As we proceed we shall meet with proper objects for testing different telescopes.

For the present, let the following list suffice.

It is selected from Admiral Smyth's tests, obtained by diminishing the aperture of a 6-in.

telescope having a focal length of 8-1/2 feet: A two-inch aperture, with powers of from 60 to 100, should exhibit [alpha] Piscium (3".5).

| [delta] Cassiopeiae (9".5), | mag.