H, A. Rowland—Studies on Magnetic Distribution. 461 
No influence of a radial contraction has been observed; nor 
is there any effect in the direction of the waves of contraction 
which can be attributed to the rotation of the earth. 
In conclusion, it may be remarked that mountain-making as 
a whole can be regarded as a stiffening of the earth’s surface, 
which process has been determined by the distribution of 
certain older rigid masses. These may be made up of mount- 
ain lines pushed up together, and crossing each other, as in 
Bohemia, or they may consist of wide extended surfaces whose 
strata, even the oldest, have retained their horizontal position, 
as in the great Russian plain. These primitive masses conform 
to no geometrical law either in outline or distribution, though 
they have determined the form and course of the folds which 
contraction has produced in the more pliant portions of the 
earth’s surface between them. E. 8. DANA. 
Art. LV.—Studies on Magnetic Distribution; by Henry A. 
Row .anp, of the Johns Hopkins University, Baltimore. 
(Continued from page 335.) 
Table I. is from a bar 174 inches long with a magnetizing 
helix 13 inch long at one end, the zero-point being at the other. 
Table IT. is from a bar 9 feet long with a helix 43 inches long 
quite near one end, the zero-point being at 1 inch from the helix 
toward the long end. ‘Table IIL is from a bar 2 feet long with 
a helix 44 inches long near one end, so that its center was 193 
Inches from the end on which the experiments were made, the 
zero-point being at the end. 
TaBLE 1. Bar ‘18 inch diameter. 0 at end of bar. 
ve Qe. ag Y. 
L. Ob- Calcu- Error of Ob- Calcu- gi of 
served. | lated. Q’e- | served. | lated. 4 
0 27 ee pene 0 0° 0 
3 2 gies pasa age 8 35 +°8 
5 2-0 2-0 0 59 66 +t 
6 5 24 1 79 8.6 a 
7 3-2 2°8 aa | 10°4 11°0 + °6 
8 27 3°5 “ 13°6 13°8 +2 
9 4°3 4:3 0 17°3 173 0 
10 5:3 5-2 PO 21°6 216 
ll 6°5 65 26°9 26°8 it 
12 UT 8-0 +3 33-4 33°3 a 
13 9°5 9:9 +4 Al‘l 41°3 + 2 
14 50°6 51-2 +6 
Q’ = 2°60(e28L-e— 2181), 
Qe — 72°60(e 23h + eh) —_ “55 A(e 28h + iia * 
