42 ALF GULDBERG. M.-N. Kl. 
sb. Letting F=0, G=o, E +0, and A=0o, we had the systems 
where å is determined by the quadratic equation 
MR — Bi +- C=o, 
and where 
TD), 
The corresponding systems of total differential equations are 
)Hdx + Eds = 0 
Edy + 1Edr — 1Cdx =o. 
6a. Letting Z=o, G—0, F + 0, and D + 0, we had the systems 
where A, and À, are the roots of the quadratic equation 
D2j? CD, + BD + FH =o, 
and where | 
A=o. 
The corresponding systems of total differential equations are 
Di,dy + Fds — Ddz = 0 
Håy + à, Dds + Dat =o. 
