of Edinburgh , Session 1885-86. 
595 
A B 
Evidently — 1 and are respectively the cosine and sine of some 
angle. Let it he a. Then we have 
7] = Pj cos (0 - aj + P 2 cos 2 (0 - a 2 ) + 
Having determined P 2 and a x for the first junction, and a 1 ' are 
determined in the same way for the second. 
Then 
and ttj' - a x = qx, 
where x is the distance between the junctions. Having calculated 
p and q, the conductivity k may be found by the formula 
K 7 T 
— PQ = ^ i 
cp 1 ■ T 
where c = specific heat, 
p = density, 
T = length of period. 
Detailed below is the full working ooit for the period during which 
the readings above given were taken : — 
Junction X. corrected for A 0 
6 Af - 2(v 0 ~ Va) + (Vi ~ Va) ~ (^4 - Vs) 
Vo = 77 - 9-01 
= -31-8-12-35-3-9= -48-05 
Vl = 15-8 = - 0-91 
.'. Aj= - 8-01 
tj 2 = 2815 = +11-44 
2 V®Bj = (vi - v 5 ) + (va ~ V 4 ) 
773 - 23-5 = + 6-89 
= 5-2 + 13-65 = 18-85 
= 14-5 = - 2-21 
.-. \/3B 1 = 9-43 .-. Bj-5-48 
V 5 = 10-6 = - 6-11 
6 |100-25 
.-.Pi = 9 706 and 04 = 145° 37' 
.*. A 0 = 16-71 
Junction II. as above. 
Vo = 7*6 = — 2 "85 
6 Af = -23-15 
Vi = 7-7 = - 2-75 
.-.A! = - 3-86 
77 2 = 11 0 = + 0-55 
2V3Bf= - 2-65 
773 = 15-05 - + 5-60 
.-. Bf = - 768 
774 = 12-2 = + 1-75 
t 7 5 = 9-15 = - 1-30 
6 [627 
.\ Pf.= 3-936, of = 191° 19'. 
A 0 = 10-45 
P 
log ^b=^a? + log e. . -.jo=708 
of - a ± = qx . • . q = '6 25 
cp 
pq- 
.-. /c= '005. 
(in C. G. S. units). 
