66 



THE NATURE BOOK 



The example of cirro-cumulus shown 

 on }iage 65 is from a photograph taken 

 at South Kensington on July 13th, 1907, 

 at 10.50 a.m. Here we see the globular 

 masses covering the north-eastern part 



was pointed in practically the same 

 direction — namely, north-east — for both 

 exposures. 



In the photograph on this page it 

 will be seen that the clouds at this time — • 



ALTO-CUMULUS CLOUDS. 

 Photographed at South Kensington, May 10, 1907, at 11,33 a.m. 



of the sky, and with some tendency to 

 form into lines. 



The next type of cloud in order of 

 descent is the alto-cumiiliis, moderately 

 large globular masses, white or greyish, 

 partially shaded, arranged in groups or 

 lines as the cirro-cumulus, and often 

 so closely packed together that their 

 edges become confused. A good instance 

 of this type is shown in the next two 

 illustrations, which illustrate a most inter- 

 esting transformation of cloud form, both 

 specimens of which come under the alto- 

 cumulus heading. The photographs were 

 taken at South Kensington on ^Iay loth, 

 1907, with an interval of forty-two 

 minutes between them, and the camera 



11.33 3-m. — formed themselves in parallel 

 lines, the globular masses in each line 

 being practically welded together. This 

 condition of things was the same all over 

 the sky in that quarter of the heavens. 

 At 12.15 the whole of this series of lines 

 had broken up into separate masses, as 

 will be observed in the succeeding illus- 

 tration. It will be noticed that the 

 lines are still fairly maintained, only their 

 direction is not quite the same as that 

 indicated in the previous illustration. 



The form of cloud which must be 

 described next — namely, the alto-stratus — 

 is not here illustrated, as not only is it 

 uninteresting from the photographic point 

 of view, but its description defines it 



