Volume I: Preface; 1. On the description of oval curves and those having a plurality of foci; 2. On the theory of rolling curves; 3. On the equilibrium of elastic solids; 4. On the transformation of surfaces by bending; 5. On a particular case of the descent of a heavy body in a resisting medium; 6. On the theory of colours in relation to colour-blindness; 7. Experiments on colour as perceived by the eye, with remarks on colour-blindness; 8. On Faraday's lines of force; 9. Description of a new form of the Platometer, an instrument for measuring the areas of plane figures drawn on paper; 10. On the elementary theory of optical instruments; 11. On a method of drawing the theoretical forms of Faraday's lines of force without calculation; 12. On the unequal sensibility of the Foramen Centrale to light of different colours; 13. On the theory of compound colours with reference to mixtures of blue and yellow light; 14. On an instrument to illustrate Poinsont's theory of rotation; 15. On a dynamical top, for exhibiting the phenomena of the motions of a body of invariable form about a fixed point, with some suggestions as to the earth's motion; 16. Account of experiments on the perception of colour; 17. On the general laws of optical instruments; 18. On theories of the constitution of Saturn's rings; 19. On the stability of the motion of Saturn's rings; 20. Illustrations of the dynamical theory of gases; 21. On the theory of compound colours and the relations of the colours of the spectrum; 22. On the theory of three primary colours; 23. On the physical lines of force; 24. On reciprocal figures and diagrams of forces; 25. A dynamical theory of the electromagnetic field; 26. On the calculation of the equilibrium and stiffness of frames. Volume II: 27. On the viscosity or internal friction of air and other gases; 28. On the dynamical theory of gases; 29. On the theory of the maintenance of electric currents by mechanical work without the use of permanent magnets; 30. On the equilibrium of a spherical envelope; 31. On the best arrangement for producing a pure spectrum on a screen; 32. The construction of stereograms of surfaces; 33. On reciprocal diagrams in space and their relation to Airy's function of stress; 34. On governors; 35. Experiment in magneto-electric induction; 36. On a method of making a direct comparison of electrostatic with electromagnetic force; 37. On the cyclide; 38. On a bow seen on the surface of ice; 39. On reciprocal figures, frames, and diagrams of forces; 40. On the displacement in a case of fluid motion; 41. Address to the mathematical and physical sections of the British Association, 1870; 42. On colour-vision at different points of the retina; 43. On hills and dales; 44. Introductory lecture on experimental physics; 45. On the solution of electrical problems by the transformation of conjugate functions; 46. On the mathematical classification of physical quantities; 47. On colour vision; 48. On the geometrical mean distance of two figures on a plane; 49. On the induction of electric currents in an infinite plane sheet of uniform conductivity; 50. On the condition that, in the transformation of any figure by curvilinear co-ordinates in three dimensions, every angle in the new figure shall be equal to the corresponding angle in the original figure; 51. Reprint of Papers on electrostatics and magnetism. By Sir W. Thomson. (Review); 52. On the proof of the equations of motion of a connected system; 53. On a problem in the calculus of variations in which the solution is discontinuous; 54. On action at a distance; 55. Elements of natural philosophy. By Sir W. Thomson and P. G. Tait. (Review); 56. On the theory of a system of electrified conductors, and other physical theories involving homogeneous quadratic functions; 57. On the focal lines of a refracted pencil; 58. An Essay on the mathematical principles o