occur in the figures relating to the light winds. The number of
days upon which the mean hourly velocity of the wind exceeds
twenty miles per hour remains fairly constant year after year.

As the greatest difficulty in connection with pumping sewage is
the influx of storm water in times of rain, it will be useful
to notice the rainfall at those times when the wind is at a
minimum. From the following figures (Table No. 13) it will be
seen that, generally speaking, when there is very little wind
there is very little rain Taking the ten years enumerated in
Table No. 11, we find that out of the 314 days on which the
wind averaged less than six miles per hour only forty-eight of
them were wet, and then the rainfall only averaged .l3 in on
those days.


TABLE No. 13.

WIND LESS THAN 6 M.P.H.

-----------+-------------+------------+--------+----------------------------------
Ref. No. | Total No. | Days on | | Rainfall on each
from Table | of days in | which no | Rainy | rainy day in
No. 11. | each year. | rain fell. | days. | inches.
-----------+-------------+------------+--------+----------------------------------
1 | 16 | 14 | 2 | .63 and .245
2 | 15 | 13 | 2 | .02 and .02
3 | 39 | 34 | 5 | .025, .01, .26, .02 and .03
4 | 36 | 29 | 7 | / .02, .08, .135, .10, .345, .18
| | | | \ and .02