Though born in Nova Scotia, I am of almost pure New England descent.

The beginning of 1856 found me teaching in the family of a planter named Bryan, residing in Prince George County, Md., some fifteen or twenty miles from Washington.

In 1860 a total eclipse of the sun was visible in British America.

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 to make some observation included in the programme.

In 1858 I received the degree of D. S. from the Lawrence Scientific School, and thereafter remained on the rolls of the university as a resident graduate.

Whenever a total eclipse of the sun was visible in an accessible region parties were sent out to observe it.

One hardly knows where, in the history of science, to look for an important movement that had its effective start in so pure and simple an accident as that which led to the building of the great Washington telescope, and went on to the discovery of the satellites of Mars.