TRANSACTIONS OF THE SECTIONS. 45 
Observations on the Climate of the Valley of the Nile. 
By T. Spencer Wetts, F.R.C.S., Surgeon Royal Navy. (Presented by 
the Marquis of NorTHAMPTON.) 
The following observations are only to be regarded as an attempt to determine in 
some degree the nature of the climatal influences to which an invalid is subjected 
during a winter voyage up the Nile. 
The observations extend from the 6th of December 1849 to the 16th of March 1850. 
The instruments were kept in a cabin in the boat of aninvalid. The cabin was 6 feet 
high, 12 feet broad, and 10 feet deep. Its floor was from 1 to 2 feet above the level 
of the river. The dry- and wet-bulb thermometer, and the barometer were fixed to 
a beam in the centre of the cabin, where they were not exposed either to the direct 
or reflected rays of the sun. There were six glass windows to the cabin, provided 
with open blinds. Some of these windows were always open during the day, so that 
the morning and afternoon observations may be considered to represent the tempe- 
rature of the open air in the shade. Sometimes a window was open until after the 
evening observation ; but more frequently this was not the case, and to this is ascribed 
the fact that the mean of the evening observations is above that of the morning. A 
register night thermometer was fixed outside one of the windows, and the lowest 
temperature observed each day is recorded. The barometer used was an aneroid, 
corrected by a standard instrument at Cairo. Three daily observations were made at 
the hours of 9 a.m., 3P.M.,and11 p.m. The following Table is an abstract of these 
daily observations :— 
and moist-bulb thermometers, 
tions of register thermometer. 
Maximum, dry-bulb thermometer. 
Minimum, dry-bulb thermometer. 
Minimum, register thermometer in 
Mean of three daily observations. 
Mean of minima by register ther- 
Mean temperature of evaporation, 
Extreme range, includiug observa- 
Mean daily range of dry-bulb ther- 
Number of days on which rain fell, 
ἐ = i 
te = ia ae 
3 Ξ ΞΕ. ὃ 
Ξ 4 EI Ξ 
3 aan ell (Sonesta Ol 
Date. 95 ὁ 55 3| 5 2 
; s2 8] ἐξ els]s 
5.5 | 8 /€2 8) 8 |2s Hy be elles 
3 = Fe ῷ 33,5 18 (88 | 3 τ 
& Ξ 3 a] a ails Εἰ Ὁ 3 ῷ ἕξ 
Ξ Ξ S = = Ξ ok Ξ Ξ ΠῚ 
aa ὃ 8] ὃ δ8ΞῈ 8/28 2/8 [ΞΕ z/ 8 | 3 
a Ξ Ι ΘΙ oe || =) i 
Dec. 6/31 25 [80 
ec. in. in. 
to31.| to io | 69|52|40|61/45|57| 8 2 | 4/f7/29! §30/ 30-1310-47| 5 
23 50 |31 | 
Jan. ... 28 50 [31 | 
to |to ὁ] 77, 4837. 6045 5414 3 | 6 |29] 40/ 10-02] 29-86) 0-55 
24 10 |33 
Feb. ...|24 20 [33 
to |to $}74|50/35| 61) 44/54/16! 4 | 7 | 22139] 10-03] 29:94 0-80 
26 50 [81 
Mar. 1 
to 16.| 26 50 |31...| 76/54/38) 62/45|55/12| 4 7 | 22138] 10-31] 30-06] 0-38] 2 
In order to judge of the advantage to be gained by an English invalid by passing a 
winter in Egypt, a comparison will be made between the results recorded in the above 
table, and those published in the returns of the Registrar-General from Mr. Glaisher’s 
reports, premising that the winter in Egypt was universally acknowledged by the natives 
to be the most severe they had suffered for many years. The laws of diurnal variation for 
England having been ascertained, the means published by Mr. Glaisher must be ac- 
cepted as correct, but this law for Egypt is not yet known. It is probable, however, 
that the means, according to my mode of calculation, are rather too high, perhaps 
from 1 to 2 degrees of the dry-bulb thermometer, and from half a degree to a degree 
of the temperature of the dew-point, The recorded atmospheric pressure is also pro- 
