If, without changing the focus, we open the slit wider, and throw the sun’s image just off the slit, so that the very bright continuous spectrum no longer dazzles the eye, we shall be able to see these flames whenever they cross the opening, for the image of the slit is focussed on the eye, and the sun and its flames are focussed on the slit, so if we virtually remove the slit by opening it wide, we see the flames; still the limit of opening is soon approached, and the flood of atmospheric light soon masks them. The red hydrogen line of the spectrum is the best for viewing them, although the yellow or blue will answer. We may also place the sun’s image so that the slit is tangential to it, in which case a greater length of the hydrogen layer, or chromosphere, as it is called, is visible, although its height is limited by the opening of the slit. By these means we are able to view a small part of the chromosphere at a time, and to go all round the sun in order to obtain a daily record of what is going on. If, however, we throw the image of the sun on a disc of metal of exactly the same size, we eclipse the sun, but allow the light of the chromosphere to pass the edge of the disc; this of course is masked by the atmospheric light, but if the annulus, or ring of chromosphere, be reduced sufficiently small, it can be viewed with a spectroscope in the place of a slit, in fact it is virtually a circular slit on which the chromosphere rests. By this means nearly the whole of the chromosphere can be seen at once. This is accomplished as follows:— The image of the sun is brought to focus on a diaphragm having a circular disk of brass in the centre, of the same size as the sun’s image, so that the sun’s light is obstructed and the chromospheric light is allowed to pass. The chromosphere is afterwards brought to a focus again at the position usually occupied by the slit of the spectroscope; and in the eyepiece is seen the chromosphere in circles corresponding to the “C” or other lines. A lens is used to reduce the size of the sun’s image, and keep it of the same size as the diaphragm at different times of the year; and other lenses are used in order to reduce the size of the annulus of light to about ⅛ inch, so that the pencils of light from either side of it may not be too divergent to pass through the prisms at the same time, in order that the image of the whole annulus may be seen at once. There are mechanical difficulties in producing a perfect annulus of the required size, so one ½ inch in diameter is used, and can be reduced virtually to any size at pleasure. From what has been said it is easy to see that we really now get a new language of light altogether, and a language which requires a good deal of interpretation. [Illustration: FIG. 202.—Distortions of F line on Sun. ]