46 HISTORY OP ASTRONOMICAL DISCOVERY. 



path of the stranger lies as far beyond what had been deemed its extreme confine, as that 

 limit is removed from the sun. The first moment of his " attack" upon Saturn, upon 

 completing the forty-feet reflector, he saw a sixth satellite, and a seventh a month later. 

 But Herschel realised his most surprising results, and derives his greatest glory, from the 

 observation of the sidereal heavens. The resolution of nebulae and the Milky Way into 

 an infinite number of stars the discovery of new nebulae of various forms, from 

 the light luminous cloud to the nebulous star of double and multiple stars of the 

 smaller revolving round the greater in the binary systems ; these were some of his reve- 

 lations to the world, as night after night, from dewy eve till break of dawn> he gauged 

 the firmament. Caroline Herschel was the constant partner of her brother in his labo- 

 rious undertakings submitting to the fatigues of night attendance braving with him 

 the inclemency of the weather noting down his observations as they issued from his 

 lips and taking, as the best of all authorities reports, the rough manuscript to the 

 cottage at the dawn of day, and producing a fair copy of the night's work on the ensuing 

 morning. He died in 1822 ; but she has survived to see the heir of his name recognised 

 by the world as the heir also of his talents and fame. It was one of the conceptions of this 

 remarkable man as bold an idea as ever entered the human mind that the whole 

 solar system has a motion in space, and is advancing towards a point in the heavens near 

 the star X Herculis. General opinion is now in favour of the idea, that not only the solar 

 but the entire stellar universe revolves around some mighty centre. 



The nineteenth century commenced with a fresh ingathering of members into the 

 planetary family. It had been deemed a matter of surprise that the immense interval of 

 about 350 millions of miles between Mars and Jupiter should be void, when only spaces 

 varying from 25 to 50 millions divide Mars, the Earth, and the inferior planets. Keppler 

 had therefore started the conjecture that a planet would be discovered in the vast region 

 between the two former bodies ; and thus bring it into something like proportion with the 

 spaces between the latter. This idea was confirmed by a curious relation discovered by 

 Professor Bode of Berlin, that the intervals between the orbits of any two planets is about 

 twice as great as the inferior interval, and only half the superior one. Thus, the distance 

 between Venus and the Earth is double that between Mercury and Venus, and the half of 

 that between the Earth and Mars. Uranus had not been discovered when Bode arrived 

 at this remarkable analogy, but the distance of that planet being found to correspond with 

 the law, furnished a striking confirmation of its truth. The respective distances of the 

 planets may be expressed by the following series of numbers, whose law of progression is 

 evident. 



Mercury's distance * = 4 



Venus - 4 f 3-0 = 7 



Earth - 4 + 3-2 = 10 



Mars - - 4 -f 3-22= 16 



Jupiter - 4 + 3'2 4 = 52 



Saturn - 4 + &2 5 = 100 



Uranus - 4 + 3-2 6 = 196 



The void in the series between Mars and Jupiter, so convinced the German astro- 

 nomers of the existence of a planet to occupy it, which had hitherto escaped observation, 

 that a systematic search for the concealed body was commenced. At Lilienthal, the 

 residence of Schroeter, an association of twenty -four observers was formed in the year 

 1800, for the purpose of examining all the telescopic stars of the zodiac. The opening 

 years of the century witnessed the anticipation substantially realised by the discovery of 



