288 Address of Sir William Thompson. 
clusive against it. 
Each meteor circulating round the Sun must fall in along a 
very gradual spiral path, and before reaching the Sun must 
have been for a long time exposed to an enormous heating 
effect from his radiation when very near, and must thus have 
been driven into vapor before actually falling into the Sun. 
Thus, if Mayer's hypothesis is correct, friction between vortices 
of meteoric vapors and the Sun’s atmosphere must be the m- 
mediate cause of solar heat ; and the velocity with which these 
vapors circulate round equatorial parts of the Sun must amount 
to 435 kilométres per second. The spectrum test of velocity 
applied by Lockyer showed but a twentieth part of this amount 
as the greatest observed relative velocity between different 
ich I had objected. But a solution, which seems to mee 
the highest degree probable, has been suggested by Tait. 
ur ed gas 
: J t 
) observed in gunnery trials, such as those ® 
Shoeburyness, when iron strikes eodtat iron at a great velocity 
