in the way of a regular and well-planned
piece of work. In the greater clearness of our sky, and the more
southern latitude of our observatory, we had two great advantages
over Greenwich. Looking back at his first two or three years of
work at the observatory, Maury wrote to a friend, "We have beaten
Greenwich hollow." It may be that I felt like trying to do the
same thing over again. At any rate, I mapped out a plan of work
the execution of which would require four years.

It was a piece of what, in astronomy, is called "fundamental work,"
in which results are to be obtained independent of any previously
obtained by other observers. It had become evident to me from our
own observations, as well as from a study of those made at European
observatories, that an error in the right ascension of stars, so
that stars in opposite quarters of the heavens would not agree, might
very possibly have crept into nearly all the modern observations at
Greenwich, Paris, and Washington. The determination of this error
was no easy matter. It was necessary that, whenever possible,
observations should be continued through the greater part of the
twenty-four hours. One observer must be at work with comparative
steadiness from nine o'clock in the morning until midnight or even
dawn of the morning following. This requirement was, however, less
exacting than might appear when stated. One half the nights would,
as a general rule, be cloudy, and an observer was not expected to
work on Sunday. Hence no one of the four observers would probably
have to do such a day's work as this more than thirty or forty times
in a year.

All this was hard work enough in itself, but conditions existed which
made it yet harder. No houses were then provided for astronomers,
and the observatory itself was situated in one of the most unhealthy
parts of the city. On two sides it was bounded by the Potomac, then
pregnant with malaria, and on the other two, for nearly half a mile,
was found little but frame buildings filled with quartermaster's
stores, with here and there a few negro huts. Most of the observers
lived a mile or more from the observatory; during most of the time I
was two miles away. It was not considered safe to take even an hour's
sleep at the observatory. The result was that, if it happened to
clear off after a cloudy evening, I frequently arose from my bed
at any hour of the night or morning and walked two miles to the
observatory t