NOCTURNAL RADIATION FROM PLANTS
SUNRISE Mean
Air Temp. 61.0 57.0 57.0 58.5 57.0 50.0 50.5 56.0 55.9
Barley 56 46 52 52 52 45 43 … 49.4
Diff. 5.0 11.0 5.0 6.5 5.0 5.0 7.5 … 6.4
Calotropis 56.5 48.0 … … … 45.5 … … 50.0
Diff. 4.5 9.0 … … … 4.5 … … 6.0
Argemone 57.0 50.0 50.0 … … … … 49.0 51.5
Diff. 4.0 7.0 7.0 … … … … 7.0 6.2
NINE P.M. Mean
Air Temp. 68.5 70.0 69.0 74.0 62.5 67.5 61.0 … 67.5
Barley … … … … 51.5 67.5 50.0 … 56.3
Diff. … … … … 11.0 10.0 11.0 … 10.7
Calotropis … 65.0 57.0 59.0 … 62.5 … … 60.9
Diff. … 5.0 12.0 15.0 … 5.0 … … 9.3
Argemone 56.0 67.0 57.0 … … … … … 60.0
Diff. 12.5 3.0 12.0 … … … … … 9.2
The upper course of the Soane being in some places confined, and exposed to furious gusts from the gullies of the Kymore hills, and at others expanding into a broad and flat valley, presents many fluctuations of temperature. The mean temperature is much above that of the lower parts of the same valley (below Tura), the excess amounting to 5.4 degrees. The nights and mornings are cooler, by 1.2 degrees, the days hotter by 10 degrees. There were also 10 degrees increase of range during the thirteen days spent there; and the mean range from day to day was nearly as great as it was on the hills of Bengal.
There being much exposed rock, and the valley being swept by violent dust-storms, the atmosphere is drier, the mean saturation point being .454, whereas in the lower part of the Soane's course it was .516.
A remarkable uniformity prevails in the depression of thermometers exposed to nocturnal radiation, whether laid on the earth, grass, or freely exposed; both the mean and maximum indication coincide very nearly with those of the lower Soane valley and of the hills. The temperature of tufts of green barley laid on the ground is one degree higher than that of short grass; Argemone and Calotropis leaves maintain a still warmer temperature; from the previous experiments the Argemone appeared to be considerably the cooler, which I was inclined to attribute to the smoother and more shining surface of its leaf, but from these there would seem to be no sensible difference between the radiating powers of the two plants.