eriods, the busiest portion of the twenty-four hours at the
Observatory, is between nine in the morning and two in the afternoon.
During this time they work in silence, the task being to complete the
records of the observations made, by filling in the requisite columns of
figures upon printed forms, and then adding and subtracting them as the
case requires. While thus engaged, the assistant who has charge of an
instrument looks, from time to time, at his star regulated clock, and
when it warns him that his expected planet is nearly due, he leaves his
companions, and quietly repairs to the room where the telescope is
ready. The adjustment of this has previously been arranged with the
greatest nicety. The shutter is moved from the slit in the roof, the
astronomer sits upon an easy chair with a movable back. If the object he
seeks is high in the heavens, this chair-back is lowered till its
occupant almost lies down; if the star is lower, the chair-back is
raised in proportion. He has his note-book and metallic pencil in hand.
Across the eye-piece of the telescope are stretched seven lines of
spider-web, dividing the field of view. If his seat requires change, the
least motion arranges it to his satisfaction, for it rests upon a
railway of its own. Beside him is one of the star-clocks, and as the
moment approaches for the appearance of the planet, the excitement of
the moment increases. "The tremble of impatience for the entrance of the
star on the field of view," says an Edinburgh Reviewer, "is like that of
a sportsman whose dog has just made a full point, and who awaits the
rising of the game. When a star appears, the observer, in technical
language, _takes a second from the clock face_; that is, he reads the
second with his eye, and counts on by the ear the succeeding beats of
the clock, naming the seconds mentally. As the star passes each wire of
the transit, he marks down in his jotting-book with a metallic pencil
the second, _and the second only_, of his observation, with such a
fraction of a second as corresponds, in his judgment, to the interval of
time between the passage of the star, and the beat of the clock which
preceded such passage."

An experienced observer will never commit an error in this mental
calculation, exceeding the tenth of a second, or six hundredth of a
minute. When the star has been thus watched over the seven cobweb lines
(or wires), the observer jots down the hour and minute, in addition to
th