217 
the idea occurs that the subsequent condensations of these 
higher groups are in some way influenced or determined 
by the antecedent condensations of homologous members 
of the lower groups, and may be the cause of the departure 
in the higher groups from the simple ratios and multiple 
relations observed amongst the elements of the series H n, 
and H2n. Such perturbations would appear to be similar to 
those which the planetary bodies exercise on each other to 
produce modifications in the forms of their orbits, but I 
leave this question to the further consideration of physicists 
and astronomers. 
The complete parallelism of the halogens and oxygens to 
each other, and their intensely electro-negative character, 
point irresistibly to the conclusion that at one period of 
their history these elements existed in a state of isolation 
from all the others. How, and under what conditions, they 
acquired their electro-negative properties can in the present 
state of knowledge be only a matter of conjecture ; but it 
may be conceived that these elements may have existed 
originally in the form of a zone or zones revolving within 
the moon’s orbit, but high above the incandescent terrestrial 
surface ; probably before the lunar substance changed from 
the annular to the globular form. These intra-lunar zones 
may have gradually acquired their electro negative properties 
by lunar and terrestrial induction, and by the loss of their 
primitive heat by radiation into space. Their orbits being 
too near the earth to permit the zones to assume the 
spheroidal form, they would upon rupture become incorpo- 
rated with the positive terrestrial elements, and remain 
dissociated till the temperature of the mass was sufficiently 
reduced to enable chemical combination to take place. If 
Draper’s discovery of oxygen in the sun be confirmed, the 
hypothesis of the existence of an intra-mercurial zone of 
negative elements which subsequently united with the solar 
positive elements is at least as probable as the assumption of 
an intra mercurial planet which has recently been discussed 
by astronomers. May not the sudden increase in the bright- 
ness of variable stars like T Coronse, Nova Ophiuchi, 1818, 
