Note 10 — Chapter V · THE SUN.
Reading edition
On May 13, 1890, at 3h, I tested the three methods alluded to on a scattered train of small spots, and derived the following measurements of length:—
By glass micrometer 76,570 miles. “ cross wires 76,610 ” “ cardboard disk 75,770 “
In this comparison I used an excellent 4-inch Cooke refractor, belonging to a friend.