848b. Two Nicol Prisms mounted for polarisation.
A. Hilger.
214 SEC. 7. LIGHT.
849. Spectroscope made by Yeates, of Dublin, fitted with
a diaphragm instead of cross threads for measurement of position
of lines. Prof. Jos. P. O'Reilly.
The diaphragm, above, being perfectly opaque, is always visible against
even the faintest lines ; moreover, it dispenses with the introduction of an
extraneous light Avhich may by its brilliancy interfere with that of faint lines.
This spectroscope is specially adapted for the examination of fluorescent
minerals, the prisms and lenses being of quartz.
850. Spectroscope, with bi-sulphide of carbon prisms and
lens, arranged for projection. Yeates $ Sons.
The prisms and collimating lens are so proportioned that no light is lost
by passing outside the prisms or otherwise.
851. Spectroscope, with compound prism and angular scale.
Yeates Sons.
852. Spectroscope, with two prisms. James How $ Co.
853. Three Foucault's Prisms.
Iceland-spar, cut in three directions.
Small rhombohedron of Iceland spar.
Cone and pyramid (black) for Guerard's apparatus.
Cone for the projection of annular spectrum.
Pyramid for the projection of four spectra.
M. Mascart's prism.
Prism of crown glass.
Two polyprisms (glass).
One poly prism (quartz).
Collection of nine prisms.
Boscowich prisms.
Fresnel's tri-prism.
Fresnel's Parallelepipeds, mounted in brass.
Laurent, Paris.
854. Prisms for direct Vision in 3 pieces.
J? >? ?5 ** V
>j ;? >?
Kochon prism.
Wollaston prism.
(small).
Achromatized Iceland spar prism.
Cube of fluor-spar.
Fluor-spar lens.
Cemented cells for spectroscopic work (9).
Tubes with platinum wire (6).
Collection of quartz and Iceland spar prisms.
Spectroscope with one prism, one and two burners.
Object-glass for projecting ray spectra.
Laurent, Paris.
II. SELECTORS. 215
854a. Collection of Prisms, for optical purposes.
-Laurent, Paris.
854b. Spectroscope. M. J. Duboscq, Paris.
854c. Prisms, by Arago. Paris Observatory.
854d. Prisms, by Borda. Paris Observatory.
854e. Collection of various kinds of Glass for optical pur-
poses. Feil, Paris.
1. Disc of Crown Glass, 4 inches.
2. Disc of Flint Glass, 4 inches.
3. Plate of Crown Glass (heavy English).
4. Parallelepiped, of ordinary flint glass.
5. Crown Glass Prism.
6. Flint Glass Prism.
7. Flint Glass Prism, (sp. gravity 4*4.)
7a. Prism manufactured by Fraunhaufer Guinand.
8. Flint Glass Prism (very heavy), sp. gr. 4 '4.
9. Flint Glass Prism, sp. gravity 4.
10. Flint Glass Prism, sp. gravity 5 '2.
11. Flint Glass Prism, sp. gravity 5 '5.
Series of Assays of the Metallic Earths.
lla. Silicate of Potassium and Calcium with Titanium.
12. Aluniinate of Silicium and Magnesium.
13. Crystallisation of Alumina and Magnesia.
14. Crystallisation of Fluosilicate of Magnesium and Calcium.
15. Alumina and Magnesia Crystallised by Fluosilicate of
Potassium.
16. Crystallisation of Fluosilicate of Aluminium.
17. Crystallisation of Barosilicate of Aluminium.
18. Crystallised Aluminate of Magnesium and Silicium.
19. Manufacture of Adamantine Boron.
20. Plate of Crystals of Aluminium.
21. Blue Obsidian.
22. Obsidian coloured by Cobalt.
23. Samples of Crown Glass, extra white.
854f. Objective of Bock Crystal, 10 centimetres in dia-
meter. M. Lutz, Paris.
854g. Astronomical Glasses, for cabinets of physics.
M. Lutz, Paris.
855. Micro-spectroscope, with prism for comparing two
spectra, and with Abbe's measuring apparatus for the direct esti-
mation of the wave lengths of dark or bright lines in a spectrum.
C. Zeiss, Jena.
216 SEC. 7. LIGHT.
This spectroscope gives the position of the bright or dark lines by means
of a scale on which the spectrum is thrown, and which, by means of its peculiar
graduation and numbering, allows the wave length at any place to be read off
in micro-millimetres.
856. Apps> Improved Gas and Electrode Holder for
Spectrum Analysis. Alfred Apps.
857. Improved Automatic Chemical Spectroscope,
invented and made by the contributor. The object glasses and
prisms by Chas. Owen, Optician, Strand.
Rev. Nicholas Brady.
Prisms with a circular face are cemented to the object glasses of the
collimator and telescope, the circular face of the prisms being of the same
size as the object glass. The base is rectangular to the surface of the object
glass, and the refracting angle about 30. The beam of light rendered
parallel by the collimating lens passes through the first half prism perpen-
dicularly and suffers no refraction, but is refracted on emergence from its
exterior face ; the refracted and dispersed beam is received on the external
face of a second object glass prism, suffers more refraction and dispersion,
and, emerging at a perpendicular incidence, is taken up and brought to a
focus by the object glass. In all positions the ray under examination
passes parallel to the base of the prisms, and therefore at the angle of
minimum deviation. The variation of the angle between the two prisms by
the motion of the tangent screw of the telescope merely brings one ray after
another into the field of view. This automatic arrangement gives a dispersion
equal to one dense glass prism of 60. Should greater dispersion be required
a prism of 60 has been arranged in the centre of the instrument, which by a
very simple automatic contrivance of one lever and a slot is moved by the
arm carrying the telescope, so that any ray is still preserved at the angle of
minimum deviation. A further advantage of this new principle is, that with
these object glass prisms the field is completely filled with light, which has
not usually been the case, unless the prisms are extra large, and therefore
expensive ; and if a train of prisms be inserted their faces only require to be
equal for them still to entirely illumine the field : thus much light is gained.
and comparatively little is lost by absorption and reflection, as the surfar
are fewer, so that the violet end of the spectrum is very extensive, an(? vue
lines beautifully defined.
858. Gas Lamp Apparatus for placing before the slit of
the spectroscope with Bunsen burners, &c., insuring the proper
adjustment of the platinum wires carrying the substance under
examination in the flame without displacing the eye from the
ocular of the telescope; and also an arrangement for quickly and
efficiently exchanging one or both burners for either one or two
vacuum tubes. Rev. Nicholas Brady*
Two photographs accompany the instrument, shoAving its use in two
different positions.
859. Ordinary Spectroscope, arranged for the exhibition
of diffraction phenomena, with apertures and gratings, &c. of
various kinds, under common and polarised light, and with the
means of observing the spectra of the diffracted beam. Designed
and made by exhibitor. Rev. Nicholas Brady .
II. SELECTORS. 217
971c. Curve for obtaining Wave-lengths of Spectra; and
Map of the absorption spectra of bromine and iodine monochloride.
Professors Roscoe and Thorpe.
857a. Automatic Motion for the Spectroscope.
Walter Baily.
The apparatus consists of an axle and four parallel discs, the outer pair being
fixed, and the inner pair rigidly connected together, and capable of turning on
the axle. Between the inner discs are four arms, which also turn on the
axle.
Taking the centre of the axle as origin, each disc has 4 slits, the equation
to their middle lines being r = F(0), r = ^(*\ r = F (?) r = F (*)- The discs
in each pair are placed with their slits parallel, but the inner discs are turned
over. The arms have straight slits radiating from the axle. A pin is passed
through the first slits of the outer discs, the 4th of the inner discs, and the
slit in one of the arms. The remaining arms are connected with the discs by
three other pins inserted in a similar manner. The first and last prisms are
fixed on the initial lines of the outer and inner pair of discs respectively, and
the four other pi-isms are carried by the arms. Motion is given by moving
the inner discs. The angles at which the slits .cross are constant and differ
f\ / g~
least from right angles if F(0) = e~~ / , which is the form adopted in the
model.
859a. Photo-Spectra of Metals and Gases, obtained
with a Browning Direct-vision Spectroscope.
John Rand Capron.
These spectra were photographed with wet plates by J. R. Capron and
G. H. Murray, for use and reference in connection with auroral investigations.
The optical apparatus consisted of a Browning direct-vision prism, with, in
the case of metals, a collirnating lens of 6-inch focus, and a projecting lens
of 9-inch focus. For the gases a similar prism was used, with collirnating
and projecting lenses, each of 4-inch focus. The photographs are enlarged
to twice the originals. The electrical apparatus consisted of a 4^-inch spark
Ruhmkorff coil, worked by four half-gallon bichromate cells, a condenser of
four glass-coated plates, and spark terminals.
The spark was placed about half an inch from the slit. Mr. Lockyer's
plpn of interposing a lens was tried in some cases, but given up, as the long
and short lines were found to be equally well observed in the spark itself.
The gases were mostly in Geissler tubes. It is proposed in further experi-
ments to get rid of the air lines by taking the spark between the metal elec-
trodes in glass bulbs, through which a gas passes.
One of the spectra represents the spark between platinum electrodes taken
in a current of coal gas passing through a tube.
The dispersion of the direct-vision prism is as follows: A =17 '62;
B = 23'62; C = 30'42; D = 50; E = 77'35; F=103'90; G=159'73. With
the instrument as used for the gases, it is found possible to photograph
faint spectra satisfactorily.
b. POLARISCOPES, &C.
861. Jellett's Saccharometer, for the measurement of the
rotation which certain fluids are capable of producing in the plane
of polarisation of the transmitted ray. Trinity College, Dublin.
218 6EC. 7. LIGHT.
This rotation is measured by the method of compensation, the original
position of the plane being restored by transmission through a column of fluid
possessing an opposite rotatory power. This fluid is contained in a vessel
closed at the bottom with glass, and the length of the column is regulated by
means of a tube, aKso closed with glass, which is capable of moving in the
direction of its axis, the amount of this movement being read off on a scale.
A full description of the instrument and of the analysing prism used in its
construction is given in the " Transactions of the Royal Irish Academy,"
Vol. XXV., pp. 373-82.
86 la. Laurent Polarimeter and Sac char ometer, with
two divisions on the plate, with inversion tube and one thermo-
meter. Laurent, Paris.
86 Ib. Saccharometer, by Soleil, with penumbra (large
model). M. J. Duboscq, Paris.
861c. Large Circle, by Messrs. Jamin and Senarinont.
M. J. Duboscq, Paris.
86 Id. Large Circle for measuring the elements of elliptic
and rotatory polarisation in solids and liquids, and reproducing
all impressions of polarisation and refraction. (This apparatus
belongs to the School of Photography.) M. Lutz, Paris.
862. Polarising Apparatus, according to Dove's system,
complete, with polyoscope and dichroscope.
Schmidt and Haensch, Berlin.
863. Simple, handy Polarising Apparatus, according to
Carl's system. Schmidt and Haensch 9 Berlin.
864. Melde's Models, for illustrating the colours of thin
leaves in polarised light. Ferdinand Suss, Marburg.
865. Melde's Model, for illustrating circular polarisation
by means of gypsum and scales of mica.
Ferdinand Suss, Marburg.
866. Paste-board Models, according to J. Miiller's system,
for illustrating the colour phenomena in polarised light,
and the uni-axial and bi-axial crystals.
J. Wilhelin Albert, Frank for t-on- Maine.
Ten models of cardboard, together with a treatise on them. Described in
J. Mullens Lehrb. der Phys., 7 Aufl., I. Bd., 3tes. Buch, caps. 9 and 10."
867. Polarising Apparatus, for projection with rotatory
analyser, according to E. Mach's system, with quartz plate and J
undulation plate. (Comp. Poggendorff's Ann., 1875, No. 12.)
J. Wilhelm Albert, Frankfort-on- Maine.
The ray of sun or electric lamp falls through a Nicol, which is protected
with a shade, upon a press, in which the object is fastened by means of spring
clamps, and passes thence through a tube which can be rotated with great
velocity. This tube is provided at one end with a shade capable of rotating
II. SELECTORS. 219
with the tube, and the analysing Nicol over which there is a slit or a square
aperture.
At the end of the tube is a deflection prism of crown glass, to which, for
some investigations, a direct vision prism is added. The raj, as it issues from
the tube, is received by a lens, which throws upon a screen a sharp image of
the slit or square aperture. This image moves in a circle as the azimuth
changes, and thus shows by quick rotation all the phenomena which, in
ordinary polarising instruments, appear successively side by side.
868. Twelve Plates with Pictures, of gypsum and mica,
lor polarised light. Prof. Karsten, Rostock.
The form of images has been chosen to repi'esent the different colours of
thin plates in polarised light. Any kind of polarising apparatus may be
employed for these observations.
869. Norremberg's Polarising Apparatus, small size.
W. Apel, Gottingen.
870. Worremberg's Polarising Apparatus, large size ;
according to the design of Professor Listing.
W. Apel, Gottingen.
The apparatus serves not only for purposes of lecture demonstration,
but also for accurate measurements. The advantage of the instrument over
the ordinary polarising microscopes lies in the circumstance that in the
Norrembery apparatus the polarised light passes to and fro through the same
crystal plate, when placed on the horizontal mirror. The movable glass
plate of the middle table serves for measuring the angle of the optical axes
by means of a graduated semicircle.
87Oa. Large Apparatus by Norremberg, improved by Wheat-
stone. M. Luiz, Paris.
87Ob. Apparatus used for observing the Polarisation of
Light in Water. J. Louis Soret, Geneva.
It is formed of a telescope tube closed on the objective side by a glass
plate. The eyepiece is formed of a " Nicol " prism.
The observer, placed in a boat, immerses the objective end of the tube
and looks through the " Nicol." He then finds the light of blue coloration
reflected by the lower strata under the surface of the water, and by turning
the Nicol ascertains if it is polarised.
See " Notes sur la Polarisation de la Lumiere de 1'Eau." Archives des
Sciences physiques et naturelles, 1869, Vol. 35, p. 84, and 1870, Vol. 39.
p. 352.
871. Apparatus for the Observation and Measurement
of the cyclopolar double refraction of Quartz in the
direction of the optical axis. Designed by Professor Listing,
executed by R. Winkel in Gottingen.
Royal Mathematical and Physical Institute of the Univer-
sity of Gottingen, Prof. Listing.
The telescope can, before being put into the holder of the apparatus, be adjusted
for distant objects, or for an object of but 2-3 meters distance from the object
glass. The Fresnel triple quartz prism is fixed in upright position in the
support below the telescope, and protected by a cardboard shade against side
220 SEC. 7. LIGHT.
lights. By means of the achromatic lens, situated below the prism, a virtual
image is produced of an appropriate object (line cut by a diamond upon glass,
&c.), placed upon the black table, which image, Avheu seen sharp and double
in the telescope, will be just as distant from the object glass of the telescope
as the latter has been adjusted for. The angle of the two images is read
off on the micrometer in the eyepiece, and from the number obtained the
diversion of the two rays after their passage through the triple prism is
calculated. The ocular can now be provided with tourmaline and ^ mica
plate, which may be used singly or combined. The tourmaline alone shows,
on turning, in all azimuths, the double image without alteration of intensity
in the component parts ; the two rays undergo, therefore, neither linear (plain)
nor elliptical polarisation. The tourmaline with mica plate below it, shows,
as well known, that both rays are circularly polarised, the one right, the
other left; the tourmaline must in this case be so adjusted that its line of
principal action be azimuth or 90, and the main section of the interposed
mica plate is turned to form with that line +45.
The aim of the measurements is to determine the refractive indices of the
two rays of opposite circular polarisation, propagated with unequal velocity
along the optical axis of the quartz.
872. Stauro scope, according to the design of F. von
Kobell, executed by Wiedemann.
Prof. Dr. Franz von Kobell, Munich.
873. Analysing Prism of Iceland Spar, made by the
inventor, the late William Nicol, in his 80th year.
Edinburgh Museum of Science and Art.
The Nicol prism is so constructed that only one polarised ray can pass
through it.
873a. NicoPs Prism for Polarising Light, by C. D.
Ahrens. W. Spottiswoode, F.R.S.
This, which is one of the largest ever constructed, has a clear field of 3
inches in diameter. With a view to saving bulk and weight, the acute angles
have been cut off, and the whole reduced to an octagonal form. The
advantages of this will readily be seen by comparing this instrument with that
by Tisley and Spiller, the field of which is greater by only a quarter of an
inch.
873b. Nicol's Prism for Polarising Light, by Tisley
and Spiller. W. Spottiswoode^ F.R.S.
This, which is the largest and purest ever constructed, has a clear field of
fully 3^ inches in diameter.
874. Soleil-Ventzke Polarising Apparatus, with several
improvements. Franz Schmidt and ffaensch, Berlin.
Soleil having introduced compensation by the use of rock-crystal, Ventzke
subsequently improved the colour-giving power, and Scheibler made further
improvements, principally in the manner of inserting the observation tubes.
Messrs. Schmidt and Haensch, besides a few minor changes, succeeded in
making improvements which greatly facilitate the use of the instrument, by
a change in the construction of the wedges, and have thus reduced the irregu-
larities frequently observed in the polarisation of diluted solutions to from
one to two tenths per cent, in each part of the scale. They have thereby
II. SELECTORS. 221
done away with the principal cause of the variations which so frequently
occur in the observations of different analysts.
875. Jellett-Corny Half-shade Polarising Apparatus,
provided with wedge compensation.
Franz Schmidt and Haensch, Berlin.
This apparatus differs from the foregoing in having the double plate re-
placed by a double Nicol's prism. In using it both fields of the apparatus
are adjusted to equal half darkness, instead of equal colour, as in the " Soleil.
The double Nicol prism was first proposed by Professor Jelett, of Dublin,
and employed by Professor Corny in Duboscq's polarise ope for circular
polarisation, known as saccharometre a penoinbre. The improvement in the
instrument exhibited by Messrs. Schmidt and Haeusch consists in combining
with it their wedge-compensation, so as to obtain the advantage of lineal
readings. The instrument recommends itself for dark solutions ; it is indis-
pensable for colour-blind operators, and prevents the colour- weariness to
which the healthy eye is liable. Its sensitiveness perceptibly exceeds that of
a Soleil.
876. Wild's Polari-Strobometer.
Franz Schmidt and Hac?isch 1 Berlin.
877. Jellett-Corny Polarising Apparatus, constructed
for circular polarisation. Franz Schmidt and Hacnsch, Berlin.
877a. Handy Folariscope with Kicol prisms to show rings
in bi -axial crystals. W. Previte Orton.
This instrument was designed by the exhibitor and made for him by
Pastorelli. Its object is to utilize the Nicols of a small microscope so as
to show the effect of polarised light in a biaxial crystal ; and further, to do
this in a handy manageable and inexpensive form.
878. Mica-preparations of mono- and bi- axial mica, for
polariscopes. (See Mineralogy.) Max. Raphael, Breslau.
879. Mica-preparations of foliaceous mosses ("Laub-
moosen "), Algal, &c., for microscopes. Max. Raphael, Breslau.
879a. Quartz Axis Plates. M. Lutz, Paris.
b79b. Amethyst cut parallel to the axis. M. Lutz, Paris.
880. Dichroscopic Lens.
Four Nicol's prisms.
Prazmowski prism.
Two Tourmalines parallel to the axis.
Iceland spar of M. Bertrand's arrangement.
Quartz and mica for compensating the refraction of crystals.
Heated crystals, felspar, gypsum, carbonate of lead.
One blue glass, red glass, and green glass.
Billet lens on stand.
Laurent.
881. Ellipsometer. Before the eyepiece of the glass a
double refracting prism is made to turn until a wire, moving per-
222 SEC. 7. LIGHT.
pendicularly to the principal section of the prism, passes through
the two intersecting points of the two reflections of the ellipse.
An index shows at the moment the position of the prism.
882. Table Polariscope, made by the exhibitor when a
youth. Rev. Nicholas Brady.
The interest of this instrument consists in showing with what simple
materials a student can construct a fairly useful apparatus, the divided circles
being common stamped protractors ; the clamping screws, teapot thumb-
screws, and the mountings of the lenses ordinary simple microscope frames.
882a. Original Apparatus for Rotatory Polarization,
by Biot. College of France, Paris.
883. Airy's Polariscope, with appliances for approximately
measuring the angle between the planes of polarisation and analy-
sation, and for determining the angle between the optic axes of
bi-axal crystals in air or in a fluid medium. Modified and arranged
by the contributor when a student. Rev. Nicholas Brady, M.A..
88 3a. Large Folariscope for Projection, by Ladd.
W. Spottiswoode, F.R.S.
A pair of Nicol's prisms, by Ladd, the first of a large size ever constructed.
They are furnished with a system of lenses for showing the crystal rings, as
well as with other contrivances for the various phenomena of polarised light.
883b. Revolving Analyser for Folariscope, constructed
by Tisley and Spiller. W. Spottiswoode, F.R.S.
A revolving analyser, consisting of a double image prism, furnished with
wheel-work, whereby it may be caused to revolve with such rapidity that the
eccentric image may remain upon the retina during a complete revolution,
and thus give the appearance of a ring of light. By this means all the phases
of polarised light as seen successively in ordinary polariscopes may be seen
simultaneously. The instrument is adapted to show all the phenomena of
chromatic polarisation, both plane and circular. An instrument for a similar
purpose was invented independently by Prof. Machs, of Vienna.
883c. Portable form of Folariscope, comprising a Nicol's
prism, a double-image prism, a plate of tourmalin, a Savart's wedge,
a bi-quartz, a dichroscope, and a quarter undulation plate. These
various parts may be used either separately or in any combi-
nations at pleasure ; and are consequently adapted either to illus-
trate the general laws of polarised light, or for actual observations
of atmospheric or other polarisation not involving actual measure-
ments. It will be observed that the tourmalin plate gives the
opportunity of using convergent as well as parallel light. The
instrument is fitted in a case 2 inches long and ^ inch in diameter,
but its size might be considerably reduced below the dimensions
of the specimen here exhibited. Mrs. W. Spottiswoode.
IT. SELECTORS. 223
883cc. Spottis wo ode's Pocket Polarising Apparatus,
consisting of Nicol's prism, Savart's polariscope, tourmaline,
double-image prism, bi-quartz, dichroscope, and ^-undulation
plate. The Avhole is packed in a leather case, 2 inches long, by
| inch in diameter. W. Ladd fy Co.
883d. Large Circle for measuring the Azimuths of Ellip-
tic and Rotatory Polarisation, and reproducing all experi-
ments of polarisation and reflection.
School of Pharmacy, Paris.
883d. Polariscope for detecting faint traces of
Polarisation independently of its direction. The wedges
are right and left-handed quartz, with their axes parallel to that
of the instrument. The eye should be placed in the focus of the
lens, with the Nicol interposed. Designed by the exhibitor and
made by Messrs. Tisley & Spiller. K. H. M. Bosanquet.
883e. Arago's Polariscope. M. Lutz, Paris.
883f. Savart's Polariscope. M. Lutz, Paris.
883g. Tourmaline Plates. M. Lutz, Paris.
883h. De Senarmont's Polariscope. M. Lutz, Paris.
884. Wheatstone's Polar Clock. To determine the true
solar time by the polarisation of light reflected from the sky.
The Council of King's College, London.
885. Latest form of Wheatstone's Polar Clock. To
determine the true solar time by the polarisation of light
reflected from the sky.
The Council of King's College, London.
Soleil's Compensator. S. Laurent, Paris.
887. Norremberg's Polarising Apparatus, with Wheat-
stone's improvements. H. Lloyd, Trinity College, Dublin.
888. Duboscq's Polariscope, for determining the incli-
nation of the axes in bi-axial crystals.
//. Lloyd, Trinity College, Dublin.
889. Wheatstone's Apparatus to illustrate the laws of
interference of polarised light.
H. Lloyd, Trinity College, Dublin.
224 SEC. 7. LIGHT.
889a. Ladd's Polariscope, consisting of a bundle of glass,
selenite design, and Nicol's prism, &c. fjT. Ladd fy Co.
2531. Photograph of a Wild's Polari-strobometer, for
determining the rotation at different temperatures. The tube
containing the liquid is surrounded by a jacket, through which
water of a given temperature flows. The apparatus is manu-
factured by Messrs. Hermann and Pfister, Bonn.
Prof. H. Landolt, Aix-la-Chapelle.
2532. Photographs of a simple Polari-strobometer with
two Nicol's prisms, constructed for holding tubes, one meter in
length, containing the liquids which can be placed in a water-bath ;
and a blow-pipe lamp, over which is suspended a platinum gauze
cage for holding the sodium salt which is used for producing the
monochromatic sodium flame.
Prof. H. Landolt, Aix-la-Chapelle.
The lamp is manufactured by Dr. Meyerstein of Gottingen, and by Feld-
hausen, philosophical instrument maker, Aix-la-Chapelle.
2533. Photograph of the same apparatus, provided with a
short tube for holding the liquid. A bottle containing a solution
of potassium dichroraate is interposed between the tube and the
sodium flame, to ensure a purer monochromatic light.
Prof. H. Landolt, Aix-la-Chapelle.
III. PHOTOMETERS.
891. Great Atmospheric Photometer. De la Rive model,
designed by M. Thury, and constructed by the Geneva Associa-
tion for the Construction of Scientific Instruments.
De la Rive Collection. The property of Messrs. Soret,
Perrotj and Sarasin, Geneva.
This apparatus is particularly intended to measure the transparency of the
atmosphere. It is used for simultaneous observation, with one eye, through
two similar eyepieces of two similar objects placed at different distances.
The difference of brightness and of tint between the two reflections indicates
the effect of the intervening stratum of air. The computation of this differ-
ence is arrived at by equalising the two images by means of diaphragms of
different aperture, and of glass plates variously tinted. The instrument is
composed of a telescope with a single eyepiece, and two objective tubes,
of which the angular distance can be varied between and 29. A system
of four total reflection prisms unites the two divergent cones in the eyepiece.
The apparatus is movable round three different axes, and may be worked in
the most varied directions. Graduated circles measure these different angular
motions. It is a general photometer, and can be specially used as an astro-
nomical photometer. De la Hive has effected with it a long series of obser-
vations on the transparency of the air. (See Comptes Rendus, vol. 63,
p. 1221.)
IV. llADIOMETEliS. 225
892. Photometer, according to Glan's system, for photome-
trical determination of the absorption spectra for homogeneous
light. Schmidt and Haensch, Berlin.
892a. Photometer, fitted with clock, governor, pressure gauge,
and all necessary apparatus complete, as adopted by the Govern-
ment of Canada. William Sugg.
893. Photometer by Bunsen, simplified by Professor Bonn.
Physical Collection of the University of Giessen, Prof.
Buff.
The standard for comparison is a pure stearine candle of known weight.
The measure wound upon the cylinder serves to determine the distance at
which the oil spot on the paper, when viewed from the second flame, is
made to disappear. First the standard caudle, and then the flame, to be
measured, are thus investigated. The intensities of the two lights are to one
another as the squares of their distances from the oil spot.
894. Photometer, for ascertaining amount of daylight.
Scottish Meteorological 'Society.
The light is reduced by turning round the graduated milled head at the
side, which works simultaneously and by equal degrees the two shades which
thus reduce the area of the aperture. At the opposite end of the box a
printed page is looked at through the eye-piece till it ceases to be legible,
when the result is read off in revolutions of the milled-head. Designed by
Thomas Stevenson, C.E., F.E.S.E., Honorary Secretary, and described in
Society's Journal, vol. iii., page 292.
895. Selenium Photometer. Siemens and Halske, Berlin.
It being the property of selenium that its electrical resistance is diminished
by the action of light, the diminution being dependent on the intensity of
the light, this apparatus is constructed with a plate of selenium forming part
of an electric circuit which is brought by rotating the cylinder containing the
plate alternately under the action of a normal candle sliding on a scale and of
the light to be measured. The normal light is adjusted on the sliding scale
until the electrical resistance of the selenium remains constant under the
action of the two sources of light, and the intensity of the light to be mea-
sured is calculated from the relative distances of the lights from the selenium
plate.
896. New Optometer, with double-refracting lens of calc-
spar, giving double readings, and greater precision in determining
the distance of sight. Prof. Carl Wenzel Zenger, Prague.
IV. RADIOMETERS.
899. Collection of Radiometers of different construction,
with lamps and screen for making experiments.
Prof. Adolph Weinhold, Chemnitz.
40075. P
226 SEC. 7. LIGHT.
The apparatus serves to perform the radiometer experiments, described
by the exhibitor in Carl's "Kepert. der Experimental Phys., 1876, Heft. 2."
Compare also the description annexed to the apparatus.
900. New Radiometers. Dr. H. Geissler, Bonn.
901. Radiometer. John Browning.
These instruments are set in motion by either light or heat ; they consist of
four small discs on two arms at right angles to each other ; the discs may be
of pith or mica ; those exhibited are made of mica, as the} r appear to be the
most sensitive to minute traces of light. One side of each disc has a dead
black surface. The action of light or heat repels the black surfaces, and
continuous motion is obtained so long as any light or heat faDs on them.
902. The late Prof. T. T. Miiller's Apparatus for
illustrating the influence of the intensity of light on its rapidity
of propagation (Poggendorff's Annalen, 1872, cxlv. p. 86.)
Prof. A. Mottsson, Zurich.
Use is made of Newton's rings, produced between a plane glass a, and
another glass b (the latter very slightly convex), which may be separated
in a known manner so as to produce differences of progression up to
50,000 waves. At this distance, the convex glass b, on which a rested at
first, radiates in the centre of a square iron vessel c on mercury. The three
screws of the support d which surrounds the glasses are fixed apart. Then,
the mercury having been allowed to flow out (through the cock 6), c is
brought down and fixed also, by means of three other screws y. The
distance can be calculated with great precision by means of the weight of
the mercury, and the known area of the vessel c.
The luminous point used is the small image at the opening of a collimatiug
tube e, lighted by a monochromatic sodium flame, upon the hypothenuse
surface of a small prism y*. From this point the rays diverge and fall on
the lens g, placed on the glass c, which makes them parallel. These rays
return, with interference, from the two reflecting faces, towards the pointy,
where the eye is placed close to the prism.
Now, if the intensity of the light be lessened by interposing absorbing
glasses, it will be seen that the greater the difference in the number of waves
the more the lines change place, the increase of rapidity being proportionate
to that of intensity.
V. REFLECTION, REFRACTION, AND DIFFRACTION.
903. Total Reflection Apparatus, for the projection of
objects placed in a horizontal position.
J. and A. Molteni, Paris.
904. Small Prism for double reflection. Laurent.
905. Coloured Rings on an 80 millimetre tripod.
Laurent.
905 a. Fresnel's Parallelepiped. M. Lutz, Paris.
V. REFLECTION, ETC. 227
908. Apparatus designed to exhibit Double Reflection,
which arises when a ray of light traversing a uui-axial or bi-axial
crystal readies the surface of contact of the crystal with the
surrounding medium. Arthur Hill Curtis.
The incident light passes through a small orifice in the cap terminating
one of the tubes. If the eye be applied to the other tube, as the stage on
which the crystal resls is turned round its vertical axis, four, three, or two
images of the orifice will be seen formed by the tAvo rays which, refracted at
the upper surface, are (in general) each doubly reflected at the lower sur-
face. A Nicol's prism is added, which, though not essential to viewing the
phenomena, may be introduced into either tube to polarise the incident
light, or to examine the planes of polarisation of the reflected rays.
I. Sphere of Calcite, 3J inches in diameter.
II. Polyhedron of Calcite, cut from a large rhombohedron
of that mineral, so as to represent the optical characters of the
crystal in directions perpendicular
1 . To the pinakoid, and along the optic axis.
2. To a prisrn plane, and perpendicular to the optic axis.
3. To the cleavage planes (of the rhombohedron) {100}.
4. To the plane {122} correlative to the cleavage rhombohedron.
(These were made by Mr. Ahreris.) ^ r f> N. S. Mashelyne.
909. Dichroic Apparatus. A. ffilaer.
910. Iceland Spar Prism, of 60, showing single refraction
for any line in the spectrum. A. ffilaer.
91Oa. Two Hicol's Prisms. South Kensington Museum.
911. Prism, with Double Reflector, of Dr. de Wecker.
Two triangular prisms are joined together at their hypothenuse;
while the observer looks directly through the cube formed by the
union of the two prisms, an observer looking obliquely sees in the
hypothenuse the reflection of the former as though in a mirror.
The lens serves to show the reflection smaller and reversed.
M. Cretes, Paris.
912. Prism, Movable, by Cretes. Two prisms of 15
each are placed in a setting. When placed base on edge, their
refraction becomes annulled: (15 15=0). When placed base
to base, their effect becomes added: (15 + 15=30). Between
these two extremes, an ascending scale of to 30 can be
obtained. The prismatic axis remains fixed, because the glasses
move equally in reverse ways. M. Cretes^ Paris.
912a. Three Rectangular Prisms, crown glass.
M. Lutz, Paris.
912b. 32 Rectangular Prisms, flint glass of various sizes.
M. Lutz, Paris.
P 2
228 SEC. 7. LIGHT.
912c. Prisms for Camera. M. Lutz, Paris.
912d. Prisms with Compartments. M. Lutz, Paris.
912e. Prisms with Compartments. M. Lutz, Paris.
912f. Bi-refracting Spar Prisms. M. Lutz, Paris.
912g. Rhomboids of Spar. M. Lutz, Paris.
912h. Collection of 12 Nicol Prisms. M. Lutz, Paris.
9121. Four Large Nicol Prisms. M. Lutz, Paris.
912j. Prisms for M. Desain's Experiments.
M. Lutz, Paris.
912k. Uranium Glass Prisms. M. Lutz, Paris.
9121. Uranium Glass Cube. M. Lutz, Paris.
912m. Three Quartz Prisms. M. Lutz, Paris.
91 2n. Prisms for Spectroscope (direct vision).
M. Lutz, Paris.
912o. Prisms for Spectroscope (direct vision).
M. Lutz, Paris.
912p. Two Pyramidal Prisms. M. Lutz, Paris.
912 q. Three Flagon Prisms. M. Lutz, Paris.
91 2r. Four Poly prisms. M. Lutz, Paris.
912s. Four Prisms for Bisulphide of Carbon.
M. Lutz, Paris.
912t. Two Isosceles Prisms of Flint Glass.
M. Lutz, Paris.
912u. Three Foucault's Prisms. M. Lutz, Paris.
91 2 v. Two De Senamont's Prisms. M. Lutz, Paris.
91 2 w. Three Braszinowski and Hartnack's Prisms.
M. Lutz, Paris.
912x. Six Hochon's Prisms. M. Lutz, Paris.
912y. Boit's Prism. M. Lutz, Paris.
912z. Large Flint Glass Prism, extra denticulated, set in
a peculiar manner. M. Lutz, Paris.
913. Instrument to show the phenomenon of conical re-
fraction, with models of FresnePs wave surface. (Soleil, Paris.)
ff. Lloyd, Trinity College, Dublin.
V. REFLECTION^ ETC. 229
914. Jamin's Optical Bank of Diffraction.
//. Lloyd, Trinity College, Dublin.
914a. Jamin's Apparatus with Parallel Mirrors.
M. Lutz, Paris.
914b. Large Steel Mirror. M. Lutz, Paris.
914c. Series of Barton's Iris Buttons, consisting of
gold and steel faces engraved upon which are numbers of very fine
lines, illustrating most beautifully iridescence or decomposition of
light from ruled surfaces. The lines on the large steel button
are 100, 200, 400, 500, 1,000, 2,000, and 4,000 to the inch.
Robert C. Murray.
915, Optical Bank, improved by Professor Clifton, to
observe the interference and diffraction of light and measure the
bands. Elliott Brothers.
915b. Collection of Six Gratings (reseaux} by Nobert of
Barth, and Steeg of Homburg. Teylcr Foundation. Haarlem.
Nobert B. of 1,801 lines in six Fans lines.
C. of 3,001
D. of 10,801 in one Paris inch.
E. of 2,001
F. of 3,001
Steeg A. of 3,201 lines in five millimetres.
Robert B and C were used by Prof. Van der Willigen for the determination
of the wave-lengths of fifty lines in the solar spectrum.
91 5c. Specimens of Circular Gratings (Reseaux) photo-
graphed on Glass. The rays of the successive circles limiting
the opaque and transparent parts are in the proportion of 1 to
4/2, */3, 4/4, 4/57 &c.
91 5d. Large Circular Grating on smoked Glass, trans-
parent traces of equal width, having rays in the proportion of
V 3, 4/7, 4/lT, </15, 4/T9, &c. J- Louis Soret, Geneva.
See " Memoire sur les Phenomenes de Diffraction produits par les Reseaux
circulaires" (Archives des Sciences physiques et naturelles, 1875, Vol. 52,
p. 320. Poggendorffs Annalen, 1875, No. 9).
