Mercury is the nearest planet to the sun, and thereby seen as most in tune with it. It is seen as the "spokesperson" for the Sun, feeding the Sun messages how he interprets and perceives it. A tranquil sun is likely to be upset by negative messages from a shaky Mercury. Despite being the smallest planet in the solar system, it is the most dense. Mercury represents communication, rationality, analyzing, adaptability and variability.
It is through Mercury that we are able to better understand the world around us, functioning as a bridge between a person and the world at large. It is important to consider that if the Sun fully believes something is bollocks, it will probably be insurmountable for Mercury to change that, no matter what aspects it makes. Mercury governs our education, environment, family, transport, communication style and physical dexterity.
Mercury is considered a personal planet, reflecting its basic psychological functions within the personality. It is only slightly less influential than the sun and the moon. Mercury rules Gemini, Virgo and is exalted within both Virgo and Aquarius.
Mercury's main influence is taking things apart and then putting them back together, presenting itself as an opportunistic planet, decidedly unemotional and curious.
Mercury rules over Wednesday, with many European languages having the word for Wednesday as similar to Mercury (Mercredi in French and Miercoles in Spanish).
Mercury is associated with health issues such as the nervous system, the brain, the respiratory system, the thyroid and the sense organs. It is linked to the animal spirits, alongside the Moon.
In Chinese astrology, Mercury is ruled by the element water which is diplomatic, kind and intuitive. In Indian astrology, Mercury is called Buddha, a word related to Buddhi ("intelligence") and represents communication.
Mercury in the Twelve Signs
♈ Mercury in Aries
Makes the intellect keen, quick at repartee, and inventive, acute, which, especially in correspondence, at times may lead to irony and sarcasm. A person with this position is a keen observer, intelligent and has a fertile mind; he has quick and clear conceptions which make him alert and ready for battle when discussion or argument arise.
Affliction makes rash, thoughtless, restless, subject to exaggeration. Fear and overstrain of thought should then be avoided, quiet, concentrated thought practiced. Inharmonious aspects may also read to stammering, especially in childhood. But seeing that this is merely a nervous trait, it will disappear as self-control increases.
Nervous headaches, neuralgia, dizziness, insomnia owing to overexertion, dullness, eye defect.
♉ Mercury in Taurus
Gives a good memory, although on the other hand learning does not come easily and quickly. Some outstanding opinions, hobbies, are usual, which become rather more and not less pronounced if met by opposition. When they are opposed quietly and logically, they will however prove not unreasonably vehement. Otherwise, Mercury in Taurus makes the native patient, reserved, steady-going, obedient, and gives love of art; judgment is guided by feeling.
When afflicted the person concerned should beware of becoming stubborn, inflexible, willful and stingy.
There is a tendency to stammer (when in a passion), difficulty with swallowing; a child with this position often has convulsions when cutting teeth. Further hoarseness, croup, sore throat, nervous deafness, disturbances in the genital and urinary organs (conjunction Virgo).
♊ Mercury in Gemini
Gives a keen, acute intellect, able to distinguish and compare clearly; not content with abstractions, but fond of realities. This position makes the native versatile, fond of novelties, witty, fitted for commerce. Mercury here is in its element and - if not afflicted - produces great clarity, logical insight and quick comprehension.
Affliction makes the native superficial, shallow, sly and gives changeable thoughts; honesty should be practiced as much as possible.
Gout and nervous pain in shoulders, arms and hands; asthma, bronchitis, pleurisy, intercostal neuralgia, nervous pain in the hips (Sagittarius). Breathing should be regularly practiced, speaking and singing be done moderately.
♋ Mercury in Cancer
Gives a very retentive memory and a summarizing view of things. Silence and devotion are the cause of success in work and career, but a weakness for praise and flattery often plays too great a part in behavior. Mercury in Cancer makes the native inventive, inquisitive, diligent, economical and tactful, but at the same time gives some inclination to gloom which is less desirable. Interest is felt in the study of antiques.
Affliction makes the native continually crave for new emotions, makes him curious and opinionated, leads to troubles in intercourse and brings financial disappointments.
Flatulence, spasms of the stomach, nervous affection of the stomach through anxiety or sorrow. The use of alcohol is very bad. A healthy imagination should be cultivated and exaggerated anxiety avoided.
♌ Mercury in Leo
The intellect is clear and pure, the style imaginative and rational. Speeches, talks, oral and written expressions having a definite aim or tendency, will succeed best and will have the desired result. Leo makes for broad conceptions and noble ideals and Mercury gives a pleasant manner of presenting them.
A certain autocracy in matters of intellect or spirit cannot be denied; contradiction or illogical arguments are always attacked, censored, and if possible made ridiculous. But sentence should not be passed too quickly! Mercury in Leo makes the native frank, kind-hearted, sympathetic, and capable of organizing, inclined to take the lead and order others, to work with great schemes, but ignore details.
Affliction renders him passionate, whimsical, and speculative.
Nervous palpitations of the heart, convulsions, fainting fits, swoons, backache, brain fatigue; beware of too great exertion, of sitting bent forward at study'
♍ Mercury in Virgo
Makes the native practical, apt to admonish, capable, fond of scientific research and of clear and logical judgement; reserved. This is a position for a student, a naturalist, who prefers to occupy himself with the careful, systematic investigations of small creatures or objects.
When afflicted the native will be irritable, caviling, inclined to set to work at many things at a time and to make light of things which are really serious.
Sensitive bowels, stomach ache, colic, diarrhea, constipation, nervous weakness, nausea, short-windedness, itching of the nose. Too much thinking should be avoided and regular habits are particularly recommended.
