5-10, 14 f., belonging to the year 605, and representing the **emergent** power of the Chaldaeans as a divine scourge of the faithless people; (b) Woes against the Chaldaeans, presupposing not only tyrannous rule over many peoples, but the beginning of their decline and fall, and therefore of date about J40 B.C. (ii.

If 1 2 and 1 1 be the thicknesses traversed by the extreme rays, and a denote the width of the **emergent** beam, the dispersion is given by 0 Sµ 0 2 - 11)/a, or, if t i be negligible, 0 = Sµt/a (6) The condition of resolution of a double line whose components subtend an angle 0 is that 0 must exceed X/a.

As the sun rises, the rays enter the prisms more and more obliquely, and the angle of minimum deviation increases; but since the **emergent** ray makes the same angle with the refracting edge as the incident ray, it follows that the parhelia will remain on the parhelic circle, while receding from the inner halo.

Hence one of the best methods of determining the magnifying power of a telescope to measure the diameter of the **emergent** pencil of rays, after the FIG.

Telescope has been adjusted to focus upon a star, and to divide the diameter of the object-, glass by the diameter of the **emergent** pencil.