THE ROYAL COMMISSION ON HISTORICAL MANUSCRIPTS Report on the papers of PROFESSOR HENRY T. FLINT (1890-1971) Physicist deposited in the Archives of the University of London Reproduced for the Contemporary Scientific London WC2A 1HP Archives Centre (csac ciara Vi Quality House, Quality Court, Chancery Lane, THE ROYAL COMMISSION ON HISTORICAL MANUSCRIPTS No. 75/31 1975 All rights reserved csac 27/4/75 THE ROYAL SOCIETY THE ROYAL COMMISSION ON HISTORICAL MANUSCRIPTS Committee on Scientific and Technological Reconds CONTEMPORARY SCIENTIFIC ARCHIVES CENTRE Papers of PROFESSOR HENRY T. FLINT (1890 — 1971) 1975 and in the Imperial War Museum, London Deposited in the Archives of the University of London Harriot Weiskittel Listed by; Jeannine Alton H.T.F. C.S.A.C. 27/4/75 Description of the collection The papers were received from Mrs. Ruth Flint; some personal papers and correspondence remain in family hands. The collection covers almost the whole of Professor Flint's life and career. deposited in the Department of Documents, Imperial War Museum, London, Ref. 74/123/1 Documents relating to his War Service 1915 — 1918 are (see Section H, 12). p. The help of Dame Marjorie Williamson and Dr. V.I. Little in identifying and dating some of the notebooks is gratefully acknowledged. Unless otherwise stated, all documents are manuscript; titles and descriptions in inverted commas are those on the manuscripts. Summary of the career of Professor Flint 18 b. 1890 1912 1915 — 1919 1920 1920 — 26 M.Sc., University of Birmingham Royal Garrison Artillery Assistant Lecturer in Physics, Cardiff University Lecturer, Reading University College Lecturer, King's College, University of London D.Sc., University of London 1925 1926 — 44 1928 D.M.R.E. College Hospital) 1933 1944 — 56 1930 1930 - 33 Honorary Fellow, King's College Reader in Physics, King's College (Diploma in Medical Radiology and Electrology) Cambridge Clinical Assistant in Radiology Department, Westminister Hospital (later — Consultant Physicist to Westminister Hospital and King's L.R.C.P. (Licentiate of the Royal College of Physicians) and M.R.C.S. (Member of the Royal College of Surgeons) Professor of Physics (Hildred Carlisle Chair), Bedford College, University of London Index of principal correspondents Lectures, addresses, working papers Location of other material Contents of the handlist A. B. C. D. Ee F. G. H. Es Committees Publications Biographical Notebooks Examining: Correspondence married Ruth Lieck 1956 H.T.F. C.S.A.C. 27/4/75 Biographical Miscellaneous printed obituaries and tributes — Bulletin, Hospital Physicists Association by Professor L.F. Bates, F.R.S., and Professor G. Stead; British Journal of Radiology, 45, p.156, by 'J.P.N.'; Appreciation by Professor 5. Tolansky, F.R.S., at meeting of Board of Studies in Physics, December 1; Memorial address, St. Mary's Church, Pillerton Hersey, 24 November 1971 List of publications, November 1944 Certificate of Ph.D. in the Faculty of Science, University of London, 25 January 1925 Certificate of registration, L.R.C.P. Application for chair of Physics at Birkbeck College, University of London: ms. draft of Flint's letter of application, curriculum vitae, list of publications, list of referees. by Professor 0.W. Richardson dated 28 January 1933 2=—page ms. draft of testimonial Miscellaneous ‘brain teasers' and mathematical problems collected by Flint B. Notebooks Picea relating to Flint's visit to Makerere College, the University College of East Africa,to advise the Senate Committee on Higher Education in the Colonies on their physics courses and the Intermediate Science Examinations: correspondence, ms. notes and typescript of report to Committee, miscellaneous printed matter re the College Official opening of Nigerian College of Arts, Sciences and Technology: programme, photographs and invitations Those documents relating to Flint's service in the Royal Garrison Artillery during the First World War have been deposited in the Department of Documents, Imperial War Museum, London. inserted) 'Conics' (with note added later by Flint ‘Wyggeston Boys! School, Leicester, 1908. Mathematics Master, H.E. Atkins') ‘*Practical physics' (with loose notes and geological maps See page 12for a descriptive list. B.1 — B.5 School Notebooks B.1 Be2 B.3 Be4 c1904 — 08 "French! 