The Via Combusta is an area of the zodiac that has a very distinct reputation for causing difficulties. Being stationed somewhere between the signs of Libra and Scorpio (the exact location of the Burnt Path is different depending on who you ask), its properties of ruin have been exaggerated over time.
The most popular or well known definition of the Via Combusta is that it stretches from 15° Libra to 15° Scorpio, this is also the longest of the different locations proposed for it throughout the tradition. The difficulty in this area of the Zodiac is likely due to many of the malefic fixed stars that inhabit the sky from the Southern Scale through the claws of the Scorpion and that they will still influence the planets that move through the area.
Other, shorter, locations of the Burnt Path are related to the exact traditional Falls of the Sun and Moon which are held to be at 19° Libra and 3° Scorpio respectively. This would imply that the destructive power of these degrees is reliant on the lack of power the luminaries have here. A darkness so deep that the brightest lights struggle to shine, and with them the life force they produce suffers.
That all being said, many astrologers assume that all planets are injured in the Burnt Path, but this doesn’t seem to be the case. Traditionally, it seems that the Moon is the only planet who is debilitated in this area. In Bonatti’s 146 Considerations, he supplies a list of the ways planets are debilitated or harmed (10 ways for those wondering), but he also has a separate list for the Moon who has her own ways of being injured (she has 17). In the list for the Moon he states that her being placed from 15° Libra to 15° Scorpio makes the Moon ill-afflicted, but this item is not on the list for the planets.
So what does this mean for horary? Well not a whole lot. If the Moon is placed in the Via Combusta in a chart, it’s likely to just show a state of emotional turmoil for our querent or some sort of inherent difficulty in their situation that is not easily remedied. It could also show someone who feels under attack in some way by their surroundings. It is perhaps easier to imagine the Via Combusta as a second place wherein the Moon can be Combust, and follow through with similar descriptive words: fear, anxiety, inability to move forward, difficulty taking information, etc.
There are a couple of instances of the Void Moon in Lilly’s Christian Astrology example charts, but unfortunately it’s almost like he doesn’t realize that is where she is due to the lack of information about his thoughts in interpreting it. There are two questions where Lilly calculated the Moon within the range of the Via Combusta, but there are also a couple charts that computer calculations show the Moon there, but Lilly’s calculations show it just outside. In both of the questions, Lilly pays much more attention to the Moon being in her fall of Scorpio and the significance this has over the person she signifies. Perhaps we should follow in Lilly’s example.