243 
CLOUD OUTLINES. 
Second Paper — Forms of Cumulus. 
By Key. SAMUEL BARBER, F.M.S. 
I N a former article in the Popular Science Review , attention 
was drawn to the importance of a close examination of the 
outlines of the various forms of cloud, and the instances selected 
for observation were the “electric cumulus,” the “anvil” 
cloud, and the “ festoon ” cloud, these being among the most 
striking examples in respect to outline, and possessing at the 
same time considerable value as weather prognosticators. Un- 
fortunately the illustrations which accompanied that article 
were accidentally omitted, and sketches are therefore appended 
to the present paper for future reference. 
At the present time we propose to bring before our readers 
some other forms of cumulus of somewhat rarer occurrence, 
and for the most part attendant on unsettled weather. 
In the first place, then, we call attention to a form which 
may be denominated “ pyramid cumulus.” Strictly speaking, 
it should be “ inverted ” pyramid cumulus, as the point or apex 
is generally downwards toward earth, or inclined at an angle 
with the horizon. The mass of the cloud, which is often very 
irregularly shaped at the larger end, partakes for the most part 
largely of the character of stratus or nimbus, and the surface 
is often marked by sinuous lines, which radiate from the apex 
upwards (fig. 1). 
The cases in which I have observed this form of cloud have 
generally been during a thunderstorm, about its climax, or 
after the rain has begun to fall ; one of the most striking in- 
stances, from which the illustration was taken, occurred during 
a storm which discharged itself about thirty miles from the 
point of observation, near Liverpool. Like the ordinary elec- 
tric cumulus,* the pyramid cumulus sometimes rises to a great 
elevation, and is visible at a vast distance, when the lightning- 
may be seen darting and playing about its surface ; thus indi- 
* See sketch, p. 247 ; and “ Journal of Meteor. Soc.” January 1872. 
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