Sex Intergrades in a Species of Crustacea.

The experiment was also made of crossing the spectra at some other angle than 0° or 180°. For instance, the rulings of the Ives grating were placed at right angles to those of the interferometer grating, as in Newton's method of crossed prisms. Seen in the telescope (adjusted for inverted spectra) the two spectra now made an elbow with each other, while the D1 DA lines were still parallel and could be put in coincidence. On using a long (meter) collimator, strong interferences were obtained in the line of symmetry of the elbow and normal to the D lines. They have the same characteristics as the preceding and persist during a displacement of mirror of about 0.3 cm.