TRANSPIRATION UNDER CONTROLLED CONDITIONS. 59 
a lessening in the rate of decrease but not by an actualincrease. The occur- 
rence of the maxima of actual and of relative transpiration was 4 and 6 
hours, respectively, before the time of maximum evaporation for the day. 
No. 7 behaved differently in that its maximum of actual transpiration coin- 
cided with the maximum for evaporation and no tendency toward a break 
in the acceleration appeared. The maximum for relative transpiration 
occurred four hours earlier than the transpiration maximum, and while a 
TaBLE 24.—Transpiration under three different evaporation conditions. Experiment X XI. 
Plant No. 6. | Plant No. 7. 
Date. Time. E ae ao os Temper: Humidity. Remarks. 
Po ae Ps ae 
! oF, p.ct. 
Aprill...) 7808 p.m. | .... |... J eee See eres ae bse Cloudy. Wind high, 
leaflets open. 
April 2...) 6 30 a.m. | 1.99 | 0.07 | 0.035 | 0.05 | 0.025 | 64.5 60 
9 03 a.m. | 2.28 24 | .105 | .2 105 | 66 58 Sunlight intermittent. 
< Leaflets, 35°. N> 
change in conditions. 
10 05 a.m. | 3.37 47 | .189| .49 | .145 67 57 
11 05 a.m. / 4.52) .387 .086| .55) .122 68 55 
12 05 p.m. | 4.58| .37) .081 .58 | .127 72 50 Do. 
2 20 p.m. | 5.44 31 .057 | 60 110 72,5 50 
3 55 p.m. | 4.97} .28| .056] .29| .058 mates 48 Do. 
*7 15 p.m. | 4.28} .20| .047|) .24| .056 “ite ae 62 Dark at close. 
Aprile’s. |) 6) -4B sate) csssee || osteo I os cares fees | gras nse : a6 
8 10 a.m, | 2.11 18} .085 | .18| .085 53 50 
9 05 am. | 2.21) .89|) .176) .32) .145 61 48 Leaflets about 20° apart 
L. after 7 a.m. 
10 05 a.m. | 2.48 40 161] .41 165 70 46 Sun bright and air almost 
still all day. 
11 05 a.m. | 3.19 35) .110| .55) .172 73.5 42 
12 05 p.m. | 3.80 44) .116) .61 161 79 40 
1 30 p.m. | 4.53 44) .097| .66| .146 88 35 
«2 85 p.m. | 4.58 44) .096| .63| .138 88 35 
4 15 p.m. | 4.52 39 | .086| .55 | .122 36 
pista 7:15 p.m. | 3.02 38 | .126/ .29| .096 77 38 s bright all 4 
rill... Sun__ brig a ay. 
P 6 36 am.|....|.... | ..... sf: | eats faa Ra Moist chamber pro- 
8 03 am. / 1.47, .03} .020)] ....] ..... aalt ae tects plant and atmom- 
9 06 am. [1.15] .01| .009]....]..... 55 70 cheb hon fall torse'ot'a 
10 03 a.m. | 1.26 08 OBS! |) esse. || 3 arate 55 80 strong wind 
11 04 am. | 1.49] .12] 081] ....) 2... 56 80 Leaflets 160° apart until 
7 4 p.m., after which 90° 
apart. 
11 59 am. {1.31 / .12 092) | urns Pc crnzn 58 85 
12 58 p.m. | 1.40] .14 LOO! | cares | anaes 58 80 
2 08 p.m. | 1.40| .17 DOE si s55.7| a au 65 75 
4 07 p.m. {1.05 ) .10 O95 | oeccie. |i dusteuaye 65 50 
: 7 30 p.m. | 3.98 | .19 Cg eee eer 70 50 
April ll... 7 45 am. jo... | ws. | ee eee ee ee alps ‘ts A r 
8 55 a.m. | 4.96] ....]..... -50 | 101 71 35 Sun bright and wind ve- 
: locity very high all day. 
9 49 am. | 4.10] ....]..... .63 | 154 72.5 32 
10 57 a.m. | 5.48) .... | ....- 75 | 138 74 30 Leaflets 10° to 15° apart 
during period of experi- 
ment. 
| 11 53 a.m. | 5.68] ....) ...-. 82) 144 80 27 
12 52 p.m. | 5.91 82 | .139 83 24 
2 00 p.m. | 6.04 90} .149 83 22 
4 00 p.m. | 5.86 87 | .148 81 22 
7 27 p.m. | 3.58 SL | £142 23 
drop and rise occur in these rates it will be seen from a comparison with 
the transpiration and evaporation rates that they are caused by a decrease 
in the evaporation rate which is not followed by the plant, and hence that 
this dip and rise are in no sense the kind under investigation in this paper. 
The intermittent cloudiness of April 2 made it advisable to repeat the 
experiment on a clear day, and consequently this was done on April 4. 