915e. Telescope with Circular Gratings. Constructed
by the Geneva Association for the Construction of Scientific In-
struments. J* Louis Soret, Geneva.
1st arrangement. The smoked glass grating is used for objective with a
common eyepiece. Looking at a gas jet (for instance) at seven metres
distance, the distance of the objective and the eyepiece being from 34 to 41
centimetres, then pulling out one of the tubes the image of the jet is seen
reversed, and coloured more or less. By pushing in the tube as much as
possible, the second image is seen green-coloured.
230 SEC. 7. LIGHT.
2nd arrangement. A common objective is used, and for eyepiece the small
photographic grating. The distance from the objective to the eyepiece
being of 50 centimetres (maximum length of the telescope), the image of the
gas jet, reversed, is obtained as in an astronomical glass. By pushing in the
tube to 31 centimetres, the direct image' is got as in the Galileo telescope.
(See Memoire sur les Phenomenes de Diffraction produits par les Reseaux
circulates, Archives des Sciences physiques et naturelles, 1875, vol. 52, p.
320.)
915f. Diffraction Grating on speculum metal. A. Hilger.
916. Refractometer, according to Abbe's system, for de-
termining the refractive indices, and the dispersion of any kind
of liquids. Carl Zeiss, Jena.
The refractometer enables the determination of the refractive index of a
liquid to be effected up to four decimals with a single drop of the substance.
The readings refer to line D, and are read off from a graduated sector.
917. Procentum Refract ometer, for determining the per-
centage of solutions and mixtures by optical means.
Carl Zeiss, Jena.
The instrument is designed for liquids -whose index lies between 1 3
and 1 4. The determination takes place at a numbered scale in the field of
view of a small telescope. Besides the scale for the absolute index of re-
fraction, there is another scale, which gives directly the per-centage strength
of saccharine liquor.
91 7a. Refractometer by M. Jamin.
Polytechnic School, Paris.
917b. Jamin's Interference Apparatus with two
Spars. M. Lutz.
91 7c. Refraction Goniometer, constructed by the Rev.
Baden Powell, and used in some of his experiments, and after-
wards by the Rev. T. Pelham Dale and Dr. Gladstone in their
earlier researches on refractive indices of liquids at different tem-
peratures. Mrs. Baden Powell.
919. Abbe's Refractometer, for determining the power of
refraction of different liquids as far as the fifth decimal, with direct
reading of the refractive index, without calculation. (Comp.
Abbe : " Neue Apparate.")
Franz Schmidt and Haensch, Berlin.
921. Apparatus on J. Miiller's Principle, for Experi-
ments on the Refraction of Rays of Light in Fluids.
Warmbrunn, Quilitz, and Co., Berlin.
92 la. Apparatus by M. Mascart for studying the Re-
fraction of Gas.
M. Mascart, Professor at the College of France.
VI. FLUORESCENT BODIES. 231
92 la. Drawing of the Apparatus used in 1842 by Prof.
Daniel Colladon to show the total refraction of light in the interior
of a vein of water. See Comptes Rendus, vol. 15, p. 800.
Prof. Daniel Colladon, Geneva.
This remarkable experiment was made on a large scale by the French
Government on several occasions at public festivals.
92 lb. Apparatus for determining the Refractive Index
of Solids and Liquids.
C. CzechovicZj Teacher of Physics at the Gymnasium,
Be lost ok, Russia.
Consists of a horizontal board and vertical divided pillar with movable
support for a telescope. The body under examination is put on a glass plane
attached over a slit in the board, through which a light beam is reflected by
an inclined mirror. A linear mark made on the upper surface of the glass
(if the body is solid), or on the upper surface of the vessel (if the body is
liquid), is brought in coincidence with a movable wire which touches the
upper plane of the body. The distance of this wire and the height and incli-
nation of the telescope give the necessary data for calculating the index with
sufficient approximation.
VI. FLUORESCENT BODIES. '
922. Fluids showing the Phenomenon of Fluorescence.
Charles Homer.
A. Soda salt of anthracene in water.
B. Fluore seine in water.
C. Eosine in water.
923. Fluids showing the Phenomenon of Fluorescence.
Charles Horner.
Small Tubes in Stand.
D. Turmeric in castor oil.
E. Harmaline in water.
F. Magdala red in alcohol.
G. Ebony wood (Amerimuum ebenus) in castor oil.
H. Induline in chloroform.
I. Esculine in water.
K. Camwood (JBaphia nitida) in castor oil.
L. Esculetine in water with alkali.
M. Fraxine (Fraxinus excelsior) in water.
N. Fustic (Madura tinctoria) in solution of alum.
924. Selection of eight fluorescent liquids.
Dr. Th. Schuchardt, Gorlitz.
Eosine. Extract of Cuba- wood.
Magdala Red. Aesculine.
Saffranine. Bichloranthracine.
Fraxine. Bisulphurous acid.
232 SEC. 7. LIGHT.
VII. PHOTOGRAPHY.
a. PHOTOGRAPHIC PROCESSES.
925. Frame containing glass negative, gelatine "relief,"
leaden " mould," and impression from the latter, showing the
various stages in the production of a "Woodbury" permanent
photograph.
Woodbury Permanent Photographic Printing Company.
926. Frame containing transparencies for the magic lantern,
printed by the " Woodbury " process.
Woodbury Permanent Photographic Printing Company.
927. Specimens of Willis's Aniline Process. Printed
from tracings by Vincent Brooks, Day and Son.
William Willis.
This is a method of photographic printing differing greatly from all other
kinds in the chemical actions involved and in the manipulations required. The
blacks of the picture are produced by the action of aniline vapour on free
chromic acid ; the paper having been first coated with the latter substance,
and exposed to light under the drawing to be copied. On placing this
exposed sheet in a chamber filled with aniline vapour the yellow unaltered
chromic acid becomes speedily blackened, and produces a permanent print.
No negative is required, but a positive print is obtained by one operation
from a positive original. The principal application of the process is the
copying of engineers' and architects' tracings.
928. Willis's Platinum Printing Process.
Wm. Willis.
This is a method of photographic printing by which the picture is made to
consist of platinum black instead of silver. The reduction of the platinum
salt, with which the paper is coated, is effected by the action of light on a
persalt of iron, which forms an additional coating to the paper, followed by
a floating of the print on a solution of potassic oxalate.
928a. Illustrations of the Heliotype Process.
B. J, Edwards and Co.
The photographs are printed in printers' ink, at an ordinary printing press,
from a film of gelatine, to which the photographic image has been transferred
by the action of light.
1. Gelatine film ready for exposure to light under the negative.
2. Film laid down upon a metal plate and inked up ready for printing
from.
3. Troof in permanent ink from the same film.
928b. Photograph Reproductions.
1. Embroidered stuff on velvet ground.
2. Faience dish, after Bernard Palissy.
3. Blue framed enamel, pate tendre de Solon.
4. Louis XIV. shield, repousse copper.
5. Incense-burners, silver filigree, enamel and stones.
VII. PHOTOGRAPHY. 233
6. Mirror, silver-gilt and precious stones.
7. Tobacco jar, gold and silver.
8. Holy -water vessel, Limoges enamel, with frame and
precious stones.
9. Hunting knife handle, silver and stones.
10. Byzantine dish, repousse copper.
11. Aliotide shell, from nature.
12. Cup, silver and rubies.
13. " The First Fable," after the oil painting by Simonetti
(Salon de 1875).
14. "After Action," after the oil painting by Marchetti
(Salon de 1875). M. Leon Vidal, Paris.
928c. Specimens of Dallastype. D. C. Dallas.
928d. Specimens of Dallastint. D. C. Dallas.
928e. Specimens of Chromo- Dallastint. D. C. Dallas.
928f. Specimens of Carbon transparencies.
Col. Stuart- Wortley.
928g. " Cleopatra," a solar enlargement on salted paper, by
R. Fenton, from a photograph of the original in the National
Gallery. Robert Sabine.
928ee. Chromo-Woodbury Type, combination of Wood-
bury type with chromo-lithography. Walter B. Woodbury.
928ef. Kaleidoscopic Photograph of Ferns.
Walter E. Woodbury.
92 8h. Seven Photographic Prints on Salted Paper,
from Waxed Paper Negatives.
Two views of Windmill for reflecting stereoscope, by B. B.
Turner.
Two views of the First Post on the road from Kief to Moscow
by R. Fenton, for reflecting stereoscope.
Two views of a Russian Cottage, for reflecting stereoscope, by
R. Fenton.
View of ruined Interior, by Le Gray. Robert Sabine.
92 8j. Two Sheets of Photographic Prints, by the Iron
and Uranium process. M. Niepce de St. Victor, 1857.
Robert Sabine.
928k. Five Sheets of Photographic Prints, from waxed
paper negatives on albumenized paper, by R. Fenton.
Robert Sabine.
9281. Ten Photographic Prints from waxed paper nega-
tives on albumenized paper, 1853. Robert Sabine.
234 SEC. 7. LIGHT.
928m. Two Sheets of Talbotype Prints from waxed
paper negatives. Robert Sabine.
928n. Two Views for the Reflecting Stereoscope;
the varnish used to render the prints transparent, having preserved
the details of image from fading. Robert Sabine.
929. Specimens of Dujardin's photo-engraving process.
Dujardin, Paris.
930. Specimens of Photo-type Printing on Zinc.
Capt. Abmy, R.E., F.R.S.
931. Gillot's Photo-type Process. Veuve Gillot.
932. First known Photograph on Glass, taken on pre-
cipitated silver chloride, by Sir J. Herschel (Slough, 1839.)
Prof. A. S. Herschel.
" Having precipitated muriate of silver in a very delicately divided state from
water very slightly muriated it was allowed to settle on a glass plate ; after 48
hours it had formed a film thin enough to bear drawing the water off very
slowly by a siphon, and drying. Having dried it I found that it was very
little affected by light, but with washing with weak nitrate of silver and drying
it became highly sensible. In this state I took a camera picture of the tele-
scope on it. Hyposulph. soda then poured cautiously down washes away the
muriate of silver, and leaves a beautiful delicate film of silver representing the
picture. If then the other side of the glass be smoked and black varnished
the effect is much resembling daguerreotype, being dark on white as in nature,
and also right and left as in nature, and as if on polished silver." Sir J.
Herschel (MS. Journal of Experiments).
937b. Original Book of Experiments made by Sir J.
Herschel on the Metallic Salts sensitive to Light.
Prof. A. S. Herschel.
933. Second Daguerreotype Proof, obtained by Daguerre
in 1839. Conservatoire des Arts et Metiers, Paris.
Lithographic Stone of Poiteven, with a proof on paper.
Conservatoire des Arts et Metiers, Paris.
935. Photographs by Daguerre. M. Fizeau, Paris.
937. Specimens illustrating the History of Photo-
graphy. French Photographic Society, Paris.
937a. Daguerreotype full-length Portrait, taken in Paris
in 1840, by special appointment, on the roof of a house in the
open air, at 6 a.m. Exposure 20 minutes, in June sun.
James Martin.
938. Instantaneous Photograph. Waves breaking on the
shore of Britain in 1876. James Martin.
939. Engravings with the Aid of Photography.
MM. Goupil et Cie., Paris.
VII. PHOTOGRAPHY. 235
Proofs obtained by impression with fatty ink on copper plates engraved by
hand, the lines on which are obtained by means of a photographic negative,
with the use of chemical substances sensitive to the action of light.
1. " Pollice verso," after the painting by Geronie.
2. " L'eminence grise," do. do.
3. " Rembrant dans son atelier " (Rembrant in his studio), after the painting
by Ger6me.
4. " II Decamerone " (The Decameron), Sorbi.
5. "La rentre"e au Convent " (The return to the Convent), Zamacois.
6. " Le premier coup de canon" (The first cannon shot), Berne, Belle -
wurt.
7. Part of the colonnade of the Louvre, from nature.
8. Reproduction of a mineralogical fragment, from nature.
9. Frame containing the two plates from which proofs Nos. 7 and 8 were
printed.
940. Photographic Prints, in ink. Thiel Aine, Paris.
CLASS THE IST.
1. Reproduction of water-colour painting A cow, after Troyon.
2. chalk drawing Park of the Marquis de Megrigny,
after Lalauue.
3. chalk drawing An old courtyard at Colombes, after
Lalanne.
4. oil painting The Resurrection, after Lazerges.
5. chalk drawing Borders of the Rhine at Mulhouse,
after Niederhausen.
chalk drawing Ruins of a temple, after Lalanne.
7. oil painting Presenting the Bride, after de Boucher-
ville.
CLASS THE 2ND.
8. Reproduction of chalk drawing In the park at Plombieres, Vosges,
after Allonge. (Salvon, 1875.)
9. of chalk drawing Rocks and lake, after Appian.
10. from nature Church of St. Augustin, Paris.
11. Opera-house, Paris.
12. Notre Dame, Paris.
13. of chalk drawing Borders of the Lake of Arandoii,
after Appian.
14. of chalk drawing Borders of a pond, after Allonge.
CLASS THE 3RD.
15. Reproduction of terra-cotta Marguerite with the jewels, after
Carrier-Bellenze.
of oil painting The imprisoned loves, after Chaplin.
17. from nature Study of foreground, stereotyped on
paper of Mr. H. Le Secq.
18 from nature Cathedral of Rheims, stereotyped on
paper of Mr. H. Le Secq.
19. of chalk drawing The Bois de Boulogne, after
Lalanne.
20. from nature Cathedral of Rheims, stereotyped on
paper of Mr. Le Secq.
21. from nature Study of foreground, stereotyped on
paper of Mr. Le Secq.
of oil painting The death of Asala.
23. of drawing Head of Christ, after Lazergues.
236 SEC. 7. LIGHT.
CLASS THE 4TH.
24. Keproduction of oil painting Diana's toilet, after Devedeux. (Imi-
tation of photography with salts of silver.)
25. from nature A hawk ; still life. (Imitation of photo-
graphy with salts of silver.)
26. from nature Sevres vases. (Imitation of photography
with salts of silver.)
27. from nature Naumachy in the Park Monceaux. (Imi-
tation of photography with salts of silver.)
28. of chalk drawing The borders of the Yeres, after
Allonge.
29. ,, from nature The bridge of Solferino, Paris. (Imita-
tion of photography with salts of silver.)
30. from nature Sevres vases. ( Imitation of photography
with salts of silver.)
31. of a print Musings, after de Moussy.
32. of terra-cotta The Mountebank's, after Deca.
943. Photo-lithography Process of Simonan and
Toovey. Veuve Simonan and Toovey.
1. Plan of the town of Liege.
2, Portrait of Archbishop St. Lambert, after an old engraving.
3-7. Topographical plans, photographed by Capt. Hanot.
8-13. Six drawings of the " Campagnie des bronzes " at Bruxelles.
14-15. Two reproductions from a line drawing by Licot de Nivelles.
16-19. Four archaeological drawings.
20. Frontispiece of an ancient MS.
This is a photo-lithographic process, and depends on the fact that if gum
be mixed with potassium dichromate, and when dry be exposed to the action
of light, it becomes insoluble. A paper is coated with gum and potassium
dichromate, and exposed under the negative of a line subject, or under an
etching on glass, having a non-actinic ground. When light has sufficiently
acted, the paper which has a faint impression of the lines is placed under a
pile of damped paper on the surface of a polished lithographic stone, and sub-
mitted to pressure for about an hour. The paper is then removed from the
surface of the stone, the insoluble part forming the lines coming away with
it. The lines of the engraving are thus left ungummed on the stone. A little
olive oil is brushed over the surface, when the gum on the stone has been
allowed to dry in a dark room. The surface is next washed, which dis-
solves away the gum, leaving the lines of the picture only. The stone
is then rolled up with a lithographic roller, and is ready for giving impres-
sions.
944. Specimens of Paul Pretsch's Photo-typography.
Warren De La Rue, F.R.S.
945. Electro-chemical Process for reproducing lithogra-
phic impressions on copper. M. Erhard.
A proof freshly pulled from an autograph, lithograph, auto-lithograph, or
a copper-plate which is intended to be reproduced, is, by this process, trans-
ferred to a copper- plate, and furnishes in a few minutes an intaglio copy of
the plate, as clean and good as the original, Avhich is in no wise injured by
the operation.
By means of this process : firstly, it is unnecessary to preserve the cum-
brous and fragile lithographic stones ; secondly, a plate in use may be repro-
vn. PHOTOGRAPHY. 237
duced so as to ensure repeated impressions ; thirdly, corrections may be made
on the copper, which could not be made on the original plate, -worn by
repeated working. The cost of reproduction on copper by Erhard's process
is small, and may be estimated at about 3 to 5 centimes per square centi-
metre.
1 . Album containing 36 maps and plans reproduced by this electro-chemical
process.
2. 10 copper plates obtained by this process, the impressions from which
are shown in the album.
946. Photoglyphic engravings, 1853.
H. Fox Talbot, F.R.S.
947. Silver prints of views in Knoll Park.
School of Military Engineering, Chatham.
947a. Proof by Papyrotype Process.
School of Military Engineering, Chatham.
947b. Specimens of Enlarging Process.
School of Military Engineering, Chatham.
948. Second Proof of Photographic Engraving,
obtained by M. Fizeau, without retouching, in 1843, and printed
in greasy ink. M. Fizeau, Paris.
949. Daguerreotype Proof, fixed by M. Fizeau's process
with chloride of gold, by Hubert, in 1840. M. Fizeau, Paris.
949a. Daguerrean Print, obtained by the continuous action
of red rays, without mercury. M. E. Becqucrel.
950. Photochromic Proofs (selection). M. Vidal, Paris.
951. Early Talbotypes.
The Council of King's College, London.
95 la. Specimens of Enamel Process. Wm. Mayland.
952. Table of Specimens of Historical Records of
Photography. French Photographic Society.
952a. Application of Photography to Cartography.
The Topographical Department of the Imperial Hussian
General Staff, St. Petersburg.
In the application of the negative process, Rupell's drying system, with
tannin, has been employed. The positive prints are either black silver copies
or blue iron pictures : preference is given to the latter if the photograph is
to be traced over with Indian ink, and the photographical ground to be
removed afterwards by etching for the purpose of producing a clean drawing.
1 . Reproductions of Central Asiatic surveys and maps.
2. Copies of plates of survey sheets in European Russia.
238 SEC. 7. LIGHT.
952b. Photolithography.
The Topographical Department of the Imperial Russian
General Staff, St. Petersburg.
Transfer on stone of a printing picture, well covered with ink, which has
been produced on a gelatine ground rendered primarily sensitive by double
chromate of potash.
Reproduction of a Hebrew manuscript of the 10th century, belonging to the
Imperial Russian Public Library.
952c. Helio-Engraving. Sediment of galvanic copper on a
photographical gelatine relief.
The Topographical Department of the Imperial Russian
General Staff, St. Petersburg.
Copies of a heliographical edition of the survey of Bessarabia, on the scales
of 1 : 100,000, and 1 : 126,000, and the survey of Finnland, scale, 1 : 42,000;
map of Khiva, scale, 1 : 580,000, transferred on stone, and prepared as colour
print.
952d. Examples of Heliographic and other Processes.
Imperial Establishment for the preparation of official
papers, St. Petersburg.
1 . Portfolio of heliographic copper-plate and mezzo-tint engravings by the
process of G. Scamoni (manager of the Heliographic Department of the
Establishment), containing :
27 reproductions of historical portraits ;
10 reproductions of fine engravings ;
12 reproductions of etchings ;
8 reproductions of drawings executed with pen and ink, water-colour,
and crayon ;
17 reproductions of pen and ink drawings ;
6 reproductions of wood engravings.
2. Heliographic plate in electrotyped copper.
3. Heliographic plate in electrotyped iron.
4. Typographic printing form in electrotyped iron, from type.
5. Typographic printing form in electrotyped iron, net-work from type.
6. Typographic printing form in electrotyped iron, net-work from relief.
7. Typographic printing form in electrotyped iron, guilloched net-work.
8. Typographic printing form in electrotyped iron, id-annealed.
9. Glass plate, with the surface irregularly broken up into floral and
other forms through a coating of gelatine ( millimeter thick), springing up
from it when dried at a temperature of about 70 C., thereby producing a
form from which an inimitable printing-plate can be made.
10. Handbook of heliography, by G. Scamoni.
b. PHOTOGRAPHIC APPARATUS.
953. Photographic Lenses for Landscape, Architec-
ture, and Copying, showing progressive improvements from the
original single meniscus lens :
(a.) Single meniscus lens, used from 1851 to 1861.
(b.) Triplet, consisting of front combination. Double convex
crown and plane concave flint ; middle combination.
VII. PHOTOGRAPHY. 239
Double convex crown and double concave flint ; back
combination. Double concave flint, and double convex
crown. Used from 1861 to 1864.
(c.) Doublet, consisting of front combination. Double convex
crown and double convex flint ; back combination,
meniscus crown and concavo-convex flint. Used from
1864 to 1874.
(d.) Symmetrical lens, introduced in 1874, and consisting of
front combination. Concavo-convex and meniscus lenses ;
back combination, exactly similar, the denser element
being on the outside in both cases. fioss fy Co.
954. Photographic Lenses for Portraiture, showing
the progressive improvements from 1839 to present date :
(a.) Original compound portrait lens. The first lens made in
England by Andrew Ross for daguerreotype portraiture in
1839.
(b.) Compound portrait lens, with Waterhouse diaphragms, in
front, Date 1851.
(c.) Compound portrait lens, with Waterhouse diaphragms,
giving a flat field. Date 1858.
(d.) Compound portrait and group lens, giving a* flat field, and
straight marginal lines. Date 1874. Ross $ Co.
954a. New Tourists 9 Photographic Apparatus for taking
Wet Plates without the use of Dark Teat, all baths and
chemicals being placed in water-tight compartments under body of
camera. Harvey ', Reynolds, and Company.
954b. Photographic Lens with which the pictures of
Mr. Fox Talbot's Pencil of Nature were taken. (This is the first
publication of photographs printed from negatives on paper.)
Presented. B. B. Turner.
955. Photographic Apparatus. " Poor man's photo
graphy," for wet collodion negatives of the smallest possible size,
but rapid and well defined. Twelve examples of negatives, 1
inch square, two framed and magnified positive copies, and the
bath-holder in which these negatives were taken.
Prof. Piazzi Smyth.
These negatives are on microscope slide glasses, and were taken with a lens
of rather less than 2 inch solar focus by Professor Piazzi Smyth, in Egypt, in
1865. They represent scenes inside the Great Pyramid by magnesium light,
and outside it by daylight, including, in one of them, camels in motion. The
two positive copies on glass, each 10 in. high, are exhibited to show to what
extent magnifying may be carried without definition being lost to any sensible
degree.
The peculiar bath-holder in which the small negatives were taken is also
shown. It has been described in the " British Journal of Photography," in
1866, with improvements, in the almanacs of the same journal for 1874 and
1876.
240 SEC. 7. LIGHT.
955a. Photographic Apparatus, by M. A. Chevalier, for
plan-drawing. M. J. Duboscq., Paris.
956. Lichtpaus Apparatus, for photographing maps, plans,
&c. Romain Talbot, Berlin.
957. Press used in printing a " Woodbury " permanent
photograph, with leaden mould in position.
Woodbury Permanent Photographic Printing Company.
958. Photographic Portrait Camera, D.
Voigtldnder and Son (Chevalier von Voigtldnder)^
Brunswick.
953a. Photographic Portrait Camera, No. 3.
Voigtldnder and Son (Chevalier von Voigtldnder).
Brunswick.
959. Photographic Lens for Astronomical Photo-
graphy. John Henry Dallmeyer.
A double combination lens (rapid rectilinear) of 4" diameter and 30"
focal length, consisting of two symmetrical combinations, each having- a focus
of 63", and composed respectively of a crown and flint-glass lens, united by a
permanently transparent cement to avoid reflection at the contact surfaces.
The flint lens occupies the exterior position in each combination. It is con-
cavo-convex, convex side external. The crown lens is a meniscus, the con-
vex side of the same radius of curvature as the flint lens.
The radii of curvatures are so apportioned between the lenses that the
spherical, and chromatic, aberrations are destroyed ; or, in other words, the
combination is aplanatic, and this for aperture to.
7 8
The lens described (one of a series) was constructed and used for photo-
graphing the sun's corona.
959a. Photographic Lens for Self-Recording Instru-
ments, i.e., Barographs, Thermographs, &c.
John Henry Dallmeyer.
A double combination lens (No. 2 C) of 2f" diameter and 4^" focus.
It consists of a cemented front and an open back-combination, having a
large angular aperture, i.e., possessing great intensity. The front, or cemented
combination, is composed of a double convex crown lens, of unequal curva-
tures, the shallow side occupying the outer position ; and a double concave
flint lens is united to the deep side of the crown, the adjacent surfaces being
identical. At an interval equal to the diameter of the front is placed the
back combination, composed of a concavo-convex flint lens, convex side
facing the front combination, and a crown lens nearly plano-convex, with the
more convex side nearest Ihe flint lens, but of different radii of curvature,
and therefore not cemented.
The ratio of foci between the front and back combinations is 2 : 3 nearly,
and the radii of curvatures are calculated to produce well defined images for
aperture = , and angle of picture = 30.
959b. Photographic Lenses for the reproduction of maps,
plans, &c., as employed at the Home and Foreign Government
Topographical Establishments. John Henry Dallmeyer.
VII. PHOTOGRAPHY. 241
1 . A triple achromatic lens of 18" focal length for copying on plates 15" x 12''.
As its name implies, this lens consists of three achromatic, or actinic,
combinations, two of which, i.e. the front and back, are positive or converging
lenses, and a negative or diverging lens placed between them. The positive
combinations, the front of 2" and the back of 3" diameter respectively, with
focal lengths of similar proportion, are composed each of a double convex
crown, and a plano-concave flint-glass, lens ; the adjacent surfaces being
identical and cemented. The convex or crown lenses occupy the external
position iu both, and the combinations are separated by an interval equal to
the diameter of the largest or posterior lens. Between the two, and propor-
tionate to their diameters or foci, is placed the diaphragm aperture, or stop ;
this is also the position of the negative achromatic combination l^" diameter,
the crown of which is in this case a double concave, and the flint a piano con-
vex nearly. This combination limits the aperture to ; it does not affect the
direction of the pencils as refracted by the front and back positive combina-
tions, which produce an image free from distortion, though too much curved
to admit of its reception on a flat screen ; but its action (that of central
pencils only) is confined to the proportionately greater prolongation of the
oblique or marginal pencils, in virtue of its negative or divergent power.
In other words, it lengthens these pencils and produces the required amount
of flatness of field, the sine qua non for copying purposes.
This lens, one of a series, was introduced in 1860, and is reported upon by
the jurors of the International Exhibition of 1862 : " As the first aplanatic
" non-distorting view lens placed within the reach of photographers, and the
" best lens extant for copying purposes, &c." It was first used in the
Ordnance Survey Office at Southampton.
2. A 3" symmetrical combination of 24" focal length for plates 18" x 16".
This lens, constructed for copying, consists of two combinations identical in
all respects ; each has a focal length of 46", and is composed of a convexo-
concave flint, and a convexo-concave or meniscus crown-glass lens ; the radii
of curvatures of the concave of the one and the convex of the other are
identical and thev are cemented.
The combinations, with their convex or flint elements external, arc
mounted in a tube a given distance apart, in this case about ^- of the compound
focal length, and midway between them is a perforation for the insertion of
diaphragms or stops. Both combinations being identical in form and focal
length, the direction of the finally emergent pencils is parallel to the incident
ones ; hence the lens is free from distortion.
Flatness of field and correction of aberrations are obtained, for the
qualities of glass employed, by the forms and foci of the component ele-
ments, and in order to suit particular requirements the construction is modified
for varying angular apertures of from to ^-, including proportionate angles
of pictures of from 35 to 90. This lens was introduced in 1866.
960. Photographic Lenses for Portraits and Views.
John Henry Dallmeyer*
1. & 2. These portrait lenses, introduced in 1866, are constructed on a new
formula, as compared with the first portrait lens, the invention of Professor
Petzval of Vienna, and which appeared in 1841.
Unlike the lenses used for astronomical photography, copying, &c., Required
to produce a sharp image of an object situated in one plane, and necessitating-
perfect correction for aberration, a portrait lens must produce a presentable
picture of the human face, head, and body, situated in different planes j or
40075. Q
242 SEC. 7. LIGHT.
possess what is called "depth of focus." A perfectly corrected lens, of
sufficient angular aperture or rapidity of action to make portraiture possible,
has no " depth of focus." An instrument, possessing a certain residual
amount of spherical aberration, solves the difficulty to some extent. Un-
fortunately, however, a lens so constructed works at its best only for a given
size of image or distance of object. If this be removed to a greater distance,
as for a smaller image, the aberration is in excess, and if placed nearer, the
converse obtains.
The lens now to be described surmounts this difficulty. Its aberrations,
both spherical and chromatic, are perfectly corrected when used intact, or as
sent out by the maker ; and by the simple turn of a screw, separating the
component elements of the posterior combination, this correction can be
modified at will, i.e. positive spherical aberration, or " depth of focus," is
obtained, proportionate in amount to the separation of the posterior lenses.
The front combination, composed of a double convex crown, and a double
concave flint glass lens, is cemented, to prevent loss of light from reflection.
The convex or crown lens occupies the exterior position. At a distance
equal to the diameter of the front is placed the back combination ; an un-
cemented compound of the same diameter as the front, but of greater focal
length, i.e. as 2:3. The crown element of the back combination is a
meniscus with its concave surface facing the front combination. The flint is
concavo-convex, the convex side external ; this lens is mounted in a cell, the
screw of which affords the means of approach to, or separation from, the com-
panion crown lens. An index and division registers the amount of separation.
The converging cone of rays refracted by the front is incident upon the
crown element of the back combination ; on emergence it is more strongly
convergent when it meets the concave surface of the posterior flint ions. / It
is evident that any alteration in position or distance at once reduces or in-
creases its effective diameter, or, in other words, its aberration (j/ 2 ). The
aberrations being perfectly corrected when the posterior flint lens is screwed
home, the index pointing zero, the smallest amount of unscrewing or increased
separation at once introduces positive spherical aberration.
In Petzval's lens the position of the lenses composing the back combination
is the reverse of the above ; i.e. the flint, or convexo-concave element, faces the
front combination, the rays when refracted by it are parallel or nearly so,
and any alteration of distance of the companion crown lens is without effect
upon the state of aberration of the objective as a whole.
The portrait lens constructed on the new formula is free from disturbing
reflex images ; it produces pictures approximately free from distortion, and
illuminates a larger angle of field. It is made of three descriptions : viz. the A
series, aperture &?*, and D -= -L.
4 o u
3. A single combination landscape lens o 2" diameter and 12" focal length
for pictures on plates 12" x 10". It is composed of three lenses, two of which
are of crown glass, but of different optical properties, and between these two
is the correcting flint glass lens. The crown lenses are deep menisci, ratio of
foci of front to back as 1:3; the flint is concavo-convex. The adjacent sur-
faces of the crowns and flint being identical they are cemented, and externally
the combination is a deep concavo-convex, the concave side facing the view or
landscape Its aperture is limited by a diaphragm plate placed at a distance
of | the focal length in front of the lens ; the stops provide apertures from
to . Correction of chromatic and spherical aberration is obtained by the
12 40
foci and forms of the lenses employed.
The angle of picture included exceeds of 70, and though marginal dis-
VII. PHOTOGRAPHY. 243
tortion of image is not entirely avoided, it is perhaps counterbalanced by the
increased brilliancy of image and equality of illumination, due to the absence
of all disturbing reflex images.
4. A Wide angle rectilinear lens of 1|" diameter, and V equivalent focal
length for 12" x 10" pictures.
This lens is constructed upon the same general principle as the symmetrical
3" combination already described, with this difference, that the lenses com-
posing it, though similar in form, are of proportionately smaller diameter,
i.e., they are thinner, and being placed nearer together, they transmit more
oblique pencils, and a larger angle of picture is included, as much as 90, with
apertures ^ to 4 ~.
This instrument is designed for photographing objects in confined situations,
such as interiors of buildings, monuments, &c., where the camera cannot be
removed to more than a given distance. It produces images free from distor-
tion and flare.
962a. Apparatus for producing photographs in permanent
pigments ; consisting of,
Registering pressure frame.
Plates of zinc, porcelain and opal glass (the plates ha\ 7 ing upon
them : a. The sensitive tissue ready for development, b. The
supporting paper stripped off.' c. The picture partly developed.
d. The picture ready for transfer).
Reservoir for hot water, with means of keeping it warm, and
grooves for the plates.
Zinc trays for development washing, &c.
Wooden stool and squeezer for the mounting of the exposed
sensitive tissue. The Autotype Company.
If a negative in half-tones be placed under a paper coated with gelatine
pigments of any kind, and potassium dichromate, and then be exposed to
light, the gelatinous film is rendered insoluble, to depths varying according
to the intensity of the light passing through the various portions of the
negative. If the paper were at this stage exposed to the uction of hot wnter^
it would be found that the soluble portions lay between the exterior surface
of the film and the inner surface of the paper. In order to develop the
picture, it is transferred by simple atmospheric pressure to a zinc plate or
other temporary and impervious support. The original paper peels off, and
the development takes place by the simple application of hot water, the shades
of the image being formed of different thickness of gelatine and pigment.
The image may be retransferred from the temporary support, or if developed
on a paper support may be left as it is, in which case, unless the negative be
reversed, the picture will appear reversed.
962 c. Sir John Herschel's Actinometer, by Robinson,
marked I and K.
The Meteorological Committee of the Royal Society.
977a. Actinometer. Prof. Balfour Stewart.
962b. Actinometers, or instruments for ascertaining the
intensity of the action of the light, and by which the exposure of
the sensitive pigment paper under the negative is regulated.
Johnson's, Vogel's, .Spencer's, Lambert's, Sawyer's, Burton's,
Vidal's. The Autotype Company.
Q 2
*
244 SEC. 7. LIGHT.
Chemicals Employed.
Granulated bichromate of potash. Chrome alum.
Colours.
Indian ink, vegetable black, Paris black, plumbago, Indian red, Venetian
red, vermillion, purple madder, brown madder, Vandyke brown, indigo, lac de
vin, various kinds of gelatines.
962c. Pigmented Papers, in various colours, with subjects
printed to show the various shades.
962 d. Transfer Papers (i.e., papers prepared with insoluble
gelatine, and upon which the pictures finally rest).
962e. Sawyer's Patent Flexible Support (being paper
prepared with insoluble gelatine and an aqueous solution of lac,
upon which the picture is first developed previously to its transfer
to the final support. The Autotype Company*
962f. Reversing Mirror, being a piece of plate glass
polished to a perfectly true plane, and silvered by a chemical
process used to produce reversed negatives, enabling them to be
printed by the single transfer process of permanent pigment
printing. The Autotype Company.
9G2g. Wave Bath, for nitrate of silver solution (being a new
and convenient form for sensitizing large plates with a compara-
tively small quantity of solution. The Autotype Company.
962h. Sawyer's Collotype Process.
The Autotype Company.
Glass plates prepared with gelatine and isinglass, potassium dichromate,
&c., hardened by a spirituous extract of gum resins, upon which the photo-
graph is impressed by the action of light ; after which they are placed in a
type printing press, damped, and inked by lithographic rollers.
(a.) Plate in first stage of preparation.
(6.) Plate ready for exposure under negative.
(c.) Plate after exposure under negative.
(d .) Plate after being inked up in the press.
(e.) Plate with the same picture partly showing on the paper and partly
on the plate.
988i. Pour Prints from Photographs, by Paul Pretech's
mechanical process. Robert Sabine.
VIII. EDUCATIONAL.
963. Frame with 163 Photographs on Glass, for projec-
tion by the lantern, for instruction in the natural sciences.
Romain Talbot, Berlin.
VIII. EDUCATIONAL. 245
964. Tour simple Models, for instruction in the use of the
telescope and the microscope.
J. WilJielm Albert, Fr ankf or t-on- Maine.
The four models for optical instruction are open instruments with lenses
and shades. They show the course of the rays and illustrate in a simple
manner the Galilean, astronomical, and terrestrial telescopes, and the com-
pound microscope.
These models are largely used in German and foreign educational insti-
tutions.
964a. Sciopticon and three Manuals.
W. B. Woodbury.
965. Coloured Chalks for lectures, with a Black Board.
C. Blattner, Munich.
966. Interference Apparatus by Fresnel, executed for edu-
cational purposes by Ch. Jung, Giessen.
Physical Collection of the University of Giessen, Prof.
Buff.
918. Apparatus for demonstrating the Refraction of
Light in liquids, according to J. Miiller.
J. Wilhelm Albert, Frankf or t~on- Maine.
The semicircular plate of the refraction apparatus is of glass, ground
on its outside and having the scale burnt into it in black. The ray refracted
from the liquid appears therefore on the outside of the graduated plate and
can thus be viewed by large audiences.
