46 REPORT—1850. 
bably about 0-003 too great. These allowances being made, a close approximation 
to the truth will be arrived at. 
The mean temperature of the air for the period of my observations at Greenwich was 
39° 3’; on the Nile it was 61°. 
The medn temperature of evaporation at Greenwich was 37°4; in Egypt 55°: 
The mean temperature of the dew-point at Greenwich was 34° 1'; in Egypt 50°'8. 
The mean elastic force of vapour in Egypt was 0°384 ; at Greenwich 0-214. 
The mean weight of water in a cubic foot of ait in England was 3 grains; in 
Egypt 4,8; grains; but still, uwing to the higher temperature, the air was much 
drier in Egypt. At Greenwich the mean additional weight of water required to satu- 
rate a cubic foot of air was only τς of a grain, while on the Nile it was 13 grain, If 
we represent air completely deprived of moisture by zero, and air completely saturated 
as unity; the mean degree of humidity on the Nile was 75 per cent., while at Green- 
wich it was 85 per cent. 
The mean readings of the barometer in the two countries very nearly approach 
each other ; in Egypt beiig 29°99, at Greenwich 29°87. A glance at the Table, however; 
will show how very small the extreme range of the instrument was on the Nile. 
The average weight of a cubic foot of air at Greenwich was 549 grains; in Egypt 
527 grains. 
Rain fell in various districts of England on averages from thirty-one to sixty-one 
days ; while in Egypt it only fell on five days, and on three of these a shower was 
of aut a few tiinutes’ duration. On two days rain fell heavily at Cairo for several hours: 
The mean daily range of the temperature of the air at Greenwich was 11°37 ; in 
Egypt 10°31 ;- but while the mean extreme range in Egypt was 38, at Greenwich it 
was but 29, the mean extreme range in the cabin being only 7 degrees below that 
on the grass at Greenwich in the open air. 
Fog was occasionally but rarely observed. It was general in the Delta in the early 
morning, but above Cairo it was only observed on three occasions. 
On the Six Climates of France. By Dr. C. Martins. 
The author stated that France paitook of the climates both of cofitinental and 
séa-girt countries. He wished at present to consider six climatal subdivisions, viz.— 
1. the north-east or Vosgian; 2. the north-west or Séquanian; 3: that of the 
west or Armorican; 4. the south-west or Girondin; 5. the south-east or Rhoda- 
nian; 6, and finally, the Mediterranean or Provengal climate. Upon éach of these 
subdivisions he enlarged, detailing the features of the country, the rivers, mountain- 
ranges, sea-coasts, geological structure, differences of level, and state of cultivation 
in each case, with the prevailing aid most important features in the actual climate 
of each. Dr, Martins exhibited a map of France with these six regions distinguished. 
He stated that hitherto the labours of the meteorologists of Frahce had no chahhel 
of publicity at their command, but that a journal devoted exclusively to meteorology 
was about to be established. 
Mr. Follett Osler exhibited Papers containing Registers from his new Integrating 
Anemometer. A sheet of plain paper placed in the instrument under a registering 
pencil is moved forwaid by rotating hemispherical fans, at the rate of one inch for 
every ten miles of air that passes; this same pencil, having a lateral motion given 
to it by a vane, records the point of the compass from which the wind blows; and 
a clock hammer descending every hour, strikes its mark on the margin of the paper 
to express the time. Thus, in a single line, are given,—l1st, the length of the cur- 
rent; 2ndly, the ditection of it; and 3rdly, the time occupied in passing a given 
station marked hourly, or at any shorter interval that may be desired. 
