UTAH ACADEMY OF SCIENCES 113 
from uranium, and whose atomic weight is less than 
225.96? This explanation is in accord with the behavior of 
lead, which is already well authenticated. Another very 
interesting question arising here, is why does ordinary 
lead have an atomic weight of 207.2? Is it a mixture of 
radio lead with a lead atomic weight 208 or greater? If so, 
where did this heavy lead originate—from thorium, of 
atomic weight 232.4, by loss of 6 helium atoms, or is it a 
synthetic element, instead of the decomposition product? 
The question of course cannot be answered by speculation, 
but some information would be secured by actually sep- 
arating from ordinary lead its constituent heavy and light 
leads. Work along this line is actually under way. 
It follows from this discovery of leads of different 
atomic weight, that the atomic weight of the chemical 
elements is not the characteristic function it has always 
been held to be. Rather, it is the position of the element 
in the atomic series which governs its physical and chemi- 
cal properties, and any given position in this series may be 
occupied by a group of elements, chemically identical, 
and inseparable, but of different atomic weights. It may 
even be that all of our chemical elements are such groups 
of “‘isotopes’’, the atomic weight of the element being the 
average for the group. 
The decomposition of the chemical atom is, then, a 
matter of unquestioned fact. Does the reverse process 
occur, and are atoms being synthesized as well as decom- 
posed? The answer to this question cannot, at present, be 
made with assurance. There are many things, however, 
which indicate such a possibility. Nitrogen and hydrogen, 
and phosphorus and hydrogen unite to form compounds 
which react with acids to give salts very much like cer- 
tain well known metallic salts. The negative group in 
ammonium salts, for example, gives practically all the 
analytical reactions of the potassium ion. This group 
certainly is not an element, and this may represent the 
limit in which we may proceed in this direction. Atomic 
disintegration has proven, so far, to lie outside the influ- 
ence of any force at our command, and atomic synthesis 
may likewise demand the use of forces at present un- 
known, or uncontrolled. It is not at all improbable, how- 
ever, that atoms are being continually synthesized, per- 
