213 
distances in the adjoined media: (CO 4 PV) in air, VT inair, 2q 
in glass, NM in air, (ML + JH) in air. When the first path is 
compared with this last, use being made of equation (9), the path 
in the second (the prolongable) arm of the interferometer proves to 
ni ee AES dea a 
nen EG i 
aE: rd : r ? 
Aa 
BE Tae ee ee 
UEA ES 5 
N \ an ID 
KL eve 
ese Ale ir 
ee We 
Fig. 7. 
be 2u(q—p) + 2 VT + 2d (A—y) longer than that of the first. When 
: nya 7 
we now also take into account the phase-shifting 5 forward when 