967. Educational Apparatus, for elementary experiments
on Refraction. Prof. Dr. J. J. Oppel, Fr ankf or t-on- Maine.
This apparatus is only a modification of the old experiment of viewing
a coin at the bottom of a basin full of water. The coin is replaced by a white
line upon black ground, and the water by a movable cube of glass. The
position of the eye is fixed^by a dioptric plate.
968. Educational Apparatus for illustrating astronomical
refraction and its effect on measured heights of stars.
Prof. Dr. J. J. Oppel, Fr ankf ort-on- Maine.
The eye looks through a dioptric plate over a wooden globe (" earth ")
towards a few stars and the rising moon, which appears above or below the
horizon, according as the piece of glass, which represents the refracting
atmosphere, is lifted up or removed by means of a contrivance attached to it.
969. Two Colour-tables, for illustrating " colour blindness/ 1
with greenish glass (absorbing the ends of the spectrum) belonging
to them. P ro f- D T - J J- Oppel, Franhfort-on- Maine.
Both tables, each with 10-12 colour-couples upon black ground, have
reference to the most frequent form of achromatopsy, the so-called red, and
green, blindness. The one table contains colour-couples which are most
generally mistaken for one another ; the other those that are never mistaken.
The green glass, added to the tables, enables a normal eye to get an idea of
that peculiarity of vision.
246 SEC. 7. LIGHT.
970. Apparatus for illustrating the Colours of double
refracting Bodies, in the form of a Gothic window, composed of
gypsum plates systematically arranged according to the colours ;
with a blackened glass plate belonging to it.
Prof. Dr. J. J. Oppel, Franhfoi't-on- Maine.
971. Some characteristic Drawings for illustrating the
Stroboscopical Principle, with manifold movements, as, for-
wards and backwards, centripetal and centrifugal, undulatory,
oscillatory, and quite irregular.
Prof. Dr. J. J. Oppel, Frankfort- on- Maine.
Is a collection of those principal forms of periodic movements which . can
be represented stroboscopically.
IX. MISCELLANEOUS.
897. First Heliostat, invented by 'sGravesande.
Prof. Dr. P. L. Rijke, Ley den.
(See 'sGravesande's "Physices Elementa Mathematica, " ed. III., Tom.
I., page 715.) 'sGravesande was an eminent Dutch geometrician, b. 1688,
d. 1742.
898. Heliostat, G. Johnstone Stoney's modification, made by
Spencer and Sons, Dublin, a cheap and useful form.
Prof. W. F. Barrett.
971aa. Self-adjusting Heliostat, mounted on a declination
bar magnet. Dr. Stone.
97 lab. Mounted Prism of Quartz. Dr. Stone.
97 lac. Mounted Prism of Iceland Spar. Dr. Stone.
971ad. Equatorial Heliostat for maintaining a reflected
beam of solar light in a constant position, applicable to places
whose aspect will admit of a beam of light from the north only
being obtained.
By changing the dial wheel of the clock, it may be used from
the south as a polar instrument. Conrad W. Cooke.
It consists of a plane mirror, adjustable in declination, revolving upon a
polar axis and driven by a clock. The clock has two interchangeable dial
wheels whose circumferences are respectively one-half and one-fourth that of
the wheel upon the polar axis of the mirror. By using the smaller, the mirror
is driven round once in 48 hours, and if the instrument be placed due north
of the spot to which the reflected beam is to be directed, and in the same
equatorial plane with it, and adjusted in declination, the beam will be main-
tained in that plane and in a fixed meridional direction.
By substituting the larger dial, the mirror will rotate once in 24 hours, and
if the instrument be placed due south and in such a position that its polar
axis passes through the spot to be illuminated, the beam will be equally constant
in direction from the south.
IX.-^ MISCELLANEOUS. 247
Heliostat and glass prism. Prof. A. S. Herschel.
97 la. Wheatstone's Apparatus. Paris Observatory.
971b. Interferential Apparatus, by Arago.
Paris Observatory.
3699. Reflecting Stephanoscope.
Prof. Dr. Lommel, Erlangen.
(1.) The little apparatus is intended for the observation of interference
phenomena produced by a dimmed (triibe) mirror. The mirror is at one
end of a short brass tube, which has a lateral excision, and contains a second
tube, whose one end is cut off at an angle of 45 to the axis, and is there closed
with a plane glass. If the light of a candle is allowed to fall through the
lateral apertures upon the plane glass, so that it is reflected vertically to the
mirror, it will, on being viewed through the tubes, appear surrounded by
Newton's rings, which pass, when the tube is slightly inclined, into the so-
called WkewelVs bands. If a pencil of solar rays is caused to enter by the
lateral opening, and a lens of large focus is put on to the end of the second
tube, the above images can be thrown upon a screen.
3700. Erythroscope. Prof. Dr. Lommel, Erlangen.
The erythroscope is an eye-glass of combined blue cobalt glass with red
copper-suboxide glass, which gives passage only to the ultra red before
line B. Since chlorophyll does not absorb this colour, the green parts of a
plant appear, when viewed through the erythroscope, quite light coloured ;
the foliage of a tree in sunshine, for instance, will appear as light as a white
cloud, and form a light spot upon the dark ground of the sky.
3701. Melanoscope. . Prof. Dr. Lommel, Erlangen.
The rnelanoscope, a combination of dark red copper glass and light
violet glass, allows chiefly the red rays between B and C to pass, which are
absorbed with avidity by plants. Viewed therefore through the rnelanoscope
plants will look very dark, almost black. This contrivance and the preceding
one show in an instructive manner that plants absorb eagerly the middle
portion of the red part of the spectrum, but not at all the ultra red.
3702. Erythrophytoscope I.
Prof. Dr. Lommel, Erlangen.
This combination of Simmler, consisting of blue cobalt glass and dark
yellow iron oxide glass, transmits ultra red up to B, and also to yellow-green,
blue-green, and blue. Leaves, looked upon through it, appear coral red, the
sky blue, the cloud reddish-violet, the soil violet-grey.
3703. Erythrophytoscope II.
Prof. Dr. Lommel, Erlangen.
The erythrophytoscope II. , combined of blue cobalt and light red copper
glass, allows, besides ultra red, only blue-green and blue to pass. The effect
is similar to that of the preceding combination, only more striking.
It should be remarked that, only vegetable and anilin green appear, as
described under these combined glasses; mineral green would look dark
blue-green.
3704. Coloured Gelatine Leaflets as objects for the spectro-
scope. Prof. Dr. Lommel) Erlangen.
248 SEC. 7. LIGHT.
To demonstrate the absorption phenomena of soluble colouring matters,
plates of isinglass, which had been dyed with the colouring matter, are re-
commended, instead of the solutions. To protect these plates against dust,
&c., they may be placed between two glass plates. By placing feebly
coloured plates in a fan- shaped way upon one another, the increase of absorption
by increasing thickness may easily be illustrated.
972. Mixoscope (colour-mixer), executed according to the
directions of the exhibitor by M. Ph. Edelmann, Munich.
Prof. W. von Bezold, Royal Polytechnic School,
Munich.
This apparatus gives the true colour resulting from the combination of two
colours by actual trial with the brush, and thus a correct colour table can, by
its means, be made with greater facility than with the revolving disc. The
achromatised calcspar prism is so to be adjusted that on looking through the
apparatus only six squares should be visible. It is easy to find this position
through moving the telescope and turning the prism. On bringing the two
colours to be mixed under two of the square openings, these colours will be
right and left of the mixed colour, which fills the middle part of the three
contiguous squares. If, now, the other two apertures contain the true optical
compound colour, the two central squares will appear in the same tint.
Compare the description annexed to the apparatus.
973. Clockwork for colour discs, for lecture purposes,
according to Kiihne's and Becker's principles.
Rud. Jung, Heidelberg.
The clockwork, provided with a strong spring, is capable of rotating
coloured discs of 28 centim. diameter with such velocity that a disc covered
with the tints of the spectrum will appear white. By a simple contrivance the
one or the other of the spectrum colours can be excluded, and thus its com-
plementary and contrast colour produced. By inserting a second axle, the
movements of the clockwork can be retarded.
1065a. Colorimeter. M. Laurent^ Paris.
3659. Three Diaphragms and lamp stand for magic lantern.
Laurent.
3659a. Diaphragms (4), various. Laurent, Paris.
974. Apparatus for demonstrating the Glory on bedewed
Meadows, consisting of glass globes filled with water.
Prof. Dr. Lommel, Erlangen.
975. Apparatus for demonstrating the Glory on bedewed
Meadows, with solidified drops of Canada balsam.
Prof. Dr. Lommel, Erlangen.
These glass globules serve to demonstrate why dew drops shone upon by the
sun appear so brilliant just round the shade of the head of the observer. The
explanation is that each dew drop is a lens concentrating the rays upon the
ground below the drop, which latter sends them back diffused.
If the glass globules are placed upon a sheet of white paper, and the shadow
of the observer's head is permitted to fall into the circle, the globules will
IX. MISCELLANEOUS. 249
appear very brilliant ; as soon, however, as the white reflecting sheet is
removed, and the globules rest on a dark dull ground, the brilliancy at once
disappears.
The preceding experiment can also be well executed with solidified drops of
Canada balm.
97 5a. Apparatus of M. Sravais, for producing halos,
parhelia, and other kindred phenomena. W. G. Lettsom.
It consists of a hollow equilateral prism made with plates of parallel glass.
The prism is filled with water at an orifice on the top. It is fixed on a
vertical axis rotating by clockwork. With 100 revolutions in a second it
reproduces the varied series of positions of the vertical prisms of ice producing
parhelia. The prism is to be illuminated by a beam of sunlight, or by a lamp
at a distance of 8 or 10 yeards. The apparatus reproduces also the Anthelion ;
by substituting for the prism a quadrangular plate of glass turning round on
one of its vertical edges. If striae are traced on the surfaces of this plate,
the anthelion becomes traversed by two symmetrical arcs, arranged in the
form of a St. Andrew's cross.
See M. Bravais's Memoir e sur les Halos, Paris, 1847, p. 266, 4to. ; or
Journal de I'EcoIe Royale Poly technique, XXXI. cahier.
976^ Four Absorption Cases, all in glass, 5 and 10 mm.,
and two pieces for spirits and water.
Warmbrunn, Quilitz, and Co., Berlin.
977. Bunsen's Apparatus for Experiments in Spectrum
Analysis, a battery of four Ley den jars, a stand with arrange-
ments for producing a spark spectrum, with holder for spectrum
tubes. Reiser and Schmidt, Berlin.
978a. Apparatus for measuring the magnitude of Gas
Jets at a distance. Invented by Mr. C. Wolfberger.
Geneva Association for the Construction of Scientific In-
struments.
This apparatus, invented by the civil engineer Wolfberger, is intended for
the comparison of gas lamps from the street level.
Founded on the principle of the sextant, it is composed of two mirrors :
the one fixed, the other movable parallel to the first along a graduated scale.
In order to measure the magnitude of the gas jet, the operator holding
the instrument by its handle on a level with the visual ray, and looking
through the sight, observes simultaneously, in a direct line, the jet to be
measured, above the fixed mirror, and indirectly the image of the same jet by
double reflection. The screw-head placed below the handle is then turned,
until the right edge of the jet, seen in a direct line, coincides with the left
edge of the jet, seen by reflection. The magnitude of the flame, ascertained,
is then shown on the metallic scale which is read in millimetres.
978b. Patent Illuminating Power Meter, for showing the
illuminating power of gases in the terms of the Parliamentary
sperm candles and the standard quantity of five cubic feet of gas
per hour by the observation of one minute. William Sugg.
250 SEC. 7. LIGHT.
979; Trepiscope. An optical apparatus made by the late
Richard Roberts, C.E., of Manchester, and first shown at the
meeting of the British Association at Dublin in 1835.
The Committee, Royal Museum., Peel Park, Salford.
On being turned by hand or by power the card on the disc is caused
to revolve from 6,000 to 40,000 times a minute; on viewing the re-
volving disc through the eye-kole, the printing on the card can be read with
ease and distinctness.
The time given for one view of the card may not exceed the 150,000th of
a second when the disc is revolving at the highest speed.
980. Radiograph.
The Committee, Royal Museum, Peel Park, Salford.
A small apparatus to show that the spokes may be counted whilst the wheels
revolve at a very high velocity. Invented by the late Richard Roberts, C.E.,
of Manchester.
979a. Phosphoroscope, by Becquerel..
M. J. Duboscq, Paris.
979b. Phosphorescent Tubes, set in the form of writing.
These tubes preserve their brilliancy in the darkness long after
being exposed to solar light. Alvergniat Freres, Paris.
981. Newtonian Disc, for rotating movement transmitted by
caoutchouc bands. Luizard, Paris.
981a. Newton's Apparatus. M. Lutz, Paris.
983. Pair of Reflectors, for the demonstration of the laws
of reflection. Elliott Brothers.
983a. Reflector of 22 mm. diameter, for Foucault's telescope.
M. Lutz, Paris.
983b. Apparatus illustrating Persistency of Vision.
S. F. Pichler.
983c. Magic Mirror. Robert von Tarnow.
This mirror is a curiosity, and consists of a brass concave disc with finely
polished surface. At the reverse rough side there are several Arabic charac-
ters in relief. By exposing the polished surface to the rays of the sun in such
a way that they reflect them on the wall, the Arabic figures of the reverse
side of the disc become plainly visible in the reflected light on the wall.
983c. Selenium Eye* C. W. Siemens, F.R.S.
994. Government Safety Magazine Lamp.
J. Gardner Sf Sons.
Constructed at the request of the Home Office. The aim was to invent a
lamp which would burn in a powder magazine and other dangerous places in
perfect safety, and would exclude the powder which, it is well known, is found
IX. MISCELLANEOUS.
251
floating in powder magazines and stores in the form of fine dust. After a series
of experiments it was ascertained in the most conclusive manner that all safety
lamps wholly or partially constructed of gauze are useless for this purpose, the
gauze failing to exclude the powder dust, which, collecting inside the lamp ex-
plodes. Now the flame of a powder explosion is so much more violent than that
of gas that it instantly penetrates the gauze and carries through with it
incandescent particles of powder.
This patent safety magazine lamp has, therefore, been constructed on the
following principle :
To prevent risk of explosion
from the entry into the lamp
of the fine powder dust which
may be present in a powder
magazine or store, the air pas-
sages which supply this lamp,
and also the exit passages for the
burnt air from the flame, are con-
structed so that the air must
pass under and over a series of
screens. Air to support com-
bustion enters the lamp under
an inverted outer ledge, and
then passes through holes made
in the casing to a narrow space
formed by an inner lining ; so
that the air must first pass up
to reach the holes in the casing,
then down the inner space, and
finally up another narrow space
before entering the lantern.
The top part of the lamp is
constructed on substantially the
same principle, that is, the exit
air passages are made zig-zag ; but, in case they ever become clogged with
soot, two out of three parts which form the passages are hinged to the
casing, and are secured in place by a spring lock. When these parts arc
unbolted they can be turned back on their hinges and easily cleared of any
soot that may have become deposited therein.
The bottom and sides of the lamp are the only parts fixed to one another,
and the burner is dropped in through the top of the lamp, which is then
secured with a spring lock as already mentioned.
Every detail of the outer casing of the lamp has been carefully con-
sidered, and there are no projecting parts where dust can accumulate and
settle. The lamp has a bull's-eye lens in front; the side lights are glazed
with glass one-eighth of an inch thick, protected by strong copper wire. The
handle moves on a pivot. The burner is a f -inch flat wick, and a reflector is
added to increase the brilliancy. The lamp and lantern are made of copper,
bright tin, or tin japanned.
The highest temperature of the outer casing of the lantern has been 126
the exploding temperature of powder being 600.
Spectacles, for shooting.
G. W.Richter.
252
SECTION 8. HEAT.
WEST GALLERY, UPPER FLOOR, ROOM ( Q
I.SOURCES OF HEAT.
984. Double-Chambered Lamp and Reservoir for heat-
ing water or air, or both. There is no blast-pipe, or communi-
cation between the chambers. J. L. Milton.
The heat is generated by the combustion of methylated spirit, and applied
on the principle of driving a ring of flame from the holes in the top of the
outer chamber against the flame issuing from the inner compartment, thus
securing a great and continuous heat. The spirit in the inner chamber alone
requires to be lighted. A chambered and tubed reservoir accompanies the
lamp. The consumption of 1 oz. of methylated spirit in the outer, and ^ oz.
in the inner chamber, will produce and maintain, for from 10 to 15 minutes,
as great a heat for a vapour-bath as most persons can bear.
985. George's Patent Gas Calorigen, for warming and
ventilating apartments. John F. Far wig.
The peculiarity of construction in this gas stove, which diffuses heat prin-
cipally by convection, consists of an outlet so arranged with regard to the
inlet (both being external to the apartment) that only so much air passes
either way as is required to support and carry off the products of
combustion.
The heat generated by combustion warms a thin coil of sheet iron in the
interior of the stove, the coil being in communication at one end with the
external atmosphere, and at the other with the apartment ; thus a stream of
fresh air, which is warmed in its passage, is drawn into, and equally diffused
throughout, the apartment.
986. Eunsen Burner, improved form, with air jet to increase
the temperature of the flame to any required extent without
re-adjustment of height or position. Thomas Fletcher.
In the above, the blow-pipe flame obtained with the blast tube, when confined
by the loose cap, is compact and very powerful, owing to the partial mixture
of air before the blast begins to act.
987. Injector Gas Furnace, with blower, for the treatment
of refractory substances at very high temperatures.
Thomas Fletcher.
This furnace will burn perfectly, in the same space, any available gas
supply from 10 to 50 ft. per hour, or more, giving temperatures in exact
proportion. With ^ inch gas supply, day pressure, starting with a cold
furnace, silver can be melted in three minutes, cast iron in eight minutes, and
i. SOURCES. 25a
cast steel in 25 minutes. With a f bore gas-pipe the furnace can be con-
structed to give the same results in half the time, and so on in proportion, the
power being limited only by the gas supply and the fusibility of the refractory
clay jacket. A small foot blower only is necessary to create a current of air
in the burner tube, the jet of air from the blower acting as an injector, and
drawing in the air required for combustion from the atmosphere. By closing
the air slide to a greater or less extent the same burner acts equally well in
proportion with any gas supply from 10 cubic feet per hour. The texture of
the refractory casing is cellular throughout, and the loss of heat by radiation
is practically nil.
988. Low Temperature Gas Burner, to dispense with
drying closets, sand and water baths, and adapted for drying,
evaporating, boiling, &c. Thomas Fletcher.
This burner gives a range of temperature from a gentle current of warm air
without visible flame to clear red heat, and is so perfectly under control that
a common glass bottle may be placed on tripod, and heated to required
temperature, without risk of fracture.
For very low temperatures, the ring must be lighted through the lowest
opening. This gives a steady current of heated air through the gauze above
For boiling, &c., a light must be applied on the surface of the gauze, thereby
providing a large body of blue flame, which can be urged by the blast-pipe
until it gives a clear red heat.
989. Hot Blast Blowpipe, for temperatures up to the
fusion of platinum. Thomas Fletcher.
The air jet in the above is coiled round the gas pipe in a spiral form, and
both are heated by three Bunsen burners underneath, which are controlled
by a separate tap. By this arrangement the power is double that of the
ordinary blow-pipe. When the jet is turned down to a small point of flame
it will readily fuse moderately thick platinum wire.
990. Gas Crucible Furnace, for temperatures up to white
heat, and requiring neither blast nor attention. Thomas Fletcher*
991. Gas Muffle Furnace, requiring neither blast nor
attention ; for temperatures up to fusing point of cast iron.
Thomas Fletcher*
992. Diagram of the Porcelain Furnace at Sevres,
part of it being open to show the interior construction. Painted
by Mr. Hubertus Sattler.
Dr. Alexander Bauer, Professor, Polytechnic Institute^
Vienna.
993. Diagram of the Bottom of a Blast Furnace for
Smelting Iron.
, Dr. Alexander Baiter , Professor, Polytechnic Institute +
Vienna.
995. Gas Furnaces. Perrot System.
Geneva Association for the Construction of Scientific In-
struments.
254 SEC. 8. HEAT.
These may be set up wherever gas is laid on ; the slightest draught is suffi-
cient ; and in default of a chimney in the workroom it is enough to let out the
funnel through a window pane. The shape of these furnaces varies according
to their intended use. There are two principal models, the melting furnace,
and the muffle furnace ; the latter is advantageously used for assaying copper,
gold, and silver, for roasting minerals, and for melting metals for analytical
purposes.
Temperatures up to 1,300 and 1,400 degrees can be obtained rapidly and
with economy, and once obtained can be maintained unchanged during any
length of time, and may be reduced at will.
996. Cowper's Regenerative Fire-brick Hot-blast
Stoves. E. A. Cowper.
The diagrams and model of regenerative fire-brick hot-blast stoves are
illustrative of the progress of science as applied to heating the air supplied as
a blast under pressure to blast furnaces for smelting iron ores and iron stone.
In early times the air was always used cold, but a blast heated in cast-iron
pipes was introduced by Mr. J. B. Neilson in 1829, and from that time till
the year 1857 the temperature of the blast was generally only about 600
Fahrenheit, but by the application of regenerative fire-brick hot-blast stoves
the temperature of the blast has been raised to 1400 and 1500 Fahrenheit,
and has been accompanied by a very large saving of fuel, amounting in some
cases to 7 cwt. o qrs. 14 Ibs. of coke per ton of iron made, whilst at the same
time a largely increased make of iron has been produced, varying from 20 to
30 per cent, of the original make of iron. The entire wear and tear of cast-
iron pipes is avoided, as the air only passes over fire-brick surfaces previously
heated by the combustion of the waste gases obtained from the top of the
blast furnaces. Two stoves are used alternately, one heating blast whilst the
other is being heated. Two or three stoves will heat the blast for two or
three blast furnaces.
996a. Drawings of Bull's Patent Semi-continuous
Brick Kilns. Hermann Wedekind.
These kilns have been worked with great success in India and are now
being introduced into this country. .
They are the cheapest kilns with regard to cost of building and effect a
saving of nearly two-thirds of the expenditure usually involved, and are espe-
cially suitable for temporary works.
The effective mode of feeding invented by Hofmann, has also been applied
by Bull to his kiln with great success.
996b. Model of Hofmann's Circular Kiln.
Hermann Wedekmd.
Hermann's Patent Annular Ovens for the continuous burning of bricks and
tiles, limes and cements, at a saving of from two-thirds to three-fourths of the
fuel usually employed.
It is the joint invention of M. Fred. Hofmann, of Berlin, and M. A. Licht.
of Dantzig.
It is now well known and appreciated by the tra.de in this country, and has
been extensively employed by the Government on the extensive works at
Portsmouth Dockyard, where five of the kilns have been working at a great
saving to the country. About l millions of bricks are daily burnt in them
in England alone. Taking coal at an average price of 10s. per ton, this in-
vention will give a saving of at least 60,0007. per annum. In burning lime
equally favourable results have been realised as in burning bricks.
n. EXPANSION. 255
997. Gas Lamp, consisting of four Bunsen burners, and
provided with an air-regulating system.
S. Hoogewerff, Dr. Phil., Rotterdam.
This lamp, which is intended for heating tubes, was constructed by
Mr. Verkerck, mechanical engineer, Utrecht, under the directions of Dr.
Hoogewerff, and belongs to the middle school at Rotterdam.
998. Gas Lamp (Bunsen's system), intended for heating
porcelain vessels of large size.
S. Hoogewerff, Dr. Phil, Rotterdam.
It was constructed, under the directions of Dr. Hoogewerff, by Mr.
Verkerck, mechanical engineer, Utrecht, and belongs to the middle school at
Rotterdam.
999. Apparatus for showing the liberation of heat during
solidification. Will. Haak, Neuhaus am Rennweg, Thuringen.
II. EXPANSION.
lO88a. Apparatus, by Peter von Musschenbroek, a
Dutch mathematician (born 1692, died 1761), to determine the
relative values of the Coefficients of the Expansion of Solid
Bodies. Prof. Dr. P. J. Rijke, Leyden.
1097b. Original Apparatus, by M. Dulong and Petit, for
measuring the Dilatation of Mercury with overflow thermo-
meter. Polytechnic School, Paris.
1097c. Apparatus for measuring .the expansion of
Bodies by Heat. Physical Institute, Freibiirg.
lO97d. Apparatus to demonstrate the mechanical
effects of the expansion of Fluids by Heat.
Prof. Boscha, Royal Polytechnic School, Delft.
lO90b. Original Apparatus of Regnault for the Dilata-
tion of Gases. College of France, Paris.
1075. Apparatus for demonstrating the Expansion of
Solids by Heat. A. Steger, Kiel.
y
1090. M. Fizeau's Apparatus for measuring the Co-
efficient of Dilatation.
Conservatoire des Arts et Metiers, Paris.
1082a. Photograph of M. Fizeau's Apparatus for
determining the Coefficients of Dilatation.
M. Laurent, Paris.
1082b. Microgoniometer. An instrument for measuring
the expansion of metals by heat. Prof. Dr. F. Pfaff.
256 SEC. 8. HEAT.
1087. Model of Circular red hot Copper Railway, for
causing a metal ball to rotate by means of unequal expansion by
heat. George Gore, F.R.S.
Model in wood of circular railway, which when formed of copper heated to
redness, and a thin cold ball of German-silver placed upon it, the ball rotates
by the influence of unequal expansion produced by the heat. ( See Philo-
sophical Magazine, August 1859.)
III. THERMOMETRY AND PYROMETRY.
Air Thermometer, in the form first given by Galileo.
The Royal Institute of " Studii Superiorly Florence.
Padre Benedetto Castelli, one of Galileo's disciples, writes about the ther-
mometer as follows : " I recollect an experiment shown me, about the year
" 1603, by our Sig. Galileo. He took a glass bottle of about the size of an
" egg, having a neck nearly two palmi in length and as thin as a wheat
" straw, and having warmed it well with his hands, he then turned its mouth
upside down into a vessel placed underneath in which there was a little
water. When he had removed his hands from the bottle the water began
immediately to rise in the neck, and mounted higher, by more than a palmo,
than the level of the water in the vessel. Sig. Galileo made use of this
effect to construct an instrument for examining the degrees of heat and of
cold, concerning which much might be said."
And then Vincenzo Viviani, another disciple of Galileo's, in the life of that
great man, which he wrote between 1593 and 1597, states that Galileo
invented the thermometer.
1828. Registering Thermometer of Fontani.
The Royal Institute of 11 Studii Superiori" Florence.
Thermometer, cinquantigrade, with spherical bulb. The
freezing point corresponds to 13 "5. The academicians used this
thermometer for the meteorological observations instituted first
by them in 1654. Accademia del Cimento.
Thermometer, cinquantigrade, with cylindric bulb. The
point of ice melting corresponds to 13 '5.
Accademia del Cimento.
Thermometer, settantigrade. The freezing point is at 23 5.
Accademia del Cimento.
Thermometer for bath. When immersed in the bath it must
indicate 49, as is written in the upper little ball.
Accademia del Cimento.
Thermometer, with foot divided in 470, corresponding to
26 centig. It served for the experiment made to ascertain
whether the cold of ice reflects itself from the mirror like the
heat of burning coals and light. Accademia del Cimento.
Thermometer, with elaborate foot. An object of art.
Accademia del Cimenta*
III. THERMOMETRY. 257
Thermometer in winding form, very sensitive, height 32 cm. ;
the spiral tube is 2 * 30 meters long. Accademia del Cimento.
Thermometer, with balls (thernioscope). The alcohol dilating
by heat, the little balls fall one after another according to their
weight. Accademia del Cimento.
The Accademia del Cimento was founded by Prince Leopoldo de' Medici,
brother of the Grand Duke Ferdinand II. , who also greatly favoured it. The
first assembly was held at the Palazzo Pitti ia Florence on the 18th of June
1657 ; and it chose for a device the celebrated motto " Provando e Ripro-
vando." After ten years of existence, Prince Leopold having been made a
Cardinal, the academy -was dissolved.
1075a. 'sGravesande's Ball and Ring Pyrometer, for
showing expansion. Harvey, Reynolds, and Co.
1076. Musschenbroek's Pyrometer made in the first half
of the 18th century, with five different metal bars, and an autograph..
Property of His Highness Prince Pless, Schloss Fiirstenstein.
The Breslau Committee.
The apparatus has been constructed after the description and drawing
given on p. 12 and Table XXX. of Musscbenbroek's "Tentamina Experimen-
" torum .Naturalium Captorum in Academia del Cimento, Lugduni, 1731,
" Pars. II." The orthography of the French, on an annexed slip of paper, is
that of the beginning of the last century. The instrument, which is in capital
condition, may therefore be considered as one of the oldest of its kind.
1O27. Original Spirit Thermometer, of the Florentine
Accademia del Cimento (17th century).
The Royal Institution of Great Britain.
Presented to the Royal Institution by Sir Henry Holland, Barti, F.R.S.
1003. Photographs of Old Thermometers ; a small al-
cohol thermometer, with Florentine scale, and four larger ones by
Michelo du Crest (1754).
Prof. Hagcnbach-BiscJwff', Director, The Physical Insti-
tute in the Bernoullianum, Basle.
In these alcohol thermometers zero indicates the temperature of the cellar
under the Observatory of Paris, and 100 the boiling point of water.
1070. Wedgwood's Pyrometer, invented in 1782.
Edinburgh Museum of Science and Art*
Dry clay when exposed to high temperatures contracts uniformly, and
Wedgwood believed that by the amount of contraction the temperature
which produced it could be measured. The instrument, however, is not
trustworthy. This specimen was made by Josiah Wedgwood, and presented
to the Edinburgh Museum by his grandson Mr. Godfrey Wedgwood.
1O67. Wedgwood's Pyrometer, consisting of pieces of clay,
contracting according to the heat to which they are exposed. These
are afterwards slid along the gradually diminishing and graduated
groove in the brass plate, and so indicate the degree of heat ta
which they have been exposed. Robert Garner, F.R.C.S*
4007A R
258 SEC. 8. HEAT.
1078. Early Pyrometer (by Funiey).
The Council of King's College, London-
1079. Dani ell's Pyrometer, employed in researches by
Professor Daniell. The Council of King's College., London.
lO52a. Original Air Thermometer, by M. Renault.
College of France.
1000. Thermometer. " The Great Pyramid temperature
scale, and its standard reference point of 50 P." With a map of
the world to illustrate the advantages of this standard.
Prof. Piazzi Smyth.
This consists of a large table thermometer, graduated according to the in-
dications of the Great Pyramid system of standards ; firstly, by colours into
fifths of the distance between freezing and boiling of water, and then each
fifth into 50, or 250 for the whole distance.
A map of the world on an equal-surface projection accompanies the
thermometer, and exhibits the mean temperature of the whole earth's surface
according to the Great Pyramid scale ; illustrating also the territorial and
international advantages to all civilised nations of adopting the mean tem-
perature standard of the Great Pyramid, viz., 50 Pyr. or 68 Fahr., as the
temperature reference standard for all human purposes, scientific, social,
and commercial.
1001. Legible Spirit Thermometers, with line at above
and below the proper temperature of a room, so that the degree
can be read off at a long distance, at the opposite side of a large
room, or at the ceiling, for experiments in ventilation.
Peter Hinckes Bird, F.R.C.S. Land.
1002. Apparatus for determining the Boiling Point of a
small quantity of Fluid.
The Secondary Government School, Assen (Netherlands).
In this simple apparatus, constructed after the design of Dr. A. Van Hasselt,
(teacher at the school for middle-class education at Assen), the small tube is
filled for the greater part with mercury ; the remaining space with the fluid.
The tube is then turned upside down into a small beaker-jar, which is also
filled with mercury ; part of this must be removed until the quantity left rises
about one or two centimetres above the bottom of the jar. When the appa-
ratus has been placed in the large beaker -jar, water or oil is poured into the
latter, so that the tube is quite immersed. The jar is then heated, agitating
the fluid meanwhile with a moving apparatus.
The millimetre scale serves to determine the height of the fluid in the larger
jar, together with the difference between the position of the mercury in the
tube and that on the outside of it. In determining this difference, the pressure
of the fluid in the larger beaker-jar and the barometric height must be taken
into consideration.
To know whether a fluid is homogeneous, two experiments must be made,
one with a fluid Avhich is partially evaporated. In both cases the results
must be the same.
When the vapour of the fluid in the tube has the pressure of one atmosphere
the boiling point of the fluid must be observed.
III. - THERMOMETRY. 259
13Z5a. Air Thermometer after Riess.
Warmbrunn, Quilitz, $ Co., Berlin.
1004. Trough for comparing Thermometers, provided
with in- and out-flow tubes for water, and stirring apparatus.
Dr. J. W. Gunning, Professor of Chemistry at the " Athe-
nceum illustre" Amsterdam.
The thermometers are placed in a movable frame, in which they may be
transported from one trough into another containing water of another tem-
perature. Two sheets of glass, placed on either side of the frame, prevent the
inner portion of the water from cooling.
1005. Dial Thermometer, designed by L. E. Briihne, Ley den.
Dr. D. de Loos, Director of the Secondary Town School,
Ley den.
This thermometer is intended to admit of a large number of students seeing,
from a distance, the change in the volume of the mercury as the temperature
varies.
In the mercury is a small glass tube, balanced by another similar tube, both
being joined together by a thread, which is suspended over a small copper box,
at the extremity of which is a needle moving over a dial.
1006. Mercurial Dial Thermometer, adapted for class
experiments on specific and latent heat.
Prof. W. F. Barrett.
The expansion of the mercury in the bulb of the thermometer lifts a small
iron piston which communicates its motion to the index hand. Small varia-
tions of temperature are thus readily seen by a large class, e.g., the expansion
of the glass of the bulb causing a momentary retreat of the index hand, is
seen to be the first effect produced by heat on the bulb. By making the scale
on glass the dial can be projected on a screen and determination of specific and
latent heat made before a large class ; electric contact can also be made by
the hands, and thus a self-registering thermometer constructed. The instru-
ment was made by Mr. Yeates, of Dublin.
\-A-\ t+ t -
1011. Various Thermometers, of different kinds, in metal,
ivory, porcelain, glass, and wood. Elliott Brothers.
'
1012. Standard Thermometer. Elliott Brothers.
1013. Insolation Thermometer, for determining the inten-
sity of the rays of the sun (maximum thermometer), with holder.
' BerliH ~
1O14. Eight Normal Thermometers, executed by Greiner
and Geissler, Berlin.
Imperial Admiralty Hydrographical Bureau at Berlin,
and Deutsche Seeivarte, Hamburg.
These thermometers are employed in the stations of the Naval Observatory
and in the Imperial Navy. o 491!}
R 2
260 SEC. 8. HEAT.
101 5a. Thermometer, with corrected Freezing Point.
W. Gloukhqff, St. Petersburg.
This thermometer is constructed on a principle much used in Germany.
To "it is added only a contrivance to render the scale more steady, and to
correct the error of freezing point, by raising or lowering of the scale. By
unscrewing the upper metallic cap of the thermometer, this contrivance
becomes visible.
1016. Reaumur's Scale. Dring and Page.
Formerly much used in Germany and Russia, now mostly in Norway and
Sweden, and some parts of Denmark. The zero of this scale is at the melt-
ing point of ice. The interval between this and boiling point is divided
into 80 degrees.
1017. De Lisle 's Scale. Dring and Fage.
This scale is seldom used; zero is fixed at boiling point; the interval
between this and freezing point is divided into 150 degrees.
1018. Six's Thermometer on a porcelain scale' (named
after its inventor, Mr. Six of Canterbury) for registering extremes
of temperature. Dring and Fage.
The indices are little pieces of steel coated with glass which are enabled to
retain their position in the tube by means of a hair fastened round them, and
by this means the highest or lowest temperature is recorded.
1018a. Six's Thermometer with a very flat bulb which
renders it as sensitive as an ordinary mercurial thermometer.
S. G. Denton.
1018b. Six's Thermometer with mercurial wet bulb ther-
mometer attached, thereby combining four instruments in one,
namely, maximum, minimum, hygrometer, and present tempera-
ture. S. G. Denton.
1019. Long Brass-Cased Thermometer. Showing the
difference in length of the mercurial column after being pointed
and divided with the whole length of the tube immersed in water
at the various temperatures between 32 and 212 ; the same with
the bulb only in the water. Dring and Fage.
1020. Very delicate Spiral Bulb Thermometer. Ex-
tremely sensitive, capable of indicating small variations of tem-
perature. Dring and Fage.
1022. Standard Thermometer, calibrated throughout,
Dring and Fag c,
A standard thermometer divided on the tube, used for purposes where
great accuracy is required. The tubes used for these thermometers are
selected with great care, particular attention being paid to the uniformity of
the bore. The method of ascertaining this is usually performed as follows :
A portion of mercury is introduced into the tube, and the length it occupies
is noted ; it is th%p carried a little further on, and its length compared with
III. THEBMOMETRY. 261
the former length. So on all down the tube ; if the length has decreased
from the first measurement, it shows that the bore of the tube has increased,
and vice vers&. The process is known as calibration.
