Does The Earth Receive Heat From The Sun?

sphere as to the sun , both being equally necessary for its production . The greatest amount of heat is , of course produced when the sun ' s action is vertical , hence we have more heat in summer than in winter . It is worthy of notice that in

the equatorial regions , where the heat is greatest , there , also , the atmosphere preponderates . Flammarion , in bis work on the atmosphere , says the ratio of the polar diameter is three-fourths of the equatorial diameter of the atmosphere . Glaisher states that Laplace proved even a greater difference , namely , that the polar diameter is onl y two-thirds of the equatorial , as

rr u u Mean read-Height abore fa f the sea * Barometer . Feet Inches . Level of the ocean 0 29-92 Greenwich Observatory 159 20-74

Toulouse do . 650 29-37 Geneva do . - 1 , 339 2 S' 58 Summit of Vesuvius -- --- - 3 , 937 25-98 Guanaxuato ( Humbolt ) 6 , 837 23-62 The Monastery of the Great St . Bernard - - 8 , 130 22 * 17 Summit of Etna -. 10 , 893 20 ' 0 S

Several aeronautical ascents ( Flammarion ) - - 13 , 124 18-70 Summit of Mont Blanc 15 , 748 16-69 On the Chimborazo ( Humbolt ) ... - 20 , 014 14 * 17 Aeronautical ascent ( Gay Lussac ) - - - 22 , 966 12-79 Do . ( Glaisher ) - 26 , 247 10-79 Do . do . - - - 29 , 000 9-75 In the highest ascent do . .... 37 , 000 7 ' 00

Not only does the density of the atmosphere diminish as we ascend , but Flammarion estimates , from a large number of experiments tried under varying circumstances with a clear sk y , that the mean fall of the temperature is 7 ° Fab . for

the first 1 , 600 feet from the surface of the ground ; 13 ° at 3 , 280 feet ; 19 ° at 4 , 900 feet ; 23 ° at 6 , 560 feet ; 27 ° at 8 , 200 feet ; 31 ° at 9 , 840 ; 34 ° at 12 , 500-an average of 1 ° Fah . per 340 feet . Again , it is well known that when a

body radiates heat , the amount received from it is inversely as the squares of the distance . Therefore , at great elevations , under a vertical sun , there should be more heat ; instead of which , at the height of four or five miles only , the mountains are eternally covered with snow . With regard to the method adopted for

represented in the diagram below , in which the outer line indicates the extent of the atmosphere :

The following table has been formed from a series of observations made , which shows how rapidly the wei ght of the atmosphere decreases by ascending to great elevations : —

estimating the total amount of heat radiated from the sun , by exposing a known surface of mercury in a shallow vessel ( the pyrheliometer ) , it appears to me most unsatisfactory ; for if the mercury were to be exposed to the sun ' s rays at an elevation of a few milestheninstead of its being

, , heated , it would be frozen solid j consequently the heat indicated would be nil . The value of the experiment , therefore , is nil too . If the same vessel , minus the mercury , were to be openly exposed for some time , in all probability it would be partially filled

with rain water , and it would be equally reasonable to conclude that the water as well as the heat comes from the sun , for in each case both the heat and the water diminish , in proportion as the experiment is tried at greater elevations , until both alike are totally absent .