'Scripture' 'French!* B.5 . 1908 1904 =— 05 H.T.F. C.S.A.C. 27/4/75 36 B.6 — B.26 University notebooks (the date given is that of the first lecture B.6 B.7 B.8 B.9 'Statics. Applied Mathematics. Course I? in the course) "Pure Maths. Course II'* ‘Pure Mathematics. Course II' 'Hydrostatics. Applied Mathematics. Course I! B.10 "Pure Maths. Course II' October 1909 October 1909 December 1909 April 1910 April 1910 B.11 B.12 B.13 B.14 B.15 B.16 ‘Applied Mathematics. Course II' (with loose notes inserted) October 1910 "Physics. Pure Science. Course III' inserted) (with loose notes October 1910 ‘Pure Mathematics. Course III' (index given on page 1) May 1911 "Theory of potential! ‘Theory of potential (2). homogeneous co-ordinates' Some theorems on curves — December 1911 October 1911 'The theory of functions' right are from Dr. Heath's notebook. added at later times from various sources.') (with note 'The notes on the The left have been January 1912 "Convergence' (with same note as in item B.16) January 1912 September 1912 'Fourier's Series!’ 'Functions?t "Ricatti'ts equation’ "Spherical geometry and trigonometry'* September 1912 'The theory of functions of two variables? February 1972 April 71912 "De Moivre's Theorem and some deductions from it! "Total and partial loose notes and examination questions inserted) differential equations' (with 'Pure Mathematics. Notes of lectures to Course III. Conic Sections! January 1922 Notes on articles (by Planck, Hertz, de Donder, Pauli and others) Notes on articles and books read (partial index on cover of notebook) "Legendre coefficients, II and Spherical harmonics! "Lecture notes on the theory of relativity' October 1912 January 1913 October 1913 March 1914 February 1915 Ce 1919 — 22 March 1921, 1927 H.T.F. C.S.AC. 27/4/75 4. B.30 B.31 B.32 B.33 B.34 B.35 B.36 B.37 B.38 B.39 ‘Generalized dynamics. (notes for lectures) The quantum theory of Spectrat January 1923 'The kinetic theory of gases. Conduction of heat? ‘Practical organic chemistry' (notes for lectures) "Lectures of general dynamics’ to post-graduate students on the development December 1923 January 1924 October 1926 "Lectures to 2nd and 3rd year Honours physics students! October 1927 Notes on 'the association of a surface with the track of a particle in space—time'. Notes on various articles read. c.1931 ‘Notes for first lecture'; chronological list of subjects of of lectures (1937-38); drafts for some lectures 1935 = 38 ‘Notes on statistical mechanics. theory of relativity' Notes on the special November 1936 Copies of examination papers for external students, University of London,pasted in notebook with miscellaneous notes by Flint 1934 — 36 VIntermediate examinations 1937 July ': copies of examination papers for external students pasted in notebook. page carries a note by Flint of the examiners for each paper. The first 1937 — 38 "Thermodynamics. Advanced course? Lecture notes on heat "Lectures on the Subject of Sound 1938 1935 = 38 April 1938 1939 — 48 1939 — 40 Lecture notes with draft of 'The kinetic theory Various ideas for research etc. especially on Meson field ‘Radiation’ of gases! added in August 1947 Notes and drafts on 'The Anomalous Zeeman Effect? and ‘Statistical Theories' line theory).' Conduction in Parallel Wires. Electromagnetic theory of absorbing media. Conduction in parallel wires with discontinuous dielectric. Theory of coaxial cable (field theory compared with usual 'The theory of the propagation of electromagnetic waves along hollow metal cylinders and wires': draft with notes of bibliographical references Wartime lectures on radio "1. 2. 3. 4. c.1939 1940 c.1940 ce1940 c.1940 — 44 "Notes on cylindrical coordinates? Lecture hotes on electromagcetism H.T.F. C.S.A.C. 27/4/75 "lecture notes on general physics for advanced students! 