1023. Pour Thermometers. Showing the different scales
principally in use. Fahrenheit, Celsius or Centigrade, Reaumur,
and De Lisle. Dring and Fage.
Fahrenheit's scale is used principally in Great Britain, its Colonies, and the
United States. The zero of this scale is obtained from a mixture of salt and
snow ; thirty-two degrees is the point at which ice begins to melt, and 212, or
boiling point, from boiling water, when the barometer stands at 29 905. One
advantage of this scale is that temperatures may often be expressed in whole
degrees, whereas in other scales fractions of degrees are frequently necessary.
1024. Celsius or Centigrade Scale. Generally used on the
continent. Dring and Fagc.
The zero of this scale is that point at which ice begins to melt, and 100
the point at which Avater boils when the barometer stands at 760mm. Celsius
is the name of the inventor of this scale ; it is called Centigrade from its
being divided centesinially.
1025. BecquerePs Thermo-Electric Thermometer.
Conservatoire des Arts et Metiers, Paris.
1025a. Becquerel's Thermo-Electric Pyrometer.
Conservatoire des Arts et Mi tiers.
1026. Hodgkinson's Actinometer. Described in the
Proceedings of the Royal Society, vol. XX., p. 328.
Kew Committee of the Royal Society.
This is a large thermometer, filled with alcohol coloured blue, and having a
bore much contracted for a great part of its length, in order that the scale
may be very open ; at its top it opens out into a large chamber, which receives
the superfluous fluid at the time of observation.
A tin case, capped with glass at both ends, prevents the access of extra-
neous rays to the bulb of the instrument at the time of observation.
1028. Drawings, various, partly new, of constructions of
Differential Atmospheric Thermometers.
Dr. Leopold Pfaundlcr, Professor of Physics, Innsbruck.
This plate presents a general view of all possible forms of construction,
which partly appear as modifications of Berthelot's atmospheric thermometers,
partly are based on independent principles.
Fer further details, see Transactions of the Imperial Academy of Sciences at
Vienna, Vol.LXXIL, 1875.
1029. Melloni's Thermo-Electric Apparatus.
M. Ruhmkorjf.
1029a. Line Pile for Spectrum and Galvanometer.
M. Ruhmkorft\
1286. Nobili's Thermo-Electric Pile, of 54 pairs of bis-
muth and antimony bars, soldered alternately together ; the smallest
temperature between the two faces of the pile develops a current,
readily indicated by a suitable galvanometer. Elliott Brothers.
262 SEC. 8. HEAT.
1033. Thermometer Electric Alarum, for giving notice
when a given temperature is reached. Dr. Letts.
The apparatus consists of an open thermometer with large bulb and wide
tube. A platinum wire is sealed into the bulb, and another wire passes down
the tube. The latter can be so adjusted that at a given temperature its end is
touched by the mercury in the tube. The two wires being connected with an
electric bell and battery, as soon as the mercury touches the wire, contact is
made and the bell rings.
The apparatus was used in experiments with the glass digester, and served
to give notice at some distance from the room in which the latter was being
heated when the desired temperature had been reached, thus rendering an
actual observation of the temperature unnecessary, and so preventing all
danger in case of an explosion.
1034. Normal Thermometer, divided in tenths of a degree
from to 105 C.
Will. ffaak, Neuhaus am Renmoeg, Thuringen.
1035. Normal Thermometer, in a narrow glass cylinder
with a small mercury bulb ; divided in tenths of a degree from
to 105 C. Witt, ffaak, Neuhaus am Rennweg, Thuringen.
1036. Normal Thermometer, divided to tenths from 35
to +50 C. Will. ffaak, Neuhaus am Rennweg, Thuringen.
1038. Two Thermometers, for chemical work, from 10 C
to +360. Will, ffaak, Neuhaus am Rennweg, Thuringen.
1039. Two Thermometers, from 100 to 360.
Will, ffaak, Neuhaus am Rennweg, Thuringen.
1040. Two Thermometers, from to 150.
Will, ffaak, Neuhaus am Rennweg, Thuringen.
1041. Two Thermometers, with divisions etched on the
tube. Will, ffaak, Neuhaus am Rennweg, Thuringen.
1045. Various Pressure Thermometers, on the plan of
Mitscherlich. See accompanying pamphlet.
Prof. Mitscherlich, Munden.
1046. Metallic Thermometer for Lectures, on the plan
of W. Beetz, constructed by Sauerwald, of Berlin. Consult the
adjoining description and scheme. P ro f- Bcetz, Munich.
1047. Model of an Apparatus for measuring Tempera-
tures by means of Thermo-batteries.
Dr. J. Fernet, Breslau.
The apparatus permits the quick and trustworthy determination of the
temperature of the several soldered places, as well as the differences of
temperature of any two soldered places.
in. THERMOMETRY. 263
In the first case the resistances of the single conductors (except the
resistances of the two soldered places, which are exposed to constant tempe-
ratures, and show always the same resistance) may be different. In the other
case the resistances of all soldered places must he capable to be made equal.
1048. Diagrams, illustrating the application of the Apparatus
for the Measurement of the Temperature of the Earth
and of metal tools. Dr. J. Fernet, Breslau.
1049. Normal Thermometer, divided in tenths of a degree
from -5 to +105 C. Ch. F. Geissler and Son, Berlin.
1050. Chemical Thermometer from - 10 to +360 C.
Ch. F. Geissler and Son, Berlin.
2582. Collection of Thermometers.
Dr. H. Geissler, Bonn*
105Oa. Thermometer for Cooking, range to 6OO F.
Harvey, Reynolds, and Co.
See Mrs. Buckton's book "Jiealth in the House," page 153.
1051. Apparatus for determining the Temperature of Fusion.
(Compare the adjoined description.) Prof. Dr. Himly, Kiel.
1052. Air Thermometer on the plan of Jolly. Compare
PoggendorfF s Annalen, Jubelband, 1873.
University of Munich (Prof. v. Jolly)*
1053. Thermopile on the plan of Melloni of 64 bismuth anti-
mony elements. Wesselhoft, Halle*
1054. Thermometer Stick for measuring temperatures at
some depth. Ludwig Meyer, Berlin.
The instrument, adapted for depths down to 3 feet, is chiefly distinguished
by the strength of its construction.
The bulb is in the nickel clamp, which latter stands by means of mercury
in thermal connexion with the bulb. This mercury serves also as buffer ta
the thermometer bulb.
The horn clamp is replaceable by an iron screw, which facilitates the intro-
duction of the thermometer into the ground.
Care is taken that only the clamp be thermo- conducting, not the whole
tube.
1055. Milligrade Thermometer. The milligrade scale is
one in which the interval of temperature between the freezing
and boiling points of mercury is divided into one thousand
degrees. John Williams, F.C.S.
According to Dulong and Petit, mercury freezes at ^39* 44 C., and boils
at + 360 C. For convenience, assuming that the freezing point is 40 C.,
the interval is therefore 400 degrees C., thus it follows that 2| degrees
milligrade are equal to 1 degree centigrade. Upon this scale the following
results are obtained. Water freezes at 100 M. and boils at 350 M., the
264 SEC. 8. HEAT.
interval 250 being just one-fourth of the interval between the freezing and
boiling points of mercury. Many other substances also show a curious
relation in the interval between their freezing and boiling points to that of
mercury, facts which are not obvious upon other thermometric scales.
The practical advantages of this system of graduation consist in the com-
parative.smallness of the degrees, thus avoiding in many cases the necessity
of the use of fractions to express the boiling point of substances ; also that
the zero point being so low the scale is a continuous one, all numbers under
100 M. representing temperatures below freezing water, but avoiding the
necessity of the use of the minus sign, and at higher temperatures as 1,000
is approached, giving a clear idea that the heat is arriving at the extreme
limit of thermometric registration.
In practically graduating this thermometer reference is not made to the
freezing or boiling points of mercury, but the freezing point of water is
marked as 100, and the boiling point as 350, and the scale carried upwards
or downwards as required.
The conversion of centigrade degrees into milligrade degrees, or vice versa,
is extremely simple. A centigrade degree multiplied by 2^, and 100
added, gives the milligrade degree, thus 40 C. multiplied by 2^ is 100, and
100 added gives 200, the degree on the milligrade scale. The correspondence
between the Fahrenheit and the milligrade graduation is not so simple, as
the interval on the Fahrenheit scale between the freezing and boiling points
of water being 180 F., higher numbers are required to be used in the
calculation. The following are the lowest common numbers for the scales :
25 milligrade, equal to 10 cent, and equal to 18 Fahr.
Thus it follows that the following rules can be applied to calculate one
scale with the others
To convert centigrade into milligrade degrees - n x 5-f-2 + 100.
To convert milligrade into centigrade degrees - n 100 x 2-r5.
To convert Fahrenheit into milligrade degrees - n *- 40 x 25-^-18.
To convert milligrade into Fahrenheit degrees - n x 18-^-2540.
lO55a. Thermometer, with 19 differently graduated scales,
traced on a silvered metal plate ; the centre is occupied by the
thermometer-tube and bulb. This instrument was made in 1754.
Prof. Buys-Ballott, Utrecht.
1055b. Four Registering Thermometers.
E. Cetti and Co.
1055c. Siemens* Pyrometer. E. Cetti and Co.
lO55d. Metallic Thermometer, indicating two tempera-
tures. Francis JPizzorno, Bologna, Italy.
The movements of the index are in this instrument produced by the dilata-
tion of two zinc blades which in the figure are seen edgewise. Along the
graduated arc can be fixed two sliding pieces ; if the index touches one of them,
it closes an electric circuit and rings a bell. Two small pearls carried by a
thread stretched between the extremities of the graduated arc, and which are
displace! by the index in its movements, serve to indicate the maximum and
minimum temperature.
1055e. Five Thermometers, various. E. Cetti and Co.
1055f. Mathiessen's Differential Thermometer.
E. Cetti and Co.
m. THERMOMETRY. 265
1068. Pyrometer, of iron and copper, for lecture illustration.
Yeates and Sons.
The above consists of a compound bar of iron and copper, bent into the
form of U) one arm of which is firmly attached to the stand ; the other arm is
free, and carries a long index. If the compound U be immersed in a beaker
of boiling water, the index will move over several degrees of the scale.
1069. Reflecting Pyrometer, for showing by projection the
difference of expansion of different metals. locates and Sons.
1074. Pyrometer. 0. Schiittc, Cologne.
The pyrometer for determining the temperature of the heated blast-current
deserves particular attention on the part of proprietors, overseers, &c. of
foundries, on account of the simplicity of its construction, which is proof
against deranging influences, although constantly exposed to a destructive
element, viz., the glowing hot current, the more especially as no pyrometer
has been made as yet with which temperatures up to 600 degrees Celsius and
more can be continuously determined.
By the application of this pyrometer it will be possible to control at any
time the apparatus and the stokers, and in cases where Siemens' or other
similar apparatus are employed, to determine the exact time when the same
must be reversed. The pyrometer, likewise, indicates any disturbing in-
fluences occurring in the flues, variations in the fuel, in the atmosphere, &c.,
and thus offers the best guarantee that the heating of the apparatus is not
forced to such an extremity as to cause the destruction of the pipes, stop-valve,
&c.
1071. Copper Pyrometer, for determining the temperature
of blast when highly heated. E. A. Cowper.
The temperature of the blast is readily ascertained by heating a small
piece of copper in it, and then dropping the copper into a pint of water in a
copper vessel surrounded by a non-conductor, and where a thermometer
shows one degree for every fifty degrees the copper had been heated. The
thermometer is provided with two scales, one fixed, showing the temperature
of the water, the other sliding, showing the temperature of the blast.
1074a. Water Pyrometer. C. W. Siemens.
The pyrometer consists of a copper vessel, capable of holding rather more
than a pint of water, and well protected against radiation by having its sides
and bottom composed of a double casing, the inner compartment of which is
filled with felt. A good mercury thermometer is fixed in it, having, in addition
to the ordinary scale, a small sliding scale, graduated and figured with 50
degrees to 1 degree of the thermometer scale ; there are also some cylindrical
pieces of copper provided with the pyrometer, each accurately adjusted in
size, so that its total capacity for absorbing heat shall be l-50th that of a pint
of water.
In using the pyrometer, a pint (0*568 litre, or 34 - 66 cubic inches) of water
is measured into the copper vessel, and the sliding pyrometer scale is set with
its zero at the temperature of the water as indicated by the mercury thermo-
meter ; a copper cylinder is then put into the furnace or hot blast current
the temperature of which it is wished to ascertain, and is allowed to become
heated for a time varying from 2 to 10 minutes, according to the intensity of
the heat to be measured.
It is then to be withdrawn and quickly dropped into the water in the
copper vessel, where it raises the temperature of the water in the proportion
266 . SEC. 8. HEAT.
of 1 degree for each 50 degrees of the temperature of the copper. The rise
of the temperature may then be read off at once on the pyrometer scale, and,
if to this is added the temperature of the water as indicated on the mercury
thermometer before the experiment, the exact temperature required is
obtained.
For very high temperatures platinum cylinders may be employed instead
of copper.
1074b. Electrical Pyrometer. C. W. Siemens.
The electrical resistance of metal conductors depends upon their dimensions,
material, and temperature ; an increase of the latter causing a corresponding
increase of resistance. The law of this increase is known.
Thus, the resistance of a conductor being ascertained at zero centigrade,
it can be calculated for any temperature, and vice versa ; if the resistance can
be found by measurement, the temperature can be calculated. This is the
principle upon which Siemens' electrical pyrometer is based.
A platinum coil of a known resistance at zero centigrade is coiled on a
cylinder of fire-clay, protected by a platinum shield, which is placed in an iron
or platinum tube, and then exposed to the temperature to be determined.
Leading wires are arranged to connect this coil with an instrument suitable
for measuring its resistance, and from this resistance the temperature can be
calculated.
The instrument supplied for this purpose is a differential voltameter.
The differential voltameter consists of two separate glass tubes, in each of
which a mixture of sulphuric acid and water is decomposed by an electrical
current passing between two platinum electrodes. The gas which is
generated is collected in the long cylindrical and carefully-calibrated top of
the tube, and its quantity is read off by means of a graduated scale fixed
behind the tubes.
Movable reservoirs are provided communicating with the tubes to regulate
the level of the liquid.
The current of the battery is divided (by passing a commutator) into two
circuits, one of which consists of standard resistance in the instrument and
the platinum electrodes in one tube ; the other, of the resistance to be
measured and the electrodes in the other tube. The quantities of gas de-
veloped in the two tubes are in inverse proportion to the resistances of their
respective circuits, therefore one of the resistances, viz., that in the instrument,
being known, the other can be calculated.
Directions for use : Fill the battery glasses with pure water, or, in case
of the power of the battery decreasing, with a solution of sal-ammoniac in
water. Connect the poles to B and B' on the commutator. Expose the small
end of the pyrometer-tube, as far as the cone, to the heat to be measured, and
connect the terminals x, x r } c to the ends of the leading cable bearing corre-
sponding letters. Connect the other end of the leading cable to the terminals
x, x', c on the voltameter.
The differential voltameter is to be filled with the diluted sulphuric acid
through the reservoirs, the india-rubber cushions being lifted from the top of
the tubes. The commutator is to be turned so that the contact springs on both
sides rest on the ebonite. The liquid in both tubes is to be regulated to the
same level (zero of scale), and the india-rubber cushions to be let down again.
Give the commutator a quarter of a turn, and the development of gas will
commence almost immediately. Turn the commutator half round every ten
seconds to reverse the current. Keep the current passing until the liquid has
fallen in the tubes to at least 50 degrees of the scale, then put the commutator
in its first position, so that the contact springs rest on the ebonite ; read off
the level of the liquids on the scale marked V, and the scale marked V ; find
III. THERMOMETRY. 267
these numbers in the table under V and V, and the intersecting point of the
lines starting from these figures gives the temperature.
- For a new experiment adjust the levels as before.
1077. Bailey's Patent Civil Engineers' Pyrometer, for
ascertaining the temperature of flues, &c., with sheath and box-
wood handle to enable managers of works and others to carry
it about with them for use when necessary. W. H. Bailey 4* Co.
1080. Bailey's Patent Flue Pyrometer, for testing the
temperature of boiler flues, hot-air chambers, stoves, galvanisers,
&c. W. H. Bailey $ Co.
lOSOa. Hobson's Patent Hot Blast Pyrometer.
Joseph Casartelli.
In this instrument the aim is to tone down the temperature of the blast by
an admixture of a constant proportion of cold atmospheric air, so that the
highest temperature likely to have to be recorded is brought within the range
of a good mercurial thermometer. The hot blast is introduced in the form of
a jet, which by suitable arrangement is made to induce a stream of atmospheric
air ; the mixed stream then passes on, and impinges on the bulb of the thermo-
meter. The scale has been laid down by experiment, and the instrument gives
the same reading as Siemens' copper ball pyrometer. It is found that pressure
does not affect the result ; and, as all the instruments are made exactly alike,
the same result is invariably obtained. By the use of this instrument much
time is saved, and the result is more trustworthy than with any other instrument
in use.
1080b. Casartelli's Improved Pyrometer, for ascertaining
the temperature of flues, stoves, &c. Joseph Casartelli.
This instrument consists of two different metals of different ratios of expan-
sion, and any permanent set which may take place in the metals is compensated
by the fact that the set will take place in opposite directions. The scale is laid
down by experiment. It is so constructed that it is only necessary to expose
one half of the stem to the action of the heat.
1081. Bailey's Patent Bakers' Pyrometer, "Bakers'
Guide," for ascertaining the temperature of bakers' ovens, and
enabling them to prevent the possibility of the bread becoming
burnt, by keeping the oven at one uniform temperature.
W. H. Bailey $ Co.
1082. Wood and Bailey's Patent Blast Furnace Pyro-
meter, for ascertaining the temperature of hot blasts.
W. H. Bailey $ Co.
o)
268 SEC. 8. HEAT.
IV. C ALORIMETRY.
1063a. Original Apparatus of M. Hegnault for ascer-
taining Specific Heat by observing Refrigeration.
College of France, Paris.
lO97a. Diagrams (3), representing the Apparatus of M.
Regnault, by M. d'Obelliane. Polytechnic School, Paris.
1064. Lavoisier's original Calorimeter.
Conservatoire des Arts et Metiers, Paris.
Pabre and Silbermann's original Calorimeter, for
measuring the heat disengaged in combustion.
Conservatoire des Arts et Metiers, Paris.
lO64a. Original Vessel, by Dulong, for measuring Specific
Heat by Refrigeration. Polytechnic School, Paris.
1064b. Original Apparatus, by M. Hegnault, for ascer-
taining the latent Heat of Steam at diiferent pressures.
College of France, Paris.
1057. Apparatus employed by Dr. Andrews in his experiments
on the amount of heat disengaged in the combination of hydrogen
and other combustible gases with oxygen. Dr. Andrews, F.R.S.
The gases contained in a cylindrical vessel of thin copper are exploded by
the ignition of a fine platinum wire, and the heat is measured by the rise of
temperature of the water in a calorimeter, capable of being rotated gently
round its horizontal axis.
1058. Apparatus for determining the amount of heat produced
in the combination of liquids and solids with 'oxygen.
Dr. Andrews, F.R.S.
1058a. Fabre and Silbermann's Calorimeter.
L. Golaz, Paris.
This apparatus consists of:- 1. A large brass vessel closed by a cover in
two parts and open in the centre. 2. A thin copper vessel coated with silver
in the interior. 3. A vessel like the preceding, fitted with a cover. The
calorimeter is supported in the centre of the second enclosure. The space
between it and the second enclosure being lined with the skin of a swan. In
the interior of this vessel is placed an agitator and a thermometer, made with
great precision.' All these different enclosures are placed in a large and
solid triangular support, having two plates united by three copper columns.
The combustion chamber is a thin copper vessel, having at its upper
extremity an opening closed by a plug flush with the side of the chamber,
and provided with a tube by which the gases and the products of the com-
bustion are discharged. A helix formed by a thin tube is fixed to this
opening, and so arranged that the gases pass through it from end to end, and
are discharged at the upper extremity, whence they are collected in vessels
placed for that purpose. A second tube is fixed to the combustion chamber
reaching to the lower part, and serves for introducing the oxygen into the
IV. CALORIMETKY. 269
chamber. The stopper is formed of a piece of metal exactly fitting the upper
part of the combustion chamber, and carrying two tubes, by one of which can
be introduced the pipes for hydrogen or oxygen according to the nature of the
combustion desired. The other is used for watching the combustion. For
that purpose it is closed at its lower end by a threefold plate, of glass, quartz,
and alum ; a small looking-glass is placed at the upper end of this tube, and by
this means all that is going on in the interior can be seen.
lO58b. Regnault's Apparatus for determining Specific
Heat of Gas. L. Golaz, Paris.
This apparatus, constructed for M. Regnault by the exhibitor, consists of
three parts:
1. This affords the means of obtaining a current of gas, the velocity of
which is constant and can be regulated as desired.
2. The bath, which imparts a determinate initial temperature to the gas.
3. The calorimeter in which the gas parts with its excess of heat.
The first part of the apparatus is composed of a copper reservoir, holding
about 35 litres, and provided with two stop-cocks. It is placed in a vessel
filled with water, which keeps it at a temperature sensibly constant, and
always accurately known. The central reservoir is full of gas under a pressure
determined by a syphon pressure gauge.
The flow of the gas is regulated by a delicate valve formed of a vertical
tube, in which a close fitting spindle works by means of a micrometer screw.
The end of the spindle is conical, and fits into a corresponding seating at the
bottom of the tube. The diameter of the spindle is slightly diminished about
one centimeter above the cone. The gas passes into the valve through a
capillary opening at the apex of the conical seating, and passes out round the
diminished part of the spindle to the outlet pipe, which is about a centimeter
above the inlet. In connexion with the outlet pipe is a syphon pressure
gauge. The amount of clearance given to the valve is indicated by a
graduated disc fitted to the top of the spindle.
The oil-bath which heats the current of gas consists of a cylindrical vessel,
in which is a helical tube ten metres in length. Its extremity is connected
with the calorimeter by means of a nozzle, in which is fitted a small tapering
glass tube by means of a cork, through which it passes. The bath has a cover
at the top, through the middle of which passes a square rod carrying an
agitator ; a short tube fixed to the cover, near the exit of the gas, allows of
the introduction of a thermometer, so that the temperature of the gas before
entering the calorimeter can be ascertained.
The boiler is preserved from immediate contact with the surrounding air
by means of a metallic jacket, which serves at the same time as a support ;
the base of this support is furnished with levelling screws ; an iron column
placed behind supports a rod with a clamp holding a horizontal bar, at the
end of which is a pulley over which passes the cord sustaining the agitator.
The bath is warmed by a gas lamp.
On leaving the bath, the gas goes into the calorimeter, which consists of a
cylindrical vessel of thin brass, provided with a nozzle through which the
gas enters, and 4 shallow cylindrical boxes, through all of which the gas
passes successively. These boxes communicate with one another and with the
lower vessel by means of tubes suitably arranged ; on leaving the uppermost
box, the gas discharges itself into the atmosphere by a short tube. A very
thin strip of brass bent spirally is in the interior of each box ; so that the gas
on leaving the principal vessel traverses successively the superposed boxes,
circulating the while for a long time in contact with their cold sides and in
the ducts which offer sections sufficiently large for resistance to be but very
270 SEC. 8. HEAT.
feeble. All these boxes are contained in a cylindrical vessel made of brass,
into which a determined volume of water, at a known temperature, is poured.
In this first envelope is a thermometer and an agitator. To preserve the
calorimeter from irregular currents of air it is enclosed in a second vessel,
the bottom of which is provided with three small cones made of wood or
cork, on which is placed the calorimeter. This vessel has a hole in the side
to allow the tube of the calorimeter to pass through, and a cover in which are
two holes, one of which affords a passage for the discharge tube, and the
other for the stem of the agitator. It has, moreover, a third opening through
which the thermometer is introduced. Finally the calorimeter and its enve-
lopes are supported and fixed at their proper height by means of an adjustable
foot.
The details of the experiments made, and the latest information published
by M. Eegnault, will be found in the " Meinoires de 1' Academic des Sciences,"
vol. 26, p. 41.
1058bb. Regnault's Apparatus for determining the
Specific Heat of Solids. L. Golaz, Paris.
This apparatus, made by the exhibitor for M. llegnault on a new pattern,
enables experiments to be made with great ease and rapidity. It is com-
posed of three distinct parts : 1. The stove for heating the body which is
to be investigated. 2. The apparatus for the production of steam. 3. The
calorimeter.
1. This consists of three concentric tubes closed at their upper ends by a
copper plate attached by bolts to the circumference of the outside tube, at the
centre there is an opening of the size of the central tube and closed by a
metallic plug with double sides, in the centre of which there is another
opening in which a thermometer is fixed. At the lower end of the tubes
there is bolted a metallic plate similar to the one above, and terminating
in a cone ; the central tube also has an outlet at the base of this piece, the
second enclosure descends near the sides of the cone, the third enclosure
is attached to this piece. The vapour issuing from an apparatus to be
described further on reaches the lower part or base of the cone, between the
first and second enclosure, circulates all round and warms the centre, leaves
this chamber by holes made at the top of this tube and passes once more into
the third enclosure, whence it goes into the neighbouring condenser.
2. The apparatus for producing the steam is a copper boiler furnished
with three .tubes, the first of which, placed in the centre, receives an
apparatus of copper in which the steam on its way back is condensed 5 above
the condenser is a funnel fed by a current of water which accelerates con-
densation ; a return tube reaches to the bottom of the boiler and serves as a
passage for the condensed vapour. The second tube, which is the largest, is
used as a conductor for the vapour to the stove. The third one, which is
small in diameter, brings the vapour which can be condensed in the stove
directly into the boiler. The condenser is bound to the enclosures by tubes
provided with junctions.
3. The calorimeter is composed of two concentric vessels supported on a
wooden stand with square columns, and on one of them is placed a copper
block, which serves to fix the thermometer. Under this support there is
screwed a copper carrier, which slides on a guide of the same metal fixed to
the table of the apparatus. A sliding wooden screen intercepts the radiation
of the rest of the apparatus from the calorimeter. A chair suitably placed
supports the stoves, and a support connected with the table serves to fix at a
convenient height the apparatus for producing the vapour.
IV. CALORIMETKY. 271
The body to be studied is placed in a small metallic basket suspended in
the middle of the central tube of the stove ; a thermometer indicates the tem-
perature of this part of the apparatus. When the moment has come for
bringing down the body into the calorimeter the screen must be lifted up, and
the carrier which supports the thermometer made to slide on the copper guide
until it reaches a certain point fixed on the guide. With one hand the basket
is let slip, and with the other the detent of a rapidly acting spring appliance
is released. The body being thrust into the calorimeter it must be brought
back to its former position and the screen then lowered. This apparatus,
which is easily worked, enables M. Regnault's experiments on this subject to
be repeated most accurately.
1058c. Jamin's Calorimeter. L. Golaz, Paris.
This instrument, made for the designer, is constructed on the same principle
as M. Favre's, but being only used for demonstrations its construction is
simpler. It consists of a cylindrical vessel of glass, provided with an iron
cover to which are fixed two iron tubes reaching down into the cylinder, the
stern of the thermometer being placed vertically in the cover. A small glass
funnel is placed over a stop-cock terminating in a capillary glass tube, which
serves for filling the apparatus.
lOSSd. Bunsen's Absorptiometer. L. Golaz, Paris.
This apparatus consists of a wooden stand, to which is fixed an iron ring
carrying two yertical supports, united at the top by a circle to which is fixed
a plate on hinges. Along one of the columns is placed an iron tube, having
at its upper end an iron funnel ; at the lower it enters the vertical opening, of
a three-way cock. One of the horizontal openings communicates with a
chamber made in the centre of the stand, and the other communicates with
an outlet; thus it is possible either to make the mercury run into the
chamber, or, by turning the cock another way, to permit it to escape.
On the upper surface of the wooden stand has been made a deep groove, at
the bottom of which is fixed a washer of vulcanized india-rubber. A glass
cylinder, the ends of which are perfectly true, rests in this groove, and fits
the top of the stem ; the plate, which is used as a cover, is provided with an
india-rubber disc, and rests on the top of the glass cylinder.
The absorption-tube is open at its lower end, and cemented into a socket
made of iron, having a screw thread which fits into an iron block cut away at
the sides. A rotary motion about its axis is sufficient to cause the opening
or closing of this tube, an india-rubber washer being placed at the junction.
On the part of the block which is not cut away are fixed two springs of
steel, which retain it in the hollow of the stand and in two diametrically
opposite grooves which are placed there ; a slight friction is thus produced,
permitting however the opening and shutting of the absorption tube. At the
centre of the higher plate of the cover is an iron socket on which is stretched,
by means of a ring screwed to it, a piece of india-rubber ; in lowering the
cover the point of the tube enters into the socket, and the tube is found per-
fectly fixed at the centre.
1058e. Regnault's Air Thermometer. L. Golaz, Paris.
This apparatus is composed of a glass cylinder terminating in a capillary
stem bent at right angles, and supported by a metal stand, having in its
centre a tube on which is placed the stem of the thermometer. The screw
272 SEC. 8. HEAT.
adjustment, with two pointers, is used to take, by means of the cathetomtter,
the height of the mercury in the small glass vessel which is placed underneath
the apparatus. Above is arranged a glass cylinder which serves to hold the
ice in the experiment. A bent tube lets the water which runs off escape.
lO58f. Regnault's Apparatus for determining Specific
Heat of Liquids. L. Golaz, Paris.
This apparatus consists of a cylindrical copper vessel, having at its lower
extremity a lateral conical appendage. In the axis of the vessel there is a
cylinder of brass which receives the liquid to be experimented upon, and which
is furnished at its upper part with a vertical tube, into which is inserted a
thermometer, giving the temperature of the liquid. The cylinder terminates
.in a stop-cock inclined downwards, and having at its lower extremity a tube
which, after having traversed the conical space, is soldered to the cylinder,
enters the tube of the calorimeter at the other side of the stop-cock, and
terminates in a tube which goes through the wall of the cylinder. It is by
this tube that the key of this stop-cock enters, it being worked from the
exterior. A hole made in the hand of the key establishes a current of air
which drives the liquid into the calorimeter, at the same time that the stop-
cock is turned for that purpose.
A double wooden screen, fixed perpendicularly, cuts off all radiation from
the vessel which is being heated or from the calorimeter. Two iron arms
fixed to the upright of the screen support the vessel at such a height that a
gas burner may be placed underneath.
The calorimeter consists of a brass cylinder, into which passes the liquid
experimented on, and of a flat vessel containing a thin screw- shaped blade
for the purpose of condensing the vapour which might be generated by the
liquid in the vessel. A brass receptacle surrounds this first calorimeter,
a second one, resting upon feet made of wood or cork, surrounds the first.
The height and the position which must be given to the calorimeter are regu-
lated by a stand with a movable column. The description of the experiments
with this instrument is to be found in " Memoire de 1' Academic," tome 26,
page 262.
This apparatus is constructed of glass, copper, or platinum, according to
the nature of the liquids upon which it is desired to operate. The one exhi-
bited is made of platinum.
1058g. Favre's Mercury Calorimeter.
L. Golaz. Paris.
This apparatus consists of a large spherical reservoir of cast-iron, resting
on a support of iron, surrounded with a non-conducting substance. Under-
neath is made a vertical opening, through which a steel piston passes, being
set in motion by a screw provided with a winch-handle. Near the centre of
the sphere there is a cast-iron tube on which is screwed a steel stop-cock,
terminating in a small glass ball, to which is fitted a carefully calibrated
horizontal thermometer. The graduations on the stem of this thermometer
correspond with its interior capacity ; it is supported by two wooden columns,
which rest upon a solid bench opposite the stem, and on the corresponding
side are two iron tubes, placed obliquely with regard to the vertical diameter
of the sphere. These two tubes, called "mouffies," are immovably fixed to
the iron sphere, and extend to its interior. They are thus completely sur-
rounded with mercury when the reservoir is full, an operation which is very
easily accomplished by means of two stop-cocks placed opposite to the
plunger. A small glass pipe of a particular shape is used for bringing liquids
V. HAPIATIOX. 273
into the " mouffles." The divisions on the stem of the thermometer are read
by means of a micrometer. To protect the large bulb of the thermometer
from the influence of the temperature of the exterior, it is surrounded by a
wooden box, in which is placed flannel and swan's down.
1060. Thermometric Tube for determining the calorific capa-
cities of different liquids. Elie Wartmann, Geneva.
A thermometric tube, being part of the exhibitor's apparatus for the
determination of calorific capacities in liquids. A full description of the
method is printed in the number for May 1870 of the " Archives des Sciences
physiques et naturelles." An electric chronoscope, such as Sir Charles
Wheatstone's, expresses in thousandth parts of a second the time necessary
for the cooling between two constant temperatures of the same body (the ther-
mometric tube) when immersed in equal volumes of different liquids, at the
same initial degree of heat.
1061. Apparatus made by De la Rive and Marcet for
measuring the specific heat of Gases. A small copper calori-
meter, containing a very thin serpentine gold pipe.
Lucien de la Rive, Geneva.
1O63. Drawing of an Apparatus for determining the calo-
rific capacity of liquids.
Dr. Leopold Pfaundler, Professor of Physics at Innsbruck.
In a box protected against draught there are placed two calorimeters one
filled with water, the other with the liquid to be tested. An electric current is
passed through the two spiral wires, of equal resistance, which are inserted in
the fluids.
Two paddles stir the liquids, and two thermometers measure the tempera-
ture.
The respective capacities for heat are calculated from the proportion of the
increment of heat.
V. RADIATION.
1O56. Hargreaves's Thermo-radiometer, for measuring
loss of heat by radiation from walls of furnaces, sides of steam
boilers, &c. James Hargreaves.
The silver-plated copper vessel is filled with water and enclosed in the
case, the blackened face then being exposed for a given time (say five
minutes) to the radiating surface, a thermometer inserted in the neck
of the vessel shows the elevation of temperature due to radiation. The
lieat is calculated as follows, either in calorics or British thermal units.
WS(T-t) _ x ^rh ere -y^g _ we ight and average specific heat of vessel
a m
and its contents ; t, temperature of the same before exposure ; T, temperature
of the same after exposure ; a, area of blackened face of vessel ; and m, time
of exposure, whence may be calculated the amount of fuel necessary to
replace the heat lost by radiation.
40075. S
274 SEC. 8. HEAT.
1O62. Apparatus used in researches on the Absorption
of Radiant Heat by gases and vapours.
Prof. Tyndall, F.R.S.
Phil. Trans., 1861.
1065. Pair of concave Reflectors of Prima German
silver, 500 mm. in diameter, on brass stands, with supports for
carbon and tinder, for experiments on radiant heat.
Warmbrunn, Quilitz, and Co., Berlin.
1066. Melloni's Apparatus for the investigation of the
laws of radiant heat. H. Lloyd, Trinity College, Dublin.
1072. Fouillet's Actinometer, for sidereal radiation.
Conservatoire des Arts et Metiers, Paris.
lO72a. Actinometer, for measuring the intensity of
Solar Radiation. J. Louis Soret, Geneva.
It is composed of a tube, of the diameter of about 35 millimetres, closed at
one end, and blackened inside. The end, which can be opened by removing
the stopper, is furnished with a diaphragm. The central tube is encircled with
a concentric brass wrapper, which has to be filled up with pounded ice, or with
snow. The apparatus is upheld by a horizontal axle upon a wooden support.
This axle is formed of a tube which, on one side, lets out the rod of the ther-
mometer (lacquered and blackened), and on the other may be adjusted to an
air-exhausting pump. The apparatus is directed towards the sun ; the orien-
tation is obtained by means of the exterior appendiculse.
See " Recherches sur Pintensite calorifique de la radiation solaire. Comptes
Rendus de 1'Association Fra^aise pour I'Avancement des Sciences," 1st
Session, Bordeaux, p. 282.
1072b. Actinometer.
M. Desains, Member of the Institute, Paris.
1073. Fouillet's Pyrheliometer, for observations on solar
heat. Conservatoire des Arts et Metiers, Paris.
VI. ABSORPTION.
1084. Ice-making Machine ; system of Raoul Pictet & Co.
Raoul Pictet fy Co., Geneva. Geneva Association for
the Construction of Scientific Instruments.
This machine manufactures ice by means of anhydrous sulphurous acid.
This substance has the following advantages :
1 . It is without action upon metals and fatty substances,
2. It gives but slight pressures, never exceeding 4 atmospheres in a
temperature of 30 centigrade.
3. It is free from all danger of ignition or explosion.
4. It is the least expensive volatile liquid.
This machine turns out 12 kilogrammes of ice per kilogramme of coal
consumed.
