148 
ON THE PERIODIC AND NON-PERIODIC VARIATIONS 
deduced by a similar process at Konigsberg by Bessel, at Paris, Turin and Padua b\ 
Kamtz, at Berlin by Madler, and at Prague by Fritsch and Jelinek, are collected 
by the last-named meteorologist in his memoir ‘‘ On the daily march of the principal 
meteorological elements deduced from hourly observations at the Prague Observa- 
tory,” published in the Transactions of the Imperial Academy of Sciences at Vienna 
in 1850, and are as follows : — 
Days on which, the mean temp, 
of the year is passed through. 
Maximum. 
Minimum. 
April 21 
Konigsberg . . . 
. x4ugust 1 
January 9 
October 20 
Berlin (18 years) 
. July 18 
January 19 
April 19 
October 21 
Berlin (92 years) 
. July 22 
January 12 
April 17 
October 16 
Prague (8 to 9 years) 
. July 24 
January 26 
April 16 
October 20 
Prague (76 years) 
. July 23 
January 19 
April 15 
October 18 
Paris 
. July 28 
January 15 
April 18 
October 19 
Turin 
. July 27 
January 3 
April 18 
October 26 
Padua 
. July 26 
January 15 
April 20 
October 15 
These may be compared with the corresponding epochs at Toronto, as derived 
respectively from the six-years and the twelve-years seiies discussed in this paper. 
Toronto (1842, 5 to 1848,5) July 28 February 14 April 19 October 15 
Toronto (1841 to 1852) July 28 February 12 April 25 October 17 
The anomalous character of the North American winter, so visible in the Chrono- 
Isothermal Plate, is also marked by the very late occurrence of the epoch of the 
TtiinimuTn temperature, and the great dissimilarity in that respect fiom all the other 
stations. The systematic character of this anomaly is further shown by the fact, that 
every hour in the twenty-four has its minimum temperature between the 7th and 17th 
of February; the minimum occurs earliest, viz. on the 7th of February, at the hour 
of 2 p.M. ; the minima of the hours of the night, or from 9 p.m. to / a.m. inclusive, 
fall the latest, viz. on the 15th, 16th and 17th of February ; those of the intermediate 
hours on the intermediate days and in regular progression. The hours from 6 a.m. to 
9 P.M. inclusive, or those of the day, have their maximum temperature between the 
20th and 30th of July ; those of the night, or from 1 1 p.m. to 5 a.m. inclusive, from 
the 3rd to the 12th of August. The portion of the twenty-four hours which is 
warmer than the mean temperature of the day varies considerably at different 
seasons ; in part of November there are fourteen of the observation hours colder, and 
only ten warmer than the mean temperature of the day ; in the greater part of July 
twelve of the observation hours are colder and twelve warmer ; and in all the rest of 
the year thirteen hours colder and eleven warmer. This is seen in detail in Table III. ; 
the dark lines which separate the additive from the subtractive corrections pass 
between the hours which are above and those which are below the mean temperature 
on every fifth day of the year. On the average of the whole year the mean tempe- 
