Front Matter

ADVERTISEMENT. The Committee appointed by the Royal Society to direct the publication of the Philosophical Transactions, take this opportunity to acquaint the Public, that it fully appears, as well from the Council-books and Journals of the Society, as from repeated declarations which have been made in several former Transactions, that the printing of them was always, from time to time, the single act of the respective Secretaries till the Forty-seventh Volume; the Society, as a Body, never interesting themselves any further in their publication, than by occasionally recommending the revival of them to some of their Secretaries, when, from the particular circumstances of their affairs, the Transactions had happened for any length of time to be intermitted. And this seems principally to have been done with a view to satisfy the Public, that their usual meetings were then continued, for the improvement of knowledge, and benefit of mankind, the great ends of their first institution by the Royal Charters, and which they have ever since steadily pursued. But the Society being of late years greatly enlarged, and their communications more numerous, it was thought advisable that a Committee of their members should be appointed, to reconsider the papers read before them, and select out of them such as they should judge most proper for publication in the future Transactions; which was accordingly done upon the 26th of March 1752. And the grounds of their choice are, and will continue to be, the importance and singularity of the subjects, or the advantageous manner of treating them; without pretending to answer for the certainty of the facts, or propriety of the reasonings, contained in the several papers so published, which must still rest on the credit or judgement of their respective authors. It is likewise necessary on this occasion to remark, that it is an established rule of the Society, to which they will always adhere, never to give their opinion, as a Body, upon any subject, either of Nature or Art, that comes before them. And therefore the thanks, which are frequently proposed from the Chair, to be given to the authors of such papers as are read at their accustomed meetings, or to the persons through whose hands they received them, are to be considered in no other light than as a matter of civility, in return for the respect shown to the Society by those communi- cations. The like also is to be said with regard to the several projects, inventions, and curiosities of various kinds, which are often exhibited to the Society; the authors whereof, or those who exhibit them, frequently take the liberty to report and even to certify in the public newspapers, that they have met with the highest applause and approbation. And therefore it is hoped that no regard will hereafter be paid to such reports and public notices; which in some instances have been too lightly credited, to the dishonour of the Society. The Meteorological Journal hitherto kept by the Assistant Secretary at the Apart- ments of the Royal Society, by order of the President and Council, and published in the Philosophical Transactions, has been discontinued. The Government, on the recommendation of the President and Council, has established at the Royal Obser- vatory at Greenwich, under the superintendence of the Astronomer Royal, a Magnet- ical and Meteorological Observatory, where observations are made on an extended scale, which are regularly published. These, which correspond with the grand scheme of observations now carrying out in different parts of the globe, supersede the necessity of a continuance of the observations made at the Apartments of the Royal Society, which could not be rendered so perfect as was desirable, on account of the imperfections of the locality and the multiplied duties of the observer. A List of Public Institutions and Individuals, entitled to receive a copy of the Philosophical Transactions of each year, on making application for the same directly or through their respective