VII. CONDUCTION. 275
1085. Apparatus for Freezing Water, constructed by
Mr. Bieberich. Compare the adjoined instruction for use.
University of Munich (Prof. v. Jolly).
1086. Small Ammonia Ice Machine.
Vaast and Littmann, Halle.
VII. CONDUCTION.
1091. Bespretz's Apparatus for showing the Conduction
of Heat in metals with 9 thermometers.
Warmbrunn, Quilitz, and Co., Berlin.
109Oa. Three Original Bars, by Despretz, used in his
experiments upon the Laws of Conductivity.
The Faculty of Sciences \ Paris.
1038. Forbes 9 Iron Bar for Thermal Conductivity, with
its crucible. P ro f' Tait.
1089. German Silver Bar, of same size, cast for same
purpose. Prof. Tait.
1059. Biacalorimeter. To measure the resistance which
liquids offer to the passage of heat. Frederick Guthrie.
Two conical platinum vessels, having their bases accurately plane, are sup-
ported so that their bases are parallel, horizontal, and nearly in contact. The
lower cone is fixed, and, being provided with a vertical tube fitting air-tight
in which water stands at a known height, serves as an air thermometer and
calorimeter. The upper cone can be adjusted by a micrometer screw at any
distance from the lower one. Through the upper cone a current of warm
water or steam is passed. Between the bases of the cones is introduced the
liquid whose thermal resistance is to be measured.
1092. Zngenhousz's Apparatus for demonstrating the Con-
duction of Heat, with nine rods of different metals.
Warmbrunn, Quilitz, and Co., Berlin.
1093. Apparatus intended to produce the Curves of Ther-
mic Conductivity on the surface of bodies.
M. Jannetaz, Paris.
On the glass support are placed plates coated with grease, which may be
coloured. The current of a battery is made to pass through the small platinum
ball, which is at the end of wires of the same metal, and which are put into
contact with the plate.
S 2
276 SEC. 8. HEAT.
1093b. Four Boxes, containing plates subjected to the action
of the above apparatus, and showing the isothermic curves pro-
duced by the fusion of the grease upon
A. Bluish schist, from the valley of Sulvan, near Vernagaz.
B. Coal schist, from neighbourhood of Motivon, near the Col
de Voza.
C. Another schist from the Col de Voza.
D. Septypite from Tholy (Vosges).
E. Clayey schist.
F. Hyaline quartz, with faces cut parallel with the axis.
G. Trooshte, silicate of zinc, with faces cut parallel with the
axis.
H. Gneiss, fine grained, from the Val Anzasca, Monte Rosa.
M. Jannetaz. Paris.
VIII. POLARISATION.
1095. Forbes' Mica Plates for the polarisation of heat by
refraction. University of Edinburgh.
The mica is split into numerous thin films by careful application of heat,
and fixed in the wooden tubes at the proper polarising angle.
IX. MISCELLANEOUS.
Lens of Benedetto Bregans, 42 cm. in diameter, given to
the Grand Duke Cosimo III. after 1690. With this lens Avesani
and Yargioni, 13 years after the extinction of the Accademia del
Cimento, made the well-known experiments on the combustion of
the diamond and other precious stones. Afterwards it served the
celebrated Sir Humphry Davy for his researches on the chemical
constitution of the diamond.
The Royal Institute of" Studii Superiorly Florence.
Plaster Model of Thermo dynamic Surface.
Prof. J. Clerk Maxwell.
1O97. Apparatus employed by Professors Stewart and
Tait for producing rapid Rotation in a Vacuum.
Prof. Balfour Stcivart.
The driving shaft is of iron, and passes into the receiver through an iron
tube containing mercury, which acts as a barometer.
This instrument was constructed and in part devised by E. Beckley, of the
Kew Observatory, for an experiment conducted by B. Stewart and P. G. Tait.
The mechanical principle of its construction is as follows : The receiver in
which the rotation takes place is in fact the extended vacuum of a barometer.
Through the mercury of this barometer a shaft communicates a slow motion
to some machinery in the receiver. The velocity of this motion is there
greatly increased by means of a suitable train of wheels, until at length a
vertical disc is made to rotate with great rapidity on a horizontal axis. If
LS. MISCELLANEOUS. 277
this disc be made to rotate in an ordinary obtainable vacuum it will become
heated, and the question is to determine whether this heating of the disc is
entirely due to the friction of the residual air, or to something else.
Two wires, covered with gutta percha, carried through the bed-plate of the
apparatus, convey into the receiver a thermo-pile arrangement, by means of
which the temperature of the disc may be measured. This thermo-pile may
either measure the increased temperature of the disc after rotation by radia-
tion in which case it is fitted with a reflecting cone ; or it may be made to tap
the surface of the disc after rotation in which case there is an arrangement
working through a barometric tube, by means of which the pile may be
brought up to the disc in vacuo after rotation. Finally, there is an arrange-
ment, working also through a barometric tube, by means of which a vessel
containing some peculiar chemical substance may be uncovered in vacuo at
will. The object of this is to reduce the pressure of the vacuum by chemical
means. For instance, if we have a carbonic acid vacuum made as low as it
can be made by ordinary means, a vessel containing moist potash would be
uncovered, and a great part of the residual gas absorbed. The experimenters
by this means have obtained a vacuum as low as 0*025 in. The conclusion
from these experiments appears to be, that there is a certain heating of the
disc which does not depend on the residual air.
1O98. Effects of Heat on Nature. 9 Senarmont crystals
for heat. Laurent.
1100. Automatic Fire Extinguisher and Alarm. For
ships, factories, and all places where steam apparatus is employed.
Sanderson fy Proctor.
The action of the apparatus is as follows :-
Thermometers are fixed on the ceiling or elsewhere in the room, and are
set to complete an electric circuit at a given degree of heat, each thermome-
ter being in connexion with a galvanic battery and electro-magnet. A steam
valve is also fixed in the room, communicating with the valve at the boiler.
As soon as a fire breaks out, and raises the temperature of the nearest ther-
mometer to the given degree, the electric current is complete, and the electro-
magnet, by a very simple contrivance, opens the steam valve in the room and
the valve at the boiler, the steam rushes into the room at the existing pressure
of the boiler and effectually extinguishes the fire. Simultaneously with the
action of the electro-magnet, an electric alarm and indicator are set in motion,
thus giving prompt notice of the fire, and indicating its position.
1101. Prism of Bock Salt, 50x60 mm.
IV. Steeg, Homburg vor der ffohe*
1102. Lens of Bock Salt, 75mm. in diameter, and 300mm.
in radius. W. Steeg, Homburg vor der Hohe*
1103. Plate of Bock Salt, 60x60 mm.
W. Stceg, Homburg vor der Hohe.
1104. Diagram of the Tbermo dynamic Belations of
Aqueous Vapour for pressure up to 30 atmospheres.
Obcrbergrath E. Althaus, Breslau.
These diagrams have appeared on a smaller scale, and accompanied by a
memoir entitled : The Boiler Systems for High Pressure, and their Applica-
tion to Mining Engines, Part III., in the " Zeitschr. fur das Berg-, Hiitten-, und
278 SEC. 8. HEAT.
" Salinenwesen, im Preussischen Staate. Herausg. im Minist. fiir Handel,
" Gewerbe, und offentliche Arbeiten. XXIII. Bd., 5 Lief."
HO4a. Two Photographs, representing the Thermo- venti-
lator when open and closed. M. Wellesen^ Christiania.
This instrument, which is useful as a means of promoting health, consists
of five parts, comprising a regulating balance for heat, and a valve for fresh
air, which is self-closing, and can keep out the cold. The smaller part of
the iron and brass tube (to which a foot or stand is fixed for exhibiting pur-
poses) gives a clear idea of the system by which the thermo-ventilator is
applied to the internal orifice of the atmospheric tube.
1105. Apparatus of sheet metal, constructed by the exhibitor,
for demonstrating the Causes of Disturbances in the Draught
in Chimneys, as well as the influence of wind and weather.
It is at the same time a means of studying the general motion of
air produced by heat (ventilation). Compare the adjoined de-
scription. Prof. Dr. Meidinger, Carlsruhe.
11 05 a. Apparatus for quickly communicating a Given
Temperature to a Liquid, and to maintain it at this temperature.
W. Gloukhoff, Warden of Russian Standard Measures.
It is used in the determination of the density of the liquids ; for the
verification of alcoholometers, hydrometers, &c. ; at normal, or any other tem-
perature. The principal part of this apparatus is a cylindrical metallic
stirrer, immersed in the liquid to be experimented upon, contained in a very
solid glass cylinder. The warm or cold water, poured in small quantities, in
the interior hollow space of the stirrer, by means of a glass funnel introduced
in one of the two metallic tubes communicating with the hollow space, and a
few movements up and down of a stirrer, will very quickly warm or cool the
liquid, and thus bring it to a determined temperature. The syphon, introduced
in another tube, serves to empty the stirrer. In the glass disc, covering the
glass cylinder, are two apertures: the large one, for weighing solid bodies in
liquids, immersing in it the hydrometers, &c. ; and the small one for a ther-
mometer to determine the temperature of the liquid.
llO5b. Apparatus for keeping a Constant Temperature
in an air or water bath.
The Secondary Government School, Assen (Netherlands),
This gas regulator, constructed after the design of Dr. A. Van Hasselt,
teacher at the school for middle-class education at Assen (Netherlands), was
made principally by J. Van Eossum, servant in the laboratory.
The air thermometer, connected with the regulator and with a large Bunsen
cell, is partially filled with mercury, so that only the upper bulb and a
great part of the tube contain air.
When the desired temperature has been reached, the wire of platinum is
screwed down, so as to reach the mercury, at which moment a current from
the cell passes. This current passes through the wire, which is coiled round
the iron tube in the apparatus, through which the gas is flowing, and which is
used as an electro-magnet.
The little iron valve on the side of the tube, covered with a thin plate of
caoutchouc, which now shuts the tube, has a small aperture, which lets pass
gas enough to prevent the lamp from being extinguished.
279
SECTION 9. MAGNETISM.
WEST GALLERY, GROUND FLOOR, ROOM F.
I. NATURAL MAGNETS.
Natural Magnet, mounted by Galileo, weighing six
ounces. He presented it to the Grand Duke Ferdinand II. del
Medici. It is made in the shape of an urn and holds a weight of ten
pounds. The Royal Institute of " Studii Supcriori" Florence.
Galileo was the first to arm natural magnets, and thus succeeded in making
them bear very much greater weights ; he proved, at the same time, that
the same loadstone can bear a greater weight when in several pieces than
when it is in one block ; and that moreover its attractive power can be in-
creased by loading it by degrees with an increasing weight.
Natural Magnet, armed by the Accademia del Cimento.
Accademia del Cimento.
The members of the Accademia del Cimento found that the poAver of this
magnet was not lost by passing through very many substances ; and that its
attractive force varied according to its position with regard to the poles of the
earth.
1106. Great Natural Magnet; one of the largest known.
See Lamont, " Handbuch des Magnetismus," 1867, p. 107.
Teyler Foundation, Haarlem.
Weight, with the armature - 152 kilograms.
Force - K P i 114
1107. Natural Magnet, mounted in brass case, with steel
poles, and soft iron keeper. Elliott Brothers.
llO7a. Natural Loadstones (two), Russian, in perforated
and painted metal cases. Bennet Woodcroft, F.R.S.
II. PERMANENT ARTIFICIAL MAGNETS.
11O8. Collection of Artificial Magnets, lately forged by
M. Van Wetteren, and magnetised at Teyler's Museum.
Teyler Foundation, Haarlem.
A. Single magnet, weight 2 '17 kilogr. ; greatest original force, 51 '3
kilogr. ; permanent force, 35 9 kilogr.
280 SEC. 9. MAGNETISM.
B. Compound magnet. No. 3,053. Weight, 1 52 kilogr. ; greatest original
force, 36*4 kilogr. ; permanent force, 27*7 kilogr.
C. Two single magnets. No. 3,003. Weight, 0-51 kilogr.; greatest
primitive force, 19 '5 kilogr.; permanent force, 12 '4 kilogr. No. 3,005.
Weight, 0-52 kilogr.; greatest" original force, 18 '6 kilogr.; permanent
force, 13-7 kilogr.
A third open keeper with movable side plates.
The box, C, forms a school apparatus, to demonstrate the effect of mutual
contact of the magnets, and of the constitution of the keeper, on the distribution
of free magnetism, on the weight that can be suspended, and on the deflections
of the needle produced by the magnet when open, and when more or less
closed.
See the memoir of Prof. Van der Willigen, Avhich will soon appear in the
Archives du Musee Teyler.
1109. Great Artificial Magnet, forged and magnetised in
1850 by Messrs. Van Wetteren and Logemann, according to the
directions of Dr. Elias, whose property it is.
Teyler Foundation , Haarlem.
Newly magnetised at Teyler's Museum.
Weight - 28 kilograms.
Original force " - - 260
Permanent force - - 200 ,,
1109a. Large Artificial Magnet made of thin Plates.
M. Jamin^ Paris.
10 1O. Photograph of a Horse-shoe Magnet, made by
Johann Dietrich, of Basle, in I75o.
Prof. Hagenbach-Bisclioff, Director, The Physical Insti-
tute in the Bernoullianum, Basic.
1111. Permanent Bar Magnets (pair of), in case.
James Hoiv fy Co.
1112. Compound Horse-shoe Magnet. James How $ Co.
1112a. Series of Permanent Magnets, bar form, in
wooden cases for students. Harvey, Reynolds, and Co.
1113. Logemann's " Magnet, being a powerful battery
of steel-plate magnets. Frederick Guthrie.
11 13 a. Magnets by M. Jamin. M. Breguet, Paris.
1113b. Magnet, Jamin's, with plates 0'05 m. in width.
M. Breguet, Paris.
1113c. Large Artificial Magnet, and fittings.
M. Jamin, Paris.
III. ELECTRO-MAGNETS. 281
III. ELECTRO-MAGNETS AND ELECTRO-MAGNETIC
ENGINES.
1115. Large Electro-Magnet, for showing magnetism and
diamagnetism. Elliott Brothers.
1115a. Small Electro-Magnet by M. cFObelliane, bearing
thirty times its own weight. Polytechnic School, Paris.
1116. Three Electro-Magnets.
The Committee, Royal Museum, Peel Park. Salford.
One of which is a circular plate, 4^ inches diameter ; another, a plate
4^ inches square ; and the third, 4 inches, with one armature ; the 4-inch
magnet will sustain a load of 1,400 Ibs. to 1,500 Ibs. Made by the late
R. Roberts, C.E., of Manchester.
1117. Powerful Electro-Magnet.
The Committee, Royal Museum, Peel Park, Salford.
Of the horse-shoe form, with an elliptical section. Made by the late
R. Roberts, C.E., of Manchester.
1118. Surface Electro-Magnet made in 1840. When fully
excited, the armature is retained with a force of upwards of a ton.
J. P. Joule, D.C.L., F.R.S.
1119. Electro-Magnet, on Joule's Construction, mounted
so as to serve for supporting weights, or for experiments on Dia-
magiietism. Dr. Stone.
1119a. Electro-Magnet, by Repmann.
M. Breguet, Paris.
1119b. Electro-Magnet, by Jablochkoff.
M. Breguet, Paris.
1119a. Small Electro-magnet. H. L. Rutter.
10 2O. Tubular Electro-Magnets. John Faulkner.
In this system iron cases are used, of such size and thickness as ensures
the utilisation of the maximum magnetic effect.
The object is to accumulate and utilise all or a portion of the electric power,
and thereby when desirable prevent the loss that takes place in electro-
magnets usually employed in electrical appliances.
1121. Diagrams (30), illustrating the Great Waste of
Power in Electro-Magnets as heretofore made, and the
economy of tubular electro-magnets. John Faulkner.
These diagrams are produced by. scattering iron filings upon paper, prepared
with paraffin, placed above ordinary electro- magnets and improved electro-
magnets respectively.
282 SEC. 9. MAGNETISM.
1122. Objects illustrating the applications of tubular
Electro-Magnets. John Faulkner.
1. A. Electro-magnets; various.
2. B. Electric bells ; various.
3. C. indicators ; various,
4. D. ,, semaphore actuators ; various.
5. E. ,, telegraph sounders ; various.
6. , key and sounder on one base.
7.
9.
10.
separate.
sounder with movable cover.
with movable core.
with movable coil.
11. F. brass and iron separators.
12. G. pottery glaze iron extractors.
In the sounders a movable cover of wire is made partially or totally to
cover the coil by means of a regulating screw. In case of partial failure of
the battery, the instrument can be increased in power by a suitable alteration
of the position of the wire cover.
1123. Froment's Engine. An electro-magnetic machine
depending upon the successive .attraction by fixed electro-magnets
of bars of soft iron fastened on a wheel and parallel to its axis.
Frederick Guthrie.
The successive magnetisation and demagnetisation of the magnets is
effected by the action of cams on the axis of the wheel, which lift ivory
rollers, and so displace springs to which they are fastened.
1124. Helmholtz's Electro-magnetic Engine.
F. Rob. Voss, Berlin.
The advantage of this machine is that it is set in motion by a very small
galvanic force ; with two Bunsen elements it will drive one of Professor
Helmholtz's double-syrens or one of his centrifugal commutators.
Professor Helmholtz has applied a contact-arrangement to the commutator
of the Siemens' bobbin, which surpasses all former ones in that it avoids great
surfaces of friction, thus attaining greater power and speed.
1124a. Electro-magnetic Machine, with velocity regu-
lator. Helmholtz.
Physical Institution of Berlin, Prof. Helmholtz.
The current which drives the electro-magnetic machine is interrupted
by the centrifugal regulator whenever the velocity exceeds a certain limit,
whereupon the driving force ceases. Using a current which is only a little
stronger than what exactly suffices for the normal velocity, exceedingly
constant velocities of rotation are obtained. (Described by M. Exner in the
Sitzungsberichte of the Vienna Academy, Math. Natura. section, vol. LVIIL,
part II., page 602.)
1125. Electro-magnetic Engine. F. Sto/trer, Leipzig.
1125a. Electric Motive Power, acting on a pump.
M. Loiseauj junior , Paris.
1125b. Electric Motive Power, acting on a jet of water.
M. Loiseau, junior , Paris.
IV. MAGNETISATION. 283
1125c. Electric Motive Power, acting upon a hammer.
M. Loiseau, junior, Paris.
1125d. Electric Lighting Apparatus.
M. Loiseau, junior, Paris.
1125e. Electric Telegraph. M. Loiseau, junior, Paris.
1401. Electro-Magnetic Gyroscope, with double motion.
G. Trouve, Paris.
1125f. Electro-Magnetic Machine, invented by Sir Charles
Wheatstone. The Council of King's College, London.
1125g. Electro-Magnetic Engine, patented by Thomas
Allan, No. 14,190, A.D. 1852; and No. 2,243, A.D. 1854.
H.M. Commissioners of Patents.
This engine is so constructed that when set in action several electro-
magnets are formed one after the other, and give successive impulses in the
same line or direction to an upright rod or bar, capable of being moved longi-
tudinally to any desired extent.
1125h. Electro-Magnetic Machine, invented by Sir Charles
Wheatstone. The Council of King's College, London.
11251. Electro-Magnetic Machine, invented by Sir Charles
Wheatstone. The Council of King's College, London.
IV. APPARATUS FOR INVESTIGATIONS CONNECTED
WITH PHENOMENA OF MAGNETISATION.
1126. Apparatus showing a remarkable property of
magnetised Soft Iron Tubes.
Prof. Dr. A. von Waltenhofen, Prague.
On a balance are suspended a tube and a solid cylinder, both of soft iron,
the cylinder being much heavier, and therefore counterbalanced by adding a
brass weight to the tube, or by filling it with shot. Both tube and cylinder
are introduced into an electro-magnetic helix, fixed upright beneath the
balance at the bottom of the apparatus (as in the electro-magnetic balance of
Becquerel). The coils are joined so as to unite the poles of a Bunsen's cell,
or any other voltaic cell of small resistance.
On completing the circuit, a suction force is exerted on the tube and the
cylinder, tending to draw them into the helices. The tube or cylinder will
then appear the heavier, according as the electric current possesses less or
more strength. This change can be performed at pleasure by means of a
Wheatstone's rheostat, introduced in the path of the current.
The theory of this phenomenon is given in the Sitzungsberichte d. k.
Akademie d. Wissenschaften. Juli Heft, 1870.
284 SEC. 9. MAGNETISM.
1126a. Apparatus by Th. Petrouphevsky, Professor at the
University of St. Petersburg, for measuring the distance of the
Magnetic Poles in straight magnets from their ends.
Imperial University of St. Petersburg.
A straight magnet is suspended horizontally at a point where one of the
poles is approximately supposed to be. Another straight magnet, much
shorter than the first, is placed in the same horizontal plane, perpendicularly
to the suspended needle. A slow movement can be given to this second
magnet along a divided scale, horizontal and parallel to the suspended needle.
The mutual repulsive action of the two magnets is greatest when the direc-
tion of the axis of the small magnet passes through the magnetic pole
sought, provided that the suspended magnet remains perpendicular to the
second magnet. To fulfil this condition an auxiliary magnet is used, which
ie. placed on the other side of the suspended magnet, and which is to produce
an equal, but contrary, effect to the second magnet. This method of finding
the poles has been described in Russian in the " Messenger of Mathe-
matical Sciences" (Wiestin), and since, in Poggendorff's Anualen, Bd. 152,
s. 42. It requires the use of three distinct appliances: 1st. A bifilar
apparatus for suspending cylindrical magnets. 2nd. A measuring apparatus,
having a small magnet that can be moved parallel to itself while remaining
perpendicular to the direction of said movement. - The apparatus has two
divided scales, and is supplied with a microscope, two levels, and two small
telescopes of short focus. These two appliances are placed alongside, and
parallel to one another, and, approximately, in the magnetic meridian. The
third (No. 3) apparatus consists of a divided scale placed perpendicularly to
the suspended magnet. Along this may be moved a small magnet, of which
the function has been explained above. The second apparatus enumerated
was constructed by Mr. Brauer, of St. Petersburg; from the designs of Pro-
fessor Petrouchevsky.
1126b. Apparatus for so-called " Normal " Magneti-
sation, by Th. Petrouchevsky, Professor of Physics at the Uni-
versity of St. Petersburg. Imperial University of St. Petersburg.
An iron cylinder for magnetising, placed symmetrically in a magnetising
coil, may receive very different distributions of the free magnetism, accord-
ing to the length of the coil, but the distribution does not depend on the
strength of the current. The inventor has discovered that the distribution of
the remanent magnetism, or rather the distance between the poles, remains
alsvays the same, independently of the length of the coil or the strength of the
current. At a fixed length of the coil, the magnetic poles of the electro-
magnet and the poles of the remanent magnetism coincide, so that the electro-
magnet, placed horizontally and perpendicularly to the magnetic meridian
before a sensitive magnetic needle, acts upon it in the fixed direction (say,
the direction of the meridian itself) during the circulation of, and after the
cessation of, the current ; in the latter case, the poles of the permanent magne-
tism act. The poles are then almost at the ends of the magnetising spiral,
the length of which is about 0*8 of the iron cylinder, independently of the
length and diameter of the cylinder. This arrangement of the poles of the
electro -magnets is called " normal." The apparatus used in these researches
are composed of two very distinct parts. The first apparatus contains two
brass cylinders, surrounded with wire spirals ; by turning one of these
cylinders, the number of spirals can be lessened on the one, and increased on
the other. Inside one of these cylinders is placed the iron to be experimented
upon. This apparatus is set upon a table covered with marble plates moving
IV. MAGNETISATION. 285
in two directions, perpendicular to one another. The other apparatus is a
needle, called "unipolar," suspended by means of a cocoon thread, with two
microscopes.
1127. Ring of Elias for magnetising artificial magnets of large
size. Teyler Foundation, Haarlem.
A magnet of 28 kilogrammes weight has been recently magnetised by this
ring in Teyler's Museum.
Dr. Elias proposed more than 25 years ago his ring-coil for the production
of artificial magnets of all dimensions, by an intense galvanic current. His
artificial magnet here exhibited has lately been re-magnetised, with a slight
modification of his method by Prof. Van der Willigen in the Teyler Museum,
by this ring with the current of forty Bunsen elements of the usual large
size.
1128. Apparatus for showing to an audience the effects of
the superficial tension of liquids (Tomlinson's Cohesion Figures) ;
magnetic curves or the movement of liquid films, &c.
Prof. W. F. Barrett.
1129. Bar of Metallic Nickel, 20 inches long and inch
diameter. George Gore, F.fi.S.
1130. Three Plates of Metallic Nickel, 6 inches long and
1J inch wide. George Gore, F.R.S.
1131. Small Nickel Horseshoe, for making a Nickel
Magnet. George Gore, F.fi.S.
1132. Plate of Metallic Cobalt, 6 inches long and 1^ inch
wide. George Gore, F.R.S.
1135. Horseshoe Magnet of Nickel, used by Sir William
Thomson in his experiment on the effect of magnetism on the
thermo-electric quality of nickel. Result published in the Trans-
actions of the Royal Society for the year 1856, Bakerian Lecture.
Edinburgh Museum of Science and Art.
1136. Apparatus for showing a series of molecular and mag-
netic changes in a red-hot iron bar ; and designed also to show
the influence of traction, compression, and torsion upon such
changes. The latter experiments have not yet been made with it.
George Gore, F.R.S.
See Philosophical Magazine, Sept. 1870.
1136a. Apparatus for exhibiting molecular changes occur-
ring during the heating and cooling of iron wire.
Prof. W. F. Barrett.
When an iron or better a steel wire is raised to a white heat, a sudden
contraction occurs at a dull red heat, the apparatus exhibits the phenomenon
first noticed by Mr. Gore ; when the wire is allowed to cool after being
286 SEC. 9. MAGNETISM.
/'
raised to a white heat a corresponding expansion at a red heat was found by
Prof. Barrett, who also discovered that at this moment a crepitating sound
was emitted, the wire resumed its magnetic state at this period, and further-
more, a sudden reglowing of the wire takes place. These phenomena at this
critical temperature are also associated with changes in the conductivity and
thermo-electric property of the wire, as discovered by Prof. Tait. See Phil.
Mag. Dec. 1873, Jan. 1874, and Report Brit. Ass., 1875, p. 259.
1136b. Apparatus designed by G. Gore, F.R.S., far exhi-
biting the effects of stress upon the magnetisation of iron.
Prof. IV. F. Barrett.
1136c. Gore's Apparatus for exhibiting the torsion of an
iron wire produced by axial and transverse magnetisation.
Prof. W. F. Barrett.
1136d. Apparatus and Diagrams, to illustrate the elonga-
tion of unstrained iron produced by magnetisation.
Prof. W. F. Barrett.
1137. Coulomb's Torsion Balance for magnetic and electric
observations. Warmbrunn, Quilitz. and Co., Berlin.
1137a. Electro-Magnetic Helix, on wooden tube. Used
in electro-torsion experiments. George Gore, F.R.S.
1137b. Two Wooden Tubes, upon which to form electro-
magnetic helices for electro-torsion experiments.
George Gore, F.R.S.
1138. Apparatus for the demonstration of Magnetic
Friction, constructed by the late M. Kleemann in Halle.
Prof. Dr. Dove, Berlin.
V.-APPARATUS FOE INVESTIGATIONS CONNECTED
WITH DIAMAGNETISM.
1139. Glass Tubes prepared by Faraday for testing the
magnetic and diamagnetic character of Gases.
The Royal Institution of Great Britain.
The tubes containing the gas to be examined were suspended in the mag-
netic field of a powerful magnet, the result being either attraction or repul-
sion of the tubes as the gases they contained were either magnetic or dia-
maguetic. Phil. Trans,, 1850.
1 140. Bars of Borate of Lead Glass, made and used by
Faraday, for the action of magnets on polarized light.
The Royal Institution of Great Britain.
Phil. Trans., 1845,
VI. TERRESTRIAL MAGNETISM. 287
1141. The Diamagnetic Box of Michael Faraday, con-
taining spheres, cubes, and bars of diamagnetic metals ; tubes of
various liquids, bars of borate of lead, glass, various crystals,
cradles, supports, &c., used by Faraday in his researches on
diamagnetism. Prof. Tyndall, F.R.S.
1142. Instrument used in researches on the Polarity of
the Diamagnetic Force. Prof. Tyndall, F.R.S.
Phil. Trans., 1856.
1143. Specimen of " Faraday's Heavy-glass."
George Gore, F.R.S.
1144. Electro-Magnet for Induction and Diamagnetic
Experiments, made in 1850, of a broad plate of annealed iron,
so as to obtain a large induQed power from a small voltaic source.
J. P. Joule, D.C.L., F.R.S.
The coil is composed of a bundle of copper wires, and has a resistance
about equal to that of a Darnell's cell, exposing a surface of one foot square.
1144a. Large Diamagnetic Apparatus, with glass case,
rods, &c. Warmbrunn, Quilitz, fy Co., Berlin.
1143a. Magnetic Bench, for showing the Rotation of the
Polarized Bay. Dr. W. H. Stone.
1144a. Electro-Magnet, for showing the rotation of a
polarised ray. Dr. Stone.
1144b. Vacuum Tubes (2), to show the rotation of the
spark round the magnetic poles. Dr. Stone.
VI. APPARATUS FOR THE OBSERVATION AND RE-
GISTRATION OF THE TERRESTRIAL MAGNETIC
ELEMENTS.
DIP AND INTENSITY INSTRUMENTS USED IN MAGNETIC
SURVEYS ON SHORE AND AT SEA.
EXHIBITED BY THE ADMIRALTY HYDROGRAPHIC DEPARTMENT.
1145. Dip Circle for observations at sea, fitted with special
arrangements for finding the magnetic meridian. By Nairn and
Blunt ; date, 1772-1834.
This instrument may be considered as intermediate in construction between
that made by Nairn for Captain Phipps, in his voyage towards the North Pole
in 1773, and the Fox circle introduced by Mr. R. W. Fox in 1834, hereafter
described.
288 SEC. 9. MAGNETISM.
It is suspended by an universal joint, from a wooden stand carrying one
adjusting screw. The needle, 9 inches long, with steel axles, vibrates within
a circle graduated to 20', and the ends of the axis are fitted to work in the
agate holes of two adjustable screws in the vertical bars supporting the circle,
and otherwise strengthening the instrument. The sliding pointers on the
graduated circle are intended to be adjusted to the mean position of the needle
when the motion of the vessel causes it to vibrate on either side of the dip.
The screw on the under side of the circle works the metal supports on which
the needle is placed until adjusted in the agate holes. A thermometer
graduated to 38 is placed inside the instrument.
The peculiar arrangement for ascertaining the magnetic meridian consists
of a small compass gimballed at the end of a wooden arm. The other end of
this arm has a brass fitting to fix on pins in the graduated circle on the top of
the frame. The motion of the arm in azimuth causes the whole apparatus
to move in the wooden stand until the Dip Circle is in the magnetic meridian,
as indicated by the compass.
1146. Dip Circle and Intensity Apparatus. Fitted with
arrangements for ascertaining the magnetic meridian by three
methods. By Dollond ; probable date, 1776-1834.
The Dip Circle is made after the pattern described by the Hon. Henry
Cavendish in the Phil. Trans., vol. xlvi., in which the dipping needle rolls
upon horizontal agate planes, and a contrivance is applied for lifting it off
and on to the agates at pleasure. A milled headed screw works this lift, and
an adjacent butterfly screw, an arrangement for causing the needle to vibrate.
The vertical circle is graduated to 20' ; the outer circle of the base plate is
also graduated to every 45.
The direction of the magnetic meridian may be ascertained by two methods
other than that usually adopted: 1. An edge bar horizontal needle fitted with
an agate cap may be placed on the steel point fixed to a balanced axis pro-
vided for placing on the agates like the dipping needles. The coincidence of
this needle with the plane of the vertical circle shows the latter to be in the
magnetic meridian. 2. The same edge-bar needle can be placed on a pivot
screwed in the centre of the graduated circle at the bottom of the travelling
box.
Of the three dipping needles, two are flat and one cylindrical and sharply-
pointed. The axes are made of gun metal, and one of the flat needles is fitted
with a brass cone on Mayer's principle.
Intensity Observations. For this purpose the box which carries the dip
circle is fitted with two apertures filled with glass, and a torsion circle on the
top. The two flat needles, one of gun-metal for eliminating torsion, and the
other for horizontal vibrations, have metal pins screwed into the centres by
means of which they are attached to the stirrup suspended by silk fibres from
the torsion circle. The vibrations are observed through the glass sides, and
the magnetic meridian by the edge-bar horizontal needle before described.
This apparatus closely resembles that used by David Douglas on the north-
west coast of America and the Sandwich Islands in 1829-34.
1147. Dip Circle. By Eobinson; date, 1830-75.
In this circle the needles are 6 inches long, flat and pointed. They move
on agate planes in the centre of a graduated circle, and observations are read
off by means of lenses fixed in the ends of a moveable arm centred on one of
the glass sides of the instrument.
The advantages of this form of dip circle are: 1. That both the needles
can be read off for nearly every angle of dip. 2. Portability, from compact-
VI. TERRESTRIAL MAGNETISM. 289
ness of stowage in the box, as the vertical circle is fitted so as to be readily
detached from the horizontal.
An instrument of this kind was used by Major Estcourt during the survey
of the river Euphrates in 1836.
1148. Dip and Intensity Circle invented by R. W. Fox,
F.R.S. By Mr. George, of Falmouth ; date, 1834-75.
The principal object of this instrument is the observation of Dip and In-
tensity at sea, and when placed on a properly constructed gimballed table
this can be accomplished, except in very bad weather.
The needles are flat, tapering from the axis to a point, and 6 9 inches long.
The axles are finely pointed, and work in the jewelled holes fitted to the
bracket and centre of a concentric disc in the back of the instrument, which
also carries the bracket. The grooved wheel on the axis is used for carrying
the hooks and deflecting weights in intensity observations. In the holes in
the cross arms of the verniers at the back of the circle, the deflectors, N and
S, are screwed for dip and intensity observations, and are set at any required
angle by means of the graduated circle. Of the two large thumb screws in
the back of the rnoveable disc, one works the bracket when mounting the
needle and vice vers& ; the other works the clamp. At other times they are
used in conjunction for the purpose of moving the disc when altering the bear-
ings of the needles in the jewels. The pointed projection between these
screws, when rubbed by the ivory disc, opposes the effect of friction in the
needle and jewels.
The needles are packed in metal cases with screw ends, and may thus be
used as deflectors.
Instruments of this construction have been largely and successfully used in
the various magnetic surveys made at sea in H.M.'s ships.
1149. Hansteen's Intensity Apparatus ; date, 1819-50.
This form of intensity apparatus is that first adopted by M. Hansteen in
his magnetic survey of Norway and the Baltic shores in 1819-24, and since
largely used by various observers. The vibrating needle is cylindrical,
pointed at the ends, 2 65 inches long and 0-15 inches in thickness. It is
suspended from the moveable pulley at the end of the brass tube by a fibre of
silk secured to a brass strap and loop in its centre. By means of the pulley
the needle can be adjusted to the required height in the vibrating box.
The value of the observations depends on the permanency of the magnetic
condition of the needle.
1150. Portable Magnetic Dip Circle, 3J in. needle, made
for, and used by, the late Sir John JShuckburgh. The dividing is
very fine, and believed to be Ramsden's. G. J. Symons.
GENERAL.
1176. Photograph of an Inclinatorium (Dip Circle), by
Daniel Bernoulli, completed by Johann Dietrich of Basle, in 1751.
Prof. Hagenbach-Bischoff, Director, The Physical Insti-
tute in the Bernoullianum, Basle.
This instrument gained the Prize of the Academy of Paris in 1743.
40075. T
290 SEC. 9. MAGNETISM.
1177. Dip Circle, for determining the magnetic inclination ?
adapted to needles of various lengths. (Barrow, London.)
H. Lloyd, Trinity College, Dublin*
1178. Theodolite Magnetometer, 9-inch circle, and colli-
mator magnets. (Jones, London.)
//. Lloyd, Trinity Collet, Dublin.
1179. Dip Circle or inclination compass. James How fy Co.
1180. Magnetometer, Kew pattern, constructed to^determine
the magnetic axis and the magnetic moment of a magnet, and the
direction and intensity of the magnetic force of a given place.
Elliott Brothers.
The instrument consists of two distinct parts. For the observations of the
deflection magnet, the copper box screwed to the centre of the azimuth circle
is used ; underneath this passes, through the centre, a divided metal bar with
a vernier carrying a magnet ; at right angles to this bar is the observing
telescope. The hollow vibration magnet, with a scale on glass at one end
and a collirnating lens at the other, is observed through another telescope.
The latter magnet is suspended in the mahogany box above the copper box.
1184. Declinometer for sea and laud observations.
Carl Bamberg, Berlin.
