— 91 — 
tertiar\' carbon atoms in double linkages. His experiments now show, 
that mentho- and carvomenthene, which both contain the double linkage 
in the nucleus, do not react with zinc chloride and acetic acid; menth}l 
chloride can also only be added very slowly to menthomenthene. 
Tetrahydrotoluene behaves in exactly the same manner as the menthenes. 
But the conditions are different with camphene and fenchene, on whose 
history and constitutions Kondakow expresses himself in detail; here 
the isomerides of the two hydrocarbons which contain the double 
linkage in the side-chain, are those which give rise to the formation 
of esters of tertiar}^ alcohols. 
It follows that in some degree Kondakow' s supposition, as at first 
expressed, has been confirmed, but with this reservation, that a double 
linkage with a tertiary carbon atom can only then be detected in 
hydroaromatic compounds by this method (i. e. by absorption of organic 
acids in the presence of zinc chloride), when it is present in the side- 
chain, and not when it occurs in the nucleus. 
We would here mention that Ert schikowsky has already years 
ago employed zinc chloride as a substitute for sulphuric acid in 
Bertram's hydration-method. 
In a treatise entitled ''Zur Geschichte der Fenchene", O. Wallach^) 
opposes Kondakow's statement on the development of the ideas 
regarding the constitution of fenchene, a statement w^hich does not 
agree on all points with the actual facts. He shows there that Kon- 
dakow's reproach, that he (Wallach) had only formed an opinion 
on the constitution of these hydrocarbons by appropriating the vie\^'S 
expressed by Kondakow, is perfectly untenable, and only proves 
the awkwardness of the situation which results when one chemist 
invades the sphere of action of another, without awaiting the com- 
pletion of the particular subject by the earlier investigator. 
Sabinene. In continuation of his researches concerning sabinene, 
the hydrocarbon characteristic of oil of savin, F. W. Semmler has 
made a further stud}^ of the sabinene ketone CgHj^^O which is formed in 
the oxidation of sabinene with potassium permanganate^). In conformit}' 
with its saturated character, this ketone undergoes very little change if it 
is attempted to oxidise it further with potassium permanganate; on the 
other hand, it is readily split up into a dibasic acid CqH^^O^, if it is 
submitted to the action of an alkaline solution of bromine. As this acid 
^) loum. der mss. phys.-chem. Ges. 28, 132; compare Bull. Soc. chim. III. 16 
2) Journ. f. prakt. Chemie II. 65 (1902), 586. 
^) Berliner Berichte 35 (1902), 2045. 
