GEOCHEMISTRY: CLARKE AND KAMM 
401 
The pair of symmetrical components illustrated at {a) is typical of 
the Balmer series of hydrogen. The separation of such components 
has been taken as a measure of the field, the constant obtained by 
Stark being used in each case to calculate the field intensity. The form 
illustrated in (6) is typical of lines which show no appreciable Stark effect. 
While it is distinctly broadened in its lower portion, there is no doubt 
that the greater part of that broadening is due to increased intensity 
in the stronger field. The illustration (c) represents those components 
of He 4388 whose electric vector is perpendicular to the field. It shows, 
in order from left to right, two components having a < 0 and & < 0, one 
component having a<Oand & = 0, one having i?<Oand 6>0, and fin- 
ally, two having = 0 and 6>0. The line sketched at {d) is He 4922. 
The type (e) is very common in neon as is also type (/) . A few lines in 
neon are of the general type illustrated at {g). At Qi) is shown the ap- 
pearance of a typical new line. It is very broad and intense in the 
field but does not exist where the field is zero, or at least is so faint 
that it produces no effect on the photographic plate. 
A detailed statement of the results together with a full description 
of the apparatus and method will be published shortly. 
^ Stark, J., Elektrische Spektralanalyse chemischer Atome, Hirzel, Leipzig, 1914; Ann. 
Physik, Leipzig, 48, 1915, (193). 
2 Koch, ].,Ann. Physik, Leipzig, 48, 1915, (98), Cf. J. Sta.rk, Elektrische Spektralanalyse 
( hemischer Atome, 73. 
^Brunetti, R., Nuovo Cimento, Pisa, 10, 1915, (34). 
♦Evans, E. J., and Croxson, C, Phil. Mag., London, 32, 1916, (327). 
»Lo Surdo, A., Roma Atti Acc. Nuovi Lincei, 22, 1913, (664); 23, 1914, (82); Physik. 
Zs., Leipzig, 15, 1914, (122). 
NEW ANALYSES OF ECHINODERMS 
By F. W. Clarke and R. M. Kamm 
UNITED STATES GEOLOGICAL SURVEY. WASHINGTONi 
Communicated April 18, 1917 
In a recent publication of the United States Geological Survey^ Clarke 
and Wheeler have reported 250 analyses of the shells and skeletons of 
marine invertebrates; analyses which were made in order to determine 
what each class of organisms contributes to the formation of marine 
limestones. In that investigation the echinoderms and alcyonarians 
were peculiarly interesting, not only because they were notably magne- 
sian, but also because the proportion of magnesia in them was found to 
be related to temperature. The warm water forms were all relatively 
rich in magnesium carbonate, while the cold water forms were much 
