72 HERSCHEL AND HIS WORK 



observers, suspecting, and with good reason, that a 

 well-kept watch would reveal unknown wonders in 

 the depths of space, undertook to search for other 

 planets. Had photographic plates or charts then been 

 part of the equipment of an observatory, the work 

 would have been easy, and the reward certain. But 

 plates and star -charts were not known; and the 

 twenty - four workers laboured and toiled in vain. 

 An outsider carried off first honours on the first day 

 of the century Piazzi of Palermo, who had visited 

 Slough, had talked with Herschel and his sister, and 

 perhaps drawn a breath of inspiration from them 

 and their surroundings. The beaten twenty-four 

 astronomers did not retire from the field. Two years 

 later, Dr. Olbers, of Bremen, discovered another asteroid, 

 Pallas; and two years later still, Harding, in the 

 same neighbourhood, discovered a third, Juno. Olbers, 

 wisely using imagination in the pursuit of science, 

 came to the conclusion that these small bodies were 

 pieces of a planet which had burst or exploded, and 

 that other pieces would be found floating about in 

 space. He acted on the idea, and rediscovered Piazzi's 

 Ceres, which had been lost again, as well as a fourth 

 asteroid, Vesta. Then the hunt for more pieces of the 

 disrupted planet ceased, till, about forty years later, it 

 again received a fresh impetus from Hencke's discovery 

 of Astrsea, and was continued by Mr. Hind at the 

 Regent Park Observatory in London, and others, with 

 such success that floating pieces have been netted by 

 hundreds, grumbled at as nuisances, and assigned the 

 honour of having been thrown off direct by the sun 

 himself, not blown into space by a disrupted planet. 

 One of these pigmy planets was named Lucre ti a, after 



