158 IV. CLIMATE. 



conformity witli the usages of tlie most scientific nations of 

 the Continent. The centigrade thermometer might even 

 now give increased facilitj'^ for a scale to connect mean 

 temperature with latitude, by aid of decimals and minutes, 

 without the inconvenience of less exact fractions in the 

 form of quarter and half degrees. The sea-level tempe- 

 rature, in latitude 51 at the south-east angle of England, 

 was considered above to be represented by 50 on Fahren- 

 heit's scale. This is equal to 10 on the centigrade scale. 

 And in allowing one-hundredth of a degree of centigrade 

 temperature, as a decrease for every two minutes of lati- 

 tude northward, a descending scale is obtained which 

 differs very little from that of half a degree of Fahren- 

 heit's thermometer for one whole degree of latitude. 

 Each minute or geographical mile would thus be imder- 

 stood to correspond with 0.005 of centigrade temperature ; 

 two minutes with 0.01 ; sixty minutes with 0.3, the deci- 

 mal figiu'e for a whole degree. The scale would run 

 thus : — 



Lat. 51 53 53 54 55 56 57 58 59. 



Temp. 10 9.7 9.4 9.1 8.8 8.5 8.3 7.9 7.6 

 Reckoned in this manner, the rate of decrease northward 

 would be very slightly slower or less than that before 

 given as adapted to the thermometer of Fahrenheit. It 

 is true that either of these rules, for connecting the ther- 

 mometrical scales with geographical latitude in Britain, 

 involves a kind of forced uniformity, more precise and 

 even than may be warranted by recorded facts. But inas- 

 much as they are both deduced from the thermometrical 

 registers of temperature, as recorded for many different 

 places, they will in the main be found to represent those 

 facts without much deviation from the most correct 

 among them. 



