12) FE. Loomis—Results derived from an examination of the 
We thus see that in a period of fifteen months there were 
twenty-six cases in which a total rain-fall of eight inches in 
eight hours was followed by a total rain-fall of more than four 
inches in the next eight hours; there were sixteen cases in 
which it was followed by a similar rain-fall for a third period 
of eight hours; there were eight cases of a fourth period of 
eight hours; five cases of a fifth period; three cases of a sixth 
eriod; and one case of a seventh period of eight hours. 
hese rain-areas which succeeded each other in order of time, 
that these rain-areas had in all cases a proper movement of 
translation in the direction of the stations here indicated. In 
some cases this apparent movement resulted from a slight 
increase of precipitation in one part of an extensive rain-area, 
and a decrease in some other part. This remark will probably 
explain two or three of the cases in which the apparent move- 
ment of the rain-area was from east to west. In one case 
however, viz: October 19th, 1878, the rain-area did unques- 
tionably advance westward for forty-eight hours as shown on 
e average rate of motion of the rain-areas indi- 
cated by numerals in the table, is 20°7 miles per hour. 
This table shows that great rain-areas are seldom of long 
continuance. In twenty-three cases the same rain-area con- 
tinued for at least two periods of eight hours; in seven cases 
it continued for at least three periods; and in only two cases 
did it continue for more than three periods, that is, twenty-four 
hours. We thus see that rain-areas with a total rain-fall of at 
least four inches in eight hours, for eighty stations, seldom con- 
tinue for more than twenty-four hours, only two or three such 
cases occurring in the United States during a year. This fact 
seems to indicate that the causes which produce rain, instead 
of deriving increased force from the rain-fall, rapidly- expend 
themselves and become exhausted. This fact cannot be ex- 
plained by supposing that the vapor of the air has all been 
ake ems because these cases chiefly occur near the At- 
antic 
that movement to the air which is requisite to a precipitation 
of its vapor, become exhausted after a few hours exercise. 
Of the fifty-five cases included in the. table on p. 2, in 
twenty-seven cases the place of greatest rain-fall was on the 
Atlantic coast. But only one-fifth of all the stations are on 