'Matrix geometry. equations in nuclear fields and a more general Dirac equation 75" Theory of the co—efficients. Vector 'Five dimensional geometry' 'The theory of relativity and the quantum theory'* 'Field theory of particles without spin' 5 August 1945 1945 - 55 1945 =- 55 ce1950 c.1947 B.50 B.51 B.52 B.53 B54 B.55 B.56 Be5T B.58 B.59 B.60 B.61 Lecture notes on thermodynamics and on heat radiation September 1951 'The first order equation of the quantum theory! (the title of the first entry; see complete list of contents on first page ) 1951 — 52 Notes on Dirac's Theory of Magnetic Poles (1948) C.1950—53 'Huygen's principlet (first entry in set of lecture notes) Notes for undergraduate lectures on heat 'The formal grounds of the theory of relativity': notes on Einstein's 1914 papers "Reflection of e.m. waves at a boundary separating two media with condirection' (with loose notes on quantum statistics inserted) neds n.d. n.d. 0s Notes on ‘Theory of dielectrics' Lectures on Notes on tAdiabatic P, Ehrenfest, 1916) Lecture notes ‘A theory of the electron! etc. invariants of the quantum theory (by 165 ‘tthe principles of dynamics! 4 "Atomic Moments. 4-dim. unitary theory. notes on matrix notation'* Lecture notes: ‘radioactivity’, ‘theory of perturbations’* etc. with notes on practical problem exercises September 1923 "Practical zoology': anatomical drawings and notes (with loose notes inserted); back of book contains notes on organic chemistry Lecture notes 'Simple—coordinate transformations! etc. NeGs Neds ned. nmi,” ned. n.d. Lecture notes Lecture notes 'gyroscope', 'Cyclotron! etc. H.T.F. C.S.A.C. 27/4/75 Boll Notes on X-ray treatment, bone diseases, tuberculosis. Notebook also contains notes on the quantum theory and draft of an introduction beginning 'The attempt to unite the first order equations of the quantum theory with the theory of relativity. . ‘Matrix analysis and geometry’ and 'A metrical theory and matrices' .* and misc. notes entitled Notes on radiation treatments (see index in book) Notes on 'T.B., spleen, ovaries, ringworm, menstruation! Notes of lectures given in Ghana Notebook of lectures ‘Nuclear models? Jamary 1935 ned. n.d. 1958 Nids Lectures, addresses, working papers. Some of the following are complete manuscripts for invitation lectures or addresses; others are shorter notes, perhaps for university C.1 C.2 ‘The Screening of University of London Examination answer book. lectures. Very few are dated and many are untitled. ¥ ° . " ", "Uncertainty in Physics’. University College of South Wales Examination answer book: notes on transformation of equations. Envelope, "Intermediate Lecture Notes': misc. lectures on Physics, some dated 1937. King's College London Examination answer book, Components of A.C.Circuits', ‘Application of Fourier's theorem to the determination of frequency’. Magnetic Theory of a Polarizable Medium’. ‘Distant Parallelism & Matrix Representations employed on the Quantum Theory!. 'The Analogy between the Field Theory of the Nucleus and the Electro— 'On the Electrodynamic Scalar & Vector Potential’. ‘Colour’. 'Hering's Theory of Colour Vision’. 'The Analogy between the Electron & the Proton'. C.S.A.C. 27/4/75 'The effect of a discontinuity in the dielectric surrounding Lecher wires’. "Ultimate measurements of space & time in Physics’. 'Particles and Waves’. Untitled (on the laws of Physics) Untitled (on the laws of Physics) "Particles! "Difficulties concerning the Theory of the Electron' 37pp. Nov. 29th 1954. C.19 Address on the Centenary of the birth of Max Planck. C.20 "Bubbles and Drops', lecture—demonstration for children. C.21 Script of broadcast on University of London and University College of West Indies. C.22 — C.25 Manuscript & 3 lectures on the Chemical Elements. C.22 C.23 C.24 C.25 52pp. Ms. notebook ‘The Chemical Elements,'lecture at King's College Maxwell Society dated 15.1.51. 'The Chemical Elements. A Limitation to their Number' Untitled lectures on elements. C.26 C.27 C.28 C.29 C.30 C.28 —- C.30 3 lectures on Diathermy. C.26, C.27 2 lectures on Discontinuity in Physics. ‘Discontinuity in Physics', Inaugural Lecture at Bedford College, Nov. 28th 1944 Untitled lecture, perhaps for British Association. ‘Modern Ways of Applying Heat to the human body', lecture at London School of Medicine Dec.15 1950. Ms & typescr. 