Plate XXIII. 
| 
rT “N\ a 
amu Hl . <a git z 
= A r L-; ce E 
Bic T peal | 
Z 
a See 
| ep ill 
| et| 
ee 
3+ 
: 
pe 
Serco : 
—4 
| 
bee 
al 
t— 
Construction showing Hy 
the Minimum LATENT HEAT of |__ 
QUARTZ 
a 
—| 
1500° 
2000° 