♎ Mercury in Libra
Gives a correct intuitive view of various matters, including articles of commerce. Has well-balanced thoughts for making plans, the gift of, comparison, and knowledge of goods. It will prove profitable to work in cooperation, to buy in association, to study and repeat with others. Mercury in Libra makes the native thoughtful, kind, humane; eloquent and more or less refined in intercourse, whilst he also loves and has a talent for music and art.
Affliction however, renders him unbalanced and arouses dishonest tendencies. His best work is done in combination with and under the guidance" of a sympathetic person, because otherwise some of the things which should be done will neither be begun, nor finished.
Affections of the kidneys, anuria, obstruction in the uretic tubes, nephritis, lumbago, dizziness, nervous headaches (Opposition Aries), eye troubles (Opposition Aries). It is bad to stand or study too long at a stretch.
♏ Mercury in Scorpio
Gives a well-developed, penetrating intellect. The native naturally takes great interest in all that is hidden, mysterious and peculiar, and no pains will be spared to get to know more of the mysteries surrounding, human lite. During school years most work will be done in natural history, cosmography etc. whereas in later life there will probably be much aptitude for the study of medicine (doctor, surgeon, nurse).
Great power of concentration and clear logical conceptions enable the native with the aid of a few observed facts to diagnose correctly. Very likely there may have been sexual experiences in early youth which do not leave a pleasant recollection. It will therefore, be very good to try and find an equivalent experience in some form of New Thought or other.
Mercury in Scorpio makes the native resourceful, gives much insight, and a great attraction on the one hand to the study of occultism, and on the other to mechanical pursuits for which he has much capacity.
Affliction makes sly, mysterious, sharp in remarks and admonitions, impudent, bold, querulous and apt to take things badly, obstinate, skeptical and sarcastic.
Pain in bladder and genitals, very sensitive genitals, sexual troubles, deafness, stammering, hoarseness (Opposition Taurus). Anxiety and fear and absent-mindedness should be overcome.
♐ Mercury in Sagittarius
renders the native quick and apt to say things which strike home and make for enmity. What is felt to be true is expressed to everybody and defended without any regard for the requirements of good breeding (especially with a Mercury - Mars aspect). Otherwise, this position makes him thoughtful, prophetic, earnest and religious. The problems of life are contemplated and advice to seekers is readily given. In social life, an inferior position will be more suitable than a responsible post.
The desire to go out into the world is very strong, also the wish to gather knowledge and express own thoughts to those who are willing to listen. Being a mist earnest thinker, Sagittarius often feels superior in his surroundings and does not therefore usually feel at home with, idle chatter and gossip. Mercury in Sagittarius moreover makes the native fond of justice, religion, and philosophy, freedom of thought and speech, also of traveling.
Affliction gives little perseverance, makes him rash, dissolute, changeable, given to caustic expression, both in speech and writing; dishonest and inclined to sophism
Weakness of hips and thighs, sciatica, paralysis, nervousness, nervous cough, asthma, pleurisy -(Opposition Gemini). This position warns against too much study and too great a strain on the mind.
♑ Mercury in Capricorn
The planet of the concrete mind in the particularly concrete sign Capricorn makes for a clear and logical faculty of thought. Conclusions are only based upon palpable facts and in every study, the greatest possible objectivity is displayed. In this way, very practical results are easily obtained and also understood by others, but much time will be required for this because in this position Mercury loses some of his quick, intuitive activity. He will not learn quickly, but thoroughly. Mercury in Capricorn further renders the native orderly, systematic, economic and diplomatic; it gives concentration of thought, reserve, dexterity and ambition.
Affliction makes him suspicious and melancholy, stingy rather than economical, jealous, spiteful, sly.
Rheumatism in the knees, gout, skin diseases, itching of the skin, intestinal troubles through anxiety and fear, costiveness, nervous indigestion, flatulence, backache.
♒ Mercury in Aquarius
Greatly strengthens the mental and intellectual faculties. The mind is very active, original and at times shows some glimpse of genius. Memory is particularly good and if sufficiently and regularly trained, might even recall facts and conditions of former lives. This position gives the desire for a large circle of cultured and intellectual acquaintances; only in intercourse with the other sex, it will be somewhat difficult to draw the line between purely mental understanding and, personal attachment. And yet this is desirable for the development of moral consciousness and social position.
Otherwise, this position is favorable for the study of human character and produces an agreeable talker, able to put forward new ideas in society. Mercury in Aquarius makes the native intuitive, independent, idealistic, a lover of art, sociable, inclining to abstract thought; astrological study attracts, as also spiritualistic and telepathic research.
Affliction makes him inclined to philosophize vaguel, renders unfaithful, critical; easily leads to slander and "sponging".
General nervous disorder, neuralgia, bad circulation of the blood, impure blood, twinging and smarting pain in the whole body, hysteria, impotence to walk, varicose veins, neuralgia. of the heart, palpitations of the heart. Such a person should not give way to fantasies of fear but use his reason to control them.
♓ Mercury in Pisces
The planet of the reasoning mind is somewhat strange in Pisces and therefore causes a continual conflict between logic and the "assurance of feeling". Things are often sensed as perfectly certain, for which no reasonable explanation can be given. This is usually caused by an excessive mobility of thought and too little "pure" reason. Moreover, the native's great openness to others' ideas often causes confusion.
For that reason, he has very little ability for purely intellectual discussion, although the fitness of others in this respect is much appreciated. Mercury in Pisces makes the native psychic, mediumistic, kind, and good-natured; inclines to mysticism and makes him sensitive to harmony and beauty.
Affliction leads to absent-mindedness, disposes to worry, gloom, despondency, listlessness, superficiality.
Sensitive feet (also too cold and damp), cramp and gout in the feet, phthisis (Square Gemini), general weakness and limpness, deafness. The feet should be kept dry and warm; the brain free from anxiety and excessive exertion.