To accomplish this a light framework may be constructed in the shape of a truncated cone. At its narrow end it slips or screws on to the eye-end of the telescope, and it may be made of any length required, in proportion to the size of solar disc which it is desired to obtain. It should be covered with black cloth, and its base may be a board with white paper stretched on it to receive the image, which is viewed through a small door in the side. In place of the board with white paper, other expedients may be tried. Noble recommends a surface of plaster of Paris, smoothed while wet on plate glass, and this is very good if you can get the plaster smooth enough. I have found white paint, laid pretty thickly on glass and then rubbed down to a smooth matt surface by means of cuttle-fish bone, give very satisfactory results. Should it be desired to exhibit the sun's image to several people at once, this can easily be done by projecting it upon a sheet of paper fastened on a drawing-board, and supported at right angles to the telescope by an easel. The framework, or whatever takes its place, being in position, the telescope is pointed at the sun by means of its shadow; when this is perfectly round, or when the shadow of the framework perfectly corresponds to the shape of its larger end, the sun's image should be in the field of view. CHAPTER IV THE SUN'S SURROUNDINGS We have now reached the point beyond which mere telescopic power will not carry us, a point as definite for the largest instrument as for the smallest. We have traced what can be seen on the visible sun, but beyond the familiar disc, and invisible at ordinary seasons or with purely telescopic means, there lie several solar features of the utmost interest and beauty, the study of which very considerably modifies our conception of the structure of our system's ruler. These features are only revealed in all their glory and wonder during the fleeting moments in which a total eclipse is central to any particular portion of the earth's surface.