92 THE HABITAT 
Koelera-Andropogon-psilium 
April 25, 1901. Clear. South wind. 
WATER- 
TEMPERATURE LIGHT HUMIDITY CONTENT WIND 
TIME P.M.| 3:20 | 3:24 /3:30/3:35/3:40...... Ruaive 3:45 | 3:55 % 2:40 | 8:05 
STATION |14¢ m.|Surf.| 5 | 10 | 15 |14g m.| Surf.!14g m.|Surf.} 5 | 10 | 15 |114 m| Surf. 
1......e.| 27.8 | 29.6 ]17.8/15.8/10.9]......]..... 57 | 59 |17.7/14.6/17.4| 740 | 280 
Drs iat ...| 26.5 | 31.3 |18.3/16.6/12.8!...... veee{ 59 | 59 |17.9|12.2/14.3] 1100 | 510 
Be. seeae-| 26.9 | 28.5 [18.9/14.2/13.5]....../. 0... 58-| 59 |16.5/16.9119 | 980 | 520 
Bioko acne 26.2 }30 |16.8/13.2/11.6)......|..... 63 | 66 |24.4/21.3124.8] 920 | 460 
Bissceeee| 28 | 32.4]18.6]14.6/14.9]......]..... 59 | GO |10.7/17 |17.2] 1080 | 490 
6:......./ 28 |40.8/23.8116 15 |....../.:...] 51 | 51 | 5 | 8.3]10.3] 1010 | 410 
Mean ye 26.4 /30.8|16 |13 11 |......]... ..| 68 | 70 [27 |24.3)21.4, 680 | 52 
Quercus-H icorta-hylinm 
April 20,1901. Clear. Southeast wind. 
WATER- 
TEMPERATURE LIGHT HUMIDITY CONTENT . WIND 
Bins 10:40 |10:46/10 :50/10:55}11:00} 12:00 |12:05] 11:10 [11:20 4 11:30 11:45 
ae 1144 m.|Surf| 5 | 10 | 15 |12¢ m.|Surf.[134 m.|Surf.| 5 | 10 | 15 |114 m,) Surf. 
1...../16 |25 | 9.6| 8.4] 7.81! .08 | .o6| 73 | 81 |24.2/19.2/19.5| 208 | 0 
Dos ek 16.2 |30.5| 8.5] 8.4] 7.8! .11 | .09 | 73 | 86 !22 Jjo2.5/19.4'.375 | 2 
3,....| 16.2 |17.8] 7.6| 7.8] 8 08 | .06| 73 | 95 |22.1/20.4|21.6| 640 | 6 
sci 15.6 |26.2/10.6} 8.4] 8.2] .06 | .03 | 81 | 95 |95.4|23.1/22.4) 275 | 12 
5.....| 17.6 |25.4| 7.6] 7.4] 7.2] .03 | .02| 90 | 95 |27.2|19.8118.8) 178 | 2 
6.....| 16.2 |20.2] 8.41 7 | 6.2] .02 | .01 | 32 | 90 |27.6/20.8/18.8) 115 | 4 
WT opsnty, 15.8 |17.2|' 6.4] 6.4] 6.1] .05 | .04| 82 | 90 {23.8119 19.3] 60 | 0 
METHOD OF ECOGRAPH BATTERIES 
136. A battery of recording instruments..consists of a selagraph, a psy- 
chrograph, and a thermograph, to which an anemograph is added when pos- 
sible. As stated before, the determination of water-content by the geotome 
method is more satisfactory than by any automatic instrument yet devised. 
When the base station is located where the sunlight is unobstructed, which 
should be the case whenever possible, it is tnnecessary to include a selagraph 
in those batteries placed in similarly exposed stations, since the light values 
will be the same. As a rule, batteries are established within different zones 
or different habitats, except where a highly diversified habitat is made the 
subject of special inquiry. Such a restriction arises from the fact that ex- 
pense, care of operation, etc., place a limit upon the number of batteries, 