'Short-wave Diatherny' ‘Physical aspects of Gamma—-radiation Therapy’. 11 Feb 1937. lecture to King's College Maxwell Society Feb.12th 1943 'The Development of Telegraphy', Bedford College Maths. & Phys. Soc. Feb 23 1949 ‘Submarine Telegraphy'. Address: 'The material and the spiritual: a new review of an old problem’, given at East & West City Ruridecanal Conference 3 speeches at school prize-givings, one at Quintin School,St. John's Wood, and 2 others. C.31 — C.33 3 lectures on Telegraphy. C.31 C.32 C.33 1958 1937 H.T.F. G.S.A.0e 27/4/75 C.36 C.37 C.38 C.39 C.40 C.41 C.42 C.43 C.44 C.45 C.46 C.47 C.48 C.49 C.50 6.51 0.52 C.53 C.54 C.55 C.56 C.57 ‘Mechanical Example of Coupled Oscillators’. ‘Perturbation in an Assembly of Independent Systems'. 'Theorem of Bloch'. 'Classical Statistical Theory’. *Brownian Movement’. 'Specific Heat'. ‘Note to illustrate Matrix mechanics’. "Fundamental Physical Constants', with related offprints & notes. *Low Pressures'. 'The Common Emitter Amplifier’. 'Transistors'. *Impedance*. ‘Input Impedance of the Cathode Follower’. "6 Qualities concerned with knowledge of the structure of the universe’. notes on Spin, etc. tPossible forms of field eqns.'. Misc. working papers & shorter notes. 'tInteraction of Elementary Particles’. ‘Deduction of exchange forces between the neutron & proton’. Printed copies of examination papers, typescripts of notes on practical surgery. Flint's notes on medical lecture courses; answers to revision examination questions, annotated. Professor E.0.Lawrence, Professor F.L.Hopwood, Dr.A.Bouwers. 1938. Typescr. of Report for Westminster Hospital Radiotherapy Dept; tThe Neutron', typescr. with special reference to neutrons in biology & medicine; list of publications relating to biological effects of neutron (c) 1938; copies of exchange of letters between jork & corresp. on Radiotherapy (c) 1930 — 38 1924 — 28 1922 ~ 27 H.T.F. C.S.A.C. 27/4/75 D; D1 Committees British Medical Association Committee on Radioactive Substances: minutes, memorandum, draft of letter from the Committee to the Secretary, Ministry of Health re the manufacture and use of radioactive substances Royal Society Committee on Symbols: minutes, report De} British Committee for Radiological Units: correspondence and various proposals for reconstitution D.4-D.13 University Grants Committee Professor Flint served as assessor of claims for scientific and technical equipment of new buildings and laboratories. General correspondence with U.G.C. Westfield College, University of London: correspondence, copy of Flint's report University of Birmingham: correspondence, report King's College, Durham University: correspondence, lists of equipment 1959 - 68 1961, 1967-68 1959 - 62 1959 - 61 1959 = 63 1961 — 66 1963 1964 — 66 1964 - 67 1965 1965 1966 D.4 D.5 D.6 D.7 D.8 Ee4 Ee5 % DY D.10 Det D.12 University College of Wales, Aberystwyth: correspondence, lists and costs of equipment, draft of Flint's report to U.G.C. University College of Swansea: correspondence and report Nottingham University: correspondence, schedules of equipment Sheffield University: correspondence, ms. and typescript drafts of report University of Southampton: correspondence, ms. and typescript drafts of reports to U.G.C. Chelsea College of Science and Technology; University of Exeter; College of Advanced Technology; Birmingham: corres— pondence 1953 lave Mechanics: hardbound copy of 8th edition with many pages removed for insertion in E.4 Wave Mechanics: paperback copy of 8th edition (1953) with extensive revisions and insertions ms. Draft of introduction and chapters I figures used in book. 247+ pages. E.i — E.3 Advanced Practical Physics for Students (with B.L. Worsnop) ¢.1923 E. Publications —- VI, drawings of 1953 H.T.F. C.S.A.C. 27/4/75 E.6 Wave Mechanics: proof copy of 9th edition (1967) with miscellaneous annotations and revisions E.7 — BE. 9 ‘The Quantum Theory. Its geometrical formulation and Preface begins 'This book is written as a an account of some fundamental problems.': ms. draft of 7 chapters. contribution to the study and teaching of the quantum theory.' and is dated November 1963. do not correspond to those of The Quantum Equation. 