The Fourth Harmonic: The 4th harmonic shows how we deal with stress, strain, and struggle. When you construct a 4th harmonic chart, all of the conjunction, square, and opposition aspects in the original horoscope appear as conjunctions and this makes them easier to see. Of course, these aspects are pretty easy to see in the original horoscope as well, so what's the point? The point is that the minor aspects, the semi-square (45 degrees) and sequa-square (135 degrees), which are difficult to spot by a quick visual inspection, now appear as oppositions, and can be seen at a glance. Not only that, but other minor stress aspects (22 ½ degrees, 67 ½ degrees, 157 ½ degrees), which can take a very long time to locate, now become squares. In the 4th harmonic, whole patterns of stress aspects can be spotted, and this gives you a big edge for interpretation.
The horoscope of Francisco Assis, the Brazilian serial killer who killed at least nine women, doesn't seem, at first, to be excessively violent. But when you look at Francisco's 4th Harmonic Chart, you see another story. The Sun is opposite Venus, which can give feelings of being unloved. Yes, but lots of people have that and they don't become serial killers. What they don't have is Uranus making square aspects in the 4th harmonic to both the Sun and Venus. Uranus can make one prone to sudden, hysterical outbursts. Still, everyone born that day had the same thing. What else is there here to drive him over the edge? The Ascendant also makes stress aspects. It opposes Uranus and squares both the Sun and Venus. This makes a Grand Cross, a rare and highly stressful pattern. The Ascendant is very sensitive to changes in the time of birth. In the 4th harmonic chart, this Grand Cross could only have formed in a time interval of about 20 minutes!
But there's more to come. Mercury (the mind) Mars (violence) and Saturn (depression) make a T-Cross formation (another stressful configuration) in the 4th harmonic as well. Once again though, everyone born that day had the same thing. Why is this case different? Take another look at the birth chart. There is a close semi-square between Mars and the cusp (beginning) of the 8th house (death). Not only that, but Mars rules the sign of Aries, which happens to be the sign on the cusp of the 12th house (psychological problems) as well. This is the classic 8th house-12th house connection frequently found in the charts of serial killers. Where does the 8th house cusp land in the 4th harmonic chart? Opposite Mars, with square aspects to both Mercury and Saturn. It forms another Grand Cross. And this too, could only have been formed in an interval of about 20 minutes. It could take hours to see this in a birth chart. In the 4th harmonic chart, the conclusion leaps out at you.
What happens though, if you have harmonious aspects (sextiles and trines) in a 4th harmonic chart? The best example of that comes from Hamblin's "Harmonic Charts." It is the horoscope of a little known French Marshal from World War I, Franchet d'Esperey. Hamblin claims that sextiles and trines in a 4th harmonic chart show "effort towards pleasure, or pleasure in effort." In other words, someone who likes stress, strain, and struggle. Hamblin quotes Gauquelin's description of him:
"...he drove cars at maniacal speed and shot windows when there was nothing better to shoot."
In d'Esperey's 4th Harmonic Chart, there is a Grand Trine between the Sun, Mars, and Pluto, a perfect aspect pattern for a soldier. A Moon/Venus conjunction sextiles the Sun and Pluto and opposes Mars, making for a Kite formation. Here is someone who had an emotional need (the Moon) for action and violence (Moon/Mars) and got a lot of pleasure from it (Moon/Venus).
Muhammad Ali's 4th Harmonic Chart also has a lot of harmonious aspects, especially to the Mid-Heaven. The Sun makes a sextile and the Moon a conjunction, and both aspects are within one degree of being exact. This means that stress, strain, and struggle are more likely to bring him before the public. The Mid-Heaven also has a trine from Jupiter and a sextile from Uranus. In Ali's Birth Chart, Jupiter rules the 5th house (sports and games) and Uranus rules his 7th house (open enemies), a perfect setup for someone to become famous through competitive sports.
Robert Blake, the actor arrested for his wife's murder, has a 4th Harmonic Chart with a highly stressful T-Cross formation. There is a conjunction of the Moon (feelings, emotions) and Neptune (imagination, film), which helped him in his film career, but it is opposite Pluto (extremes) and all three of these planets make a square to Jupiter (expansion and over optimism). There is hostility towards women here, and when his emotions go, they can really go (Moon, Jupiter, Pluto T-Cross), especially if he happens to be under the influence of alcohol or other intoxicants (Neptune).