MODERN SCIENCE. 207 



appeared to follow an arithmetical progression, began to 

 observe the heavens between Mars and Jupiter, with a view 

 to discover the missing planet which should, in accordance 

 with the law, be found in that region. This law, called 

 BODE'S LAW, because this mathematician (1747 1826) set 

 it forth clearly and insisted upon its value, is a striking 

 instance of the soundness of empirical knowledge at times, 

 and may be stated thus : If under Mercury we write zero, 

 and under Venus 3, and then go on doubling this number 

 under each planet in succession (from the sun), 6 under 

 Earth, 12 under Mars, 24 under Asteroids, 48 under Jupiter, 

 96 under Saturn, 192 under Uranus, 384 under Neptune, 

 and to these numbers add up 4, we obtain the numbers 

 which closely correspond with the relative distances of the 

 planets Neptune excepted, the discrepancy with regard to 

 it being 88. This law has been of great service to astronomy, 

 for Kepler (and later Titius) expressed his belief, founded 

 upon it, that an undetected planet revolves between Mars 

 and Jupiter, and effectively, after the discovery of Uranus, 

 which afforded an additional proof of the law, Bode having 

 strongly suggested that the gap between Mars and Jupiter 

 should be surveyed, Piazzi, on the first day of our century 

 (January I, 1801), discovered CERES, the first asteroid known. 

 This planet, lost for a few months, was rediscovered by 

 Gauss after remarkable calculations of its orbit. But CERES 

 was only the first of a multitude of asteroids revolving in 

 the gap ; for soon PALLAS and VESTA were found by Olbers, 

 and JUNO by Harding (18021807). In 1845, a fifth 

 asteroid, ASTR^EA, was discovered; in 1847, three more were 

 found, and from that time until now, not a year passed 

 without some being added to their number until there were 

 as many as 389 of them known up to 1894. Seventeen were 

 found by Karl Luther alone, 10 by Hind, 9 by Gasparis, 

 14 by Goldschmidt, 7 by Pogson, 9 by Watson, and so 

 forth. It has been suggested that their large number is 

 due to the explosion of a large planet, but as their distances 

 vary between 200 and over 300 millions of miles, and the 

 inclination and eccentricity of their orbits vary beyond those 

 of other planets, it is more probable that the cause of their 