The instrument is furnished with gimbals for use at sea, but may be fixed
for observations on land. The magnetic system, which is provided with a
mirror, oscillates upon a point, and is constructed for reversal ; the ad-
justment is effected by means of a collimator telescope, and orientation from
terrestrial and astronomical objects.
1185. Deviation Magnetometer, for determining the mag-
netic relations on iron vessels. . Carl Bambcrg, Berlin.
The deviation magnetometer enables determinations of deviation (horizontal
and vertical) to be read off on points, and also determinations of horizontal
and vertical intensity by oscillations and deviations. A small telescope serves
for determining orientation from terrestrial and astronomical objects. The
instrument may be mounted on the same stand as the compasses.
1190. Drawing of a Dip Circle. J. P. Joule, F.R.S.
The needle, constructed of a thin ribbon of annealed steel, weighing
20 grains, is furnished with an axis made of a wire of standard gold. This
axis is supported by threads of the Diadema Spider attached to the arms of a
balance suspended by a fine stretched wire. The whole is hung by a wire
which can be twisted at the head through 180. At the bottom is attached
a paddle immersed in castor oil, which brings the instrument speedily to rest
in a fresh position. The deflections are read off by a short-focus telescope,
placed on an arm revolving on an axis in the centre of the circle. With this
instrument the dip can be determined within the fraction of a minute of a
degree in less than a quarter of an hour.
With this drawing is exhibited a specimen of the THREAD of the DIADEJUA
SPIDER, also THREAD of the DIADEMA SPIDER COCOON.
VI. TERRESTRIAL MAGNETISM. 291
1191. Portable Unifilar Magnetometer. An instrument
for determining the horizontal intensity of terrestrial magnetic
force ; and also the declination.
Keic Committee of the Royal Society.
It consists of two parts : one for determining the time of vibration of a
suspended magnet ; the other for determining the amount of deflection it pro-
duces when caused to act upon a second needle.
In addition there is a third magnet, which is subsequently suspended,
and its position referred to the astronomical meridian, by means of a
mirror, which serves to allow of an observation of the sun's azimuth being
made.
Used by the Rev. S. J. Perry, F.B.S., during the late Transit of Venus
Expedition to Kerguelen.
1192. 12-inch Dipping Needle. Royal Society.
1192a. 12-inch Variation Needle. Royal Society.
1193. Kew Pattern Dip Circle.
Kew Committee of the Royal Society.
Dip circle of the pattern adopted by the Kew Observatory, having needles
3 ins. long, which are read by microscopes, carried by a circle in front of the
needle frame. It is also provided with accessory needles, for determining
total force, after the method of Dr. Lloyd.
1196. Portable Theodolite for the observation of the Mag-
netism of the Earth, constructed by Dr. Meyerstein, Gottingen.
Prof. Dr. A. Kundt, Strasburg.
1197. Edelmann's Telescope with graduated Scale,
for reading reflecting instruments (small).
M. Th. Edelmann, Munich
1198. Edelmann's Telescope with graduated Scale,
for reading reflecting instruments (large).
M. Th. Edelmann, Munich.
1199. Edelmann's Telescope with graduated Scale,
for two observers. M. Th. Edelmann, Munich.
1200. Edelmann's Rider, for observing two objects at the
same time by means of a telescope with graduated scale.
M. Th. Edelmann, Munich.
1201. Edelmann's Declination Magnetometer.
M. Th. Edelmann, Munich.
1202. Edelmann's Variation Instrument for Declina-
tion. M. Th. Edelmann, Munich.
1203. Edelmann's Variation Instrument for Horizontal
Intensity. M. Th. Edelmann, Munich.
T 2
292 SEC. 9. MAGNETISM.
1204. Edelmann's Variation Instrument for Vertical
Intensity. M. Th. Edelmann, Munich.
1205. Edelmann's Magnetometer for declination, vertical
and horizontal intensity. M. Th. Edelmann, Munich.
1206. Portable Magnet Theodolite.
M. Th. Edelmann, Munich.
1207. Weber's Earth Inductor, new construction.
M. Th. Edelmann, Munich.
1207 a. Book, containing special treatises on some of the
above instruments. M. Th. Edelmann.
1207b. Book, containing the description of the above-named
apparatus. M. Th. Edelmann.
1209. Photograph of Gauss's Bifilar Magnetometer.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1210. Photograph of the observing Telescope, belonging
to the above.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1211. Photograph of Gauss's Earth Inductor.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1212. Photograph of the Multiplier and Needle. For
the determination of Inclination and Absolute Intensity.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering> Director.
1213. Photograph of the Auxiliary or Deviation Needle.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1214. Photograph of the Theodolite for the determination
of the Declination.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1215. Description of the above-named instruments ; Gauss's
Works, vols. 1-7.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
VI. TERRESTRIAL MAGNETISM. 293
1216. Dipping Needle with microscopes for the observation
of the needle points, constructed by Dr. Meyerstein in 1843.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1217. Microscopic Apparatus for the determination of the
Collimation of Dipping Needles, constructed by Dr. Meyer-
stein in 1843.
Magnetic Department of the Observatory, Gottingen, Prof.
Dr. Schering, Director.
1218. Reflecting Dip Circle, after Dr. Meyerstein.
Physical Institute of the University of Gottingen, Prof.
Dr. Riecke.
The instrument is so constructed that the magnetisation can be effected
either by touching with a steel magnet, or by means of electric coil. In
order to carry out the latter, the case is carefully taken off and the coil pushed
over pillar and needle.
1219. Model for the illustration of the Deviation in Iron
Ships, after Neumayer, constructed by the Joint-stock Company
for the Manufacture of Meteorological Instruments, formerly
Greiner and Geissler.
Hydro graphical Department of the Imperial Admiralty,
Berlin.
This model represents an important apparatus of instruction, which
illustrates all the phenomena of deviation and compensation of the com-
passes. The apparatus is in use in the institutions of the Imperial Navy
and schools of navigation.
1220. Gauss's Magnetometer, constructed by Breithaupt
and Son, Cassel, with apparatus for suspension.
Polytechnic School in Cassel, Dr. Gerland.
The instrument has been constructed, according to the instructions and
under the supervision of Professor W. Weber in Goettingen, by Messrs.
Breithaupt and Son. Since the magnetometer with which Gauss and Weber
had carried out their magnetic labours, and which is identical with the one
here exhibited, has not been sent to London, this instrument may be con-
sidered as one of the oldest of its kind in the present exhibition.
1221. Photographic self-registering Horizontal Force,
or Bifilar Magnetometer, constructed in 1847, at the Kew
Observatory, by Mr. Francis Ronalds.
Kew Committee of the Royal Society.
Described in the British Association Eeport for 1849.
The magnet, 15 inches long, is suspended in a loop of fine wire, by means
of a pulley, forming a bifilar arrangement. It carries, attached to its lower
side, a light brass bar, which moves a little shutter in front of an oil lamp,
allowing a pencil of rays to pass through a hole in it. The light is then
thrown, by means of a lens, upon a daguerreotype plate, which is steadily
drawn upwards by means of a clock.
294 SEC. 9. MAGNETISM.
The curves upon the daguerreotype plates were sometimes etched in, and
engravings subsequently worked off, or tracings were made upon sheets of
gelatine, which, being preserved, allowed the silvered plates to be repeatedly
used.
This instrument was superseded by the improved magnetographs erected at
Kew by Mr. Welsh in 1857, which have since remained in almost continuous
action.
The suspension frame originally fitted has been replaced by one not belong-
ing to the instrument when in use.
1222. St. Helena Magnetometers.
(1.) Declinometer instrument and telescope, used at St. Helena,
1840-1849.
(2.) Bifilar magnetometer and telescope, used at St. Helena,
1840-1849.
(3.) Vertical force magnetometer, used at St. Helena, 1840-
1849. Kew Committee of the Royal Society.
The three magnetometers, the declination, horizontal force, and vertical
force instruments, respectively, were made by Grubb, of Dublin, and formed
one set of those used in the Colonial Magnetic Observatories, founded by the
Government in 1840. The instruments were described in the Report of the
Royal Society Committee of Physics, &c.
These instruments were erected at St. Helena in 1840, and constantly
observed from that date until 1849.
The declinometer consists of a magnet bar, suspended by fibres of untwisted
silk, and carrying a collimator arrangement of lens and scale, the whole
being enclosed in a cylindrical casing, perforated with windows, through
which the scale is viewed by means of a telescope.
The bifilar is a somewhat similar arrangement, but the support of the
magnet is formed of two parallel wires, which are twisted so as to bring the
magnet into a position at right angles to the meridian.
The vertical force magnetometer is a light magnet 12 inches long, carrying
a brass frame with cro&s wires at each end ; it is supported by a steel knife
edge, bearing on agate planes, and its movements are observed by micro-
scopes, fitted with micrometers, by which the position of the cross wires on
the magnets is read.
1223. Declination Compass, used by Sir J. Richardson and
Capt. Pullen.
Kew Committee of the Royal Society.
It consists of a square glazed box, containing a compass card, which is
formed of a light metal divided circle, and two spring needles, connected to
an agate cap in the centre. This is mounted so that it can either be suspended
by a silk thread, or rest upon a point in the ordinary manner.
Two microscopes are fixed vertically above it, so that the divisions on the
circle may be read by them, concave metallic reflectors being fitted to them
for the purpose of illuminating the scale at the time of reading off.
1224. Portable Apparatus for vibrating a Magnet, used
by Capt. Barnett, in H.M.S. "Thunder," in 1841.
Kew Committee of the Royal Society.
VI. TERRESTRIAL MAGNETISM. 295
It is a glazed box 4 inches square, standing on a levelling stand, and carry-
ing a brass suspension tube 6 indies in length. It also has an ivory circle
fixed to its bottom.
There are two magnets 2 7 inches long, each of which when not in use
is kept in a separate little copper box, where, fitted to an armature, it is
embedded in iron filings.
1225. Dip Circle used by Sir James C. Boss.
Kew Committee of the Royal Society.
A Robinson dip circle, with four 6-inch needles, supported on agate planes,
and read off direct on the circle of the instrument.
1225a. Apparatus for discovering the Magnetic Poles
in Magnets and Electro-Magnets, by Professor Th. Petrouchevsky.
Imperial University of St. Petersburg.
A fine metal wire is stretched within the magnetic meridian, above a sensi-
tive marine compass. Within a distance of 6 m from the compass, the pole
of which is to be determined, and below the same wire, a magnet is placed,
so that its two arms are horizontal, and perpendicular both to the meridian
and to the wire. The loaded needle of the compass usually deviates through
the effect of the magnet, but in a special case it may be made to remain
within the plane of the meridian. To effect this the line passing through the
two curved magnet poles must pass also within the plane of the meridian, a
thing easily accomplished. In the case of electro-magnets, besides the two
bobbins forming part of the electro-magnet, a third bobbin is used, intended
to compensate the effect of the first two upon the loaded needle. The de-
scription of this method, which presumes that both poles are equidistant from
the extremities of the magnet, as also the results of experiments, are published
in the Russian work " Cours de Physique Experimentale," by M. Petrouchevsky,
and since in the " AnnaJen der Physik," by Poggendorf.
1226. Forbes' Hemispheres for illustration of Lectures on
the Earth's Magnetism and Temperature.
University of Edinburgh.
1227. Gambey's Declination Compass.
Conservatoire des Arts et Metiers, Paris.
1228. Self-registering Bifilar Magnetometer, with ap-
paratus for determining the temperature-correction of the magnets
employed in several automatic instruments, from the displacements
of the photographic trace due to observed changes of temperature.
Chas. Brooke, F.R.S.
1229. Self-recording Magnetometer.
Chas. Brooke, F.R.S.
Rough home-made apparatus, by which the first automatic records of mag-
netic variation by reflected light were obtained. The cylindrical lenses are
water-lenses.
1229a. Self-registering Balanced Magnetometer, with
compensation for changes of temperature, and warm water en-
velope for testing the same. The compensation is effected by
the weight of the column of mercury in a thermometer tube.
Chas. Brooke, F.R.S.
296 SEC. 9. MAGNETISM.
1229b. Self-registering Barometer.
Clias. Brooke, F.R.S.
1229c. Photographic Apparatus, for registering simulta-
neously the variations of both the above instruments.
Chas. Brooke, F.R.S.
1229d. Self-registering Bifilar Magnetometer, with
compensation for changes of temperature, and warm- water envelope
for testing the same. Chas. Brooke, F>R.S.
The compensation is effected by diminishing the lower interval of the
double suspension, by means of the differential expansion of glass and zinc,
in proportion to the diminished magnetic energy of the bar, due to elevation
of temperature.
Photographic apparatus for registering the variation of the above, by means
of a reflected pencil of light.
1230. Photographic self-registering Decimation Mag-
net, constructed in 1846, at the Kew Observatory, by Mr. Francis
Ronalds.
Kew Committee of the Royal Society.
Described in the Philosophical Transactions for 1847, vol. I.
The magnet, 2 feet long, when in use, was suspended by a silken skein,
9 feet long, on its under side ; it carries a brass bar, from one end of which
hangs a perforated metal plate, which, moving in front of a lamp, permits a
pencil of light to fall upon a daguerreotype plate, carried slowly upwards by
a clock suitably arranged.
The magnet is surrounded by a damper, made by electrotyping a frame of
mahogany with copper. Both are enclosed in double wooden cases, having
both surfaces covered with gold paper.
This instrument was superseded by the improved Kew magnetographs,
which have been in almost continuous action since 1858.
1231. Instrument for the determination of the position
of the point of convergence of the rays of the Aurora
Borealis, both when it is below the horizon and also when it is
above the horizon at the appearance of the Corona.
Prof. Hcis, Munster.
The ball, resting in the pan, can after a few trials be brought into such
position that several diverging pencils of the aurora borealis on the northern
or the southern sky are, when properly viewed, covered by the rod which
passes through the centre of the ball. The point of this rod, which can be
moved up and down in the ball, shows, when the instrument is set according
to the astronomical meridian, the azimuth and altitude of the converging point
of the aurora pencils. This point of convergence does not exactly coincide,
as the exhibitor has shown at the time of the great display of aurora borealis,
Feb. 4th, 1872, with the point towards which the inclination needle directs.
From the deviation of the two points, the height of the aurora can be cal-
culated.
The instrument, which is easily manipulated, is much recommended to
arctic explorers.
Instrument for navigators in the Arctic Regions for ascertaining the con-
nexion of the Northern Lights with terrestrial magnetism, and for determining
VI. TERRESTRIAL MAGNETISM. 297
the altitude of the Northern Lights. By means of an instrument designed by
the exhibitor, the point of convergence of the uortli light rays is to be
accurately determined, as well when at the appearance of the corona it is
situated above the horizon, as when it is below the same, and in regard to
altitude and azimuth. By the deviation of the point of convergence from the
direction of the dipping needle, the height of the north light rays can be
calculated.
1231b. Compass with Diamond Fin.
Ernst Winter, Hamburg, EimstusteL
298
SECTION 10. ELECTRICITY.
WEST GALLERY, GROUND FLOOR, ROOM F.
I. APPARATUS FOR PRODUCING AND MAINTAIN-
ING DIFFERENCES OF ELECTRICAL POTEN-
TIAL.
a. FRICTION AND INDUCTION MACHINES.
1233. Electrical Machine, having ebonite plate 3 feet in
diameter. Frederick Guthrie.
This machine gives sparks 13 inches long.
1233a. Priestley's Electrical Machine. Royal Society.
1267. Winter's Machine, with 18-inch ebonite plate and
condenser attached, for the accumulation of electricity.
Elliott Brothers.
Large Double-Plate Vulcanite Friction Electric Ma-
chine. Dr. W. H. Stone.
1233a. Large Electrophorus, with ebonite plate, 360mm.
diameter. Warmbrunn, Quilitz, fy Co., Berlin.
1234. Carre's Electric Machine. Prof. W. F. Barrett.
This is an induction machine or continuous electrophorus, but the loss from
the inductor is replaced by a small attached frictional machine.
1234:a. Froment's Electric Pendulum.
Prof. W. F. Barrett.
The pendulum is kept in motion by a current passing round the electro-
magnet which lifts a small weight that is released as the pendulum descends.
A control clock is in connexion with the pendulum.
1234b. Crystal of Tourmaline, mounted to show
Pyro-Electricity. Prof. W. F. Barrett.
This crystal during heating or cooling exhibits polarity at its extremities.
It is pivoted on a diamond cap.
I. ELECTRICAL MACHINES, ETC. 299
1234c. Electrical Machine, by Singer, used by Mr. Francis
Ronalds in his early experiments in the discovery of the electric
telegraph ; described in his work on the electric telegraph,
dated 1823. Kew Committee of the Royal Society.
It is an ordinary cylinder machine of blue glass, standing on glass columns.
1235. Bertsch's Machine. Frederick Guthrie.
A negatively excited sheet of ebonite leans against a revolving disc of the
same material. On the other side of the revolving disc, one above and one
below, are electric rakes. The conductor in connexion with the lower rake
becomes negatively charged, the other one positively.
1236. Holtz's Machine. Frederick Guthrie.
A good example of this machine in one of its original forms, with windows
and armatures. It gives a current of sparks over an interval of 8 inches.
1237. Electrical Machine,' based on Holtz's principle, with
ebonite discs. Dr. L. Blcekrode, The Hague, Holland.
This machine is constructed for generating electricity on the principles of
induction as first employed by Holtz. The form is very much simplified,
and the only material used is ebonite (india-rubber combined with sulphur).
Two forms are constructed by the exhibitor ; the single ebonite machine
with one fixed disc and another rotating before it, and the double ebonite
machine. The latter consists of one fixed disc with paper armatures placed
in the ordinary way but on both sides, a double system of conductors, and
two rotating discs. The construction is no more complicated than that of the
single machine, yet the quantity of electricity is exactly doubled.
The advantages of the machines constructed in this way, supported by ex-
perience of more than two years, may thus be briefly stated :
(1.) The ebonite machines, constructed on the system of the exhibitor, with
ebonite of a good quality (which may be easily had but must be care-
fully chosen) are at least as powerful in their action as the machines
with glass discs, but they surpass them in being less costly, not
liable to be broken, and much less dependent on the condition
of the atmosphere. This must be appreciated in England, where, as
is the case in Holland, glass electrical machines (working by
induction) often remain inoperative owing to atmospheric moisture.
(2.) Although of very simple construction, they are very useful and power-
ful machines.
(3.) From a theoretical point of view they present many interesting pro-
perties when compared with machines in which glass is employed,
and this led to the conclusion that they differ in their .mode of
producing electricity. An experimental investigation of this machine,
stating its peculiarities, has been published in Poggendorff s Annalen,
1875, No. 10, pp. 278, 279.
1241. Di-Electrical Machine. M. Carre.
4560. Photograph of the " Cecchi Electrical Machine,"
formed of two discs, which are placed partially one over the other,
the one of caoutchouc, and the other of glass, with parallel axes.
Prof. Filippo Cecchi, Florence.
300 SEC. 10. ELECTRICITY.
The Cecchi electrical or dielectrical machine is composed of two discs
with parallel axes. The upper disc is of india-rubber, and is supported by
an axis of glass ; the one below is of glass on an axis of metal. The axis of
the glass disc has on one side a large pulley, and the axis of the other disc a
small pulley, and by means of a continuous cord, not crossed, there is trans-
mitted to the caoutchouc disc a rotatory motion eight or ten times faster than
that of the glass-disc ; both the discs turn in the same direction. The discs
are partially placed one above another, and are very close but without touching.
The upper part of the caoutchouc disc passes between tAvo arms furnished
with metallic points, and connected with a large sphere of brass insulated at
the extremity of a long glass rod. To this sphere is attached the hook of a
condenser or else a Leyden jar formed by a barometer-tube with very thick
walls. The lower part of the same disc passes before a comb of metallic
points, called a T-comb, which communicates with the external armature of
the condenser, and with two friction cushions of the glass disc, and then with
the ground, and also with an exciter formed by a tube of brass with a ball at
the end. When the discs are revolving, the large sphere becomes charged
with negative electricity. This machine with discs of 80 centimetres diameter
has given sparks of the length of 42 centimetres free in the air.
1242. Holtz's Machine, with four plates. M. Ruhmkorff.
1242a. New form of Holtz's Machine.
Francis Pizzorno, Bologna, Italy.
This machine has the property of working well whatever may be the hy-
grometric condition of the air. since the two glass plates are placed in
a crystal case hermetically closed. The air of the case is maintained con-
tinually dry by means of drying substances.
The conductors issue from the case and unite at the two Leyden jars which
appear on the front of the figure.
1242b. Fixed Disc for a Holtz's Machine.
Augustus Righi^ Professor of Natural Philosophy, Bologna.
The greatest possible difference of potential between the conductors of a
Holtz's machine depends on the difference of the potentials of the paper sur-
faces carried by the fixed disc. But this latter difference is limited by the
discharges which continually occur along the fixed disc. An ebonite plate is
joined perpendicularly on the fixed disc, separating it into two parts, so that
the discharges must follow the two faces of the plate. The potentials of the
paper surfaces are increased, and the sparks between the conductors become
longer.
This machine possesses four rows of points, namely, the two rows of points
of the conductors, and the two rows of points obliquely communicating.
1242c. Large Electrical Machine, with double ebonite
plates and Waiter's ring, formerly the property of Lord Lindsay.
Dr. Stone.
1268. Replenishes Designed by Sir W. Thomson for re-
storing electricity to the Leyden jar of his quadrant electrometer.
Elliott Brothers.
A small charge being given to the Leyden jar, the replenisher increases or
decreases the difference of potentials between the two coatings of the jar by a
constant per-centage per half turn.
J. ELECTRICAL MACHINES, ETC. 301
1243. Old Electrical Machine, with glass cylinders, one of
which is covered with sealing wax^ so as to obtain both positive
and negative electricity.
The Council of King' s College, London.
1244. Nairne's Early Electrical Machine, with glass
globe. The Council of King's College, London.
1245. Cylinder Electrical Machine.
The Council of King's College, London.
1246. Plate Electrical Machine, with four rubbers.
The Council of King's College, London.
1247. Armstrong's Electric Boiler or Hydro-Electric
Machine. The Council of King's College, London.
1248. Volta's Electric Lamp, or apparatus for lighting gas
by means of an electric spark.
The Council of King's College, London.
It contains a leaden bottle for the generation of hydrogen gas. In the
orifice are two wires separated from each other, which are connected to the
two plates of an electrophorus. One of the wires is connected with the tap,
so that the upper plate of the electrophorus is raised at the same time that
the hydrogen is allowed to escape at the orifice, and the spark from the
electrophorus sets fire to the hydrogen and thus lights the lamp.
1729. Glass Globes for producing Electricity by rubbing
with the hand. The Council of King's College, London.
The globes are caused to revolve by means of multiplying wheels and a
band of rope. The globes may be exhausted, and they then become luminous ;
the greatest amount of electricity or " fire " was obtained from them when
they were exhausted. In the one with a large brass cap, a small wooden disc
could be inserted with threads distributed round its edge ; when the globe
was excited the threads stood out from the edge of the disc. Constructed
about A.D. 1720.-
1249. Induction Electric Machine. T. Rob. Voss, Berlin.
As there is no glass in Germany which insulates perfectly, Professor
Helmholtz has used Leyden jars made of ebonite or vulcanite, which can
keep electric charges for 14 days, or 14 times longer than the glass jars of
Kirchhoff.
The advantages of this instrument are: (1.) That the quadrants with
the needle and mirror can be easily removed, so that any change in the needle
or misplacement of the mirror may be examined with certainty.
There are new arrangements in the Leyden jar for raising or turning the
needle without shaking the entire instrument (a thing to be avoided).
1249b. Combined Holtz's and Bertch's Induction Ma-
chine, with arrangement for separating the same.
Harvey, Reynolds, and Co.
302 SEC. 10. ELECTKICITY,
1249c. Induction Electric Machine. J. Teller, Munchen .
The fixed disc has neither holes nor cuts, which were hitherto considered
indispensable.
1249d. Toepler's Induction Machine.
Royal Institution of Great Britain.
The apertures usual in the fixed disc are here dispensed with ae unnecessary,
the disc is thus rendered less breakable, and a greater action is obtained.
The apparatus is very simple in construction and can easily be taken asunder
for cleaning. The driving disc is at the same time utilised as the exciter of
-electricity.
1250. Holtz's Electric Machine, with fixed induction
surface. Borchardt, Hanover.
1251. Holtz's Electric Machine, with movable induction
surfaces. Borchardt, Hanover.
1542d. Electric Machine, with large ebonite disc.
C. Etler.
1252. Machine for exciting Positive and Negative Elec-
tricity. E. Stohrer, Leipzig.
It has the form of a small disc electric machine. According as one or
other brass ball at the end of the caoutchouc frame is taken hold of, a quantity
of positive or negative electricity is obtained.
b. GALVANIC BATTERIES.
1285a. Apparatus for Volta's Fundamental Experi-
ment, with arrangement for chloride of calcium, two brass, one
copper, one zinc plate, and insulating handle.
Warmbrunn, Quilitz, <$* Co., Berlin.
1253. Water Battery.
The Council of King 's College, London.
1254. Daniell's Battery, employed in researches by Pro-
fessor Daniell. The Council of King's College, London.
1255. Early Voltaic Batteries:
Babington's battery.
Cruikshank's
Wollaston's
Sturgeon's
The Council of King 1 s College, London.
1256. Hare's Calorimotor, or Deflagrator.
The Council of King's College, London.
1257. De La Hue's Powder Chloride of Silver Battery.
Tisley and Spiller.
I. BATTERIES. 303
1257a. Porty Cells of a Rod Chloride of Silver Battery ?
being part of a battery of 8,040 cells.
Warren De La Rue, F.R.S., and Hugo W. Muller, F.R.S.
The elements consist of a flattened silver wire and a zinc (non-amalga-
mated) rod. The electrolytes are a solution of chloride of ammonium, 23
grammes to a litre of water, and fused chloride of silver cast on to the silver
wire.
When the terminals are not connected, the battery is quite inactive ; one
such battery has been in action since November 1874. In order to prevent
contact between the chloride of silver and the zinc rod, the rod of chloride of
silver is encased in a tube of vegetable parchment open at both ends. The
cell is a glass tube closed with a paraffin stopper.
Such a battery will evolve three cubic centimetres of mixed gases per
minute, if connected up with a voltameter containing one volume of sulphuric
acid, and eight volumes of water.
This battery is particularly well suited to experiments with a large number
of elements, on account of its constancy.
8040 cells give a spark in air between a point (positive) and a plate
(negative) of 0'342 inch (8 '68 mm.) ; the striking distance (distance explosi ve)
is shorter when the point is negative and the length of the spark is materially
affected by slight differences in the form of the point ; the point used is
parabolic in form and is made of copper wire 0*125 inch (3 '175 mm.) in
diameter, the plate 1*1 inch (27 "94 mm.) in diameter. The length of the
spark between a point and a plate appears to be in excess of the ratio of the
square of the number of cells ; for example 8,000 will give a spark 64 times
as long as the spark from 1,000 cells. Between two spherical surfaces of
3 inches (76 '2 mm.) radius and 1*5 inch (38*1 mm.) in diameter; the
striking distance (distance explosive) is only 0*038 inch (2'1 mm.) ; between
spherical surfaces the law of the striking distance being in the ratio of the
square of the number of cells does not hold. When a resistance is introduced
into the circuit of 6,000,000 Brit. Ass. units (ohms), a series of intermittent
brilliant sparks is obtained like those from an electrical machine ; but without
resistance when the spark jumps the ordinary voltaic arc is formed. The
current of 8,040 cells passes through a residual Irydrogen vacuum of 38 mm.
tension in a tube 1-6 inch (40*6 mm.) diameter, and 27 inches (58 '58
centimeters) between the terminals ; the current of 1,200 cells passes with a
tension of 2 mm.
1258. Portable Medical Battery, with modified form of
De La Rue's chloride of silver and zinc elements.
Tisley and Spiller.
1259. New Galvanic Battery for Domestic Purposes.
Aurel de Ratti,
This Zinc-Carbon Battery is charged with a saturated solution of sulphate
of magnesia or Epsom salts, a very cheap material. The flask above the cell
is filled with crystals of this salt, on which a saturated solution of the same is
poured until the flask is quite full. The cork with the glass tube is then
forced down till the solution rises and fills the tube. A small cork is loosely
fixed in the open end of the glass tube. No air must be allowed to remain in
the tube or flask. The latter is now inverted, and the tube introduced through
the round hole in the lid. The flask will be held in position by the projecting
cork fitting into the round hole. The end of the glass tube will thus be im-
mersed in the solution in the jar. The carbon- plate is finally pushed through
304 SEC. 10. ELECTRICITY.
the square aperture in the lid, and by a simple manipulation the cork is
pushed from the open end af the glass tube.
1259a. Muirhead's new Manganese Battery.
Warden, Muirhead, and Clark.
The positive plate is of zinc of a hollow cylindrical form placed in a perforated
vitreous chamber. The negative plate is of platinized carbon, surrounded with
lumps of platinized carbon and di-oxide of manganese. The exciting liquid
is a solution of muriate of ammonia. Its electro-motive force is 1 6 volts,
internal resistance, 2 ohms. Electro-motive force of a Daniell cell, 1 1 volts.
1260. Gas Voltaic Battery devised by W. R. Grove, Esq,,
M.A., F.R.S., Professor of Experimental Philosophy in the Lon-
don Institution (now The Hon. Sir W. R. Grove), and described
by him in a communication read before the Royal Society, May
llth, 1843. Experiments with this battery are described in a
postscript, dated July 7th (Phil. Trans., 1843, p. 91).
London Institution, Finsbury Circus, E.G.
It consists of a series of Woulfe's bottles, into the necks of which glass
tubes closed at one end are fitted by grinding ; each tube contains a slip of
platinum foil, coated with finely divided platinum, the slip being connected
with a wire sealed into the end of the tube, and terminating outside in a
little cup ; the cups being filled with mercury, the tubes may be connected by
wires dipping into the mercury. When the Woulfe's bottle and its tubes are
filled with dilute sulphuric acid, and one of the tubes is then charged with
hydrogen and the other with oxygen, in quantities such as will allow the
platinum to touch the acid, and the ends of a wire are dipped into the cups
at the tops of the tubes, an electric current is produced. At the same time
the gases in the tubes gradually diminish in volume, the volume of hydrogen
which disappears being double that of the oxygen ; the current being gene-
rated, in fact, by the formation of water.
1260a. The Original Nitric Acid Battery.
The Hon. Sir W.R. Grove, F.R.S.
1261. Grove's Gas Battery, made by Spencer and Son,
Dublin. Prof. W. F. Barrett.
The current in this battery is produced by the gradual union of the gases
oxygen and hydrogen, which fill the alternate upright glass tubes. Strips of
platinum passing down the tubes serve for making metallic connexion
with the gases.
1262. Constant Gas Voltaic Battery devised by W. R.
Grove, Esq., M.A., F.R.S., Professor of Experimental Philosophy
m the London Institution (now The Hon. Sir W. R. Grove), and
described by him in a communication to the Royal Society, dated
May 30th, 1845. London Institution, Finsbury Circus, E.C.
To charge the apparatus, the stopper is removed from the end of the tube,
and the glasses are filled to the top of the narrow platinum plates with
acidulated water ; acid is also poured into the end vessel, so as to cover the
lump of zinc. The hydrogen which is evolved by the action of the zinc
on the acid gradually expels the air from the main channel, and, when this is
I. BATTERIES. 305
judged to be the case, the stopper is inserted; the hydrogen will now rapidly
descend in all the tubes until the zinc is laid bare, and then remain stationary.
A gas battery is now obtained, the terminal wires of which will give the usual
voltaic effects, the atmospheric air supplying an inexhaustible source of
oxygen, and the hydrogen being renewed as required by the liquid rising to
touch the zinc ; by supplying a fresh piece of zinc when necessary it be-
comes a self-charging battery, which will give a continuous current; no new
plates are ever needed ; the electrolyte is never saturated, and requires no
renewal except the trifling loss from evaporation, which indeed is lessened, if
the battery be in action, by the newly composed water.
1263. Element of M. Becquerel's Sulphate of Copper
Battery. Conservatoire des Arts et Metiers, Paris.
1264. Twelve Elements of Galvanic Batteries on different
systems, by Ruhmkorff. Conservatoire des Arts ct Metiers, Paris.
1266. Smee's Battery. Six cells, with arrangement for
raising the plates out of the cells. James How fy Co.
1266a. Set of Six Cell Smee's Batteries.
E. Cetti and Co.
1269. Grove's Nitric Acid Battery. Elliott Brothers.
1270. Paure's Nitric Acid Battery. Elliott Brothers.
The advantages offered in this battery are, greater constancy ; less incon-
venience from fumes, the porous cell* being a stoppered bottle ; and it not
being necessary to amalgamate the zincs, common salt being used in the outer
cell.
1271. Glass Battery Cell, with two carbon and two zinc
plates. Reiser and Schmidt, Berlin.
1272. Glass Battery Cell, with two carbon and one zinc
plate. Keiser and Schmidt, Berlin.
1273. Glass Battery Cell, with one carbon and one zinc
plate. Keiser and Schmidt, Berlin.
1274. Dipping-Battery, with 10 elements, of the exhibitors'
own construction. Keiser and Schmidt, Berlin.
1275. Dipping-Battery, with 16 elements, with pachy trope
of the exhibitors' own construction. Keiser and Schmidt, Berlin.
1276. Battery for Field Telegraph Service, constructed
for the Prussian Railway Battalion according to the plan of
Captain Witte. Keiser and Schmidt, Berlin.
1277. Leclanche Cell, for working house telegraphs, modified
by the makers. Keiser and Schmidt, Berlin.
40075. U
306 SEC. 10. ELECTRICITY.
1277a. Yeates* Improved Leclanche Cell.
Prof. W. F. Barrett.
New form of Leclanche cell, the position of the zinc and carbon are reversed,
thus rendering it less liable to polarisation, and hence far more constant than
the ordinary form. Made by H. Yeates, King Street, Covent Garden.
1278. Drawing and Description of a Galvanic Battery,
with arrangement for combining the elements ad libitum.
Dr. Tasche, Giessen.
1279. Portable Battery for Electro-therapeutic Pur-
poses. 24 elements. Prof. Beetz, Munich.
1279a. Round Immersion Battery, with automatic break
for medical purposes. J. Teller, Munchen.
By this arrangement powerful action is obtained, and a very constant current,
even with great resistance. The consumption of zinc is (in consequence
of self-amalgamation in the acid chromate of mercury solution) very small,
and this result is also favoured by the small immersion, which is limited
by the slide on the upright bars. By the automatic interrupter, the battery
can be used also with intermittent current, and such a battery current (because
without alteration of poles) is to be preferred to the action of an induction
current.
1280. Portable Battery, with Ebonite Insulations for
the investigation of tension phenomena. 16 cells.
Prof. Beetz, Munich.
1281. Delicate Battery, with four platinum-zinc elements,
two silk conducting strings, with eight reserve plates in a case.
Kgl. Chirurgische JKlinik, Breslau, Prof. Dr. Fischer.
1282. Delicate Battery, with four carbon-zinc elements.
Kgl. Chirurgische Klinik, .Breslau, Prof. Dr. Fischer.
1283. Delicate Battery, with two carbon-zinc elements, two
conducting strings, and three reserve plates in case.
Kgl. Chirurgische Klinik, Breslau, Prof. Dr. Fischer.
1284. Small Battery, with two platinum-zinc elements.
Kgl. Chirurgische Klinik, Brest au, Prof. Dr. Fischer.
In galvanocaustics (the art of destroying diseased portions of tissue by
means of the electric current) the batteries used generally consist of four
very large Grove or Bunseu elements. Wires proceed from the battery to a
piece of platinum, which is to be raised to a red heat. This collection shows
Middeldorff's original arrangement, as used in Breslau, and also recent
modifications.
Two Secondary Elements, by Plante.
M. Breguet* Paris.
Battery of 2O Secondary Elements, by Plante.
M. Breguet, Paris.
I. BATTERIES. 307
Battery of 2O Secondary Elements, by Plante.
M. Breguet, Paris.
c. THERMO-ELECTRIC BATTERIES.
Thermo-electrical Pile of Nobili, composed of 12 elements
disposed in rays.
The Royal Institute of " Studii Superiori " at Florence.
Thermo-electrical Pile of Nobili, divided into three
small ones of 12 elements each, to be combined at will.
The Royal Institute of " Studii Superiori " at Florence.
53. Thermo-electrical Pile of Nobili for the experiments
on radiant heat, composed of 37 elements, and furnished with a
conical mirror.
The Royal Institute of " Studii Superiori " at Florence.
It is well known that Leopoldo Nobili, who Avas for several years professor
at the lloyal Museum of Physical Science and Natural History of Florence,
was famous for the construction of thermo-electrical piles, of which he made
much use in his important experiments on radiant heat, partly carried out in
conjunction with the celebrated Melloni.
