_Recurrent Forms._—Certain spots observed at different times have exhibited appearances so nearly resembling each other that it has been considered the likeness may be due to something more than mere accident. Whenever such suggestive coincidences are recognized the observer should note them particularly, and secure drawings. It should be his aim to determine the exact intervals elapsing between the presentation of spots or groups of this character, and also whether they occupy the same latitude and longitude on the Sun’s disk. _Exceptional Position of Spots._—The ordinary spots are rarely seen more than 35° distant from the solar equator or within 8° of it. They usually appear in the zones from 8° to 20° N. and S. of the equator. A few exceptions may be mentioned[15]. Mechain saw a spot in July 1780 having a latitude of 40-1/3°; in April 1826 Capocci recorded one having 49° of S. latitude; Schwabe and Peters observed spots 50° from the equator. Lahire, in the last century, described a spot as visible in a latitude of 70°; but the accuracy of this observation has been questioned. Whenever a spot is seen near the equator, or very far removed from it, measures should be taken of its exact place; for it is desirable to learn something more of those disturbances which occasionally affect the more barren regions of the solar envelope. _The Solar Prominences._—Those amateurs who have included a spectroscope in their instrumental outfit will find the study of the chromosphere and prominences a most productive one. Huggins and Zöllner were the first to apply the “open-slit” method; and the study of the shape of the hydrogen prominences commenced in 1869. Tupman details (‘Monthly Notices R.A.S.,’ vol. xxxiii. p. 106) a series of observations which he secured in 1872 with a refractor of 3-inches aperture and a direct-vision spectroscope of five prisms. He mentions the cost of the entire apparatus as only £18, and says he entertains “no doubt that an equally effective instrument could be made for much less.” The prominences appear to be of different kinds, and are known as “cloud”- and “flame”-prominences. Both are liable to rapid changes. Trouvelot, in June 1874, noticed “a gigantic comma-shaped prominence, 82,000 miles high, which vanished from before his eyes by a withdrawal of light as sudden as the passage of a flash of lightning.” Since the study of these remarkable forms was rendered feasible by using a greater dispersion to open the slit of the spectroscope wide enough to see them, they have been made the subject of daily study and record. The results, so far as they have been investigated, show that the region of the Sun’s limb in which the prominences are most frequent reaches to some 40° on either side of the equator, which is somewhat greater than the area of sun-spot frequency. The chromosphere itself is probably of much the same character as the erupted prominences, and formed of little flames arranged thickly together like “blades of