eye-observation

My preparations for the Transit of Venus have respect only to eye-observation of contact of limbs.

Autobiography Airy, George Biddell, Sir 1896

For methods of observation, I rely generally on the simple eye-observation, possibly relieved of some of its uncertainty by the use of my colour-correcting eyepiece.

Autobiography Airy, George Biddell, Sir 1896

And, generally speaking, the photographs are most beautiful, and give conceptions of the continual disturbances in terrestrial magnetism which it would be impossible to acquire from eye-observation. '”

Autobiography Airy, George Biddell, Sir 1896