336 SPECIAL RESULTS IN THE URANOLOGICAL 



which is the converse of what now takes place. At first sight 

 it might seem as if the transference of the period of the 

 greatest proximity of the Earth to the Sun to the opposite 

 season of the year (to our summer instead of our winter) 

 must produce great climatic alterations ; but, in fact, sup- 

 posing such a transference to have been effected, it would 

 follow that the Sun would no longer linger for seven addi- 

 tional days in the northern hemisphere, and would no longer, 

 as at present, pass through the portion of the Ecliptic from 

 the autumnal to the vernal equinox in a space of time shorter 

 by a week than that which it requires for traversing the other 

 half of its path, or from the vernal to the autumnal equinox. 

 The difference of temperature (we here regard, exclusively, 

 astronomical climates, setting aside all physical considera- 

 tions respecting the relative proportions of sea and land in 

 the different parts of the surface of our globe) the 

 difference of temperature, I say, apprehended as liable 

 to ensue from a change of the line of the apsides, would 

 disappear almost entirely, from the counterbalancing cir- 

 cumstance, that the point at which our planet is nearest to 

 the Sun is at the same time always that at which it moves 

 most rapidly ( 53G ). The fine theorem first enounced by 

 Lambert ( 537 ), according to which the quantity of heat which 

 the Earth receives from the Sun in each part of the year is 

 proportional to the angle described in the same interval of 

 time by the radius vector of the Sun, contains within itself, 

 to a certain degree, a satisfactory reply to the supposition of 

 great climatic change. 



We have said that the altered direction of the line of the 

 apsides can exert but little influence on the temperature of 

 the globe ; and it may be added that, according to Arago 