agents, within five years of the date of publication. In the British Dominions. The Queen's Library. The Admiralty Library. The Ashmolean Society, Oxford. The Radcliffe Library, Oxford. The Royal Geographical Society. The United Service Museum. The Royal College of Physicians. The Society of Antiquaries. The Linnean Society. The Royal Institution of Great Britain. The Society for the Encouragement of Arts. The Geological Society. The Geological Survey of Great Britain. The Horticultural Society. The Chemical Society. The Royal Astronomical Society. The Royal Asiatic Society. The Royal Society of Literature. The Medical and Chirurgical Society. The London Institution. The Entomological Society of London. The Zoological Society of London. The Institute of British Architects. The Institution of Civil Engineers. The Cambridge University Philosophical Society. The Literary and Philosophical Society, Manchester. The Royal Society of Edinburgh. The Royal Irish Academy. The Royal Dublin Society. The Royal Institution, Swansea. The Asiatic Society at Calcutta. The Royal Artillery Library at Woolwich. The Royal Observatory at Greenwich. The Observatory at Dublin. The Observatory at Armagh. The Library and Museum, Barbadoes. The Observatory at the Cape of Good Hope. The Observatory at Madras. The Observatory at Paramatta. The Observatory at Edinburgh. Denmark. The Royal Society of Sciences at Copenhagen. The Royal Observatory at Altona. France The Royal Academy of Sciences at Paris. The Royal Academy of Sciences at Toulouse. The Ecole des Mines at Paris. The Geographical Society at Paris. The Entomological Society of France. The Dépôt de la Marine, Paris. The Geological Society of France. The Jardin des Plantes, Paris. Germany. The University at Göttingen. The Cesarean Academy of Naturalists at Bonn. The Observatory at Mannheim. The Royal Academy of Sciences at Munich. Italy. The Institute of Sciences at Naples. The Institute of Sciences, Letters and Arts, at Milan. The Italian Society of Sciences at Modena. The Royal Academy of Sciences at Turin. Switzerland. The Société de Phys. et d'Hist. Nat. at Geneva. Belgium. The Royal Academy of Sciences at Brussels. Netherlands. The Royal Institute of Amsterdam. The Batavian Society of Experimental Philosophy at Rotterdam. Spain. The Royal Observatory at Cadiz. Portugal. The Royal Academy of Sciences at Lisbon. Prussia. The Royal Academy of Sciences at Berlin. The Society of Experimental Philosophy, Berlin. Russia. The Imperial Academy of Sciences at St. Petersburg. The Imperial Observatory at Pulkowa. Sweden and Norway. The Royal Academy of Sciences at Stockholm. The Royal Society of Sciences at Drontheim. United States. The American Philosophical Society at Philadelphia. The American Academy of Sciences at Boston. The Library of Harvard College. Smithsonian Institution, Washington. The Observatory at Washington. The fifty Foreign Members of the Royal Society. A List of Public Institutions and Individuals, entitled to receive a copy of the Astronomical Observations made at the Royal Observatory at Greenwich, on making application for the same directly or through their respective agents, within two years of the date of publication. In the British Dominions. The Queen's Library. The Board of Ordnance. The Royal Society. The Savilian Library, Oxford. The Library of Trinity College, Cambridge. The University of Aberdeen. The University of St. Andrews. The University of Dublin. The University of Edinburgh. The Observatory, Edinburgh. The University of Glasgow. The Observatory at Oxford. The Observatory at Cambridge. The Observatory at Dublin. The Observatory at Armagh. The Observatory at the Cape of Good Hope. The Observatory at Paramatta. The Observatory at Madras. The Royal Institution of Great Britain. The Royal Society, Edinburgh. The Observatory, Trevandrum, East Indies. The President of the Royal Society. S. H. Christie, Esq., Woolwich. The Lowndes Professor of Astronomy, Cambridge. The Plumian Professor of Astronomy, Cambridge. L. Holland, Esq., London. Sir