Di 
ee ER ee 
== Pi Ory D= a (a dut iF DRE 
i 1 
IS F (a—2b'—c), E= ri (a’+2b—c), C= 
Thus we find generally 
E + h(A—B) & + 2k (E56) En Hele = (pe E) n° | dy 
+] ~k (AFB) yf — 2h (C+ C) En — = W+) |as=0 (4) 
and when C’ = 0 or a’ +c’ =0 
[E+ au —B)E + 240% + ED B) | 
-- E — k(A+ B) 7? — 2hCEq — 7 (DE) e | dE = 0 (B) 
where 
ot ; 2 (a'— DE __ t(a+e) 
en tant ta 4 yet 
Q 2 (a +5) 
D= > le-WjE 
If now we compare with (B) the first equation (1) of Art. 1 we 
have 
. hk? 
h(A—B)=1, UC —(D—E) = 
he 
—k(A+B)=1, —2hC=w — 7 @+E)=v 
which may be satisfied by taking 4 = -—— h and 
f= 0, Sid 
or 
Alk 
This first equation therefore belongs to our class VI. 
In the same way we may infer that 
(2) belongs to class V 
— 
(3) is a special case of class 
(4) belongs to class VII 
(7) is a special case of class I 
(9) is a special case of class VI 
(11) is a special case of class I. 
If now C’=—0 we compare with (4). This gives for the fifth 
equation of Art 1 
4* 
