Comet Systems. 
[April, 
igo 
Those of my readers who have read my article in the 
“ journal of Science ” (vol. vii., PP- 33 ^ h qq ie 
up J 0 „ what grounds I build up that^wh rch The 
theory running through that article wa loose 
“ r%rit n ^ 
Z'ty song-gate ihicUy““«Lr“tte Sun's surfaces, the 
comet will experience a certain amou t f reta rdation 
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approach \°o tte Sun"th“ same difficulty wUl be experienced 
ss» swsw srs:‘S| at »*fK 
the comets of Encke, Faye, &c., aie attained. < 
Sneakin^ incidentally of these last I am reminded t 
the periodical time of revolution of the former (the neares 
of the known comets to the Sun) is constantly dimmishii g, 
1 if ; Q true bv a matter of two hours or so on the 
00 Lp of each revolution, yet even this small decrease is 
b i This is orobably the corre<5t explanation. Can it be, 
then that the meteoric matter which originally caused its 
ranture from the outer space still aggregates near its pen- 
T hnn ? If so it is pretty clear that it must he of less density 
than "or m e idyl At any ?ate it is quite certain that meteoric 
matter does still exist in vast quantities in the bun s imme 
dl f Vav "''mentioned that comet systems exist both within 
the Sun’s domain and outside. The last of these weie, 
