Öfversigt af Finska Vetenskaps-Societetens Förhandlingar. 
Bd. LIX. 1916—1917. Afd. A. N:o 16. 
- Melting and boiling point of minerals I. 
An attempt to estimate the depth below the earth's 
surface at which mineral-substances of low 
boiling point may exist. 
By 
L. H. BORGSTRÖM. 
Most of the rocks and other mixtures of minerals, which 
constitute the crust of the earth melt at 800” to 1000” C. 
Mineral-substances, the boiling point of which is lower than 
these temperatures, may be brought to boil in the crevices 
and cracks of the earth. The boiling or the destillation of 
mineral-substances is of some significance in the formation 
of vein-filling mineral deposits and ore-bodies. The true 
conception of the conditions in temperature and in pres- 
sure which may bring about a destillation of this kind is 
of great geological interest. 
A dy of the laws governing the change of boiling point 
with changes in pressure may throw light on the case in 
question. The numerous formulas proposed to express this 
function are in part interpolation formulas with several con- 
stants and in part expressions founded on theoretical con- 
templations. The latter formulas contain factors of real 
significance. Unfortunately such factors are rarely deter- 
mined for mineral substances and in consequence thereof none 
of the expressions of the latter type are available for geolo- 
gical speculations. 
