Dr Muir on a Triangle and its Reciprocal. 299 
of the elements in each column is manifestly zero. In fact we may 
say that 1)7/ definition 
+ B2tt2 + Bgttg = 0 , RiPi + A2^2 + ^ 3^3 == ^ 5 ^l7l + ^272 + ^ 
+ C2tt2 + Cgttg = 0 , + Q>2^2 ■!“ ^3/^3 ~ ^ ’ ^l7l ^272 ^373 ~ ^ ’ 
or, more fully, that 
Aj A2 A3 
«i Pi 7 i 
1 0 0 
Bi B2 Bg 
^2 P2 72 
= 
0 1 0 
Cl C2 C3 
®3 /^3 73 
0 0 1 
