599 
For the sealars 4 and u from (20) follows: 
figs fale? Wise 0 6 o 6 6 5 6 (20) 
NaS NW See eon et a ale TEE) 
and from (18) for *h: 
Ien 
hi = Aj ij ij, sne ate EEE (29) 
J 
and 
OOMEN) 
or 
Dei BH) 
In the special case that in is V‚_—-normal, (B) gives: 
ine ONNIE (32) 
hence ‚h — 0. Instead of (17) then the equation holds: 
Ti, es gta bh cant aee) 
By means of the idea of geodesic alteration, that is alteration 
with respect to a geodesically moving system, a simple geometrical 
interpretation can be given to the canonical directions. In conse- 
quence of (17) and (30): 
prin Uti aver Wii ZN Sin wl ike (34) 
Now ziz1 Vin is the geodesic increment of i, when moved in the 
field along ig pro unit of length, and so i;i,? Vi, is the projection 
of this specific increment on the j-direction, i.e. the specific geodesic 
rotation in the m —j direction. Hence when „Bz is the bivector of 
specific geodesic rotation of the system i,,...,i, when moved in the 
k-direction : 
in! V tc = „Br! in A hy Pa Sent Oee rt ANNE (35) 
then i;1,2 Vin is the 7j-component of „Br: 
in ij 2 „Br = ij ik ? V iy, i] F k. . . . . . (36) 
So the nj-component of the rotation „Br is equal to the nk-compo- 
nent of the rotation „By. ) 
When i, is V,—;-normal, we get in consequence of (831) and (82): 
ATA Wee (Dm ae ar (37) 
Thus the nj-component of „Bz is zero when j # k, or: the geodesic 
h Rrcor, Dei sistemi, p. 303, gives another geometrical interpretation, in which 
he makes no useof the idea geodesically moving. Then however it is necessary to 
lay the Vn in a euclidean space of more than 7 dimensions. 
