D. Kirkwood on Certain Analogies in the Solar System. 211 
Again, “we cannot see anything which could have prevented 
either the size or the density of the earth from being different, to 
avery great extent, from what they are.”’ 
The first attempt, so far as I know, to develop a connection 
between those apparently independent elements, was made by the 
writer a few years since. Finding, generally, that law and har- 
mony characterize the operations of nature around us, I have 
ever thought it extremely improbable, since my attention was 
first turned to the subject, that the Creator had, in this instance, 
departed from his ordinary mode of action. The result of these 
efforts has been now nearly three years before the public, and has 
attracted some degree of attention. e most recent notice 
with which it has been honored is that of Professor Cherriman, 
Whose article in the last number of the American Journal of 
Science and Arts has suggested the propriety of a brief re-discus- 
sion of all the known facts which have an immediate and obvious 
bearing upon’ this interesting subject. ED 
_ The quantities to be used in our examination, it will be ob- 
served, are extremely various. Thus Jupiter’s mass is about 
3,000 times greater than Mercury’s; the interval between Saturn 
and Uranus when in conjunction is 33 times greater than that 
between Venus and the Earth in similar circumstances ; and the 
number of Saturn’s days in his year is 280 times greater than the 
humber of Mercury’s. If, therefore, all the known elements of 
the solar system, so far as applicable, consisting of magnitudes so 
widely different, harmonize together in a comp icated formula, 18 
it not, to say the least, extremely probable that this formula is the 
expression of a law of nature ? 
as tocome within the limits of error of the masses. oA 
tances, sidereal revolutions, and axial rotations severe a 
employed are those used by Professor Loomis.t I cou ‘3 te 
Encke’s masses of the Earth, Jupiter, and Saturn ; the i 0 “ 
ever, may hereafter require some slight ee or : a 
hus, I have employed the latest determination, that 0 truve, fro 
Be SSO: oa ee —————— 
Ms qihowell's Astronomy and General Physics, p. 82. 
{ Tid. [3 a one be cai table the mass of the Earth alone was errone- 
Ec pl ent tala 9h masses of the Earth and Moon. 
