CHEMISTRY: W. D. HARKINS 
11\ 
and not only do all of these elements have even atomic numbers, but in 
addition they make up 98.6% of the material of the meteorites. Of 
the remaining elements present to a great enough extent to have an 
appreciable effect upon the percentage values, 7 are odd and 5 are 
even, but in all only 1.22% are odd numbered, while 98.78% are even. 
Of the iron meteorites 99.22% of the material is made up of even num- 
bered elements, and of the stone meteorites, 97.50%. While the results 
for the earth's lithosphere are not so striking, they still show the same 
general tendency very strongly; for, of the six most abundant elements, 
only aluminum is odd numbered, and the elements of even atomic num- 
ber make up about 86% of the material. The only odd numbered 
elements other than hydrogen present in the lithosphere in amounts 
over 0.2% are aluminum, sodium, and potassium. 
Table 2 gives the average composition of iron and stone meteorites, 
arranged according to the periodic system. The numbers before the 
symbols represent the atomic numbers, and the numbers underneath 
give the percentage of the element. It will be noted that the even num- 
bered elements are in every case more abundant than the adjacent odd num- 
bered elements. The heHum group elements form no chemical com- 
pounds, and are all gases, so they could probably not remain in large 
quantities in meteorites. For this reason, and also because the data are 
not available, the heHum or zero group is omitted from the table. The 
only criticism which could be made of the system of averaging, which is 
that of including all accurate analyses, is that it places undue emphasis 
upon the iron as compared with the stone meteorites. However, since 
the two relations shown in Table 1 are true for each class of meteorites 
separately it is evident that they will be true whatever system of averag- 
ing may be chosen. 
TABLE 1 
Average Comtosition of Meteorites Arranged According to the Periodic System 
GROUP 
GROUP 2 
GROUP 3 
GROUP 4 
GROUP 5 
GROUP 6 
GROUP 7 
GROUP 8 
«) 
ODD 1 
EVEN 
ODD 
EVEN 
ODD 
EVEN 
ODD 
Even 
Odd 
Even 
2 
6C 
0.04% 
80 
10.10 
3 
llNa 
0.17% 
12Mg 
3.80% 
13A1 
0.39% 
14Si 
5.20% 
15P 
0.14% 
16S 
0.49% 
4 
19K 
0.04% 
20Ca 
0.46 
22Ti 
0.01 
24Cr 
0.09 
25Mn 
0.03 
26Fe 
72.06 
27Co 
0.44 
28Ni 
6.50 
29Cu 
0.01 
