1900. No. 5. ON PARTIAL DIFFERENTIAL EQUATIONS, ETC. 43 
6b. Letting Z=o, G=o, F + 0, and D=o, we had the systems 
ou NE 
or 
ou 
ou ou 
20, Ee oe 
where A is determined by the quadratic equation 
HP —Ch+ F=o0, 
and where 
A "0. 
The corresponding systems of total differential equations are 
AHdy + Fds = 0 
Fax + 1Fdt— iBdy =o. 
Printed 29. November, 1900. 
