ÖFVERSIGT AF K. VETENSK.-AKAD. FÖRHANDLINGAR 1881, N:ol. 19 
nately impelling and retarding one or the other of the descen- 
ding and ascending columns of heated matter thus occasioning 
great irregularity. The periodic change of position of the centre 
of gravity of the aggregate planetary mass must necessarily 
produce a periodic maximum and minimum disturbance of the 
descending and ascending currents within the solar mass. It 
will be evident, that the frequent near approach and consequent 
powerful attractior of Venus greatly complicates the question 
of maximum disturbance. 
Likväl tycka vi oss finna spår af en annan asigt om denna 
sak ehuru dunkelt uttalad i Kew-astronomernas afhandling om 
»planetary influence» (se LOCKYER p. a. s.). 
The following question may occur to our readers: How is 
it possible, that a planet so far from the sun as Venus or Ju- 
piter can cause mechanical changes so wast as those, which 
sunspots exhibit? We would reply in the following terms to 
this objeetion: We do not of course imagine, that we have as 
yet determined the nature of the influence excerted by these 
planets on the sun; but we would nevertheless refer to an opi- 
nion expressed by Professor TAIT, that the properties of a body, 
especially those with respect to heat and lisht, may be influ- 
enced by the neighbourhood of a large body ..... The mo- 
leeular state of the sun just as that of the cannon or of the 
fulminating powder may be externally sensitive to impressions 
from without . . . . (?) We may infer from certain experiments 
especially those of CAGNIARD DE LATOUR, that at a very high 
temperature and under a very great pressure the latent heat of 
vaporisation is very small, so that a comparatively small amount 
of heat will cause a considerable mass of liquid to assume the 
gaseous form and vice versa. We may thus very well suppose 
that an extremely small withdrawal of heat from the sun might 
cause a copious condensation; and this change of molecular 
state would of course by means of altered reflection etc. alter to 
. a considerable extent the distribution over the various particles 
