CONTENTS. IX 

 CHAPTER VI. 



THE PRINCIPAL SCREWS OF INERTIA. 



SECT. PACK. 



51. Introduction, . . . . . . -45 



52. Screws of Reference, , . .. . . , * . 46 



53. Impulsive Screws and Instantaneous Screws, . ..... . 47 



54. Conjugate Screws of Inertia, . . . . . . ..-.-.. 48 



55. Determination of the Impulsive Screw, ...... 49 



56. System of Conjugate Screws of Inertia, . . . . . . ib. 



57. Principal Screws of Inertia, . . 50 



58. Kinetic Energy, . . . 52 



59. Expression for Kinetic Energy, . . . . . . 54 



60. Twist Velocity acquired by an Impulse, . . . . ' . . 55 



61. The Kinetic Energy acquired by an Impulse, . . >:. -56 



62. Free Body, . . ... . ib. 



63. Lemma, . . . . . ^ ,.,,,, f . . ._ . , 67 



64. Euler's Theorem, .'.,." ib. 



65. Co-ordinates of a Screw belonging to a Screw Complex, . . . 58 



66. The Reduced Wrench, . * . ., . . 59 



67. Co-ordinates of Impulsive and Instantaneous Screws, ... 60 



CHAPTER VII. 



THE POTENTIAL ENERGY OF A DISPLACEMENT. 



68. The Potential Energy of a Displacement, .' . . .63 



69. The Wrench evoked by Displacement, . '. . . . . .64 



70. Conjugate Screws of the Potential, .66 



71. Principal Screws of the Potential, 68 



72. Co-ordinates of the Wrench evoked by a Twist, .... 69 



73. Form of the Potential, . '* 71 



CHAPTER VIII. 



HARMONIC SCREWS. 



74. Definition of an Harmonic Screw, . . . . . -73 



75. Equations of Motion, 76 



76. Discussion of the Results, 80 



77. Remarks on Harmonic Screws, 82 



