776 Wisconsin Academy of Sciences, Arts, and Letters. 
was taken at a depth of six inches; of the soil of the south 
Iback strand at a depth of one foot. The same holes were used 
each time; they were covered carefully after each observation. 
The temperature of the air was taken one meter from the 
ground near the spot where the soil temperature of the back 
strand was taken; and the temperature of the air one meter 
from the surface at the same station in the center. Other rec¬ 
ords were kept for shorter periods at other points for com¬ 
parisons. General observations on the weather were also added 
each day. 
Water Temperatures. From June 30 to July 7 the open 
water outside of the zone of vegetation varied from 67° to 70°; 
for the next five days (July 9 to 14) it remained between 70° 
and 72°; from July 15 to August 9, over three weeks, it kept 
below 70°, the lowest record being 63°. From August 10 to 
22 there came a rise again to a maximum of 78%° (except 
for one day which registered Sl^ 0 ), and a minimum of 73°. 
From August 23 to September 1 the temperature did not rise 
again to 70°, nor did it fall below 63°. There was, then, a 
gradual rise the first part of July, followed by a fall, then a 
rise again to the maximum on August 20, and another fall in 
the latter part of the month to a point below the early July 
record. 
The water inside of the zone of vegetation was usually from 
■one to two degrees warmer than the water outside; occasionally 
the two records were the same. 
The acidity of the water was tested with litmus paper when 
temperature records were made. The first test, July 4, 
showed that the water inside of the zone of water plants was 
slightly alkaline, the water outside very faintly acid. From 
then on, the open water gave no reaction except a rare trace of 
alkali, while the inner water was occasionally so; but from 
the last of July to the end of the season both waters gave evi¬ 
dences of alkalinity every day. 
Soil Temperatures. The wet soil of the strand maintained 
■a lower temperature than the water just outside of it and it 
xesponded more slowly to changes in the air. For the first 
'week in July it ranged from 56° to 59° Fahrenheit; it then 
