18 OTTO PETTERSSON, OM SOLENS STRÅLNING. 
grounds for this conclusion, the Kew astronomers have laboriously 
measured the area of all the sunspots observed by CARRINGTON 
from 1854 to 1860, and they find, as the result of their in- 
quiries, that a spot has a tendency to break out at that portion 
of the sun, which is nearest to the planet Venus ..... We 
here speak of Venus, as it appears to be the most influential 
of all the planets in this respect. Jupiter appears also to have 
much influence; and more recently it has been shown, that 
Mercury has an influence of the same nature, although more 
difficult to discuss on account of his rapid motion. Should 
therefore any two of these planets — or, still better, should all 
three — be acting together at the same place of the sun, we 
may expect a very large amount of spots, which will attain 
their maximum at that portion of the sun most remote from 
these planets: ..... 
Very recently also Mr BAXENDELL of Manchester has pu- 
blished some observations, from which we may perhaps conclude, 
that the direct heat of the suns rays varies with the state of 
the suns surface. These observations require confirmation, but 
they bear out the idea, that at these periods, there is a greater 
amount of coldabsorbing atmosphere above the suns photosphere. 
Det är kändt, att solfläckarnes uppträdande sker i kortare 
och längre perioder. Den kortare perioden 11,11 år har af CAR- 
RINGTON blifvit satt i samband med Jupiters ställning 1 för- 
hållande till solen, den längre perioden, 59 ar, tyckes regeras 
af Jupiters och Saturni kombinerade inflytande. Det är intres- 
sant att iakttaga, huru astronomerna och fysici hittils förklarat 
detta samband mellan solfläckarne och planeternas ställning till 
solen. I allmänhet anse naturforskarne, att solfläckarne uppstå 
genom de störande inflytanden, som attraktionen af planetmassorna, 
utöfvar på de upp- och nedgående strömningarne i solens gas- 
formiga omhöljen, ungefär i samma väg som ebb och flod på 
jorden åstadkommes af månens inflytande. JOHN ERICSSON ytt- 
rar (Radiant heat chapt. VI): The attraction of the planetary 
masses will seriously disturb the vertical circulation by alter- 
