one of the most important of all analytical results as regards usefulness in physical science. In the Appendices to that chapter we have introduced an extension of Green's Theorem, and a treatise on the remarkable functions known as Laplace's Coefficients. There can be but one opinion as to the beauty and utility of this analysis of Laplace; but the manner in which it has been hitherto presented has seemed repulsive to the ablest mathematicians, and difficult to ordinary mathematical students. In the simplified and symmetrical form in which we give it, it will be found quite within the reach of readers moderately familiar with modern mathematical methods. In the second chapter we give NEWTON'S Laws of Motion in his own words, and with some of his own comments-every attempt that has yet been made to supersede them having ended in utter failure. Perhaps nothing so simple, and at the same time so comprehensive, has ever been given as the foundation of a system in any of the sciences. The dynamical use of the Generalized Cöordinates of LAGRANGE, and the Varying Action of HAMILTON, with kindred matter, complete the chapter. The third chapter, "Experience," treats briefly of Observation and Experiment as the basis of Natural Philosophy. The fourth chapter deals with the fundamental Units, and the chief Instruments used for the measurement of Time, Space, and Force. Thus closes the First Division of the work, which is strictly preliminary, and to which we have limited the present issue. This new edition has been thoroughly revised, and very considerably extended. The more important additions are to be found in the Appendices to the first chapter, especially that devoted to Laplace's Coefficients; also at the end of the second chapter, where a very full investigation of the "cycloidal motion" of systems is now given; and in Appendix B', which describes a number of continuous calculating machines invented and constructed since the publication of our first edition. A great improvement has been made in the treatment of Lagrange's Generalized Equations of Motion. We believe that the mathematical reader will especially profit by a perusal of the large type portion of this volume; as he will thus be forced to think out for himself what he has been too often accustomed to reach by a mere mechanical application of analysis. Nothing can be more fatal to progress than a too confident reliance on mathematical symbols; for the student is only too apt to take the easier course, and consider the formula and not the fact as the physical reality. In issuing this new edition, of a work which has been for several years out of print, we recognise with legitimate satisfaction the very great improvement which has recently taken place in the more elementary works on Dynamics published in this country, and which we cannot but attribute, in great part, to our having effectually recalled to its deserved position Newton's system of elementary definitions, and Laws of Motion. We are much indebted to Mr BURNSIDE and Prof. CHRYSTAL for the pains they have taken in reading proofs and verifying formulas; and we confidently hope that few erratums of serious consequence will now be found in the work. W. THOMSON. P. G. TAIT. Displacements of a Plane Figure in its Plane-Composition Motion of a Rigid Body about a Fixed Point-Euler's Theorem Most general Motion of a Rigid Body Precessional Rotation-Model illustrating Precession of Equi- 78-94 95-101 102, 103 104-107 Free rotation of a Body kinetically symmetrical about an axis General Motion of one Rigid Body touching another-Curve rolling on Curve-Plane Curves not in same Plane- Curve rolling on Curve; two degrees of freedom-Curve rolling on Surface; three degrees of freedom - Trace prescribed and no Spinning permitted; two degrees of freedom-Angular Velocity of direct Rolling — Angular Velocity round Tangent - Surface on Surface - Both traces prescribed; one degree of freedom Twist-Estimation of Integral Twist in a Plane Curve; in a Curve consisting of plane portions in different Planes; in a continuously Tortuous Curve-Dynamics of Twist Surface rolling on Surface; both traces given 126, 127 Curvature of Surface-Synclastic and Anticlastic Surfaces- Meunier's Theorem - Euler's Theorem - Definition of Line of Curvature-Shortest Line between two points on a Surface. Spherical Excess Area of Spherical Polygon-Reciprocal Polars on a Sphere-Integral change Integral Curvature-Curvatura integra-Horograph-Change Flexible and Inextensible Surface-Flexure of inextensible Developable-Edge of Regression-Practical Construction of a Developable from its edge-General property of Inextensible Surface-Surface of constant Specific Cur- Strain-Definition of Homogeneous Strain-Properties of Ho- mogeneous Strain-Strain Ellipsoid-Change of Volume -Axes of a Strain-Elongation and Change of Direction of any Line of the Body-Change of Plane in the Body- Conical Surface of equal elongation-Two Planes of no distortion, being the Circular Sections of the Strain Ellip- soid-Distortion in Parallel Planes without Change of Volume-Initial and altered Position of Lines of no Elongation-Simple Shear-Axes of a Shear-Measure of a Shear-Ellipsoidal specification of a Shear-Analysis Displacement of a Body, rigid or not, one point of which is Analysis of a Strain into Distortion and Rotation Displacement of a Curve-Tangential Displacement-Tan- "Equation of Continuity"—Integral Equation of Continuity- Freedom and Constraint-Of a Point-Of a Rigid Body-Geo- metrical Clamp--Geometrical Slide-Examples of Geo- metrical Slide-Examples of Geometrical Clamps and Slides-One Degree of Constraint of the most general character-Mechanical Illustration-One Degree of Con- straint expressed analytically 139-153 182 183-185 186-190 |