4 CONTENTS. 



II. USE OF THE RECTANGULAR INTERFEROMETER IN CONNECTION WITH 



HORIZONTAL PENDULUM. 



PAGE. 



47. Introductory 83 



48. Apparatus. Figs. 57, 58, 59 83 



49. Equations. Fig. 60 84 



50. Observations. Fig. 61 86 



51. Observations continued. Figs. 62, 63, 64, 65 88 



CHAPTER V. The Interferometry of Vibrating Systems. 



52. Introductory 91 



53. Telephonic apparatus. Figs. 66, 67 91 



54. Observations. Figs. 68, 69 92 



55. Binlar systems. Figs. 70. 71 94 



56. Further observations. Figs. 72, 73 96 