John William Lubbock, Bart. Captain W. H. Smyth, R.N., Chelsea. Sir James South, Observatory, Kensington. In Foreign Countries. The Royal Academy of Sciences at Berlin. The Royal Academy of Sciences at Paris. The Imperial Academy of Sciences at St. Petersburg. The Royal Academy of Sciences at Stockholm. The Royal Society of Sciences at Upsal. The Board of Longitude of France. The University of Göttingen. The University of Leyden. The Academy of Bologna. The American Academy of Sciences at Boston. The American Philosophical Society at Philadelphia. The Observatory at Altona. The Observatory at Berlin. The Observatory at Breslau. The Observatory at Brussels. The Observatory at Cadiz. The Observatory at Coimbra. The Observatory at Copenhagen. The Observatory at Dorpat. The Observatory at Helsingfors. The Observatory at Königsberg. The Observatory at Mannheim. The Observatory at Marseilles. The Observatory at Milan. The Observatory at Munich. The Observatory at Palermo. The Observatory at Paris. The Observatory at Seeberg. The Observatory at Vienna. The Observatory at Tubingen. The Observatory at Turin. The Observatory at Wilna. The Dépôt de la Marine, Paris. The Bowdoin College, United States. The Library of Harvard College. The Waterville College, United States. List of Observatories, Institutions and Individuals, entitled to receive a Copy of the Magnetical and Meteorological Observations made at the Royal Observatory, Greenwich. ### Observatories | Location | Name | |-------------------|-------------------------------| | Altona | M. Schumacher | | Armagh | Rev. Dr. Robinson | | Berlin | J. F. Encke | | Bombay | Dr. Buist | | Barnaoul | M. Prang, Ist. | | Breslau | Prof. Boguslawski | | Brussels | A. Quetelet | | Cadiz | M. Cerquero | | Cairo | M. Lambert | | Cambridge | Prof. Challis | | Cambridge, United States | Prof. Lovering | | Cape of Good Hope | T. Maclear, Esq. | | Catherineburgh | M. Rochkoff | | Christiania | M. Hansteen | | Cincinnati | Dr. Locke | | Copenhagen | M. Oersted | | Dublin | Sir W. R. Hamilton | | Gotha | | | Hammerfest | | | Heidelberg | M. Tiedemann | | Helsingfors | M. Nervander | | Hobarton | Lieut. Kay, R.N. | | Kasan | M. Simonoff | | Kew | F. Ronalds, Esq. | | Königsberg | | | Kremsmünster | Prof. Koller | | Leipsic | Prof. Weber | | Madras | Major Jacob | | Mannheim | | | Marburg | Prof. Gerling | | Milan | M. Carlini | | Munich | Dr. Lamont | | Nertchinsk | M. Prang, 2nd. | | Nikolaieff | Dr. Knorre | | Oxford | M. J. Johnson, Esq. | | Paris | M. Arago | | Pekin | M. Gachkévitche | | Prague | M. Kreil | | Pulkowa | M. Struve | | St. Petersburgh | M. Kupffer | | Seeberg | M. Hansen | | Sitka | Messrs. Homann and Ivanoff | | Stockholm | Prof. Selander | | Teffis | M. Philadelphine | ### Institutions | Institution | Description | |-------------------|------------------------------| | Aberdeen | University | | Berlin | Academy of Sciences | | Bologna | Academy | | Bombay | Geographical Society | | Bonn | University | | Boston | Academy of Sciences | | Bowdoin College | United States | | Bowditch Library | United States | | Cambridge | Trinity College Library | | Cherkow | Library, Philosophical Society | | Dorpat | University | | Dublin | University | | Edinburgh | Observatory | | Edinburgh | Royal Society | | Edinburgh | University | | Glasgow | University | | Göttingen | University | | Harvard, U.S. | College | | Kiew | University | | Leyden | University | | House of Lords, Library | London | | House of Commons, Library | " " | | London | King's College | | London | Royal Institution | | London | Royal Society | | Moscow | University | | Oxford | Savilian Library | | Paris | Academy of Sciences | | Paris | Board of Longitude | | Paris | Dépôt de la Marine | | Philadelphia | Philosophical Society | Queen's Library . . . . . London. Royal Cornwall Polytechnic Society . . . . . Falmouth. St. Andrew's . . . . . University. St. Bernard . . . . . Convent. St. Petersburg . . . . Academy of Sciences. St. Petersburg . . . . Geographical Society. Stockholm . . . . . Academy of Sciences. Upsal . . . . . Society of Sciences. Washington . . . . Smithsonian Institution. Waterville, U.S. . . . College Library. Woolwich . . . . Office of Mag. and Met. Publication. Individuals. Bache, Dr. A. D. . . . Washington. Barlow, P. W., Esq. . . Woolwich. Birt, W. H., Esq. . . London. Christie, S. H., Esq. . . Woolwich. Colebrooke, Sir W. . . Guiana. Demidoff, Prince Anatole de Florence. Dove, Prof. . . Berlin. Capt. C. M. Elliot . . . Erman, Dr. Adolph . . Berlin. Fox, R. W., Esq. . . Falmouth. Gauss, Prof. . . Göttingen. Gilliss, Lt. J. M., U.S. Navy Washington. Harris, Sir W. Snow . . Plymouth. Holland, L., Esq. . . London. Howard, Luke, Esq. . . Tottenham. Humboldt, Baron von . . Berlin. Kaemtz, M. . . . Halle. Kupffer, A. T. . . St. Petersburg. Lawson, Henry G., Esq. . Bath. Lloyd, Rev. Dr. . . Dublin. Loomis, Prof. . . Princeton, N.I. Lowndes Prof. of Astronomy Cambridge. Lubbock, Sir John W., Bart. London. Lütke, Vice-Admiral . . St. Petersburg. Melvill, J. C., Esq. . East India House. Mentchikoff, Prince . . St. Petersburg. Phillips, John, Esq. . York. Plumian Prof. of Astronomy Cambridge. President of the Royal Society London. Quetelet, A. . . Brussels. Redfield, W. C., Esq. . New York. Reid, Lieutenant-Colonel . London. Riddell, Capt., R.A. . Edinburgh. Roget, P. M., M.D. . London. Sabine, Lieut.-Col., R.A. . Woolwich. Senftenberg, Baron von . Prague. Smyth, W. H., Captain R.N. London. South, Sir James . . " " Wartmann, Prof. Elie . Lausanne. Wrangell, Vice-Admiral . St. Petersburg. Younghusband, Capt., R.A. . Woolwich. ROYAL MEDALS. HER MAJESTY QUEEN VICTORIA, in restoring the Foundation of the Royal Medals, has been graciously pleased to approve the following regulations for the award of them: That the Royal Medals be given for such papers only as have been presented to the Royal Society, and inserted in their Transactions. That the triennial Cycle of subjects be the same as that hitherto in operation: viz. 1. Astronomy; Physiology, including the Natural History of Organized Beings. 2. Physics; Geology or Mineralogy. 3. Mathematics; Chemistry. That, in case no paper, coming within these stipulations, should be considered deserving of the Royal Medal, in any given year, the Council have the power of awarding such Medal to the author of any other paper on either of the several subjects forming the Cycle, that may have been presented to the Society and inserted in their Transactions; preference being given to the subjects of the year immediately preceding: the award being, in such case, subject to the approbation of Her Majesty. The Council propose to give one of the Royal Medals in the year 1849 for the most important paper in Physics, communicated to the Royal Society after the termination of the Session in June 1845, and prior to the termination of the Session in June 1848, and printed in the Philosophical Transactions. The Council propose also to give one of the Royal Medals in the year 1849 for the most important paper in Geology or Mineralogy, communicated to the Royal Society after the termination of the Session in June 1845, and prior to the termination of the Session in June 1848, and printed in the Philosophical Transactions. MDCCCL. The Council propose to give one of the Royal Medals in the year 1850 for the most important paper in Mathematics, communicated to the Royal Society after the termination of the Session in June 1846, and prior to the termination of the Session in June 1849, and printed in the Philosophical Transactions. The Council propose also to give one of the Royal Medals in the year 1850 for the most important paper in Chemistry, communicated to the Royal Society after the termination of the Session in June 1846, and prior to the termination of the Session in June 1849, and printed in the Philosophical Transactions. The Council propose to give one of the Royal Medals in the year 1851 for the most important paper in Astronomy, communicated to the Royal Society after the termination of the Session in June 1847, and