208+ pages The chapter titles The Quantum Equation and the Theory of Fields: proof copy with several insertions of ms. drafts of new pages. Notes on 2 articles by O. Klein in Z.Phys. (1926, 1927) and trans— lation of article by Th. Kaluza in Sber.preuss, Akad.Wiss. (1921) cited in chapter 2 Theory of Kaluza and Klein' of The Quantum Equation, 'The "Resonant Method of Measuring Absorbtion by Wave Guides’ 4i pp ms. draft followed by several unnumbered pages on transversewaves and another draft (1st page missing) of 47 ppe beginning ‘Boundary Conditions! Various numbered sections of a-draft of an unidentified MSS 'Note on the communication by G.A. Dirac entitled "Equation of Motion of:a Charged Particle" ': ms. draft and typescript n.d. Letter published in November issue of 'FRAM' re mathematical four— and five- dimensional geometry and atomic numbers 1939 Fundamental Lengths and Masses of Fundamental Particles': typescript "Charged particles in the theory of relativity! (with M. Williamson): typescript "A New Uncertainty Relation' (with M. Williamson): note to Nature 3 offprints of Flint's articles, one entitled 'A Method for the Measurement of Impedence by means of Lecher Wires'* by Flint 'Method discovered (with G. Williams) with note at Pillerton Hersey, Warwick. Tried out in Bristol, May 1941.! of moving charges': ms. draft of paper Several versions of a Ms. draft beginning 'It was suggested some time ago that the limit to the number of chemical elements is 96! 'The connection of the subject of the thesis with the motion 1941 — 48 Easter 1941. H.T.F. C.S.A.C. 27/4/75 E.6 Wave Mechanics: proof copy of 9th edition (1967) with miscellaneous annotations and revisions E.7 - E. Its geometrical formulation and ‘The Quantum Theory. 9 an account of some fundamental problems.': ms. draft of Preface begins 'This book is written as a 7 chapters. contribution to the study and teaching of the quantum theory.' and is dated November 1963. do not correspond to those of The Quantum Equation. 208+ pages The chapter titles The Quantum Equation and the Theory of Fields: proof copy Notes with several insertions of ms. drafts of new pages. on 2 articles by O. Klein in Z.Phys. (1926, 1927) and trans— lation of article by Th. Kaluza in Sber.preuss, Akad.Wiss. (1921) cited in chapter 2 Theory of Kaluza and Klein! of The Quantum Equation, 'The 'Resonant Method of Measuring Absorbtion by Wave Guides! pp ms. draft followed by several unnumbered pages on 41 transversewaves and another draft (1st page missing) of AT ppe beginning ‘Boundary Conditions’ Various numbered sections of a-draft of an unidentified MSS 'Note on the communication by G.A. Dirac entitled "Equation ms. draft and typescript of Motion of:a Charged Particle" 's Letter published in November issue of 'FRAM' re mathematical four~ and five— dimensional geometry and atomic numbers Easter 1941. Fundamental Lengths and Masses of Fundamental Particles": typescript 'Charged particles in the theory of relativity' (with M. Williamson): typescript 'A New Uncertainty Relation! (with M. Williamson): note +o Nature 3 offprints of Flint's articles, one entitled 'A Method for the Measurement of Impedence by means of Lecher Wires* by Flint 'Method discovered (with G. Williams) with note Tried out in at Pillerton Hersey, Warwick. Bristol, May 1941.!' of moving charges': ms. draft of paper Several versions of a Ms. draft beginning 'It was suggested some time ago that the limit to the number of chemical elements is 96! ‘The connection of the subject of the thesis with the motion H.T.F. C.S.A.C. 27/4/75 E.21 E.22 — The Commonwealth and International Library of Science, Technology, Engineering and Liberal Studies published by Pergamon Press. of the Physics Division; the file contains correspondence with editors and director of Pergamon, with Flint's co-editor, Dr. Eric J. Irons, re proposed list of books to be commissioned and re MSS submitted, with authors; comments on the