Noon 90.0 132 42.0 10.140 Noon 85.0 130 45.0 ...
Noon 86.0 138 52.0 ...
Noon 90.0 138 48.0 ...
---------------------------------------------------- Mean 87.6 133 45.8 10.140
AFTERNOON Time Temp. Black Bulb Diff. Phot.
3 p.m. 85.5 116 30.5 ...
3 p.m. 92.5 128 35.5 ...
3 p.m. 92.0 120 28.0 ...
3 p.m. 89.5 128 38.5 ...
3 p.m. 93.5 144 50.5 ...
---------------------------------------------------- Mean 90.6 127 36.6 ...
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, gra.s.s, 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 gra.s.s; _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.
IV. TABLE-LAND OF KYMORE HILLS (MEAN ELEV. 979 FEET), MARCH 3RD TO 8TH, 1848.
Hour Sunrise 9 a.m. 3 p.m. 9 p.m.
TEMPERATURE Mean 65.3 81.6 88.1 71.1 Max. 69.0 82.5 90.0 76.0 Min. 57.5 79.5 84.5 68.0 Range 11.5 4.0 5.5 8.0 WET-BULB Mean 57.7 65.3 63.3 60.3 Max. Depression 8.0 19.0 26.5 13.0 Min. Depression 6.0 14.0 21.5 8.3
Elasticity of Vapour .428 .468 .324 .433
DEW-POINT Mean 52.0 54.5 43.7 52.3 Max. 55.5 57.9 47.8 56.7 Min. 45.9 49.0 37.9 46.8 Max. Depression 14.1 33.0 46.6 21.9 Min. Depression 11.6 12.9 42.2 13.8
Weight of Vapour in cubic feet 4.710 5.000 3.417 4.707
SATURATION Mean .647 .421 .240 .542 Max. .741 .479 .295 .643 Min. .648 .344 .214 .491
Number of observations 4 3 3 4
Extreme variations of Temperature 32.5 degrees Extreme variations of relative humidity .527 Extreme diff. Solar and Nocturnal Radiation 110.5 degrees
NOCTURNAL RADIATION
SUNRISE Exposed Th. On Earth On Gra.s.s Temperature 59.5 56.0 54.7 Mean Diff. from Air 3.5 1.5 8.2 Max. Diff. from Air 3.5 1.5 8.5 Number of Observations 2 1 2
NINE P.M.
Exposed Th. On Earth On Gra.s.s Temperature 71.5 62.5 61.0 Mean Diff. from Air 3.3 5.5 8.2 Max. Diff. from Air 7.0 5.5 11.0 Number of Observations 3 1 2
The rapid drying of the lower strata of the atmosphere during the day, as indicated by the great decrease in the tension of the vapour from 9 a.m. to 3 p.m., is the effect of the great violence of the north-west winds.
From the few days" observations taken on the Kymore hills, the temperature of their flat tops appeared 5 degrees higher than that of the Soane valley, which is 500 feet below their mean level. I can account for this anomaly only on the supposition that the thick bed of alluvium, freely exposed to the sun (not clothed with jungle), absorbs the sun"s rays and parts with its heat slowly. This is indicated by the increase of temperature being due to the night and morning observations, which are 3.1 degrees and 8.5 degrees higher here than below, whilst the 9 a.m. and 3 p.m. temperatures are half a degree lower.
The variations of temperature too are all much less in amount, as are those of the state of the atmosphere as to moisture, though the climate is rather damper.
On the subject of terrestrial radiation the paucity of the observations precludes my dwelling. Between 9 p.m. and sunrise the following morning I found the earth to have lost but 6.5 degrees of heat, whereas a mean of nine observations at the same hours in the valley below indicated a loss of 12 degrees.
Though the mean temperature deduced from the few days I spent on this part of the Kymore is so much above that of the upper Soane valley, which it bounds, I do not suppose that the whole hilly range partakes of this increase. When the alluvium does not cover the rock, as at Rotas and many other places, especially along the southern and eastern ridges of the ghats, the nights are considerably cooler than on the banks of the Soane; and at Rotas itself, which rises almost perpendicularly from the river, and is exposed to no such radiation of heat from a heated soil as Shahgunj is, I found the temperature considerably below that of Akbarpore on the Soane, which however is much sheltered by an amphitheatre of rocks.
V. _Mirzapore on the Ganges._
During the few days spent at Mirzapore, I was surprised to find the temperature of the day cooler by nearly 4 degrees than that of the hills above, or of the upper part of the Soane valley, while the nights on the other hand were decidedly warmer. The dew-point was even lower in proportion, 7.6 degrees, and the climate consequently drier. The following is an abstract of the observations taken at Mr.
Hamilton"s house on the banks of the Ganges (below).
It is remarkable that nocturnal radiation as registered at sunrise is much more powerful at Mirzapore than on the more exposed Kymore plateau; the depression of the thermometer freely exposed being 3 degrees greater, that laid on bare earth 6 degrees, and that on the gra.s.s 1.4 degrees greater, on the banks of the Ganges.
During my pa.s.sage down the Ganges the rise of the dew-point was very steady, the maximum occurring at the lowest point on the river, Bhaugulpore, which, as compared with Mirzapore, showed an increase of 8 degrees in temperature, and of 30.6 degrees in the rise of the dew-point. The saturation-point at Mirzakore was .331, and at the corresponding hours at Bhaugulpore .742.
MIRZAPORE (ELEV. 362 FEET), MARCH 9TH TO 13TH, 1848.
Hour Sunrise 9 a.m. 3 p.m. 9 p.m.
TEMPERATURE Mean 61.1 76.1 86.0 76.0 Max. 63.0 83.0 ... ...
Min. 58.0 71.0 ... ...
Range 5.0 12.0 ... ...
WET-BULB Mean 48.8 58.5 61.7 63.5 Max. Difference 51.5 56.5 24.3 12.5 Min. Difference 47.0 51.7 ... ...
Elasticity of Vapour .236 .302 .295 .480
DEW-POINT Mean 34.3 41.9 41.3 55.2 Max. 39.7 ... ... ...
Min. 29.7 ... ... ...
Max. Difference 32.8 52.3 44.7 20.8 Min. Difference 23.8 15.7 ... ...
Weight of Vapour in cubic feet 2.574 3.271 3.089 5.127
SATURATION Mean .405 .324 .264 .511 Max. .450 .603 ... ...
Min. .327 .176 ... ...
Number of observations 3 3 1 1
TERRESTRIAL RADIATION.
Mean Air in Shade. Sunrise 60.0 62.5 63.0 58.0 60.9 Exposed Th. 55.0 54.5 55.5 53.0 54.6 Difference 5.0 8.0 7.5 5.0 6.4 Exposed on earth ... 56.0 50.5 54.0 53.5 Difference ... 6.5 12.5 4.0 7.7 Exposed on gra.s.s 52.0 52.5 50.5 50.0 51.3 Difference 8.0 10.0 12.5 8.0 9.6