Observational astronomy, meanwhile, was advancing to some extent independently.
Thus the differences in the wave-lengths of presumably the same lines as measured by different Arctic observers may be only partly due to unfavourable observational conditions.
With the development of observational astronomy the sidereal universe was arbitrarily divided into areas characterized by special assemblages of stars; these assemblages were named asterisms by Ptolemy, who termed the brightest stars "of the fi rst magnitude," and the progressively fainter Stars.
This observational method Cousin regards as that of the 18th century, - the method which Descartes began and abandoned, and which Locke and Condillac applied, though imperfectly, and which Reid and Kant used with more success, yet not completely.
The observational method applied to consciousness gives us the science of psychology.
