!30 



Figure 21. Ki \ i rsibi i pendulum apparatus of Defforges, as constructed by Brunncr, Paris, 

 about 1887. The clock and telescope used to observe coincidences are no1 shown. The 

 telescope shown is pan ol an interferometei used to measure rlexure of the support. One 

 mirror of the interferometer is attached to the pendulum support; the other to the separate 

 masonry pillar at the left. 



BULLETIN 240: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



