286 REPORT ON THE DISCOVERY AND NAME 



The periodical time of the innermost of Sir W. Herschel's 

 satellites is but twenty-two hours, and of his second satellite one 

 day and eight hours. Sir John Herschel proposes to call the for- 

 mer Mimas and the latter Enceladus. 



It will be recollected that the periodical time of the new satellite 

 is approximately estimated by Mr. Bond at twenty-one days. As 

 the period of Titan is fifteen days and twenty-two hours, and that 

 of lapetus seventy-nine days, it may be reasonably conjectured 

 that one, perhaps more than one, satellite remains yet undiscovered, 

 to fill up the disproportioned space. 



Such was the Saturnian system, as far as the satellites are con- 

 cerned, till the recent discovery. Some confusion existed in their 

 designation. They have hitherto been designated numerically, 

 nearly, bu* not quite, in the order of discovery ; that is to say, the 

 third from the primary has been called number one, and so on to 

 the exterior satellite, which has been called number five. The sec- 

 ond from the primary (being Sir William Herschel's first discovery) 

 has been called number six, and the interior satellite number seven. 

 In this nomenclature Huyghens's satellite, the largest and first 

 discovered, is numbered fourth, which represents neither the order 

 of discovery nor of place in relation to the primary. 



To avoid the confusion of this system, it had latterly been usual 

 to designate the group numerically, calling the interior satellite 

 number one, and so on regularly through the seven ; but this im- 

 proved nomenclature was not yet universally adopted. 



In order to provide an effectual remedy for the uncertainty of the 

 former modes of designation. Sir John Herschel, in his recent 

 great work on the Cape Observations,* has made the happy rec- 



* Results of Astronomical Observations made during the Years 1834, 5, 6, 7, 8, 

 at the Cape of Good Hope, &c., by Sir John F. W. Herschel. 4to. 1847. 