prior to the termination of the Session in June 1850, and printed in the Philosophical Transactions. The Council propose also to give one of the Royal Medals in the year 1851 for the most important paper in Physiology, including the Natural History of Organized Beings, communicated to the Royal Society after the termination of the Session in June 1847, and prior to the termination of the Session in June 1850, and printed in the Philosophical Transactions. The Council propose to give one of the Royal Medals in the year 1852 for the most important paper in Physics, communicated to the Royal Society after the termination of the Session in June 1848, and prior to the termination of the Session in June 1851, and printed in the Philosophical Transactions. The Council propose also to give one of the Royal Medals in the year 1852 for the most important paper in Geology or Mineralogy, communicated to the Royal Society after the termination of the Session in June 1848, and prior to the termination of the Session in June 1851, and printed in the Philosophical Transactions. CONTENT. I. THE BAKERIAN LECTURE.—ON THE DIFFUSION OF LIQUIDS. BY THOMAS GRAHAM, F.R.S., F.C.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 1 II. ON THE NITROGENATED PRINCIPLES OF VEGETABLES AS THE SOURCES OF ARTIFICIAL ALKALOIDS. BY DR. JOHN STENHOUSE, F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 III. ON THE MECHANICAL EQUIVALENT OF HEAT. BY JAMES PRESCOTT JOULE, F.C.S., Sec. Lit. and Phil. Society, Manchester, Cor. Mem. R.A., Turin, &c. Communicated by MICHAEL FARADAY, D.C.L., F.R.S., Foreign Associate of the Academy of Sciences, Paris, &c. &c. &c. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 IV. ON THE AUTOMATIC REGISTRATION OF MAGNETOMETERS, AND METEOROLOGICAL INSTRUMENTS, BY PHOTOGRAPHY.—NO. III. BY CHARLES BROOKE, M.B., F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 V. RESEARCHES REGARDING THE MOLECULAR CONSTITUTION OF THE VOLATILE ORGANIC BASES. BY DR. A. W. HOFMANN, F.C.S., PROFESSOR OF THE ROYAL COLLEGE OF CHEMISTRY OF LONDON. Communicated by Sir James Clark, Bart., F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 VI. ON THE DEVELOPMENT OF THE GREAT ANTERIOR VEINS IN MAN AND MAMMALIA; INCLUDING AN ACCOUNT OF CERTAIN REMNANTS OF FOETAL STRUCTURE FOUND IN THE ADULT, A COMPARATIVE VIEW OF THESE GREAT VEINS IN THE DIFFERENT MAMMALIA, AND AN ANALYSIS OF THEIR OCCASIONAL PECULIARITIES IN THE HUMAN SUBJECT. BY JOHN MARSHALL, F.R.C.S., late Demonstrator of Anatomy in University College, London; Assistant Surgeon to the University College Hospital. Communicated by Professor Sharpey, F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 VII. EXPERIMENTAL RESEARCHES IN ELECTRICITY.—TWENTY-THIRD SERIES. BY MICHAEL FARADAY, ESQ., D.C.L., F.R.S., Fullerian Prof. Chem. Royal Institution, Foreign Associate of the Acad. Sciences, Paris, Ord. Boruss. Pour le Mérite, Eq., Memb. Royal and Imp. Acad. of Sciences, Petersburgh, Florence, Copenhagen, Berlin, Göttingen, Modena, Stockholm, Munich, Bruxelles, Vienna, Bologna, &c. &c. &c. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 VIII. ON THE DEVELOPMENT OF THE RETINA AND OPTIC NERVE, AND OF THE MEMBRANOUS LABYRINTH AND AUDITORY NERVE. BY HENRY GRAY, M.R.C.S. Communicated by W. BOWMAN, F.R.S., Professor of Physiology and of General and Morbid Anatomy in King's College, London . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 IX. On the means adopted in the British Colonial Magnetic Observatories for determining the absolute Values, Secular Change, and Annual Variation of the Magnetic Force. By Lieut.-Colonel Edward Sabine, R.A., For. Sec. R.S. page 201 X. Observations on the Freezing of the Albumen of Eggs. By James Paget, Esq., Professor of Anatomy and Surgery to the Royal College of Surgeons of England. Communicated by Thomas Bell, Sec. R.S. .................. 221 XI. Researches on the Tides.—Fourteenth Series. On the Results of continued Tide Observations at several places on the British Coasts. By the Rev. W. Whewell, D.D., F.R.S. .................. 