AUGUST 27, 1897.] 
seen falling below those portions of the cloud 
which showed the most lofty tops. These extra 
heavy rains were seen falling in three places 
under the main mass of the cloud, and over 
each of these places the height of the cloud 
was noted as being especially great. While 
watching this cumulo-nimbus it was noticed 
that to the south of it there were some cumulus 
clouds developing rapidly into cumulo-nimbus 
and becoming part of the same cloud as that 
first observed. In this way the storm-front was 
seen to be extending itself gradually farther 
and farther to the south, new cumulus clouds 
continually developing into cumulo-nimbus and 
joining themselves to the parent storm-cloud. 
Thus, in an hour, more or less, a long storm- 
front was developed, extending with a N. EH.- 
S.W. front across the greater part of the western 
sky. The movement was tothe N. E. Careful 
observation of the storm-front showed distinctly 
the centers of extra heavy rainfall and the 
lighter portions in between these centers. In 
these lighter portions either no rain or light 
rain was falling. 
At sunset on June 18th, in the 8. E. trade 
(noon position, 0°16’N., 38°47’W.), some obser- 
vations of degrading cumuli were interesting. 
The afternoon sky was fairly well covered with 
trade cumuli, some of the clouds almost reach- 
ing the cumulo-nimbus stage. Just after sunset 
careful observation of these clouds showed them 
dissolving and toppling over in a very striking 
manner. The clouds were in shadow, and 
were clearly outlined against the bright sunset 
sky behind them. The process of disintegra- 
tion was of two kinds. In the first the top of 
the cloud, bending forward in the direction of 
the prevailing wind, simply toppled over to the 
northwest, breaking off, so to speak, at the 
point where it joined the main cloud mass. 
The upper part, after toppling over, quickly 
evaporated, and a long line of trade cumulus 
would thus lose their typical form and become 
flattened out into a long band, which, in time, 
also broke up and faded away. In the second 
kind of disintegration the shape of the top of 
the cloud remained unchanged during the pro- 
cess, the cloud particles simply dissolving as 
they kept their position with relation to the 
cloud base. Thus, in a few minutes, only the 
SCIENCE. 
325 
skeleton of the top of the cloud was left, and 
this also soon evaporated, leaving, as in the 
first process, a long flat band of cloud. The 
two processes were quite distinct, although they 
were both processes of disintegration. In ex- 
planation of these phenomena, it appeared that 
the second kind of disintegration occurred only 
when the clouds were large and well devel- 
oped, 7. e., where the supply of water vapor 
from below was probably still active, and the 
effect of the faster-moving upper air in blowing 
forward the top was not so strong in conse- 
quence. For this reason, the cloud kept its 
shape well, dissolving without being toppled 
over, while in the first case the cloud was 
probably in a stagnant condition, and its top 
offered less resistance to being blown over. 
In conclusion, a few directions of cloud 
movement may be of interest, although com- 
ment on them is omitted by reason of lack of 
time at the present writing. 
June 10. Lat. 26°58’N., Long. 55°417W. 
Cirro-stratus from N.W. June 11. Lat. 23° 
45/N., Long. 52°30’W. CirrusfromS. W. June 
13. Lat, 16°35/N., Long. 47°34/W. Low fracto- 
cumulus from E. N. E. (wind direction); alto- 
cumulus from N.E. June 17. Lat. 3°29/N., 
Long. 40°44’W. Cirro-cumulus from E.; cumu- 
lus from 8. E. (wind direction). June 18. On 
equator. Cirrus and cirro-cumulus from E. by 
S. June 19. Lat. 2°42’S., Long. 36°43/W. 
Cirro-stratus from E. by S. 
R. DE C. WARD. 
BUENOS AYRES, July 14, 1897. 
SCIENTIFIC LITERATURE. 
Travelsin West Africa. By MARY H. KINGSLEY. 
The Macmillan Co. 1897. 16 plates, 29 il- 
lustrations in the text. Pp. xvi. + 743. 
Cloth $6.50 
An interesting book in spite of some defects. 
It takes Miss Kingsley 120 pages to get settled 
down to the subject of her ‘beloved southwest 
coast ;’ and the 400th page is passed before you 
reach the valuable portion of the book. 
There is little, past, present, or even future, 
in connection with West Africa that does not 
get a touch from her facile pen. There is how- 
ever an easy flippancy of manner in the story 
