14 M£T£OROLOGr> 



produces uo more than is supposed to be the temperature of space^ 

 viz. 68® below zero, a degree of cold which prevails in Arctic regions 

 before the close of their long winter. The nearness of the moon, 

 and the quantity of reflected light proceeding from it, has led to the 

 conjecture that when at full, it may occasion a rise in temperature ; 

 careful experiments, however, have demonstrated, that no perceptible 

 rise of the thermometer occurs from this cause, even when the moon 

 is at full, at its greatest altitude, and in perigee, or at its nearest dis- 

 tance from the earth ; moreover, a record of the weather, at the 

 quadratures and changes, perigee and apogee of the moon, during a 

 fifty years course of observation, exhibits such varied results as leaves 

 no possibility for the construction of even an approximative theory of 

 the weather dependent on lunar action. From the eccentricity of the 

 moon's orbit, and its nearness to the earth, its attraction on the earth's 

 atmosphere is slightly variable : it is, however, ascertained that no 

 sensible effect is produced in the weight of the atmosphere by these 

 causes not at all affecting barometic pressure : indeed it is more than 

 probable that any minute perturbative effects from this source are so 

 far overruled by the many causes at all times operating in bringing 

 about atmospheric change, and which may perhaps on a future occa- 

 sion be stated, as to render the minute fluctuations dependent upon it 

 quite irreducible to law, and utterly undiscoverable by observation. 

 All mutual planetary connections with which we are made demonstra- 

 bly acquainted depend upon the following law, viz. — their influence is 

 in the inverse ratio of the square of the distance ; that is to say, at 

 twice any given distance only one fourth of the influence, and in that 

 inverse proportion for every variation. Now, from the incommensura- 

 bility of the periods of all the planets, every successive conjunction of 

 any two takes place in different points of their orbits ; hence the 

 difference of distance from the earth, say of Saturn, in successive con- 

 junctions of Jupiter and Saturn, amounts to 700 millions of miles : in 

 one conjunction of Jupiter and Saturn, Saturn maybe distant from 

 the earth 800 millions of miles, in the next conjunction of the same 

 planets he may be distant 1500 millions of miles ; now from the 

 operation of the law just named, the influence of Saturn on the 

 earth at a distance of 1500 millions of miles, would only be l-4th 

 of its influence at a distance of 800 millions, so that the greatest 

 diversities hi result would accompany every conjunction, — but what 