227 XII. Experiments and Observations upon the Properties of Light. By Lord Brougham, F.R.S., Member of the National Institute, and of the Royal Academy of Naples .................. 235 XIII. General Methods in Analysis for the resolution of Linear Equations in Finite Differences and Linear Differential Equations. By Charles James Hargreave, Esq., LL.B., F.R.S., Professor of Jurisprudence in University College, London .................. 261 XIV. Electro-Physiological Researches.—Eighth Series. By Signor Carlo Matteucci. Communicated by W. R. Grove, Esq., F.R.S. .................. 287 ERRATA. The plant mentioned by Professor Macaire in his paper, published in the Philosophical Transactions for 1848, p. 253, as Tamus communis, is not Smilax aspera, as suggested in the note at that page, but Bryonia dioica. Page 243, line 9, for E read F. ——— 257, line 25, for light read night. ——— 257, line 29, for polarity read polarization. ADJUDICATION of the Medals of the Royal Society for the year 1850 by the President and Council. The Copley Medal to Professor Hansen, for his researches in Physical Astronomy. The Royal Medal in the department of Chemistry, to B. C. Brodie, Esq., F.R.S., for his "Investigations on the Chemical Nature of Wax," published in the Philosophical Transactions for 1848 and 1849. There being no paper in the department of Mathematics coming within the terms of the award of the Royal Medal, it was awarded to Thomas Graham, Esq., F.R.S., for his paper "On the Motion of Gases," published in the Philosophical Transactions for 1849. The Rumford Medal to M. F. J. D. Arago, for his "Experimental Investigations on Polarized Light," the concluding memoirs on which were communicated to the Academy of Sciences of Paris during the last two years. The Bakerian Lecture for 1850 was delivered by Michael Faraday, Esq., F.R.S., and entitled "Experimental Researches in Electricity.—Twenty-fourth, Twenty-fifth, Twenty-sixth and Twenty-seventh Series. On the magnetic condition of oxygen," &c. CONTENTS XV. Discussion of Meteorological Observations taken in India, at various heights, embracing those at Dodabetta on the Neelgherry Mountains, at 8640 feet above the level of the sea. By Lieutenant-Colonel W. H. Sykes, F.R.S. . . . . . . 297 XVI. On the Pelorosaurus; an undescribed gigantic terrestrial reptile whose remains are associated with those of the Iguanodon and other Saurians in the Strata of Tilgate Forest, in Sussex. By Gideon Algernon Mantell, Esq., LL.D., F.R.S., F.L.S., Vice-President of the Geological Society, &c. . . . . . . . . 379 XVII. On a Dorsal dermal Spine of the Hylaeosaurus, recently discovered in the Strata of Tilgate Forest. By Gideon Algernon Mantell, Esq., LL.D., F.R.S., F.L.S., Vice-President of the Geological Society, &c. . . . . . . . . 391 XVIII. Supplementary Observations on the Structure of the Belemnite and Belemno-teuthis. By Gideon Algernon Mantell, Esq., LL.D., F.R.S., F.L.S., Vice-President of the Geological Society, &c. . . . . . . . . 393 XIX. On the Algebraic Expression of the number of Partitions of which a given number is susceptible. By Sir J. F. W. Herschel, Bart., K.H., F.R.S. . . . . . . . . 399 XX. Experiments on the Section of the Glossopharyngeal and Hypoglossal Nerves of the Frog, and observations of the alterations produced thereby in the Structure of their Primitive Fibres. By Augustus Waller, M.D. Communicated by Professor Owen, F.R.S. . . . . . . . . . . . . . . . . . . . . . . . 423 XXI. Influence of Physical Agents on the development of the Tadpole of the Triton and the Frog. By John Higginbottom, Hon. Fellow of the Royal College of Surgeons of England. Communicated by Thomas Bell, Esq., Sec. R.S. . . . . . . . . 431 XXII. On the Temperature of Man within the Tropics. By John Davy, M.D., F.R.S., L. & E., Inspector-General of Army Hospitals . . . . . . . . . . . . . . . . 437 XXIII. On the Oils produced by the Action of Sulphuric Acid upon various Classes of Vegetables. By John Stenhouse, Esq., Ph.D., F.R.S. . . . . . . . . . . . 