118 NEW PUBLICATIONS. 
Reduction of the Meteorological Observations made at the Royal Horticul- 
tural Gardens, Chiswick, in the years 1826-1869. By James 
GLAISHER, F.R.S., erc. (a Supplement to Vol. II. of the Journal of 
the Roy. Hort. Soc., New Series). 1871. 
The observations of temperature and rainfall for forty-four years are 
here reduced to easily-consulted tables, forming a most useful and valu- 
able addition to the sources of information on the climate of London. 
The first series of tables shows the mean temperature, calculated from 
three daily observations, and carefully corrected for every day of each 
will be found uniformly higher than those supplied by Mr. Glaisher for 
the ‘Flora of Middlesex’ (printed in Introduction, p. xxxvi.), whi 
were obtained by combining the registers kept at Somerset House, 
Epping, Lyndon (Rutlandshire), and the Royal Observatory. The mean 
of the forty-four years at Chiswick is 49°9°. In a second series of tables 
is presented the difference above or below the estimated mean temperature 
for every day in all the years, expressed by + and — signs. The great 
» o 
of temperature affect vegetation greatly, but they seldom occur alone. 
ecessary for the operation of open-air horticulturists to know 
markable changes from day to day, are very striking. ‘These extremes 
I 
A very important inquiry with reference to plants is the daily range of 
temperature. The actual degree of cold to which a plant may have been 
range for every day for forty-four years is exhibited. There is great 
variety in this respect. In the winter the range varies from 1° to 40% 
and in the summer it may even exceed this, “ being dependent on the dif- 
ferent directions of the wind, the more or less cloudy state of the sky; 
and the different conditions of the weather generally." Taking the aver- 
age of all the years, the smallest daily range is found on January 15th, 
and the largest on July 5th. ; 
e statistics of rainfall are equally full. The fall for each day, 
: 
month, and year is given, Th 
uent i 
re very unusual. Such falls are most fre- 
the day in the winter months a 
all recorded, 1:96 in., was in October, 
quent in July. The heaviest f. 
