56 REPORT—1840. 
the constancy or inconstancy of climates from ancient times to 
the present*, would do well to recollect that their criteria are 
almost all drawn either from extreme temperatures, or from the 
facts of botanical geography, neither of which give true indi- 
cations of the mean annual temperature of a climate. 
48. From various remote regions we continue to receive in- 
teresting reports of the mean temperature, which seem gene- 
rally to be more carefully and consistently made than in stations 
of easier access. It is indeed surprising, in how few points of 
the civilized parts of Europe the mean temperature can be said 
to be known with any degree of exactness, to which the verifi- 
cation of thermometers is an indispensable preliminary. We 
may mention, as particularly interesting amongst observations 
in the most inhospitable regions of the globe, the observations 
at Nova Zemblat, Dr. Richardson's reduction of those of Parry 
and Franklin, the observations of Beechey, Ross, and Back, in 
their respective voyages, the last of whom observed the greatest 
natural cold yet registered}; Kupffer and Brewster§ on the 
temperatures observed on the north-west coast of America, and 
Arago upon similar observations by Macloughlin ||. Mr. Web- 
ster has given a list of extreme winters observed in North 
America ¥ ; and Dr. Daubeny some observations on the climate 
of that country** ; Mr. Trevelyan has reprinted his paper on 
the Climate and Vegetation of Farve, with additions+7. 
49. We have already observed, that it appears, by a reference 
to the Paris Tables, that a long series of years of observation 
is required to obtain with certainty the mean temperature of a 
place t{. It is probable that the temperature of the ground is not 
liable to so great fluctuation, and therefore that kind of obser- 
vation should be made wherever practicable. This does not, how- 
ever, supersede the necessity of long-continued meteorological 
observations with verified instruments made under proper pre- 
cautions ; and we hope to see the Plymouth observations, and 
those conducted at the various magnetic stations fixed upon by 
* See on this interesting subject Arago, Annuaire, 1834; Schouw on the 
Climate of Italy (Ed. Phil. Journal, July 1840), and an anonymous paper in 
the Phil. Mag., Aug. 1840. 
t+ Supra Art., 37—40. t Ibid. 
§ Phil. Mag., 3rd Series, i. 427. || Comptes Rendus (Paris), i. 266. 
q Silliman’s Journal, xxviii. 183. The valuable Meteorological Reports from 
the State of New York are still continued, and, through the kindness of Dr. 
Romeyn Beck, I have received them down to 1837. 
** Brit. Assoc., Eighth Rep., Sect. p. 29. tt 4to. Florence, 1837. 
+¢ The longest extant series of meteorological observations worthy of any 
confidence is probably that at Berlin, printed in Dove’s paper on Non-periodic 
Variations of Temperature (Berlin, 1840). It extends from 1719 to 1839; the 
greatest annual temperature was 9°69 R. in 1756: the least 4°°38 R. in 1740. 