Mss, printed material re the series Professor Flint was a Managing Director E. 26 Extensive correspondence of Dr. Eric J. Irons; Flint probably took overthe files after Dr. Irons' death in 1963. The correspondence, which is arranged chronologically, contains the originals of Flint's letters(of which he himself kept no copies)and Irons' correspondence with editors and directors of Pergamon, with outside referees, with prospective authors of physics books in the series. The index is selective; a full list of correspondents appears on the cover of each file. E.27. ‘Rigid Dynamics': typescript with extensive annotations by Flint and Irons E.28 D.29 Misc. ms. drafts of book reviews (titles of books unknown ) Misc. reminiscences and obituaries of Dr. Sydney Marsh, Sir Edward Appleton, William Wilson, Sir Owen Richardson F. Examining 1960 — 63 F.1 Wee F.3 F.4 F.5 G. Gel F.6—F.7 Misc. references and testimonials Drafts and suggestions for examination questions Questions for D.Phil. candidate, reports on D.Phil.theses (unidentified) External examining: University College, Ibadan, Nigeria: correspondence, drafts of examination papers External examining: University of the West Indies: corres— pondence, copies of examination syllabus External examining, University of the West Indies: corres— pondence, Flint's suggestions and comments on proposed examination questions, the University's examiners' comments of miscellaneous scientific correspondence Correspondence One file. H.?.F. C.S.A0C.. 27/4/75 He Location of other material Deposited in the Department of Documents, Imperial War Museum, Ref. 74/123/1. War Service 1915 — 1918 1. 3 vols.personal diaries,1915 — 1918,relating to training,active service,demobilisation and return to university career; pencil and ink,with some later annotations and some erasures and deletions. ‘Army Book 3! and tArmy Book 152',containing notes taken during training. ‘Army Book 136',dated 25 April 1917; notes of personnel 4015S Bty. R.G.A.,civil and military status,subsequent history etc. ‘Army Book 152',Jan. — March 1918,inscribed by Flint 'Temporary Target Book of 306 Siege Battery,situated at the Village of Vendeuil in the sand pit South of the village on the road S.Quentin — La Fére. The position was held from early in Jan 1918 to about March 10th 1918 during the time of anticipation of a full German attack; which finally came on March 2ist. & caused the whole 5th Army to retreat. defend the position in a hand to hand fight & our orders were to "be buried in Vendeuil if necessary." This book contains details of preparations made by us to 7. 8. 9. Photographs of Abbeville; views of Ypres before and after war. Misc. field orders 1917 — 1918,by or to Flint. Ms. Misc. maps and charts of France and Belgium,some with notes by Flint. Misc. aerial photographs of artillery bombardment,dated 1917 — 1918. Personal material: Flint's Commissiom and Discharge papers; his Army book 439; photographs of his Battery and comrades,souvenirs, press cuttings and correspondence; includes photographs and letters "picked up on the battlefield",some French and German. 10, Misc. printed Instruction Books,dictionaries etc. H.T.F. C.S.A.C. 27/4/75 i Index of principal correspondents Adams, Sir Walter Bellamy, Edmund Henry Booker, H. G, Bouwers, Ae Buckley, E. Je Davidson, P. M. Deacon, George Edward R. Dungey, Je W. Furth, R. Haskey, H. Hunt, 5S. W. E. Hutchinson, George William G.1 G.1 D.12 D.10 Irons, Eric J. E}27 = B.26 D.7 E.25,E.26 Jones, G. 0. Lawrence, Ernest 0. Kennedy, Alfred James Little, Victor I. Lyon, Arthur J. 0.57 E.23 E.23 E.21 Lipson, Henry Solomon Be23 Keith Anderson Hope (Baron Murray of Newhaven) G.1 E.22,E.25 D.6 D.4 Owen, Edwin Augustin Murray, ask wi. L. Masriera, Miguel Maxwell], Ian Robert Moon, Philip Burton : D.10 H.T.F. C.S.A.C. 27/4/75 Roberts, John Eric Rochester, George Dixon Runcorn, Stanley Keith Taylor, Alfred Maurice Tolansky, Samuel Tucker, David Gordon D.3 D.10 D.7 E.23 F.3 E.21, E.25, E26 Wolfenden, Sir John(Frederick) Wood, Ce. We Wright, Raymond H. W. D.4 E.21 F.5
FLINT, Henry T v2
Published: 16 January, 2024 Author: admin