Now if our observer describe a circle, and draw a diameter inclined according to above table, this diameter would represent the sun's equator if the axis of the sun were square to the ecliptic-plane. But this axis is slightly inclined, the effect of which is, that on or about June 10 the sun is situated as shown in fig. 14 with respect to the ecliptic _ab_; on or about September 11 he is situated as shown in fig. 13; on or about December 11 as shown in fig. 12; and on or about March 10 as shown in fig. 15. The inclination of his equator to the ecliptic being so small, the student can find little difficulty in determining with sufficient approximation the relation of the sun's polar axis to the ecliptic on intermediate days, since the equator is never more _inclined_ than in figs. 12 and 14, never more _opened out_ than in figs. 13 and 15. Having then drawn a line to represent the sun's ecliptical diameter inclined to the horizontal diameter as above described, and having (with this line to correspond to _ab_ in figs. 12-15) drawn in the sun's equator suitably inclined and opened out, he has the sun's actual presentation (at noon) as seen with an erecting eye-piece. Holding his picture upside down, he has the sun's presentation as seen with an astronomical eye-piece--and, finally, looking at his picture from behind (without inverting it), he has the presentation seen when the sun is projected on the screen. Hence, if he make a copy of this last view of his diagram upon the centre of his screen, and using a low power, bring the whole of the sun's image to coincide with the circle thus drawn (to a suitable scale) on the screen, he will at once see what is the true position of the different sun-spots. After a little practice the construction of a suitably sized and marked circle on the screen will not occupy more than a minute or two. [Illustration: _Fig. 12._] [Illustration: _Fig. 13._] [Illustration: _Fig. 14._] [Illustration: _Fig. 15._] It must be noticed that the sun's apparent diameter is not always the same. He is nearer to us in winter than in summer, and, of course, his apparent diameter is greater at the former than at the latter season. The variation of the apparent diameter corresponds (inversely) to the variation of distance. As the sun's greatest distance from the earth is 93,000,000 miles (pretty nearly) and his least 90,000,000, his greatest, mean, and least apparent diameters are as 93, 91-1/2, and 90 respectively; that is, as 62, 61, and 60 respectively. Mr. Howlett considers that with a good 3-inch telescope, applied in the manner we have described, all the solar features may be seen, except the separate granules disclosed by first-class instruments in the hands of such observers as Dawes, Huggins, or Secchi. Faculae may, of course, be well seen. They are to be looked for near spots which lie close to the sun's limb.