Generally defined as between 15°Libraand 15°Scorpio (although differing
sources place it at various points from the end of Libra to
the beginning of Scorpio). The
term translates as “fiery road” or “combust way” and it is considered to be a hostile
and debilitating area, particularly detrimental to the Moon. The basis of the
unfortunate reputation is possibly an early association with malefic stars,
such as the claws of the Scorpion; the fact that the Sun is in detriment in
Libra (losing its strength at the autumn equinox); the Moon is in fall in
Scorpio; and the two malefics are powerful (Saturn dignified in Libra by exaltation;
Mars dignified by sign in Scorpio).
Al Biruni's 11th century definition reads as follows:
The Combust Way
The Combust Way is the last part of Libra and the first of Scorpio. These two signs are not congenial to the sun and the moon on account of the obscurity and ill-luck connected with them, and because each of them is the fall of one of the luminaries. They also contain the two malefics, the one by exaltation (Libra, Saturn) the other by house (Scorpius, Mars). The peculiarity which has given the name muhtariq [burning] is that the exaltation of Saturn is near, the fall of the Sun being on the one hand and that of the Moon on the other, while the adjacent parts of both signs are occupied by terms of Mars.
Book of Elements ... translated by R. RamsayWright, 1934, v.514, p317.
Influence, or effective force or power.
Literally ‘empty’ of influence. The term is especially
applied to the Moon when it is out orb of any aspect, and suggests a lack of
impetus to move events in any direction. Void
of course is when a planet remains out of orb of any aspect for the
duration of its movement through its sign.