1298a. Nobili's First Thermo-Electric Battery.
Prof. Dove, Berlin.
1298b. Melloni's First Thermo-Electric Pile.
Prof. Dove, Berlin.
1298c. Antinori's First Apparatus for Induction
Sparks. Prof. Dove, Berlin.
This apparatus was bought at an auction in Florence, after Nobiii's
decease.
1286b. Thermo-Electric Apparatus by Seebeck.
1. Ring of copper and antimony.
2. Cylinder of copper and antimony, 46 mm. in diameter and
22 cm. in length.
3. Six circular discs ; diameter 10 cm. ; of copper, brass, and
other alloys.
4. Square disc, 16 cm.
o. Two rods, Bi. Sb.
Prof. Dr. Dove, Berlin.
(Property of the lloyal Academy of Sciences at Berlin.)
1265. Pouillet's Thermo-Electric Battery.
Conservatoire des Arts et Metiers, Paris.
1285. Thermo-electrical Battery, bismuth and antimony.
Geneva Association for the Construction of Scientific In-
struments.
U 2
308 SEC. 10. ELECTRICITY.
1286. Nobili's Thermo-Electric Pile, of 54 pairs of
bismuth and antimony bars, soldered alternately together ; the
smallest difference of temperature between the two faces of the pile
develops a current, readily indicated by a suitable galvanometer.
Elliott Brothers.
1235c. Apparatus intended for producing Thermo-electric
Currents in a special manner.
Imperial University of St. Petersburg.
It consists of ten straight electro-magnets, with their poles joined alter-
nately so as to form a zig-zag. The iron cores arejiot in direct contact but are
connected by small brass cylinders to which they are soldered at their extremities.
These small cylinders carry brass plates and rods ' placed alternately. When
the apparatus is to be used, these plates are heated approximately up to 100
centigrade ; the brass rods are cooled with crushed ice, and then the galvanic
current of a six element battery (carbon, zinc, chromic liquid,) is passed
through the bobbins of the electro-magnets, odd or even numbers. The
thermo-electric current produced \>y the iron cores produces a strong devia-
tion of the needle of a sensitive galvanometer of small resistance.
The fact of the heterogeneousness of magnetised metals and non-magnetisc
metals was discovered by Sir W. Thomson. The apparatus here described is
constructed by Prof. T. Petrouchevsky, Professor at the University of St.
Petersburg. The first experiments made with this apparatus, slightly altered
however, have been briefly described in Russian in the " Journal of the Russian
" Society of Chemistry," and in that of " The Physical Society of the Univer-
" sity of St. Petersburg," Vol. 6, Section Phys., p. 107 (1874).
1287. Hoe's Thermo-electric Battery of 96 pairs. Con-
venient for lecture experiments. George Gore, F.R.S.
Attains its maximum power in about one minute. May be heated to low
redness. Decomposes water freely. Will excite an electro-magnet to sus-
tain 2 cwt. It has an arrangement, or " current transformer," by means of
which its entire power can be employed with three different combinations of
its elements, viz., as 96 by 1, 48 by 2, or 24 by 4, and changed instantly from
one combination to another. The connexions of the " transformer " require
no cleaning. Made by W. J. Hauck, Vienna.
1288. Small Single-cell Apparatus, with platinum-plates,
for showing the thermo-electric properties of liquids.
George Gore, F.R.S.
(See Philosophical Magazine, Jan. 1857.)
1289. Single-cell Apparatus, for examining the thermo-
electric properties of liquids. George Gore, F.R.S.
(See Proceedings of the Royal Society, 1871.)
1290. Large Single-cell Apparatus, with platinum-plates,
for showing the thermo-electric properties of liquids.
George Gore, F.R.S.
I. BATTERIES. 309
1291. Pour-cell Apparatus, with copper plates, for showing
the thermo-electric properties of liquids. George Gore, F.R.S.
(See Philosophical Magazine, 1857.)
1292. Twelve-cell Apparatus, with platinum-wire elec-
trodes, for examining the thermo-electric properties of liquids.
George Gore, F.R.S.
(Sec Proceedings of the Royal Society, 1871.)
1293. Model of the most improved form of apparatus for
investigating the thermo-electric properties of liquids. Used with
ribbons of platinum, gold, palladium, and silver.
George Gore, F.R.S.
1297. Thermo-Battery. Siemens and Halske, Berlin.
1297a. Thermo- Electric Pile, small student's form, nickel-
plated. Harvey, Reynolds, and Co.
1298. Thermo-Electric Pile (Noe's system), with 64 ele-
ments, heated by gas. The electro-motive power equal to six
Bunsen elements. P. Dorffel, Berlin.
The elements, consisting of a round rod (positive) and thin wires (nega-
tive), are arranged in two opposite rows of 64 elements each, whose heating
bars (cast of positive metal and protected against the flame by copper casing)
project in a row into the open space between the elements, so that they are
all alike heated by the stand of Bunseu burners below, and convey the currents^
to the elements. The cooling of the other junctions is effected by means of
metallic cooling-plates attached to them, supported by the wooden frame
under the elements. The electro-motive force is equal to 6 Bunsen or 120
Jacobi-Siemens' units. The resistance = 2 45 Siemens' units. The pile
contains a Dove's Pachytrope, in order to arrange the elements in groups of
1, 2, or 4, by means of which the resistances and the electro-motive force may
be changed.
1299. Thermo-pile (Noe's system), with 20 elements in
radiating arrangement, heated by gas. The electro-motive power
is equal to one Bunsen element. P. Dorjfel, Berlin.
Here the elements are arranged radially, so that the heating bars all
run to a middle point, where they can be heated by the single flame of a
Bunsen burner. The cooling is done with metal plates which are rolled into
a tubular form, and serve at the same time as stands for the battery. The
electro-motive force is equal to 1 Bunsen or 20 Jacobi-Siemens units. This
apparatus (as also the next, 1300) is recommended for small experiments in
electrolysis, &c.
1300. Thermo-electric Pile (Noe's system), heated by a
spirit lamp, with 20 smaller elements, and consequently of greater
resistance. The electro-motive power is equal to one Bunsen
element. Resistance equal to 0'52 Siemens' units.
P. Dorffel, Berlin.
310 SEC. 10. ELECTRICITY.
1301. Thermo-electric Pile (Noe's system), heated by a
spirit lamp, with 10 smaller elements. Its electro-motive power is
equal to 0'5 Bunsen element. P. Dorffel, Berlin.
Designed specially for medical use, in connexion with a small induction
apparatus. Should long action be desired it is well to place the battery with
lamp in a vessel with water, to avoid the great heating its small size involves,
and to increase the action.
1294. Thermo-Electric Battery or Clamond Pile.
Thermo- Electric Company.
The poles or generators are constructed of zinc and antimony, both being
metals bearing great electrical properties. The electricity is given out with-
out any intermediate agency, except heat, which is generated as gas ; coke
or charcoal is consumed. Economy in maintenance, and cleanliness in ap-
plication, gives this arrangement an advantage over other batteries, and the
current obtained is constant and free from polarisation or exhaustion.
1301a. Thermo-Electric Generator (diamond's
Patent). Constructed either for electrotyping, plating, gilding,
or telegraphy. A pile of 100 bars, with a gas jet burning 4 feet
per hour, will deposit an ounce of copper per hour.
Thermo- Electric Generator Company (Clamond' s Patent).
The Thermo-Electric Piles or Generators are constructed of elements, one
pole of which is tinned iron, the other being an alloy of two parts of antiniony
to one of zinc. The iron is cast into the alloy, and thus a perfect connexion
is made. The pairs thus formed are then laid side by side, and being cemented
together, form a ring or crown (the cement used is a mixture of asbestos and
silicate of soda) ; one crown being complete another is laid above it, though
insulated from it by the same cement, and so on, giving the pile a cylindrical
form. The junctions are heated thus : Up the centre of the pile is placed u
perforated earthen tube and gas issuing from a Bunsen's jet burns at the per-
forations, heating an iron core red hot, which radiates its heat to the junctions
of the pairs, thus the flame never impinges on the metals, and all oxidization,
&c. is obviated ; the heated air passes over the top of the iron core, and
curling down, escapes by a pipe from the bottom of the pile. The elements
of each crown are connected in series, but the terminals of every crown are
brought into a wooden support and can be connected at will for high tension
or great quantity. As a standard of power the following may be used :
A 100 bar pile consuming 4 feet of gas per hour has E.M.F. 5 volts., Int.
Res. 1 ohm.
A 240 small tension bar pile, consuming 4 feet of gas per hour has E.M.F.
12 volts., Int. Kes. 6 ohm.
Piles are also made to be heated by coke or charcoal, and a battery having
an E.M.F. of 20 volts, and Int. Res. of 4 ohms burns 2 Ibs. of coke per hour.
Petroleum is also used for heating the piles.
1301b. Thermo-Electric Pile of Hydrogenium.
Prof. Dewar.
Consists of alternate layers of Palladium and Jlydrogemum ; electro-
motive force equal to that of iron and copper.
1O96. Thermo-electric Diagram for teaching purposes.
(Trans. Roy. Soc. Edin,, 1872-3.) Prof. Tait.
I. INDUCTION COILS. 311
d. INDUCTION COILS.
1303. RuhmkorfPs Coil. Frederick Guthrie.
The current from a galvanic battery passing through a spiral of copper
wire magnetises the soft iron bars placed within it, which by their attraction
so move a steel spring as to interrupt the current. The current being thus
broken, the magnetisation ceases until the current is again restored. The
result is a very rapid making and breaking of the current in the spiral or
primary wire. Outside the primary are many miles of fine insulated copper
wire called the secondary wire. Connected with the primary by wires, one
on each side of the contact breaker, is a tin-foil condenser. This absorbs
the extra-current when the primary is broken, and serves to augment the
secondary when the primary is made. The interior magnetism acts in the
same direction.
1304. Six-inch Induction Coil, and Browning's Spark
Condenser, for obtaining spectra of metals by the induction
spark. John Browning.
When using the spark condenser the amount of coated surface introduced
may be varied at pleasure, and the density of the spark thus regulated.
13O4a. Apps' Patent Induction Coil, giving sparks of
17 in. in air, with a battery of five Grove's cells, platinum,
5x3 in. immersed. Alfred Apps.
13O4b. Henry's Induction Coils.
The Council of King* s College, London.
13O4aa. Large Induction Coil, with thick secondary wire
(10^ miles in length), and improved form of contact-breaker
by which a long interval of contact is obtained. Horatio Yeates.
This is wound on the plan proposed by Dr. Fergusson (in two divisions),
the secondary wire which is No. 32, B. W. G. is 1O| miles long. The primary
wire, No. 8, B. W. G. is wound in two laps.
The condenser is composed of 70 sheets of tinfoil, 26 x 16, insulated with
paraffine paper.
The contact-breaker, which is so formed as to give a long interval of
contact, is also furnished with an adjustment by means of which the coil can
be worked with a very small battery, and maximum results obtained with the
largest suitable battery.
1305. Large Induction Coil, with Foucault's break ; will
give 18-inch sparks. A cube^of glass which was pierced by this
coil. M. Ruhmkorjff.
1305a. Electric Necessaire, containing Ruhmkorff bobbins.
M. Laiseau, jun., Paris.
1306. Induction Apparatus for medical purposes.
Keiser and Schmidt, Berlin.
1307. Induction Apparatus for medical purposes.
Keiser and Schmidt, Berlin,
312 SEC. 10. ELECTRICITY.
1308. Induction Apparatus for medical use.
Reiser and Schmidt, Berlin.
1309. Spark Induction Machine, No. 1, with armature and
Geissler's tubes. Kciser and Schmidt, Berlin.
1310. Spark Induction Machine, No. 2, with armature and
Geissler's tubes. Reiser and Schmidt, Berlin.
1311. Spark Induction Machine, length of spark, six milli-
meters. Reiser and Schmidt, Berlin.
1312. Spark Induction Apparatus, length of spark, one
centimeter. Reiser and Schmidt, Berlin.
1313. Spark Induction Apparatus, length of spark, 4'o
centimeters. Reiser and Schmidt, Berlin.
1314. Spark Induction Apparatus, length of spark, 8
centimeters. Reiser and Schmidt, Berlin.
1315a. Great Induction Coil.
66 Leyden jars and fittings.
6 stands for jars.
The Roijal Polytechnic Institution.
c. MAGNETO-ELECTRIC MACHINES.
1303 a. First Induction Machine, called " de Pixii,"
constructed under the direction of Ampere.
College of France, Paris.
1686. Galvanometer of Nobili.
The Royal Institute of" Studii Superiori" at Florence.
Rose of Metallic Colours obtained by means of electricity
by Leopoldo Nobili.
The Royal Institute of " Studii Superiori" at Florence.
A very great number of liquids and metals were subjected by Nobili to
experiments in order to obtain, by means of electricity, the coloured rings
which bear his name; and exceedingly important are his observations on
the complete scale of colours which he succeeded in forming and which yet
exist at Florence.
1687. Original Magneto-electrical Machine of Leopoldo
Nobili and Vincenzo Antinori, which gave, on the 30th of
January 1832, the first spark, before Leopold II.
The Royal Institute of " Studii Superiori " at Florence.
This is the first machine with which the induction spark was obtained by
means of an artificial magnet. The anchor (ancora) tied by a thread, and
movable like a lever round a pivot, is detached from the loadstone by a blow,
while at the same time, by means of a spring, the electrical circuit is in-
I. ELECTRICAL MACHINES, ETC. 313
terrupted, so that the spark appears at the point of interruption. Faraday,
who was the first to observe the induction currents, obtained the spark by
using an electro-magnet ; the arrangements, however, of Nobili and Antinori
were the first that constituted a true magneto-electrical machine. And we
may also remark that, at the same time, Nobili and Antinori obtained the
electric spark, likewise, by means of the natural magnet of the museum, an
enormous parallelepiped of about 50 x 65 x 78 centimeters in dimension.
1114. Saxton's Magneto-Electric Machine. Copy of the
original machine made by Mr. Saxton, and exhibited by him
before the third meeting of the British Association, held at Cam-
bridge in the year 18337 John O. N. Butter.
This machine was made specially for the contributor by Mr. Saxton,
immediately after the meeting at Cambridge, and has been in his possession
ever since. It is capable of producing sparks, shocks (through the tongue),
and decomposes water. It also reproduces the ordinary phenomena of electro-
magnetism.
The machine is described in Daniell's " Introduction to Chemical Philosophy,"
1843, p. 585, sec. 873.
1316. Ladd's Dynamo-Magneto-Electric Machine.
William Ladd $ Co.
Invented March 1867. (See Proceedings of the Royal Society, No. 91,
1867.)
This was the first machine with two armatures, one being employed to excite
the electro- magnets and the other to produce an electric current, which may
be used for any purpose to which a battery is applicable.
1316a. Ladd's Dynamo-Magneto-Electric Machine,
with two wires on one armature. This machine will heat 15
inches of platinum wire. William Ladd $ Co.
1317. The first Magneto-Electric Machine, with circular
magnets, 1866. William Ladd fy Co.
1318. Magneto-Electric Machine, with circular magnets,
larger form, 1867. William Ladd $ Co.
1319. Magneto-Electric Machine (direct current).
James How fy Co.
1320. Magneto-Electric Machine (Duchenne's form).
James How fy Co.
1321. Magneto-Electric Machine (Clark's form). An early
machine by Logemann^ of Haarlem. James How fy Co.
1322. Electro-Magnetic Coil Machine, for medical ap-
plication. Primary and secondary currents. James Hoiv fy Co.
1323. Magneto-Electric Machine, with alternate current
for production of light. La Societe V Alliance.
A magneto-electric machine, with four discs or 64 bobbins with alternate
current for the production of light. This machine requires a driving power
of 3 H.P. when revolving from 400-450 times per minute.
314 SEC. 10. ELECTRICITY.
1324. Magneto-Electric Machine, to be worked by hand
or steam. La Societe V Alliance.
This machine with eight bobbins is for the purpose of demonstration with
direct and alternate current, and can be worked by hand or steam.
1325. Experimental Magneto-Electric Machine, the
first constructed in which electricity and magnetism, rendered
active by the expenditure of mechanical force, were made to act
and re-act on one another in such a way as to greatly increase the
development of their forces. S. Alfred Varley.
This machine was the first of its class, and acted on what was a new princi-
ple at the date of its construction. The new principle consisted in making
electricity and magnetism, rendered active by the expenditure of mechanical
force, act and re-act on one another in such a way as to greatly increase the
development of their forces. In this machine iron bobbins wrapped with
insulated wire are revolved between the poles of very feeble magnets made of
soft iron. The electricity (small in amount when the machine is first put in
motion) which is developed in the insulated wire of the bobbins passes, by
means of a commutator, through convolutions of insulated wire surrounding the
soft iron magnets, and renders them more highly magnetic. The magnetism
of the soft iron magnets being thus increased, develops a correspondingly
increased quantity of electricity in the revolving bobbins, which re-acts on the
soft iron magnets, rendering them still more highly magnetic.
The expenditure of mechanical force giving motion to the machine is
greater as the magnetism and electricity developed increase, the consumption
of mechanical force having relation to the quantity of electricity rendered
active.
1326. Gramme's Magneto-Electric Machine, for electro-
typing. H. Fontaine.
1327. Gramme's Magneto-Electric Machine, for electric
light. H. Fontaine.
1328. Gramme's Magneto-Electric Machine, for electric
light of great power. H. Fontaine.
1329. Gramme's Magneto-Electric Machine, for demon-
stration. H. Fontaine.
1315. Magneto-induction Machine.
Gustav Baur, Stuttgart.
This apparatus, containing several electro-magnets and a current re-
gulator, is furnished with double coils of wire, and may be used to set in
action electric apparatus of very various resistance and with very quick
interruption of current, e.g., Kuhmkorff coils. In general, any experiments
may be made with it that are made with batteries of 1-6 Bunseii elements.
It is suitable, for medical purposes, galvanocaustics, &c., and, if a part of
the rotating electro-magnets be wound with fine wire, for production of a
constant current up to 60 Meidinger elements.
1330. M. lie Koiix's Electro-Magnetic Apparatus, for
showing the effect of magnetism on copper discs. M. Ruhmkorff.
I. ELECTRICAL MACHINES, ETC. 315
1331. Model of a Magneto-Electric Machine, designed to
illustrate the advantage gained by the use of an electro-magnet in
place of the usual permanent magnet. William Raynoi\
This model of a magneto-electric machine is one that has been constructed
for the purpose of showing the great increase of the electric current by the
use of an electro-magnet in place of the permanent magnet, when such magnet
is excited or charged by a galvanic cell ; and this plan may be applied with
advantage to all magneto-electric machines using soft iron magnets.
1331a. Sketch and Description of an Improvement in
Magneto-Electric Machinery. This improvement is ob-
tained by using two armatures on one spindle, to be fixed one on
each side of the magnet, and placing them at right angles to each
other, so that one is in full action when the other is changing its
polarity. William Raynor.
1332a. Portable Magneto- Electric Machine, with double
coiled magnet. Harvey, Reynolds, and Co.
1249a. Volta Faradaic Machine, with arrangement in the
pocket for taking shocks ; also giving interrupted or continuous
current, the batteries being of the constant Leclanche form.
Harvey, Reynolds, and Co.
1336. Dynamo-Electric Light Apparatus, making 480
revolutions per minute, with an expenditure of 6 horse-power gives
a light of from 12,000 to 1,5,000 normal candles.
Siemens and Halske, Berlin.
In these machines the inner iron core is fixed. Around this core revolves
a German silver bobbin, upon which is wound in a peculiar manner eight
double circuits of covered copper wire, these circuits terminating in the
metallic segments, which are successively brought as two opposite poles into
contact with the wire brushes. The magnetic field in which this bobbin
revolves (on its own axis) is formed by electro-magnets, the continuation of
the cores of which are curved iron bars, and these bars are so arranged as to
be brought as near as possible to the revolving bobbin. The current given
by these machines is continuous and in one direction.
1336a. Dynamo-Electric Light Apparatus. This ma-
chine gives a light of 4,000 normal candles with 850 revolutions
of the armature per minute, with an expenditure of work equal to
3 horse-power. Siemens and Halske, Berlin.
133Gb. Dynamo-Electric Light Machine producing a
light equal to 1,000-1,300 normal candles with about 1,100 revo-
lutions of the induction cylinder per minute and an expenditure of
1 to \\ H.P. The machine is 640 millimetres in length, 540 milli-
metres width, and 225 millimetres height.
Siemens and Halske, Berlin.
1336c. Magneto-Electric Machine to give a constant
current. The apparatus has 50 steel magnets, and the current
316 SEC. 10. ELECTRICITY.
produced is equal to that from 8-10 Bunsen's elements. The
armature is rotated by hand. Siemens and Ifalske, Berlin.
1336a. Various Examples of Magneto- Electric Appa-
ratus.
Electro-magnetic machine by Gramme, with a Jamin magnet of
0'08m.
Magneto-electric machine, by Gramme, for electric light of 150
burners.
Magneto-electric machine, by Gramme, with electro-magnet for
laboratory.
Magneto-electric machine, by Gramme, with a Jamin magnet
(small model).
Magneto-electric machine, by Gramme, with a Jamin magnet
(large model with fly-wheel and treadle).
Exploder, with Jamin magnet (large model) with bobbin, cable,
and key.
Exploder, with Jamin magnet (medium model).
M. Breguet, Paris.
1336d. Magneto-Electric Machine. H. L. Rutter.
f. OTHER MODES OF PRODUCING ELECTRICITY OR ELECTRIC
CURRENTS.
1337. Apparatus, designed (o obtain electric currents by
means of the combined action of gravity and motion. Preliminary
experiments only have yet been made with it.
George Gore, F.R.S.
1338. Apparatus for investigating electric currents produced
by the friction of different metals. (Not yet completed.)
George Gore, F.R.S.
1341. Delezenne's Circle. An instrument for developing
electrical currents by the agency of terrestrial magnetism.
Elliott Brothers.
1342. Apparatus by which Forbes procured an Induction
Spark from a Natural Magnet. Trans. R. S. Edin., 1833.
University of Edinburgh.
II. APPARATUS FOR REGULATING THE PLACE
AND TIME AT WHICH THE EFFECTS OF AN
ELECTRIC DISCHARGE OR CONTINUOUS ELEC-
TRIC CURRENT ARE PRODUCED.
1343. Six Specimens of Tubular Binding Screws for
making electrical connexions. George Gore, F.R.S.
II. REGULATORS (PLACE AND TIME). 317
13 4:3 a. Specimens of Wire for Electric Apparatus.
1. Copper wires, covered with gutta-percha (1, 2, 25).
2. Copper wires, covered with gutta-percha and cotton (3).
3. Copper wires, covered with cotton (4, 5, 6, 9, 11, 12, 13, 14,
26).
4. Copper wires, covered with silk (7, 8, 10, 15 to 23, 27).
5. Elastic poires, with their cordons (24).
6. Covered wires of various metals, with statement of their
resistance. Madame Bonis, Paris.
1235a. Apparatus for uniting several Galvanic Elements
into one of large surface, so as to preserve the entire strength of
the current by lessening the resistance.
Imperial University of St. Petersburg.
To effect this, two metal cylinders, each bored with seven holes parallel to
the axle, and fitted with screws, are used. In one cylinder, the six ends of
conductors connected with the positive electrodes (anodes) of the elements
are inserted, and in the other, the six conductors connected with the negative
electrodes (cathodes). The seventh hole is reserved for a conductor, the
section of which is equal to the total section of the six other conductors.
This last conductor issues from the opposite side of the cylinder. The appa-
ratus here described is used by Prof. Petrouchevsky in St. Petersburg.
1345. Single Plug Key, to close or break contact for long or
short durations. Elliott Brothers.
1346. Fall-hammer, to obtain perfectly equable closing of a
circuit.
Prof. Engelmann, Physiological Laboratory and Ophthal-
mological School, Utrecht.
On a brass prismatic lever, movable round a horizontal axis, slides the
bridge, a copper cover having underneath two amalgamated copper points.
On depressing a spring the lever falls from a nearly vertical position, and
plunges the bridge into two mercury vessels, movable on a horizontal slide,
and connected with the battery. A spring prevents the bridge from rebound-
ing. Velocity of fall to be regulated by moving the bridge on the lever with
corresponding displacement of the mercury vessels on the horizontal slide.
The bridge being in the primary circuit of an induction apparatus, the
breaking is every time to be effected at another place of the circuit, before
lifting the bridge from the mercury, in order to prevent oxidization of the
mercury by the spark.
The instrument can easily be managed with one hand.
1347. Firing Key, f or torpedoes, &c. A simple contact key,
with a movable piece of vulcanite, which can be brought between
the two platinum contacts to prevent fatal results by accidentally
closing the circuit. Elliott Brothers.
1348. Apparatus for reversing the direction of an
Electric Current. Used with an electro-magnetic torsion ap-
paratus. George Gore, F.R.8.
(See Philosophical Transactions of the Royal Society, Vol. 164, p. 529.)
318 SEC. 10. ELECTRICITY.
1348a. Current-reversing Electrode.
J. Teller, Munchen.
This gives a more convenient change of current than the commutators so
far as electro-medical apparatus is concerned.
1349. Double Reversing Key, used for cable testing.
Elliott Brothers.
1350. Thomson's Reversing Key, used in connexion with
the electrometer, for facilitating the measurement of the electro-
static capacity of a cable or condenser. Elliott Brothers.
1351. Lambert's Key, constructed for charging ordischarging
cables and condensers. Elliott Brothers.
1352. Spottiswoode's Rapid Break, for use with Intensity
Coils. Tisley and Spiller.
By means of this "break the discharge in vacuum tubes can be regulated,
and the motion of the stratifications diminished or rendered stationary, as
required. See Proceedings Royal Society, June 10, 1875.
1354. Forms of discharge on making and closing an induc-
tion current. Prof. Donders, Utrecht.
The trial with the noematachograph to have the instant of stimulation
registered on the chronoscopic line by the current itself, led to the discovery :
1. That the discharge can form a long series of sparks.
2. That the electricity disappears more slowly when the spring rests on
metal, more rapidly when it rests on a plate of mica, than in the form
of sparks making holes in the paper. (Compare Onderzoekingen
gedaan in het phys. labor. Ser. 2, T. III. 1870; and Wiedemann, Die
Lehre vom Galvanismus tmd Electroinagnetismus, 2 e Auflage, 1874,
B. II., s, 360.)
1355. Drawings showing the patent system of lightning
conductors applied to buildings. J. W. Gray $ Son.
1356. Model of mid-section of a Ship, showing the patent
system of lightning conductors applied to vessels in Her
Majesty's service, &c. J. W. Gray > Son.
1357. Indestructible Solid Copper Tape Lightning
Conductors. Small and large sizes. Sanderson fy Proctor.
This form of lightning conductor possesses the greatest conducting surface.
Hitherto it has been made in short lengths riveted together ; now it is made
in any length without joints, thereby offering less resistance to the free passage
of the electric current.
1358. Copper Rope Lightning Conductors, improved.
The smallest and largest sizes. Sanderson fy Proctor.
1359. ETew Lightning Conductor Apparatus.
Prof. Carl Wenzel Zenger, Prague.
II. REGULATORS (PLACE AND TIME). 319
This apparatus consists of lightning conductors arranged symmetrically,
balls being used instead of conical points. A plan shows its application to
the I. R, Keal School, and to the National Theatre at Prague.
1360. Top of Lightning Conductor. The lower part is
made of gun metal, the upper of copper, and the extreme point of
gold or silver. Constructed according to the instructions of
Professor Ed. Hagenbach-Bischofi, in Basle. G. Linder, Basle.
The electricity escapes easily through good conductors from points and
edges ; the point does not oxidize in the atmosphere, and being a good
conductor is not liable to be melted by electricity.
1361. Needle of Lightning Conductor, brass gilt.
Geneva Association for the Construction of Scientific In-
struments.
1362. Lightning Conductors (various kinds).
John Faulkner.
Two photographs of expedients for applying lightning conductors to high
spires and factory chimneys, and for the repair of high spires and chimneys.
1363. Models of Lightning-Conductors of the latest con-
struction. Mittelstrass Brothers, Magdeburg.
1364. Apparatus serving for the separation and collec-
tion of induced currents, constructed by Dr. Th. Tasche,
manufactured by Staudinger & Co., in Giessen.
Dr. Tasche, Giessen.
1364a. Current Analyser, with glass axis, made by Jung,
of Giessen. Physical Institute ( Univ. of Giessen), Dr. Buff.
The "current analyser" can be occasionally used for experimental re-
search in voltaic induction, to separate the two induced currents, and to
study the proportion of their intensities or electro-motive forces. See Poggen-
dorff's Annalen, Vol. 127, p. 57.
1365. Binding Screws for Galvanic Work.
M. Th. Edelmann, Munich.
1366. Current-key for Beetz's Compensation Method.
M. Th. Edelmann, Munich.
III. APPARATUS FOR ACCUMULATING
ELECTRICITY.
1367. Leyden Jar of five and a half square feet coated
surface. Teyler Foundation, Haarlem.
This jar is one of the ICO jars arranged in four cases, by which Van Marum
constructed a battery of 550 square feet coated surface. The coatings of
TJHI7EE
3 4 20 SEC. 10. ELECTRICITY.
tinfoil have been renewed recently ; but all is restored in the form in which
it was used by Van Marum.
See Van Marum, " Machine Electrique," II., p. 195.
1368. Leyden Battery of 15 jars.
Teyler Foundation, Haarlem.
This battery is one of 1 6 used by Van Marum for his famous experiments,
giving a total coated surface of 225 square feet.
The coatings of tinfoil have been renewed recently ; the bottom of tea-
lead irt the case is also restored ; and the outer coating of the case bottom,
which Van Marum also made of tea-lead, has been replaced by zinc.
See Van Marum "Machine Electrique," I. p. 155, and II. p. 3.
1369. Battery of 1O one-gallon Leyden Jars.
Frederick Guthrie.
This battery stands in a mahogany frame. The jars stand upon perforated
zinc. There is an arrangement for drying them by a current of hot air.
The spark from this battery deflagrates a platinum wire a foot long.
1369a. Series of Leyden Jars, with connectors, and ebonite
covers, 10 pieces from 90 to 100mm. high.
Warmbrunn, Quilitz, fy Co., Berlin.
1369b. Battery of Leyden Jars, consisting of six jars 31 2imn.
high, in mahogany case. Warmbrunn, Quilitz, fy Co., Berlin.
1369c. Cylinder, on insulating support.
Warmbrunn, Quilitz, fy Co., Berlin.
1369d. Cylinder, with elder-pith balls.
Warmbrunn, Quilitz, fy Co., Berlin.
1369e. Sphere, on insulating support, with two movable hemi-
spheres on ebonite rods. Warmbrunn, Quilitz, $ Co., Berlin.
1369f. Large dissected Leyden Jar.
Warmbrunn, Quilitz, fy Co., Berlin.
10 7O. Spiral Leyden Jar. Frederick Guthrie.
Two sheets of ebonite, alternating with two sheets of tinfoil, are rolled up
together. The central knob is connected with the inner edge of one of the
foils ; the brass girdle is connected with the other sheet. A Leyden jar is
thus formed which is compact with a large surface.
1371. Mica-plates for insulating electrical apparatus.
Max. Raphael, Breslau.
Mica can be rendered electrical by the least friction, hence its frequent em-
ployment as an excellent insulating material, especially on account of the
facility with which it can be worked.
1372. Two Large Condensers, consisting of Leyden jars,
each 400 millimeters high and 200 millimeters in diameter.
Borchardt, Hanover.
V. DISCHARGE. 321
1372a. Adjustable Disc Condenser, which has also been
used as a spark micrometer. Sir William Thomson.
It was in this instrument that the sound produced in an air condenser by a
sudden change of potential was first heard. The lower part of the cell is
arranged to hold cups of pumice-stone impregnated with sulphuric acid.
1372b. Cylindrical Condenser, for measuring capacity in
absolute electrostatic units, described in Messrs. Gibson and Bar-
clay's paper in the Transactions of the Koyal Society for 1871.
Sir William Thomson.
1372c. Condenser for the Holtz-Bertsch Electrical
Machine. Mottcrshead fy Co., Manchester.
IV. APPARATUS FOR PRODUCING AND OBSERVING
EFFECTS OF ACCUMULATED ELECTRICITY.
1373. Apparatus for demonstrating the fundamental laws of
electrical and magnetical attraction and repulsion, made according
to the instructions of Professor Ed. Hagenbach-Bischoff, in Basle.
G. Linder, Basle.
The ebonite rods are negatively electrified when rubbed -with fur, and
positively electrified when rubbed with gun-cotton. (5ee Carl, Repertorium
der Experimental-Physik, VIII., p. 75.)
1374. Insulated Pith-Ball Stand, with mahogany arm ;
the arm is itself a box in which the pith balls may be placed when
it is not in use. The Council of King's College, London.
1648. Series of Elder Pith Figures, Butterflies, &c.
Warmbrunn, Quilitz, and Co., Berlin.
V. APPARATUS FOR PRODUCING AND OBSERVING
EFFECTS OF THE DISCHARGE OF ACCUMULA-
TED ELECTRICITY, WITH SPECIMENS OF PER-
MANENT RESULTS PRODUCED.
1375. Photographs of Sparks from a Holtz Machine, in
cold and in heated air. (See Trans. R. S. Edin., 1874-5.) Taken
by an instantaneous process, a quartz lens being employed.
Prof. Tait.
1375b. Spark Micrometer after Riess.
Warmbrunn, Quilitz, $ Co., Berlin.
1376. Apparatus used by M. Rijke to measure the distances
at which the spark of the Ley den jar passes.
Prof. Dr. P. L. Rijke, Leyden.
40075. X
322 SEC. 10. ELECTRICITY.
1377. Vacuum Tube for electric discharge. 1856.
Teyler Foundation^ Haarlem.
Masson in Paris used a Torricellian vacuum sealed by the lamp, in his
extensive researches on the electric spectrum. Some time afterward, Dr.
Geissler, in Amsterdam, made this Torricellian vacuum at the instigation of
Prof. Van der Willigen, now director of the Teyler Museum, whose property
it is at present. The experiments with this tube are described in Poggen-
dorffs Annalen, vol. xcviii. p. 487, 1856. Subsequently Dr. Geissler in Bonn
constructed his various well-known and beautiful tubes. This tube contains
a little mercury and carbonic oxide gas.
1377a, Pour Geissler's Vacuum Tubes. E. Cetti and Co.
1377b. Collection of Geissler's Tubes.
Dr. H. Geissler, Bonn.
1377c. Tube, by Geissler, for two gases.
Tube, by Geissler, forming a diadem.
Tube, by Geissler, forming a diadem.
Tube, by Geissler, with inner spiral.
Tube, for liquids, with six spirals.
Alvergniat Freres, Paris.
1377d. Three Vacuum Tubes, to show the connexion
between the resistance of rarefied air and the phenomenon at the
cathode, the so-called negative glow. Prof. Hittorf, Munster.
Apparatus (A) made by Dr. Geissler, of Bonn, consists of two balls which
communicate together by two tubes of equal width, one short and one of
spiral form 3| metres long. The electrodes of aluminium wire pass through
the balls and end in the short tube so that there is a free interval of only
2 mm. between them. The opening current of the Rhumkorff coil passes, in
consequence of the great rarefaction of the air in the tube, not by this short
path, but prefers the longer one. If the latter be stopped by closing the
glass cock, the passage is effected, but only at much greater tension, by
the short path. The tube (B) has the same arrangement, but without the
glass cock. It is used in place of (A) where the air is able to penetrate and
the required vacuum ceases. The glass vessel (C) consists of a wide reservoir
and a cylindrical tube, each of which holds one of the two equally long wires
as electrodes. The tension of electricity with which passage occurs is much
greater when the wire in the narrow part serves as cathode than when it is
anode. This may be shown if a spark micrometer be introduced in the induc-
tion current near the tube, and for each of the two directions the interval of
the balls be determined with which the current takes the path through the
tube. If the wire in the wide reservoir, being cathode, be placed in conductive
connexion with the third aluminium wire, which is in the beginning of the
cylindrical tube, the current can no longer pass over in the latter to the former
This, therefore, loses its negative light, and only with the greater tension,
such as occurs with the other direction, is the passage of electricity effected.
(Cf. Pogg. Ann., Bd. 136, p. 197.)
V. DISCHARGE. 323
1377e. Three Tubes of Glass, with rarefied air to show the
magnetic behaviour of the negative light.
Prof. Hittorf, Munster.
The aluminium wire, which is quite sheathed with glass, with the excep-
tion of the end, is taken as cathode of the opening induction-current. The
straight discharge from the cross section, when the tubes are brought over
and between the poles of an electro-magnet, behaves like a flexible conductor
which is fixed at one end and at the other freely movable, and follows the
Laplace-Biot laws. (Cf. Pogg. Ann., B. 136, p. 213.)
