Pressure and Temperature Results for the Great Plateau. 245 
(M—), the number of times the maximum temperature has fallen 
short of the mean maximum temperature of the day ; 
(M+), (m=), (m-—), the number of times respectively upon 
which the minimum temperature has exceeded, equalled, or 
fallen short of the mean minimum temperature of. the day; 
In the next six columns M, and m, give values of M and m in 
trihemera, the values entered opposite January 3rd, for example, 
being the mean values for January 1, 2, 3; 
P, the mean barometric pressure of the day, reduced to mean low- 
water sea-level, from readings taken at IX. and XV. o’clock 
INGE: 
MP, the highest pressure observed upon the date in ten years ; 
mP, the lowest pressure observed ; 
P,, MP,, mP,, trinemerial values of P ; 
(P+), (P =), and (P—), the number of times upon which the 
pressure was respectively above, equal to, or less than the mean 
pressure of the day. 
Tables 13-24 give the corresponding Kimberley temperatures 
for the same period; but the Kimberley barometric pressures are 
available for eight years only, commencing in 1890. These are for 
the hours VIII. and XX. C.M.T. 
Monthly and yearly summaries of Tables 1-24 are given in 
Table 20. | 
The successive values of M), M,, a m,, and m are 
depicted in Fig. 1, for both Durban and Kimberley ; and of MP,, P,, 
and mP, for Durban in Fig. 2. In Fig. 2 also the curve P,, only, for 
Kimberley is drawn below that for Durban and to the same scale, 
but plus 3-9 inches. 
The mean pressure curves of the two places are practically 
identical in shape, the mean daily differences being something 
over 4 inches throughout the year with certain minor periods of 
approach and recession to be more fully referred to later on. 
The variations from the mean curve are, however, much greater 
at Durban, the extreme range in the eight years, 1890-97, being 
from 29°518 inches to 30°801 inches, 2.e., 1:°283 inches, as compared 
with an extreme range at Kimberley from 25:665 inches to 
26°508 inches, 7.e., 0°843 inch. The Durban readings, however, 
are timed to give almost the greatest range possible. Readings 
taken at Kimberley at IX. and XV. would give a mean daily range 
of about 0:04 inch more than those taken at VIII. and XX., and 
most likely an extreme range considerably greater. 
The principal general differences between the temperature curves 
