SECOND RECORD OF OSCILLATIONS IN LAKE LEVEL, 
WITH RECORD OF LAKE TEMPERATURE AND OF 
METEOROLOGY, SECURED AT THE MACBRIDE 
LAKESIDE LABORATORY, LAKE OKOBOJI, IOWA, 
JULY, 1916. 
JOHN L. TILTON. 
In the “Proceedings of the Iowa Academy of Science’ ’ for 
1916 may be found a somewhat similar title for a paper in which 
data obtained in July, 1915, were discussed. It is the purpose 
of the present paper to present the records of a second year. 
These records were- obtained in part for personal information, 
and in part for reference by students at the laboratory. It is 
believed that the records (and also those of last year) are suffi- 
ciently accurate for use by those studying the limnology of the 
lake and possibly by those who may work on the heat budget. 
The 'computations of volume, given in the last paper, are here 
omitted. Unfortunately it was not convenient to obtain records 
the fifteenth of August, nor near that date, the time preferred 
for such records. 
Since from data previously obtained it was evident tidal ef- 
fects and changes in level due to changes in barometric pres- 
sure were not appreciable near the laboratory, all discussion of 
such data is omitted from the present paper. Only a part of the 
record of meteorology is here given, and that part is largely 
presented by diagrams. Wind direction and general velocity 
were noted, and data used in connection with oscillations in lake 
level, but they are not given separately in this report. 
APPARATUS. 
To ascertain the temperature at different levels in the lake a 
Leeds and Northrup “Electrical Resistance Thermometer” was 
at first used (see records of lake temperatures for June 28 and 
July 18) with excellent results; but on July 25 the lead cable 
sprang a leak, preventing further determinations by means of 
that instrument. Recourse was then had to a minimum ther- 
mometer held in a horizontal position, as extemporized the pre- 
vious year. To determine whether the pressure of water in the 
3 
