58 S. P. Langley—Possrbility of 
the same magnifying power. If we suppose, then, that the star 
observed was in the equator, and that, by a happy accident, the 
first flash came just as it was crossing the first wire, this wire 
would be sharply defined on the dise of the star and bisecting 
it, and the simultaneous record on the chronograph (made with- 
out any intervention of the observer) would evidently give us 
the same result as though the star had electrically recorded its 
the top of the rod, and by sliding the bob sufficiently down- 
ward ; with the use of a readily-constructed table, we can, given 
the ses! of a stationary horizontal wheel, concentric with 
the i 
revolv 
passing from a groove in its cireumference to the hand of the 
observer at the transit. As the upper, or ordinarily fixed, and 
the lower or constantly moving, wheel have, a common vertical 
