297 
to be entirely accidental. Several of these may be traced, for example, 
in each of the four decennial periods into which the series may be 
divided. These are called Aperiodic anomalies and their occur- 
rence has previously been announced by De Humboldt, Arago, M. 
Quetelet, and others. 
The most conspicuous of these anomalies occur in December, 
January, and February. An irregular elevation of temperature 
usually happens in the two middle weeks of December, followed 
early in January by an accession of cold, which accelerates the epoch 
of lowest temperature by at least a week, when we compare it with 
the geometric curve. This is again succeeded, in the latter part of 
January and beginning of February, by a period of comparative 
warmth. These anomalies seem to obtain at least over a great part 
of the v/est of Europe. 
The author gives the name of £; fluctuation” to the variation in 
the temperature of a given day of the year, from one year to 
another, arising from causes purely local and temporary, or, as we 
may call them, accidental. By applying the calculus of probability 
to the forty years’ observations, we might assign the iC probable 
uncertainty” in the determination of the temperature of any given 
day. The author has, however, confined himself to noting the 
highest and lowest mean temperature on a given day which has 
occurred during 40 years. These differences are sometimes very 
large. But they vary from one season to another according to a 
well-marked law. The “ fluctuation” is greatest in January, when 
it amounts to 28° or 29°, and least in July, when it is only 16° or 
17°. On the contrary, the diurnal range or difference of the 
maximum and minimum reading in 24 hours is least in December 
(9°*5), and greatest in June (18°). 
Section Seventh . — The author concludes the paper with a com- 
parison between the meteorological character of the seasons for fifty- 
six years, and the price of oats in the Edinburgh market for the 
same period, which was obligingly furnished to him by Mr Lawson. 
He has been quite unable to trace any connection between these 
classes of facts, and he recommends the subject to the consideration 
of those who are now occupied in considering the bearings of meteor- 
ology upon agriculture. When the seasons from 1795 to 1850 are 
arranged according to the price of oats, their order bears no intelli- 
gible relation to one or any of the previous classifications of those 
