E. Loomis— Contributions to Meteorology. 9 
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regions where the rain-fall does not much exceed 10 inches. 
Some change has been made in the East Indian Archipelago 
required by the three years’ observations of Dr. Bergsma. The 
changes in Central Australia are explained by the fact that 
when I prepared my former chart, the observations which were 
available were few in number and most of them included a 
period of only one year. The observations since received 
appear to indicate that throughout the whole interior of Aus- 
tralia, the average annual rain-fall is less than 10 inches. In 
Central Africa the present chart shows a greater rain-fall than 
the former one. Some of the changes are based upon new 
observations, and others have been made in deference to the 
judgment of my critics. 
_ It is hoped that this revised rain-chart may be found less 
imperfect than the preceding. I do not expect, however, that 
tt will be found perfect, and I urgently renew the request con- 
tained in my former paper that if any person whose attention 
is attracted to this map should discover in it serious defects, 
he will communicate to me the observations which indicate 
these defects, I propose hereafter to publish all additional 
observations of rain-fall which I may be able to obtain, so far 
as they indicate the necessity of changes in the present rain- 
chart, and if this chart should be found greatly in error, 
intend to issue a revised edition of it. 
Relation of rain-areas to areas of low pressure. 
In former papers I have examined the cases in which a‘rain- 
fall of two inches in eight hours has occurred at any of the 
Stations of the U. S. Signal Service, and also the cases in which 
the aggregate rain-fall at all the stations was unusually great. 
This examination has shown a marked difference between the 
effect of a great rain-fall in the northern and southern portions 
of the United States. South of the parallel of 36° we find that 
of observations, but especially because there are very extensive 
inch 
*Ppear to be always under the influence of an area of low pres: 
ure. The average distance of the principal rain-centers from 
