95 
stone of that district became charged with bitumen, the 
latter penetrated into a cavity which it traversed in long 
stalactite drops. Subsequently the cavity was more or less 
filled with crystals of calcite and sulphide of iron, which 
were deposited by the water charged with those substances 
around the drops of bitumen. The heat by which the bitu- 
men found its way into the rocks must have disappeared 
before the crystals were formed ; for had the latter been 
the result of hydrothermal action, they may have been 
coated, but certainly could not have been traversed by the 
solid bituminous stalactites. 
“ On the Boiling Points of the normal Paraffins and some 
of their Derivatives,” by C. Schorlemmer, F.R.S. 
It is generally asserted that the boiling points of the 
members of homologous series increase regularly for each 
increase of CH 2 . Thus it is stated that in the series of the 
alcohols and fatty acids the boiling point is raised 19° for 
each addition of CH 2 , whilst in other series this difference 
is sometimes smaller, sometimes larger, but always the 
same in the same series. But in many cases the boiling 
points calculated by this rule do not agree at all with those 
which have been observed. One reason for this discrepancy 
is that the compounds of which the boiling points have been 
compared are not true homologous bodies, i.e. that they 
have not an analogous constitution although they differ 
in the composition by CH 2 or a multiple thereof. During the 
last year, however, we have become acquainted with some 
true homologous series, namely, the series of the normal 
paraffins and the normal alcohols and their derivatives. 
In a paper read before the Royal Society I have already 
pointed out that the difference between the boiling points 
of the lower members of these paraffins is not the same, 
