1895 - 96 .] Mr W. N. Hartley on Changes in Oceanic Deposits. 31 
Heat Units. 
Ca + O 
= CaO (solid) 
+ 132 
Ca + O 
= CaO (dissolved) 
+ 150*1 
CaO + H 2 0 
= CaH 2 0 2 (solid) 
+ 15 
Ca+C + 0 3 
= CaC0 3 (solid) 
+ 269-6 
CaO + C0 2 
= CaC0 3 (precipitated) 
+ 19-6 
Ca + S + 0 4 
= CaS0 4 (solid) 
+ 320 
Ca0 + S0 3 (solid hydrate) = CaS0 4 *2H 2 0 (solid salt) +49*4 
S + 0 3 + H 2 0 = H 2 S0 4 (solution) +141 
S + H 2 =H 2 S (gas) +4-6 
S + H 2 = H 2 S (solution) -9 -2 
H 2 + 0 =H 2 0 (liquid) +69 
;r(C 6 H 10 O 5 ) = cellulose x( + 228-8) 
Precipitated 
H 2 S0 4 (dissolved) + CaH 2 0 2 (dissolved) = CaS0 4 *2H 2 0 + 31 ‘2 
Calcium sulphate in solution, or precipitated, has a heat of forma- 
tion derived from S + 0 4 + Ca= 141 + 150*1 + 31 ‘2 = 322’3 heat 
units. 
Fermentation of Cellulose and Starch. 
(1) C 6 H 10 O 5 + H 2 O (liquid) = 3CH 4 + 3C0 2 
' + 3(18-9) + 3(94-3) - 228-8 - 69 
Total = + 41 -8 kilo, heat units. 
The Reduction of Calcium Sulphate. 
(2) CaS0 4 (dissolved or precipitated) + CH 4 = CaC0 3 + H 2 S + H 2 0 
+ 269-6 + 4-6 + 69 - 322-3 - 18-9 
Total = + 2*0 kilo, heat units. 
(a) H 2 S (solution) + 0 = H 2 0 (liquid) + S (solid) + 69 + 9*2 
Total = +78 '2 kilo, heat units. 
(b) S (solid) + 30 + H 2 0 (liquid) = H 2 S0 4 (solution) + 141 kilo. 
heat units. 
Equations (1) and (2) represent changes which take place con- 
currently, in both cases with heat evolution. 
If the methane in (1) is oxidised as in (2) concurrently with its 
production we have a total heat evolution +47*8 units. The 
gaseous H 2 S being evolved, its heat of formation is +4‘6 heat 
units, but it soon goes into solution, and its heat of formation is 
