Donnan's Second Moment Of Realization And A Solution?

Poul Anderson, After Doomsday, CHAPTER FIFTEEN.

"So -
"It was like a knife-stab. For an instant his heart-beat ceased. He felt a sense of falling. The pulse resumed, crazily, with a roaring in his ears." (pp. 152-153)

That is a moment of realization. What was like a knife-stab? We will be told.

When I was at school, a teacher devising numbers to the base 15 suggested:

10 becomes T;
11 becomes E;
12 becomes D (for a dozen);
13 becomes B (for a baker's dozen);
14 becomes F;
15 becomes 10.

The conversion table gives us:

Monwaingi (obscure numerals unfamiliar to Ramri)
R=0
M=1
N=2
O=3
P=4
Q=5
MR=6

Kandemirian
L=0
A=1
B=2
C=3
D=4
E=5
F=6
G=7
H=8
I=9
J=10
K=11
AL=12

Thus:
Donnan says that BA=PM=25 and that ABIJ=MOQMP=2134 - but they don't work out that way for me.