158 NOMOS. 



comet is ruled by the same law which rules the earth 

 and the companion planets, and that that which 

 appears to mark the irregularity of the comet will 

 appear to be one of the most marked signs of regu- 

 larity when that law is properly understood. 



The changes in Halley's comet after the perihe- 

 lion are easily disposed of, for if the outermost layers 

 were dissipated into invisible vapour as the comet 

 passed from a colder to a hotter region in moving 

 towards the sun, it is to be expected that these layers 

 will be again deposited as visible substance as it 

 passes from a hotter to a colder region in moving 

 away from the sun. It is to be expected, also, that 

 this deposition of condensing matter should be 

 arranged in the parabolic form which has been de- 

 scribed, for that focal action of the sun's rays which 

 had raised the outermost layers from the outer side of 

 the comet as this body passed towards its perihelion, 

 will prevent these layers from being redeposited in 

 their proper place until the comet has moved suffi- 

 ciently far from the sun to allow the focus to be 

 brought as far inwardly as it was before the tail 

 began to be raised. 



It is not difficult, then, to account in some measure 

 for the metamorphoses of Halley's comet in 1835 ; 

 and here we leave the subject, for, so far as we know, 

 what may be said of this comet may be said of all 

 comets. 



Such, then, is the view which we are disposed to 

 take of the two subjects which have just been under 

 consideration; and, being so, the conclusion is that 



