806 _ The Beneficial Influence of Plants. [ December, 
Proceeding toward the mouth of the river (Jan. 16th), he 
makes the following additional observation: 
The Zambezi is very broad here (at Zumbo) but contains many 
inhabited islands. On the 16th we siept opposite one called 
Shibanga. The nights are warm, the temperature never falling 
below 80°, it was 90° Fahr. even at sunset. One cannot cool the 
water by a wet towel round the vessel.! 
Evidently the air was nearly saturated with moisture in the lat- 
ter locality, and this affords the only explanation of the evenness 
of the temperature here. 
In Australia the daily range of the thermometer is extremely 
great. The observations of Mrz W. S. Jevons? are of much 
interest, and we give an extract: 
In the interior of the continent of Australia the fluctuations in 
temperature are immensely increased. e heat of the air, as 
described by Capt. Stewart, is fearful during summer; thus in 
about latitude 30° 50’” S., and longitude 141° 18’ E., he writes: 
“The thermometer every day rose to 112° or 116° in the shade, 
while in the direct rays of the sun from 140° to 150°.” Again, 
“Ata quarter past three, P.M., on January 21st (1845), the ther- 
mometer had risen to 131° in the shade and 154° in the direct 
rays of the sun. * * * Jn the winter the thermometer was 
observed as low as 24°, giving an extreme range of 107°” From 
these data we are not surprised to hear him remark further on, 
that, “ The fluctuations of temperature were often very great and 
sudden, and were severely felt.” He says, moreover, “ It thus 
appears that even close to the ocean the mean daily range of the 
Australian climate is very considerable. It is least in the autumn 
and greatest during the cloudless days in spring.” After giving 
here a table of the seasonal variation of the rainfall in Australia, 
Mr. Jevons says that, “ It is plainly shown that the most rainy 
season of the year on the east coast is the autumn, that is, the 
three months, March, April, May. The spring season appears 
the driest, summer and winter being intermediate. 
Prof. Tyndall says :% 
Without quitting Europe we find places where, while the day 
temperature is very high, the hour before sunrise is intensely 
cold. I have often experienced this in the post-wagons of Ger- 
many; and I am informed that the Hungarian peasants, if 
exposed at night, take care, even in hot weather, to protect them- 
selves by heavy cloaks against the nocturnal chill. 
All this evidence should be sufficient to convince the most 
1 Livingston’s Travels, p. 575. 
2 Quoted by Tyndall, 
_ 8 Discourse on radiation through the Earth’s Atmosphere. 
