40 Hinrichs on Dark Lines in the Spectra of the Elements. 
Such observations therefore are most ardently desired, and it 
seems urgent to construct telescopes for this particular purpose. 
If we, in the preceding, have succeeded in making the regu- 
larity of the apparently highly irregular lines probable—for 
they certainly show ion and simple laws in their distribution 
—it may naturally be asked: what causes this distribution, and 
what will probably be the reward of continued researches in 
this direction ? 
e lines can only have one of the following two sources. 
They are either produced by the dimensions of the solid parti: 
cles or by the intervals between them, i.e., their distances. The —~ 
latter is impossible, for these lines remain absolutely the same — 
under such different circumstances as cannot but to some extent 
change the mutual distance of the particles. Hence the lines must 
be produced by the bulk of the particles or atoms themselves, andan 
exact knowledge of these laws and distances must lead us to a knowl- _ 
edge of the relative dimensions of the atoms, both as to length, 
breadth, and Peete ess. Thus optics will give us the form and 
B1Ze, as ‘chem stry has given us the weight of the atoms. The 
remarkable venalt attained by Pe ring the distance between 
the calcium groups (48) and the barium groups (4°4) seems to © 
show that one dancin of the atoms of these two elements is 7 
nearly—or if the above values should be found to be exactly 4 
equal—perfectly equal. How great the interest of such deter- 
minations is in regard to the constitution of the elementary 
bodies needs not to be accentuated. It may yet lead to an ex- 
perimental demonstration of the existence of a primitive sub- 
stance, the element of the elements. 
How the dimensions of the atoms produce these lines is an- 
other question, and it is Mea difficult even merely to suggest 
any probable connecting link between the dimension of the — 
atoms and the luminous wave. But this can not be any serious 
obstacle to the practical application to the analysis of the elements: 
for so the alkalies were decomposed by electricity although the 
connection -arvenpie therein is but imperfectly known — 
even at the present. : 
But, however this one be, we hope those physicists who are — 
fier red by the necessary delicate apparatus will find in this un- — 
pretending amps investigation sufficient inducement to 
test—an e think probable—to confirm and complete the — 
result here aodeiiis from the existing Seer eakionis that: thedark — 
of the spectra of elementary bodies are regularly distributed. 4 
Towa City, March, 1864, 
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