Address of Sir William Thompson. 289 
but varied by substituting for the iron various solid materials, 
metallic or stony. Hitherto this suggestion has not been acted 
upon ; but surely it is one the carrying out of which ought to 
be promoted by the British Association. 
Nature of Comets. 
published), until, in 1866, Schiaparelli calculated from observa- 
tions on the August meteors, an orbit for these bodies which he 
found to agree almost perfectly with the orbit of the great 
comet of 1862, as calculated by Oppolzer; and so discovered 
and demonstrated that a comet consists of a group of meteoric 
ent 
ears, since the year 902, there have been excep- 
fliant displays of the November meteors. It had 
ve 
: 3 a splendid problem for the phy- 
Per annum, Here, then, was a splendid p: ees < sk 
iful meth 
Adams, by the application of a beautiful met 
ewton just one permitted the motion of the 1 
(eer ne influ f Jupiter, Saturn, and 
by ma igrsboh ee: influence ae ’ is, 334 
