362 



HOURLY METEOROLOGICAL REGISTER KEPT AT LEITH FORT. 



Mean 



Min. 



Mean 



Max. 



Mean 



1826. 

 48-468 

 48-055 

 47-375 

 46-786 

 46-287 

 45-879 

 45-562 

 45-335 

 45-199 

 45154 

 45-345 

 45-918 

 46874 

 48-214 

 48-468 

 49-616 

 50-641 

 51-373 

 51-812 

 51-958 

 51-874 

 51-623 

 51-203 

 50-576 

 49-861 

 48-938 

 48-468 



Difference. 



: 047 

 -0-129 

 -0-250 

 -0-383 

 -0-037 

 -0003 

 + 0-046 

 -0-041 

 -0-000 

 -0-180 

 -0-215 

 -0-201 

 -0133 



0-000 

 + 0-178 

 + 0-234 

 + 0-159 

 + 0-088 



0-000 

 -0-067 

 -0-256 

 -0-330 

 -0-339 

 -0-049 

 + 0-087 



0-000 



1827. 

 48-423 

 48-056 

 47-522 

 47-070 

 46-700 

 46413 

 46-207 

 46084 

 46-043 

 46-131 

 46-396 

 46-836 

 47-453 

 48-247 

 48-423 

 49-220 

 50015 

 50-583 

 50-923 

 51-037 

 50-973 

 50-780 

 50-459 

 50-010 

 49-431 

 48-725 

 48-423 



Difference. 



-0-063 

 -0049 

 -0-309 

 -0-405 

 -0-304 

 -0-201 

 -0-041 



0000 

 -0-024 

 -0-015 

 -0-063 

 -0-117 

 -0 080 



0000 

 + 0-150 

 + 0088 

 + 0-072 

 + 0-066 



0-000 

 + 0014 

 + 0004 

 + 0-008 

 + 0-154 

 + 163 

 + 0-052 



0-000 



From this Table it appears, that the difference between the observed and the 

 calculated temperatures for 1826 and 1827, is only four-tenths of a degree of Fah- 

 renheit, a very little more than in 1824 and 1825. 



I cannot conclude these observations, without directing the attention of the 

 Society to the singular fact, that laws so regular as those we have been contem- 

 plating should have shown themselves after only four years of hourly observa- 

 tions. When we consider by how many disturbing causes the temperature at 

 any particular instant is affected — by the winds which blow over surfaces differ- 

 ently heated, — by the showers which instantly cool the air, — by the interposi- 

 tion of clouds, now screening the sun, and now giving a free passage to his rays, 

 and by many other causes, as capricious in their origin as they are irregular in 

 their influence, it cannot but appear wonderful that all these effects should be so 

 nicely balanced, as to produce a perfect compensation at every point of the 

 annual daily curve. In virtue of this compensation, we may consider the mean 

 annual daily curve as representing the mean daily progression of the solar heat, 

 whether received directly from the sun, or returned into the atmosphere, by 

 terrestrial radiation. 



