576 
Proceedings of the Royal Society 
Taking a mean of all these differences, we find that, in the tem- 
perate regions of the globe , the west coasts of the continents have 15° 
less range than the east coasts , and we have seen that this difference 
may rise to above 40°. 
An examination of the ranges on the coasts of inland seas, and 
even lakes, leads to the same general conclusion. 
In the Mediterranean the following places — Alicante (30°), 
Valencia (40°), Barcelona (30°), Perpignan (36°), Montpellier (36°) > 
Catania (39°), and Athens (38°), on east facing coasts, give a mean 
range of 36°; whilst Oran (21°), Algiers (21°), Palermo (25°), 
Naples (29°), Rome (30°), Corfu (28°), and Beyrout (28°), give a 
mean of 26° for the west facing coasts, or a difference of 10° be- 
tween the two. 
The mean of Odessa (47°) and Constantinople (33°) gives 40° of 
range for the east facing coast of the Black Sea ; and Trebizond 
(29°) and Redut Kale in Caucasia (31°) give 30° as the range of 
the west facing coast ; again showing a difference of 10° less on the 
latter coast. On the east facing coast of the Caspian Sea , taking 
the observations at Astrakhan and Lenkoran (58° and 42°), we have 
a mean of 50°, whilst Novo Petrovsk, the only observing station on 
the west facing coast, has 47° of range ; Port William (58°) and Bay 
City (55°) give 56° as the mean range of the east facing coast of 
Lake Superior ; and Michipicoten, in the centre of its west facing 
coast, has only 46° of range, again showing a difference of 10°. 
The causes of this uniform predominance of range on east coasts 
over west, might form an interesting subject for investigation. On 
no two continental coasts do we find exactly the same prevailing 
conditions of winds and currents, much less of elevation and 
form, so that the explanation of this phenomenon must rather 
be looked for in a special combination of these influences for each 
individual coast, than in any one cause acting over the whole 
earth’s surface. 
The lines of egual range are formed between different January 
and July temperatures in different parts of the globe. To show the 
manner in which these equal range lines move up and down the 
thermometer scale in their passage round the earth, a few of the 
range lines in the northern hemisphere have been opened out, as 
the isotherms were before, on each side of the meridian of Green- 
