— 94 — 
with sodium, the tetrahydro ketone absorbs only two atoms h} drogen, 
and is converted into an alcohol Cg Hjg O. The latter is specially 
interesting for this reason, that it represents a low homologue of the 
terpineol melting at 35°, as is proved by the formula 
OH 
HgC CH 
Hc» C CH9 
Borneo!. Minguin and Gregoire de Bollemont^) have 
examined a series of esters of laevo-bomeol (Ngai camphor) prepared 
by means of fatty and halogenated fatty acids, for their optical rotatory 
power. For equimolecular alcoholic solutions (Y^ gram -molecule in 
1000 cc absolute alcohol) of homologous esters of the fatty acids series, 
the same rotation, ajy = about 4,30° in a 200 mm tube, was observed 
in almost every case; for the halogenated esters examined, the rotation 
also was uniformly 4,80°. This confirms that the proposition of the 
constancy of the molecular rotatory power, laid down by Tschugaeff 
for the esters of menthol, also applies to the homologous bomyl esters 
of fatty acids; but in both cases the esters of formic acid must be 
eliminated from the series. 
A work by Minguin on isomeric borneols and their esters, which 
appears in the same publication, deals with the crystallographies) pro- 
perties of these bodies. The succinic esters of d- and 1-borneol are 
dimorphous; they crystallise from petroleum ether in hexagonal tablets, 
from methyl alcohol in rhombic prisms. Both crystal -forms are 
remarkable on account of the occurrence of certain zones which have 
also been observed with the crystals of the condensation - products 
from camphor and aromatic aldehydes, and also with camphor itself. 
If, further, a mixture of d-borneol and 1-isobomeol is converted into 
the succinate, and crystallised from methyl alcohol, petroleum ether, 
or otherwise, it always yields hexagonal tablets, and never the rhombic 
prisms. The isobornyl esters are therefore isomorphous, but not 
isodimorphous with the corresponding bornyl esters. The same thing 
occurs, if the mixture of d-bornyl and 1-isobomyl succinates is crys- 
tallised from methyl alcohol or petroleum ether. The crystals of 
racemic bomyl succinates could not be measured on account of their 
minuteness and opacity, but under a magnifying glass their totally 
different character from the active forms could be observed, such as 
^) Bull. Soc. chim. III. 27 (1902), 593."" 
-) Bull. Soc. chim. III. 27 (1902), 683. 