467 XXIV. On the Development and Homologies of the Molar Teeth of the Wart-Hogs (Phacochœrus), with Illustrations of a System of Notation for the Teeth in the Class Mammalia. By Professor Owen, F.R.S. &c. . . . . . . . . . . . . . . . . 481 XXV. Observations on the Nebulæ. By The Earl of Rosse, Pres. R.S. &c. &c. . . . . . . . . . . . . . . . . . . . . . . . . . . 499 XXVI. On the Structure and Use of the Ligamentum Rotundum Uteri, with some observations upon the change which takes place in the Structure of the Uterus during Utero-gestation. By G. Rainey, M.R.C.S., Demonstrator of Anatomy at St. Thomas's Hospital. Communicated by Joseph Henry Green, Esq., F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515 XXVII. On the Communications between the Cavity of the Tympanum and the Palate in the Crocodilia (Gavials, Alligators and Crocodiles). By Professor Owen, F.R.S. &c. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521 XXVIII. On the Structure of the Dental Tissues of the Order Rodentia. By John Tomes, Surgeon-Dentist to the Middlesex Hospital. Communicated by Wil- liam Bowman, Esq., F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529 XXIX. Sequel to a paper on the Reduction of the Thermometrical Observations made at the Apartments of the Royal Society. By James Glaisher, Esq., F.R.S., of the Royal Observatory, Greenwich . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569 XXX. On the Dynamical Stability and on the Oscillations of Floating Bodies. By the Rev. Henry Moseley, M.A., F.R.S., Corresponding Member of the Institute of France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609 XXXI. Electro-Physiological Researches. On Induced Contraction.—Ninth Series. By Signor Carlo Matteucci, Professor in the University of Pisa, &c. &c. Communicated by W. R. Grove, Esq., F.R.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645 XXXII. Contributions to the Chemistry of the Urine.—Paper IV. On the so-called Chylous Urine. By Henry Bence Jones, M.D., M.A. Cantab., F.R.S., Phy- sician to St. George’s Hospital . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651 XXXIII. Contributions to the Chemistry of the Urine.—Paper III. Part IV. On the Variations of the Sulphates and Phosphates in Disease. By Henry Bence Jones, M.D., M.A. Cantab., F.R.S., Physician to St. George’s Hospital . . 661 XXXIV. Second Appendix to a paper on the Variations of the Acidity of the Urine in the state of Health. By Henry Bence Jones, M.D., M.A. Cantab., F.R.S., Physician to St. George's Hospital XXXV. An Experimental Inquiry into the Strength of Wrought-Iron Plates and their Riveted Joints as applied to Ship-building and Vessels exposed to severe strains. By William Fairbairn, Esq. Communicated by the Rev. Henry Moseley, F.R.S. XXXVI. On the Mutual Relations of the Vital and Physical Forces. By William B. Carpenter, M.D., F.R.S., F.G.S., Examiner in Physiology and Comparative Anatomy in the University of London XXXVII. On the Condition of certain Elements at the moment of Chemical Change. By Benjamin Collins Brodie, Esq., F.R.S. XXXVIII. Supplementary Observations on the Diffusion of Liquids. By Thomas Graham, F.R.S., F.C.S. Index APPENDIX. PHILOSOPHICAL TRANSACTIONS, PART I. 1850. ERRATA. Page 245, line 13, after placed insert parallel to it. — 246, line 1, for VI. read XV. — 246, line 1, for one, A, read one, B. — 246, line 2, for B read A. — 246, line 17, after result insert in. — 246, line 19, for fringe read force. — 252, line 13, erase b=DE, and for \( \frac{1}{\sqrt{a^2 + (x-b)^2} - \sqrt{c^2 + x^2}} \) read \( \frac{1}{\sqrt{a^2 + x^2} - \sqrt{b^2 + x^2}} \). — 253, line 16, for being read between. — 254, line 19, for XI. read XII. — 254, line 21, for e, c read c, c. — 257, line 13, for 19 read 21. — 257, line 25, for light read night. — 257, line 29, for polarity read polarization. — 258, line 4, for ss read z. — 258, line 6, for \( \sqrt{v^2 + Zdz} \) read \( \sqrt{v^2 + 2fZdz} \). In figs. 6 and 7, R R' should be a straight line. In fig. 9, P should be opposite to q.