250 A. M. Mayer—Floating Magnets. 
from nature. Around each of the dots on the card-board I 
drew a black disk. The centers of these disks I joined by 
lines, in order to bring before the eye the contours of the con- 
figurations. After the diagrams of the configurations had been 
obtained in this way they were placed at a fixed distance from 
the camera, and photo-engravings were thus made of about one 
half the sizes of the original prints. 
The Morphological Laws of the Configurations.—The configura- 
tions made by the floating magnets form well marked groups 
or classes, which may be designated in order as primary, secon- 
dary, tertiary, quaternary, etc. The stable configurations of 
one Class form the nuclei to the succeeding ones. 
Looking at the diagrams the reader will see that figures 2 to 8a 
inclusive form the primaries. Figure 8d begins the secondaries, 
for it is the hexagon with 2 for nucleus. Configurations 8d, 8¢, 
9, 10, 10a, 11, 12, 18, 14, 15, 16, 17, 18a, 186 and 19a are secon- 
daries, having respectively for nuclei the primaries 2, 2, 2, 2, 
3, 3, 4, 4, 5a, 6a, 7, 7, 7, 8a, 8a. The configuration 10d is not 
found in the diagrams; it is the same as the 10 which forms the 
nucleus of 20, only the two central lateral needles are further 
removed outward from the vertical axis of the fig. 10. 
e group of 192 begins the tertiaries. Of these I do not 
give diagrams, but indicate their structure by giving the 
numbers of the secondaries forming their nuclei and then give 
the numbers of needles grouped around these nuclei. Thus, 
the structure of the configuration formed of 47 needles 1s 
indicated by 47=(18+14)+15; which means that 47 needles 
form a configuration which has 18 for its inner nucleus, sur- 
rounded by 14 needles, and these in turn surrounded by 15; 
and as 18+14 forms the tertiary which is the nucleus to this 
quaternary 47, we inclose 18 and 14 in parenthesis. 
I here give the configurations to 51 inclusive, which form 
begins the quinaries. 
he configurations of the same number of magnets are lettered 
a, 6, ¢, to indicate their degrees of stability ; a being always the 
most stable form. I have, however, lettered the configuration 
of 8 magnets in the order of their increasing areas in order to 
make them serve. better for the purpose of illustrating the phe- 
nomena. of isomerism. Really, 8c is more stable than 8d. 
Tertiaries, 
19% = 9410 25a = 12413 296 = 17412 
20a = 9+11 25d = 13412 30a = 17+13 
206 = 10410 26a = 13413 30b = 184+12 
2la = 10+11 266 = 14412 = 1841 
216 = 11410 27a = 14413 32 — 18+14 
276 = 16412 33 = 18+15 
23 =11+12 28a = 15413 34a = (8a+12)+14 
24a = 12+12 286 = 16412 
246 = 114+13 29a = 16413 
