( 205 ) 
this coefficient all but 
adopted and its fluctuations are certainly inconsiderable. 
I made use of the deviations of the monthly means from the values 
of a taken from the curve and I made the years begin with May. 
For the sake of brevity I will only give the mean results for 4 
groups, each of three years. In the last column the general means 
are set down. 
agrees absolutely with the value originally 
62—64 | 65—67 | 68—70 | T1—73 1862 —1873 
MAY f.5i +76) HM | +46; +99 + 48 
PORE were: + 4) +29; + 9} + 30 + 18 
duke ee +12; +20) — 9} +19 + 10 
August .... — 20} — 3] — 58] — 5 — 22 
September, — 26 | — 45 | —14| — 32 — 29 
October...| — 52] — 47 | —40 | — 45 — 38 
November.| — 10 | — 18] — 4[ — 55 — 22 
December. | — 30} — 8] —17 | — 20 — 19 
January...) — 9 | +1414} +14] + 1 + 5 
February | — 2| — 22} +54/ — 8 + 5 
March....| +18 {| + 6) +138); + 39 + 19 
Apel, +46) +143] +13 | + 52 + 31 
In each of the 4 partial results the supplementary inequality is quite 
evident. Its amplitude is of the same order of magnitude as in the 
period 1877—98. There appears to be no reason for assuming any 
change in this amplitude during the 12 years 1862—74. I theretore 
tried to represent the general means by a formula and it appeared 
that a pretty satisfactory representation may be obtained by a 
simple sine: 
T— Apr. 23 
Ag = + 08.0341 cos 2 x - 
565 
The sinusoïd corresponding to this formula, together with the 
points given by the observation is represented in Fig. 4. 
The differences between the observation and the curve, in thou- 
sandth parts of the second, are as follows : 
14 
Proceedings Royal Acad, Amsterdam. Vol. V. 
