64 
Proceedings of Royal Society of Edinburgh. [sess. 
atoms are composed is the same. For instance, take gold and 
silver — the velocity of the particles of the gold atom may be the 
same as that of those of the silver atom, and the gold atom may 
be larger in size though closer in the grain , which latter quality 
would admit of only the same speed of particles as that of a 
smaller atom; and greater size in an atom with only the same 
speed of particles as a smaller one would permit of greater 
compression. Thus it may he that the gold atom though of larger 
size may be more squeezable in exact proportion to its larger size, 
and thus appear to have the same volume as that of silver. That 
it is more squeezable appears from its greater valency — that is, if 
my explanation of valency be accepted. 
It is this state of various proportions of weight, size, close- 
grainedness, and velocity of particles which may exist which give 
my theoretical bubble atoms such a power of diversity in their 
qualities as to at once constitute them a source of the most 
mysterious properties, with a resemblance to the ways of nature 
which to me is irresistibly convincing. 
I have now gone as far with my theory as I intend at present. 
The subject is endless; other people with more time at their 
disposal and with better opportunities may take it up if it so 
please them. It is now about seven years since I first conceived 
the idea of the bubble atom ; and since then, during all the time 
at my disposal, when absent from duty, the subject has seldom 
been out of my mind. I hope that I may have shed some light 
on some of the darkest parts of it, but I am conscious that the 
deficiencies of my education will not admit of my going further with 
it, at least till those deficiencies are overcome, and of which I see 
very little hope at present, if ever. I have not touched at all 
on the subject of electricity, simply because I know very little- 
on the subject; but sure am I that within the folds of this theory 
lies hidden the mystery of electricity. 
{Issued separately February 21 , 1902 .) 