1377f. Three Glass Tubes of Rarefied Air and Sulphide
of Calcium^ to show the phosphorescence of the negative electric
light. Prof. Hittorf, Munster.
The negative electric discharge which, with great rarefaction, occurs at
a cathode with small surface, raises the conducting particles of gas to a very
high temperature. When strong induction currents are used, these, notwith-
standing their small mass, are capable of raising the surface of badly-conducting
solid bodies with which they come into contact to a red heat. This heating,
which the negative discharge gives in much greater degree than the positive,
produces with the best light-givers, like sulphide of calcium, a light of dazzling
intensity.
1378. Gassiot's Star. Frederick Guthrie.
This exhibits (1) the varieties of the electric discharge through various
rarefied gases in tubes of different shapes, and (2) by being rotated shows by
the retention of images the intermittent nature of the discharge.
1379. Block Specimen of Glass, 2| inches high, penetrated
vertically by an electric discharge. (By Ruhmkorffj of Paris.)
George Gore, F.R.S.
1380. Effect of Lightning. Portion of a half-sovereign and
a fragment of sheet iron fused together by a discharge of lightning
in the colony of Natal. This and other coins were in a tin box,
of which this fragment alone remained after the passage of the
discharge. Robert James Mann, M.D.
1381. Metals fused into Glass by Lightning.
Alfred B. Harding.
Frame No. 1 consists of strips of zinc, tin, and lead, fused into glass by an
actual flash of lightning, collected by means of " exploring wires " stretched
over the grounds of the late Andrew Crosse, and conveyed into his electrical
room, as shown in the stereograph. It was here accumulated in the great
Leyden battery of 50 jars, and passed thence by dischargers through the
metals, which were burnt into the glass on which the strips were laid.
Frame No. 2 contains composite strips of copper and iron, gold and tin,
and gold, silver, and copper, fused in like manner.
A photograph of the Leyden battery, with which the experiments were per-
formed, accompanies the frames.
1382. " Thunder House,** or model to illustrate the identity
of lightning and electricity, and the use of lightning conductors
X 2
324 SEC. 10. ELECTRICITY.
in protecting buildings said to be the first model of the kind,
and to have been made by Dr. PRIESTLEY with his own hands.
Conrad Wm. Cookc, M. Soc. T.E.
1383. Old Electric Egg (beginning of last century). The
property of Prince Pless. The Breslau Committee.
The great age of the instrument appears both from tradition and from
the style of the wooden frame and the nature of the brass work. It is certainly
one of the oldest instruments of the kind.
1384. Apparatus employed by Sir Charles Wheats tone to
determine the Velocity and Duration of the Electric Dis-
charge.
Rotating mirror. Spark disc. Early rotating disc with balls
and sliding rod. The Council of King's College, London.
1385. Riess* Spark Micrometer. F. Rob. Voss> Berlin.
1386. Apparatus for testing Lightning Conductors.
M. Th. Edelmann, Munich.
1387. Electrograph, for the production of electric sand-
figures, constructed, from the plan of the exhibitor, by M. Th.
Edelmann. Prof- W. von Bezold, Munich.
This serves for the study of the nature of the electric discharge in simple
or branched circuits, with the aid of sand-figures. The figures exhibited have
partly been produced with this apparatus, partly under the air pump, and by
means of a caoutchouc solution transferred from the ebonite plate to black
tissue-paper. They are accordingly not copies, but true originals, produced by
the discharge.
1388. Framed Table, with electric sand-figures.
Prof. W. von Bezold, Munich.
VL APPARATUS FOR PRODUCING AND OBSERV-
ING EFFECTS OF CONTINUOUS ELECTRIC
CURRENTS.
a. HEATING AND LUMINOUS EFFECTS.
1389. Diagram showing the Amounts of the Electro-motive
Force, and the Peltier and Thomson Effects in a Thermo-
electric Circuit of Iron-Copper, both junctions being at
temperatures under the neutral point. For teaching purposes.
Prof. Tait.
1390. Peltier's Apparatus, for studying the thermal effects
of currents in circuits composed of two or more metals.
Conservatoire des Arts et Metiers, Paris.
VI. CURRENTS. 325
b. CHEMICAL EFFECTS.
1391. Apparatus for the polar Decomposition of Water by
means of atmospheric electricity or the currents of the ordinary
electrical machine. The gases are collected in fine thermometer
tubes, by which means their absorption by the electrolyte is avoided.
Dr. Andrews, F.R.S.
1391a. Warmbrunn, Quilitz, and Co.'s Apparatus for
Decomposition of Water, peculiar construction, with gradu-
ated tubes for the separated gases and for detonating.
Warmbrunn, Quilitz, $ Co., Berlin.
1392. Bottle, containing fragments of pure Electro-
deposited Metallic Antimony. George Gore, F.R.S.
{See Philosophical Transactions of the Royal Society, 1857, 1858, and
1862.)
1393. Two Specimens of Electro-deposited Antimony;
one of the explosive, arid one of the pure variety.
George Gore, F.R.S.
1394. Hare Specimen of pure Carbon, deposited by
means of an electric current upon a rod of platinum.
George Gore. F.R.S.
c. ELECTRIC DIFFUSION AND CHANGE OF SURFACE-TENSION.
1395. Apparatus for producing Vibrations and Sounds,
and an intermittent electric current by means of the electrolysis of
a solution of cyanide of potassium and mercury with electrodes of
mercury. . George Gore, F.R.S.
The effects are produced by the alternate rapid formation and destruction
of films upon the positive electrodes. {See Proceedings of the Royal Society,
Vol. 12, p. 217.)
1395a. Electro Capillary Force Machine, after Lippmann.
R. Jung, Heidelberg.
To set this machine in action, the two wide glass vessels are first filled
to a height of 1 to 3 cm. with mercury, placed in position in the glass trough,
and then two thirds filled with pure dilute sulphuric acid. Then the two bundles
of thin glass tubes are pushed repeatedly down into the mercury, so that the
air is driven out, and the tubes and their interstices are quite filled with
mercury and acid. The bundles are then fixed by screws to their frames,
so as to be about half immersed in the mercury, and to stand in equilibrium in
the middle of their respective vessels. If the cups of the key be now filled
with mercury, and the crank, which works it, so placed that the current is
reversed a little before the opposite crank comes to its dead point, the machine
(having been connected with the poles of a Daniell battery) will commence
working, and may make as many as 100 revolutions in a minute. A Meidiii-
ger element keeps the machine in action for months.
326 SEC. 10. ELECTRICITY.
1395b. Apparatus for electric osmose.
Prof, ffittorf, Munster.
In each of the three divisions formed in the glass cylinder by the clay
plates the electric endosmose (when the vessel is quite filled -with the solution
of an electrolyte) is produced or prevented according as, on passage of the
current, the three openings are free or are closed. With the arrangement it
is proved that the transference of the ions is quite independent of the electric
endosmose. (Pogg. Ann., Bd. 96.)
d. EFFECTS DUE TO THE FORCE BETWEEN CURRENTS AND
MAGNETS.
1396. Apparatus for showing the Rotation of a Bar-
magnet on its axis by the passage through it of an electric
current. George Gore, F.R.S.
(See Proceedings of the Royal Society, Vol. 24, p. 121.)
1397. Apparatus for showing the notation of a Copper
Wire upon its axis between the poles of two magnets by passing
through it an electric current. George Gore, F.R.S.
(See Proceedings of the Royal Society, Vol. 24, p. 121.)
e. EFFECTS DUE TO THE FORCE BETWEEN CURRENTS AND
CURRENTS.
1398. Apparatus for demonstrating the Laws of Ampere.
Geneva Association for the Construction of Scientific In-
struments.
The mode of suspension used in this apparatus allows the conductor to
make a complete revolution.
The current passes from the movable conductor into an annular cup, con-
centric with the axis of motion and filled with a conducting liquid.
All the conductors are made of aluminium so as to lessen their weight as
much as possible.
The apparatus may be used for a great number of experiments ; it is spe-
cially adapted for the following demonstrations :
1. Parallel currents in the same direction attract one another, and those in
contrary directions repel one another.
2. Inclined currents in the same direction attract one another, and those in
contrary directions repel one another.
3. The attraction and repulsion of the same current are equal.
4. A sinuous current acts like a rectilinear current of the same general
direction and having the same extremities.
5. A closed current takes a direction perpendicular to the magnetic meridian.
6. A solenoid has the essential properties of a magnet.
7. The elements of the same current repel one another.
The mutual action of magnets and currents is demonstrated by means
of the same apparatus, by replacing one of the currents by one or more
magnets.
VII. CURRENTS. 327
1398a. General Table, by Ampere, with apparatus used by
him in the discovery of the action of currents.
College of France, Paris.
1399. Apparatus for demonstrating the action of Me-
tallic Discs in movement upon a metallic wire used as a voltaic
conductor. P r f- Daniel Colladon, Geneva.
Experiment performed on 4th September 1826, in presence of the Paris
Academy of Sciences, by Messrs. Ampere and Coliadon.
Bulletin de Sciences Mathematiques, by De Ferussac, vol. 6, p. 212.
1400. Model of a Circular 11 ail way, for showing the
rotation of a metal ball upon it by the passage of an electric
current. George Gore, F.R.S.
(See Philosophical Magazine, Feb. 1859.)
140Oa. Small Model of a Circular Railway, for showing
the rotation of a metal ball upon it by the passage of an electric
current. (See Philosophical Magazine, February 1859.)
George Gore, F.R.S.
VII. APPARATUS FOR REGULATING THE
STRENGTH OF ELECTRIC CURRENTS.
1402. Wheat stone's Rheostat, or changeable resistance, for
quickly adding or removing a low resistance. Elliott Brothers.
1403. Voltastat and Voltameter combined.
Frederick Guthrie.
Air-tight through the stopper of a cylindrical vessel containing dilute sul-
phuric acid pass the following: (I.) Two platinum wires coated with glass.
(2.) A long and wide tube open at both ends, the lower end reaching to the
bottom of the cylinder. (3.) A tube opening freely beneath the stopper and
above it by a very fine capillary aperture. The platinum wires are enlarged
into platinum plates of triangular form, with their apices downwards, and
further apart than their bases. Increase in the current passing by means of
the wires betAveen the electrodes causes the liquid to rise higher in the mano-
meter tube, and also, by laying bare the electrodes, increases the resistance.
1404. Voltaic Compensator, an apparatus for maintaining
the electric current derived from any sort of voltaic battery at
constant intensity.
Elie Wartmann, Professor of Natural Philosophy at the
University of Geneva.
A full description of this instrument is printed in the "Archives des
Sciences physiques et naturelles," January 1858. In addition to the principal
current, which, if constant, would do the work required) there is an aux-
iliary one, the strength of which is kept down by inserting an additional
328 SEC. 10. ELECTRICITY.
resistance. This resistance diminishes with the weakening of the principal
current, and the consequent increase of the auxiliary current compensates
that weakening.
14O4a. Regulator, by Foucault. M. J. Duboscq, Paris.
1405. Apparatus to make the Electric Light, derived
from a Voltaic Battery, constant in its position and intensity.
Elie Wartmann, Professor of Natural Philosophy in the
University of Geneva.
This apparatus, called fixateur for the electric light, was used in the years
1856 and 1857 for lighting the harbour of Geneva. A full description is to
be found in the " Archives des Sciences physiques ct naturelles," December
1857. By means of an electro-magnet and of gravity, two points of carbon
are placed and kept at such a distance that the light produced by the current
of an electric battery may be as bright as possible.
14O6b. Regulator of Electric Light, by Serrin, with glass
globe. M. Breguet, Paris.
1406. Regulator of Electric Currents, after the plan of
M. Mascart. M. Redier.
1407. Regulator for the Electric Light. M. Carre.
1408. Artificial Charcoal Sticks for the Electric Light.
M. Carre.
1409. Electric Lamps, 1 small and 1 large. These lamps
are automatic in their motion ; in them the carbon points are caused
to approach or recede from each other.
Siemens and Halske, Berlin.
14O9. Electric Lamps. These lamps are automatic in their
action, in them the carbon points are caused to approach or recede
from each other as required, without the aid of clockwork.
Siemens and Halske, Berlin.
VIII. APPARATUS FOR DETECTING AND MEASUR-
ING DIFFERENCES OF ELECTRIC POTENTIAL
AND CURRENTS OF ELECTRICITY.
a. ELECTROSCOPES AND ELECTROMETERS.
1410. Two Repulsion Electrometers constructed and
used by Van Maruin. Teyler Foundation, Haarlem.
1411. Small Pocket Electroscope used by H. B. de
Saussure during his excursions in the Alps.
M. H. Henri de Saussure, Geneva.
VIII. MEASUREMENT. 329
1412. Insulating Stand, with Air Chamber, artificially
dried by sulphuric acid, used in connexion with first portable
atmospheric electrometer. Sir William Thomson.
This stand was ordinarily attached to the top of the electrometer, as figured
in NichoPs Cyclopaedia, Art. Electricity (atmospheric), and in Thomson's Ke-
print of Papers on Electrostatics and Magnetism, XVI., 263. Sometimes as
in observations to determine in absolute measure the electric force in the
atmosphere, on the sea beach, and in boats in Brodick Bay, Isle of Arran (re-
print XVI., 281), and, with the assistance of Dr. Joule, on the Links of
Aberdeen (British Association meeting, 1851) the stand was detached from
the electrometer and laid on the ground at a distance from it with connexion
by fine wire to the insulated part of the electrometer, which also was placed
on the ground, and was read by observer lying as close to the ground as
possible.
1413. Atmospheric Portable Electrometer, No. 2, altered
for first trial of divided ring principle for a quadrant marine
electrometer, and used successfully on board the " Great Eastern/*
though not in connexion with the cable, in 1865.
Sir William Thomson.
This instrument has not been repeated, nor described in print, but it may
yet do good service at sea. Made by James White, Glasgow.
1413a. Sir Wm. Thomson's Quadrant Electrometer,
with most complete adjustments and of most perfect construction.
James White.
A descriptive pamphlet accompanies the instrument.
1413b. Sir William Thomson's Portable Electro-
meter, with most complete adjustments, and of most perfect con-
struction. . James White.
1413c. Electric Sensitizer. Sir William Thomson.
This instrument is an induction electric machine, and is used with the port-
able electrometer or other electrometer for testing the potential of a conductor
without removing any part of its charge.
1414. Atmospheric Portable Electrometer, No. 4, altered
to a plan for marine electrometer, which was discarded soon after
trial. Sir William Thomson.
1415. Atmospheric Portable Electrometer, No. 5. Per-
fected portable electrometer, on same general plan as No. 1,
described fully in Friday Evening Lecture to the Royal Institu-
tion, May 18th, 1860 (Thomson's Reprint of Papers on Electro-
statics and Magnetism, XVI., 277). Made by James White,
Glasgow. Sir William Thomson.
1416. Atmospheric Portable Electrometer, No. 10.
First of new plan described in report on electrometers and electri-
cal measurements (British Association Report for 1867, Committee
330 SEC. 10. ELECTRICITY.
on Standards of Electrical Resistance, and Thomson's Reprint of
Papers on Electrostatics and Magnetism, XX., 368).
Sir William Thomson.
In this first instrument the attracting disc turns with a micrometer screw
instead of moving in a geometrical slide, as in the portable electrometers now
made. The receptacle for pumice and sulphuric acid was dangerously placed
in the roof. This instrument was designed and first tried in the Island of
Arran in 1862. Made by James White, Glasgow.
1417. Attracted Disc Heterostatic Station-Electro-
meter on same electric principle as latest portable electrometers,
but with mechanism inverted. Sir William Thomson.
This instrument is of convenient dimensions and general plan for stationary
observations of atmospheric electricity and various electrostatic measurements.
Made by James White, Glasgow.
1418. Large Portable Electrometer of same general plan
as No. 10, altered to measure distance between two metallic con-
ductors giving sparks with electro-motive force measured by another
electrometer, in continuation of Smith and Ferguson's measure-
ments. (Proceedings of the Royal Society, 1860, and Thomson's
Reprint of Papers on Electrostatics and Magnetism, XIX., 320.)
Sir William Thomson.
Numerous accurate experiments were made many years ago by this piece of
apparatus, but the results have not hitherto been published. Made by James
White, Glasgow.
1420. Station Electrometer. Sir William Thomson.
This electrometer was used by Professor Everett in his two years series of
observations on atmospheric electricity at Windsor, Nova Scotia, described in
the Transactions of the Royal Society of London for 1868. Its electric prin-
ciple is the same as that of No. 8 of the perfected form of portable electro-
meter of the first kind. (See Thomson's Reprint, xvi. 777.)
1421. First divided Hing (semi-circular) Electrometer.
Sir William Thomson.
This was used for several years in the University of Glasgow, and described
in the Accademia Pontificia dei Nuovi Lincei, February 1857, and in Thom-
son's Reprint, xviii. 311.
The movable electrified body projects from one side of the bearing wire
far enough to travel over the flat semi-circular rings and experience their
electric force. It is kept electrified by a fine platinum wire dipping in sul-
phuric acid, which forms the outside coating of the Ley den jar below it.
1422. Attracted Disc Electrometer, with double micro-
meter screw, arranged, to give the same period of free oscillation
with different forces at different distances. Sir William Thomson.
The lower disc is insulated, the upper connected with the metal work of the
Case of the instrument and of the micrometer screws by a spiral spring by
which it is hung. By turning the torsion head, the upper end of the spring
and the sight-marks with movable stops for the lower end of the spring, are
moved through different distances, of which the former is 1| times the latter.
VIII. MEASUREMENT. 331
The instrument exhibited was made 15 or 20 years ago. The present condi-
tion of the spiral spring shows that it has become elongated through time,
without stress, because the hook at its lower end, bearing the disc, rests firmly
against the lower stop, with the stop in the lowest position that the micrometer
screws allow.
1423. First Mirror . divided Ring (semi-circular) Elec-
trometer, used at Kew for recording atmospheric electricity.
Sir William Thomson.
A specimen of the curve by which it recorded the atmospheric potential is
published in Thomson's reprint, xvi. 292. Specimen sheets of its actual work
accompany the instrument.
1424. First Trial Apparatus, towards mirror quadrant
electrometer. Sir William Thomson.
This instrument was first designed for marine use. The mirror and needle
are supported on a stretched bundle of silk fibre, as are the needle and mag-
nets of the marine galvanometer. The electric connexion between the needle
and the inside coating of the Ley den jar is made by a spiral of fine platinum
wire. These peculiarities were tested and found to work moderately well in
the trial instrument now exhibited, but have never been repeated ; nor does it
seem very desirable they should be repeated, as the balancing of the needle
on this plan, with sufficient accuracy for good work at sea, would probably be
more troublesome than the object would justify. The electric action of this
instrument was found so promising that immediately instruments were con-
structed on the same electric plan for use on land. The shape and dimensions
of the suspended needle and of the electrified surroundings of the mirror are
precisely the same as those of the quadrant electrometers now made. The im-
provements upon this original working model consist of geometrical slides for
the quadrants, mechanical details regarding the suspension, the substitution
of a fine platinum wire hanging down into the liquid in the bottom of a tall
Leyden jar for the platinum spiral, and the addition of a replenisher and
gauge for the charge of the jar.
1425. Divided Ring (semi-circular) Electrometer, de-
scribed in NichoPs Cyclopaedia, article Electricity (Atmospheric).
Sir William Thomson.
1426. Improved Helmholtz's Quadrant Electrometer.
T. Rob. Voss, Berlin.
This is well suited for school use, as it is not very expensive, and its action
is, in proportion, as good as that of larger machines.
1427. Electrometer. E. Stohrer, Leipzig.
1428. Kohlrausch's Torsion-electrometer.
Prof. Wiillner, Aix-la-Chapelle.
1429. Kohlrausch's Sine-electrometer, with two needles
of different magnetic, moment. Prof. Wiillner, Aix-la-Chapelle,
1430. Kohlrausch's Condenser.
Prof. Wullner, Aix-la-Chapelle*
All three pieces of apparatus were manufactured by Th. Schubart, of Ghent
and Marburg.
332 SEC. 10. ELECTRICITY.
The detailed description and theory of Kohlrausch's various apparatus may
be found as under :
Poggendorff's Annalen, Vols. 72 and 7 4 for the torsion-electrometer.
Vol. 88 for the sine-electrometer.
Vols. 75 and 88 for the condenser.
The apparatus which are exhibited show the forms which Th. Schubart
(late of Marburg, and now of Ghent) makes at the present time. A good
description of the present forms is given in Wiillner's " Lehrbuch der Experi-
mental-Physik," Vol. 4, 3rd edition, p. 159, and p. 299.
1431. Edelmann's Quadrant-electrometer.
M. Th. Edelmann, Munich.
1431a. Electrometer for measuring potentials, and par-
ticularly the potential of an accumulator at the moment of the
discharge. Prof. Augustus Righi, Bologna.
143 Ib. Induction Electrometer.
Prof. Augustus Right, Bologna.
A caoutchouc tube carrying several copper rings is wrapped round the non-
insulated pulleys (2, 4). If the insulated inductor (1) is charged, the rings
go from (2) to conductor (3), with charges of contrary sign, and these
charges remain in the insulated conductor (3). For, as the rings touch the
conductor (3) by means of a little pulley placed in its interior, the charge
preserved by any single ring is slight. For a very small charge of the
inductor, the conductor (3) acquires a charge great enough to be shown by
a gold leaf electroscope. If the inductor is uncharged, and the pulleys and
the rings are of the same metal and very clean, the conductor (3) remains
uncharged.
In open places the conductor (3) is charged by the sole influence of atmo-
spheric electricity.
1432. Ronalds' Electrical Apparatus, as employed by
him at the Kew Observatory ; consisting of a principal conductor,
with its glass support, umbrella, and heating apparatus ; its vol-
taic collecting lantern ; Volta's electrometers and sights ; a Henley
electrometer; a Grourjon galvanometer; a discharger, or spark
measurer ; and a Bennet's gold-leaf electroscope.
Kew Committee of the Royal Society.
Apparatus erected in the equatorial room of the Kew Observatory, in 1843,
by Mr. Francis Konalds, for the purpose of observing atmospheric electricity,
.described in the British Association Keport for 1844.
It consists of a principal conductor, which is a stout copper tube, passed
through a large aperture lined with sealing-wax in the roof of the building
in which the instrument was placed, and carrying an inverted copper tray, to
exclude rain.
The tube is supported by a stout glass core, which is kept in a dry state
by a copper funnel passing up its interior, kept contantly heated by a small
lamp.
A second lamp is enclosed in a Volta's collecting lantern, fixed to the top
*of the collecting tube.
To the cross arms at the base of the tube are attached severally: Volta's
electrometers with ivory scales, and sights for accurately determining the
angles of the deflection of the straws ; a Henley, or quadrant electrometer ;
VIII. MEASUREMENT. 333
a galvanometer, by Gourjon (the property of Sir C. Wheatstone) ; a dis-
charger, or spark measurer ; arid a Beiinet's gold-leaf electroscope.
Continued regular observations were made with these instruments for several
years.
The wooden stand now exhibited was not the original table upon which
they were placed ; that, a fixture in the Observatory, having been destroyed.
The Henley electrometer has also been replaced by a less perfect instru-
ment.
1433a. Box Electroscope, avoiding the faults of common
gold leaf electroscopes. Prof. Beetz, Munich.
1433b. Bifilar Electroscope, with copper, zinc, and con-
denser-plates for showing Volta's fundamental experiments, and
tourmaline for showing pyro-electricity. Prof. Beetz, Munich.
1434. Thomson's Divided King Electrometer and
Gauge, formerly in use for recording atmospheric electricity, at
the Kew Observatory.
Kew Committee of the Royal Society.
This instrument, which consists of two parts, the electrometer and the
gauge, was erected at the Kew Observatory in 1861, in connexion with a
photographic recording apparatus, and worked there for about four years,
producing .daily records of the fluctuations, &c. of atmospheric electricity,
which were discussed by Professor Everett, and the results published, together
with a description of the instrument, in the Philosophical Transactions for
1868, Pt. I.
It has since been replaced by an improved quadrant electrometer.
1435. Singer's Gold Leaf Electroscope, for lecture pur-
poses. Large size. Elliott Brothers.
1436. Quadrant Electrometer, being a modification of Sir
W. Thomson's delicate quadrant electrometer, used for measuring
the difference of potential between two conductors.
Elliott Brothers.
1437. Peltier Electrometer, for measuring the electrical
tension of a charge by the repulsion of a light aluminium needle,
which receives a directive force from a very small magnet
attached to it. Elliott Brothers*
1437a. Peltier Electrometer.
The British Telegraph Manufactory, Limited.
1438. Capillary Electrometer, after Lippmann.
R. Jung, Heidelberg*
A glass tube a, filled to a height of about 85 cent, with mercury, and
ending below in a fine point, dips in a cylinder b, so that its point presses
lightly against the side, where there is a microscope c placed horizontally.
The bottom of the cylinder contains mercury, and above this there is dilute
sulphuric acid which covers the point of the tube ; a platinum wire, con-
nected with one terminal of the apparatus and protected by a glass tube from
334 SEC. 10. ELECTRICITY.
the sulphuric acid, dips into the mercury. The long tube is connected above
with a small glass inverted U-tube, in which a platinum wire is fused, which,
reaching down into the mercury in the tube, forms the upper electrode. The
other end of the U-tube is connected by caoutchouc tubing with au air press,
which, on its other side, is connected with a manometer. A little mercury is
first forced through the fine point by means of the press. The microscope is
then so placed that the zero point of the eyepiece micrometer coincides with
the image of the meniscus of mercury in the capillary tube ; then the electric
source to be measured is brought into the circuit of the apparatus, its negative
pole being connected with the upper electrode. The mercury forthwith
retires, and can only be brought back by a determinate pressure with the
press.
1439. Coulomb's Torsion Balance, for measuring mag-
netic and electric attraction and repulsion. Elliott Brothers.
1439a. School Form of Coulomb's Torsion Balance.
Harvey, Reynolds, and Co.
b. GALVANOMETERS.
61. Galvanometer for hydro-electrical currents, with which
Matteucci discovered, in 1844, the muscular current.
The Royal Institute of " Studii Superiori " at Florence.
The Copley medal was awarded by the Royal Society to Matteucci for his
electro-physiological labours, and above all for his discovery of the muscular
current.
Galvanometer of Nobili, with astatic system, and bobbin
composed of eight threads to be united at pleasure.
The Royal Institute of " Studii Superiori '' at Florence.
Galvanometer of Nobili, with astatic system for the hydro-
electrical current.
The Royal Institute of " Studii Superiori " at Florence.
56. Magnetoscope of Nobili, composed of an astatic system
suspended in a glass bell furnished with a graduated circle.
The Royal Institute of " Studii Superiori " at Florence.
The first galvanometer upon the astatic system was made by Nobili, in
1825. He afterwards so improved galvanometers, that they could be adapted
to every kind of current, and be perfectly similar to one another. As to
the magnetoscope, he made use of it to detect the slightest traces of
magnetism.
1235b. Large-sized Galvanometer, for demonstrating the
principal applications of Ohm's formula.
Imperial University of St. Petersburg.
It consists of a strong brass ring, below which are two long plates, fitted at
their extremities with an adjustment for uniting the galvanic couples parallel-
wise (in quantity). Another ring, with more than 400 turns of wire, serves to
study the combination of the couples in a different way. The two rings are
united together, and can be set different distances from the needle. The
VIII. MEASUREMENT. 335
needle is furnished with two index-arms crossing each other at right angles,
the four ends of which are bent downwards at right angles, so as to mark
the deflection upon a graduation placed round the outer vertical surface of a
cylindrical ring.
This apparatus, for demonstration, is constructed according to the directions
of Prof. Petrouchevsky, Professor at the University of St. Petersburg.
1440. Galvanometer with variable resistance.
Prof. Dr. R. A. Mees, Director of the Physical Labora-
tory of the University of Groningen.
This galvanometer can be used for hydro-electric as well as thermo-electric
currents. By its aid the dependence of the sensibility of a galvanometer on
its resistance can be demonstrated.
1441. Reflecting Astatic Galvanometer, with coils of low
resistance, and with telescope and scale, for measuring thermo-
electric currents of very low intensity. Focal distance of telescope
and scale about three metres. Made by Ruhmkorff, of Paris.
George Gore, F.R.S.
1442. Galvanometer, by Colladon, with wires insulated by
a special method. This instrument was used by the inventor for
measuring the intensity of currents produced by electric friction
machines, by electricity from the clouds in 1826, and by elec-
tric fish in 1831. Prof. Daniel Colladon, Geneva.
The inventor used this same galvanometer in 1831, for studying the distri-
bution of the electric poles upon torpedoes, and the strength of currents pro-
duced by animal electricity.
Annales de Chimie et de Physique, 1826, vol. 33.
Peclet, Traite de Physique, 1832, vol. 2, p. 221 to 225.
Memoires de 1' Academic Royale des Sciences, Institut de France, vol. 10,
p. 74.
1443. Balance Galvanometer, giving indication of current
in grains or other weights in scale pans, which may be adjusted to
any standard. Invented by exhibitor in 1848.
William Sykes Ward.
1444. Galvanometer, designed by Colladon for Currents
produced by Electro-Statical Charges.
Geneva Association for the Construction of Scientific In-
struments.
Apparatus for demonstrating that the electricity drawn from friction
machines, from the clouds, &c., produces currents, of which the direction and
the intensity are measured by the deviation of the magnetic needle of a
galvanometer.
1445. Marine Galvanometers used on board H.M.S. " Aga-
memnon " and the U.S. Frigate " Niagara," in the Atlantic Cable
Expeditions of 1858. . Sir William Thomson.
A light mirror, weighing 30 milligrammes and 9 millimetres in diameter,
with single needle cemented to its back, suspended by stretched platinum
336 SEC. 10. ELECTRICITY.
wire in centre of field of coil composed of two bobbins of fine copper wire.
Micrometer screws to adjust zero by torsion of upper and lower parts of
platinum wire. The first words transmitted across the Atlantic were from the
" Agamemnon " approaching the Irish coast, and were read on one of these
instruments on board the " Niagara " approaching Newfoundland. (Encyclo
psedia Britannica, Art. Telegraph (Electric), VII. 6, and VIII. 4.) Made by
White and Barr (now James White), Glasgow.
This instrument was sent out for use on the first Ked Sea cable (1859), but
did not arrive until after the failure of the cable. It returned dismantled, and
was never set in action again. It has been superseded by the siphon re-
corder. Made by White and Barr (now James White), Glasgow.
1446a. One of the First Mirror Galvanometers, made
for the reading of messages through submarine cables, and used for
that purpose at Newfoundland in 1858. This galvanometer has an
arrangement for altering the intensity and direction of the directing
force by a double motion of the directing magnet, one varying
its distance from the suspended needle and mirror, the other giving
the magnet a motion in azimuth. This arrangement is still used
in the Astatic Mirror Galvanometer for testing submarine cables.
Sir William Thomson.
1447. Ironclad Marine Galvanometer, used on board the
"Great Eastern" in the Atlantic Cable Expedition of 1866, and
subsequently by Mr. Willoughby Smith in the Mediterranean and
Red Sea. Sir William Thomson.
This instrument is the first ironclad marine galvanometer, and the first with
suspension by stretched silk fibre instead of platinum wire. Made by James
White, Glasgow.
1447 a. Differential Galvanometer, constructed specially
for testing the locality and nature of faults in submarine cables.
It is the first instrument in which shunts were used for practical
electrometric purposes. A shunt is applied to one of the wires of
the coil so as to multiply the reading of a rheostat ten times. It
also was used for telegraphic reading purposes and for measuring
the discharge from cables. It was made in 1858, and was in
constant use for many years. W. H. Preece.
1447b. Thomson's Mirror Galvanometer, with hinged
coils, and Shunt for same. Warden, Muirhead, and Clark.
1447a. Sir William Thomson's Astatic Mirror Galva-
nometer, with hinged coils, for testing purposes.
Warden, Muirhead, and Clark.
1447b. Lamp for Mirror Galvanometer.
Warden, Muirhead, and Clark.
1447c. Portable Testing Galvanometer on gimbals, with
resistance coils and shunts. Warden, Muirhead, and Clark.
VIII. MEASUREMENT. 337
1447d. Sir William Thomson's Dead-beat Mirror
** Speaking " Galvanometer for receiving signals on long
submarine cables, provided with scale, stand, and lens. The
mirror carrying the magnets is confined in a small air-chamber
which can be contracted at will. The compressed air acts like a
cushion, and " damps " the motion of the mirror, thereby prevent-
ing oscillations. Warden, Muirhead, and Clark.
1448. Absolute Galvanometer or Magnetic Dynamo-
meter. Frederick Guthrie.
A current traverses in succession four spirals embracing soft iron cores.
Two of the so formed electro-magnets are fixed and two movable together in
a horizontal plane by means of the suspending torsion thread. The spirals
are such that the magnets repel one another. If, when no current is passing,
a beam of light reflected from a mirror attached to the movable pair falls in
a certain place, then r when a current passes, the torsion screw head must be
turned so as to force the magnets up to the same distance as before. The
repulsion or angular torsion is proportional to the square of the strength of
the current.
1449. Galvanometer for measuring large currents in definite
units. Graduated in Weber units for use with the electric light,
&c., and in ounces of silver deposited per hour, for use in electro-
plating and other forms of actual work. John T. Sprague.
1450. Patent Universal Galvanometer, indicating current
and resistance in definite units of measurement.
John T. Sprague.
This galvanometer contains four circuits, having 1, 10, 100, and 1,000 fold
degrees of action on the needle, enabling it to be used for large or small
currents. The patent dial is graduated to indicate the current in actual units,
either the British Association, Weber, or in chemical equivalents. It is also
graduated to show the total resistance of the circuit in ohms without the aid
of a resistance instrument when used with a Daniell cell. By using a fixed
resistance it shows the electromotive force of the circuit in volts.
1450a. Galvanometer for Projections.
M. J. Duboscq, Paris.
1450b. Galvanometer, for thermo-electric currents.
Luizard) Paris.
1451. Hhe Electrometer of Marianini, for observing elec-
tric discharges between the atmosphere and the earth.
Robert James Mann, M.D.
This instrument was planned by Professor Melsens. It contains a coil of
copper wire which is to be made continuous with the system of a lightning
rod, or with the earth wire of a telegraph line. When an electric spark
passes through the coil a soft iron bar in its interior is magnetised, and a
traversing magnetic needle pivoted above the coil is then deflected by it out of
the north and south line of the earth's magnetism towards either the east or
west. When the interior iron has been magnetised it must be replaced by
ii neutral bar before another observation can be made.
40075. Y
338 SEC. 10. ELECTRICITY.
1452. M. Becquerel's Electro-magnetic Balance.
Conservatoire des Arts et Metiers, Paris.
1453. Pouillet's First Compass for Sines and
Tangents. Conservatoire des Arts et Metiers, Paris.
1454. Sine-Tangent Galvanometer, for use at will either
as a sine or tangent galvanometer. Siemens and Halske, Berlin.
1455. Aperiodic Galvanometer, with telescope and scale.
Siemens and Halske, Berlin.
The needle of this galvanometer is suspended in a copper ball, which acts
as a damper, preventing vibration in any new position given to the needle.
The needle itself is in the shape of a thimble cut away longitudinally on
opposite sides, and by this arrangement the magnetic intensity is considerably
increased, and the inertia of the magnet reduced. Du Bois-Raymond has
shown that the " damping " of an astatic needle can be carried so far that the
needle does not vibrate, but directly takes up its position of deflection, and
these he has termed " aperiodically vibrating needles." Dr. Werner Siemens
has attained the same end with simple non-astatic magnets, by means of
certain forms of the vibrating magnets, and of the damping copper mass.
The vibrating magnet consists of a steel thimble, from which two opposite
sides are cut away parallel to the axis. This horseshoe magnet vibrates in a
cylindrical space in a copper ball, which forms the centre of the wire coils.
, j 1456. Inclination Galvanometer. Dr. Werner Siemens.
Intended for use particularly with the selenium photometer (ISo. 895).
The coil of the galvanometer is wound horizontally ; the needle vibrates in a
vertical plane and carries a mirror which reflects the image of a finely photo-
graphed scale (placed above) into the optical axis of a microscope.
1457. Galvanometer for testing Lightning Conductors,
constructed by the exhibitors for the .Prussian Royal Engineers.
Kciser and Schmidt, Berlin.
1458. Mirror Multiplier. E. Stohrer, Leipzig-
1459. Galvanometer, showing both inclination and declina-
tion. E. Stohrer, Leipzig.
The broad brass frame which carries the magnetic needle can be turned
about its .axis ; likewise the vertical .support in its base. Thus the needle
can be enabled to move in various planes, and the altered action of the force
measured by 
