200 
That on a farther condensation of the elementary matter, a 
transition from the spiral to the annular form occurred, 
during, or after which, the group or species under each type 
was generated in concentric zones, and in the order of their 
atomic weights, until the highest member of each species 
was formed. That as the elementary vapours began to 
condense, or assume the liquid form, their regular stratifica- 
tion would be disturbed by eruptions of the imprisoned 
vapours from the interior of the rotating mass. This dis- 
turbance would be further augmented by the subsequent 
combination of the negative with the positive elements, and 
also by the variable solubility of their newly formed com- 
pounds ; so that the evidence of such stratification of the 
elementary vapours as I have indicated, must necessarily be 
more fragmentary than that of the geological record. The 
constant association in nature, however, of several elements 
belonging to the same group, a remarkable example of which 
is the presence of lithium, potassium, rubidium, and caesium 
in a single mineral, lepidolite, appears to confirm this view 
of the primitive arrangement of elementary vapours. 
In the annexed table are arranged all the known elements 
in natural groups, wherein gaps appear as in tables II. and 
III., which indicate the existence of missing elements. The 
atomic weights of other elements which have not been 
sufficiently investigated are also determined. 
If the theory which I have enunciated of the evolution of 
elementary substances from hydrogen in definite proportions 
be correct, the numbers representing the atomic weights, 
also represent the number of particles of hydrogen from 
which the elements were formed. Where these numbers do 
not coincide exactly, as in the case of Cu=62, and its homo- 
logue of position, Zn=64, which are each a unit less than 
the classical numbers, it is not to be supposed that these 
discrepancies are due to errors of experiment, but to some 
unknown cause which prevents their true atomicity from 
being ascertained. 
