The whole phenomenon was highly characteristic. These great bands with the divergent striation might well be known as storm bands, from their almost invariable connection with the violent atmospheric movements to which they are most probably due. Plate 12 shows a much less dangerous variety of the same species, which is distinguished from it by the comparative absence of internal detail and by the curled ends. Clouds of this character have sometimes been called cirro-filum, but a comparison of the plates with the typical cirro-filum of Plate 7 will show that there is little resemblance; and the attendant weather is also in marked contrast, both of which facts imply a fundamental difference in the causes to which their features are due. Banded or ribboned cirrus is the name which they immediately suggest, and this may be rendered cirrus vittatus. This ends our survey of cirrus clouds. Any one who compares the plates so far given will see that they represent forms so diverse that it is impossible to avoid the conclusion that the conditions under which they are produced must differ not only in degree but also in kind. What those conditions are we have attempted here and there to suggest, but in no case can we feel that the explanation has been at all complete. In some cases, notably the last, we are face to face with such complicated details that it is hopeless to attempt to explain them in the present state of our knowledge. Fact upon fact must be accumulated until we can give their history from their earliest beginnings; and far more accurate and detailed knowledge of the attendant atmospheric conditions must be acquired before we can hope to rob such elaborate structures of their present mystery. This requires the co-operation of many eyes and many minds, and exact specific names must be an essential preliminary. Those which have been suggested in these pages are-- 1. Cirro-nebula, or Cirrus haze. 2. Cirrus excelsus, or High cirrus. 3. Cirrus ventosus, or Windy cirrus. 4. Cirro-filum, or Thread cirrus. 5. Cirrus nebulosus, or Hazy cirrus. 6. Cirrus caudatus, or Tailed cirrus. 7. Cirrus vittatus, or Band cirrus. 8. Cirrus inconstans, or Change cirrus. 9. Cirrus communis, or Common cirrus. FOOTNOTE: [2] The telescope with which these observations have been made is a 6·8-inch refractor equatorially mounted. CHAPTER III CIRRO-STRATUS AND CIRRO-CUMULUS