REPORT—1847. 
,37r 
of the year only. By tlio assemblage of a great body of observations frooi 
great Variety of places, normal values may now be assigned for tbe mean i» 
perature of months and seasons as well as of the year, and thus abnon&l 
<litfereaces occurring at any period or during any portion of tie year mavi 
once be recognised. From tho progress already made in this branch of Ik 
inquiry, Professor Dov’e is enabled to show, in respect to the conlineiusd 
the northeni hemiipboro, that norlhcrn and i^eutrai Asia hare what purl* 
termed a true Continental climate both in wintcraud in suoimer, vk.a«M 
winter and a hot summer; that Europe has a true insular or sea diiiiair l 
both seasons, viz.ainild winter and acold summer; and that North Americi 
inclines to a continental clinmto iti winter and to a sea climate insumiKr. 
Consistently with these distinctions, tlic isotberraals representing m® 
tenjjwratures of tho year are found in a lower latitude in America tbM* 
either Europe or Asia; the dlliurcoces between tho extremes of tempffltin 
in the year arc greater in northern and central Asia than in North Awcriei 
and greater in North America than in Europe; and the Icmniscatefonap 
the winter isotliermals around two centres, one in Asia and theothpfs 
Ajjierica, passes in the summer isothennuU into a circular form arouods 
•American centre only, 'i'he lemniscate form of the lower isofhermah inik 
northern Jicniispbere has been supposed by some philosophers toiflihcslti 
causal connexion with tlie magnetic isodynanuus of highest value, 
circuiustanco that these latter have also the form of kroniscato. Ti* 
systematic and progressive secular change which the Uodynsmic* umlff? 
has always, however, constituted a strong objection to this hypQthwh « 
cau^aJ connection; ami it now further appears that the lemniscate for® 
of the wotbernials subsiste only during the winter season; that it 
merely a periodical phase, vi’hereas the isodynamic Jeniniscates uodergo W 
snob porioilical varialioiis 
Afnny local meteorological phmnomenn previously known as renarb ' 
but insulated facts, ar«^ found to arrange themselves in due snbonliflsf*^^* 
uoxtoii with the comprehensive and systematic views which rsuhfio®* 
exloDsjve a gencralUatiou: amongst iIiHse Professor Dove laenhow-^* 
minmution of atraosjiheric pressure in Asia in summer; the 
tion of the trade-winds into monsoons; the change in the direction ot 
wt cold in the thermic wind-rose; the absence of the subtropical 
thc^ northern hiiiits of the monsoons; the small annual varialiow m 
meteorological phienomeiia in tropical America compared with the ^ 
penodical variations in tropical Asia; and the late occurrenoe 
ebroary’) of tlie mininiuiii of uunperaturo in North America. 
1 need ijot add how valuable would be a discussiou of the spco“ 
of the^ and of other cogp.ite phenomena from the pen of 
umsclf in the volumes of tho Association, accompanying thecorvrt'rt*’ 
he has so kindly promised to communicate. 
Edward Sabi**' 
