1914] Sumner, et al.: Physical Conditions in San Francisco Bay 45 
Golden Gate, and making hourly observations throughout an entire 
tidal eyele. In figure F, representing the observations of May 14, 
1912, it will be seen that the temperature of the surface water com- 
menced to rise at about the change from flood to ebb tide, until it 
5 
6 
7am 6 9 em Ipm 2 3 4 
Fig. F. Temperature readings taken at a point between Alcatraz Island 
and station H-4967, at hourly intervals, during one complete tidal cycle, on 
May 14, 1912. The continuous line is based on surface figures, the broken line 
on bottom ones. 
reached a point 2° higher than at any time during the flood. For 
the bottom water this tendency was much less regular, though the 
mean figure for the ebb was 0°18 C higher than the flood. Table 10 
is a complete record of these observations. 
TABLE 10 
HYDROGRAPHIC OBSERVATIONS NEAR GOLDEN GATE, AT STATION 5128, DURING ONE 
TipAL CycLr, May 14, 1912 
Temperature 
Current, A — Salinity 
Hour Phase of knots per Fahr. Cent. Fahr. Cent. 
A.M. tide hour Surface Surface Bottom Bottom Surface Bottom 
7:00 Flood 1.33 52.6 11.4 54.4 12.4 26.91 29.50 
7:55 Flood 2.63 54.0 12.2 54.0 2.2 28.79 29.34 
8:55 Flood 2.27 53.8 12.1 53.8 12.1 29.50 30.11 
9:55 Flood 2.00 53.7 12.1 53.8 12.1 30.28 30.37 
10:55 Flood 1.33 53.6 12.0 53.7 12.1 29.80 30.59 
11:55 Flood? 0.40 54.2 12.3 54.7 12.6 29.65 30.63 
P.M. 
12:55 Ebb? 1.59 54.7 12.6 53.8 eal 28.79 30.28 
1:55 Ebb 2.00 56.0 13.3 53.9 12.2 27.33 28.47 
2:55 Ebb 2.23 56.0 13.3 54.3 12.4 26.67 29.65 
3:55 Ebb 1.55 57.5 14.2 54.2 12.3 25.92 28.88 
4:55 Ebb 1.01 57.5 14.2 54.9 12.7 25.46 28.72 
5:55 Ebb® 0.66 57.5 14.2 55.2 12:9 25.00 28.56 
1 Ship began to swing about. 
2 Commencing ebb. 
8’ End of ebb (?). 
