ae ee 
Ea 
and carried to its limit the adsacaee obtainable in this way. 
My purpose herein is to fix attention strongly on the simple en- 
quiry whether immersions and emersions hitherto invisible may not 
be brought out to observation by narrowing an equatorially moving 
field to the utmost limit of the telescope’s stability, and pushing mag- 
nifying power to an extreme. we oe ne 
Liffects of Planetary Atmospheres. 
n 
sten upon no abrupt degree for the signal of observation. Thus, 
a 
