Popularized by Manly P. Hall in Secret Teachings of All Ages (1928) as "The Hand of Mysteries". Hall wrote it was redrawn from an 18th century watercolour, artist unknown. It can be found in a hand-copied manuscript in his collection, "Das Buch mit Sieben Siegeln" (The Book of Seven Seals):
Isaac Holland was covered in A.E. Watie's "Lives of Alchemystical Philosophers" (1888):
Contemporary with Basilius Valentinus were Isaac the Hollander and his son, who are supposed to have worked with success. They were the first alchemists of Holland, and their operations were highly esteemed by Paracelsus, Boyle, and Kunckel. In practical chemistry they followed the traditions of Geber, and their alchemical experiments are the most plain and explicit in the whole range of Hermetic literature. They worked principally in metals, describing minutely the particulars of every process. Their lives are almost unknown. "Buried in the obscurity necessary to adepts, they were occupied in the practice of the Hermetic science, and their study or laboratory was the daily scene of their industrious existence..."The German wikipedia has some other information (translated):
"Johann Isaac Hollandus was a Flemish alchemist of the 16th and 17th centuries. He published a series of papers partially with another Isaac Hollandus, probably his father, all until 1600 and published thereafter. However, it is not even certain whether it is really to historical figures and not pseudonyms. 
The earliest manuscripts are from the period around 1560 that the first prints of 1572. Later came to the 17th century apparently added other writers who published under her name. 
The vital statistics are controversial (older authors such as Hermann Kopp laid it even in the 14th century or later than the beginning of the 15th century  ) and it is little known, except that it had a reputation as an excellent chemist (eg even with Robert Boyle ). Most Isaac is assumed to be the father of Johann Isaac, sometimes as brothers, sometimes as a single person, others consider them fictional characters or pseudonyms. The name Hollandus has only to the country of origin, so that even their surnames are unknown. After Karl Christoph Schmieder  and Edmund Oscar von Lippmann they were probably Jews."
This text was first published included in "Sammlung unterschiedlicher bewährter Chymischer Schriften, ... Hand der Philosophen, Opus Saturni, Opera Vegetabilia, Opus Minerale, Cabala, de Lapide Philosophico, Nebst einem Tractat von den Irrgängen derer Alchymisten..." (1667)
The Hand of the Philosophers
This is the Hand of the Philosophers with their dear secret signs, with which the old sages united with each other and took oaths. Nobody can understand this Hand with its secret signs, unless he becomes first a juror of the philosophers, (one who swore loyalty to a philosopher), and has loyally served them in the Art Alchemia. Consequently, those who have not this Hand and do not understand its secret signs, nor have taken the oath of loyalty, are bastards in this Art. They do not possess the philosopher's treasure. That is why I advise all those who do not possess the secrets of the Hand not to start working in the alchemical Art, nor to believe books or writings, since they will all only be cheated in the Secrets of the Hand. Therefore, everybody had better be careful.
In this Hand is locked the secret of the philosophers, that is, of the seed and the earth, as will be told later.
Now then, f will teach my child and describe the secret, hidden matter of the wise philosophers and masters of the true Art Alchemia. Nobody can use it unless he take the oath and swear not to divulge the Art and secrets and hidden signs of the sages, except he finds that it would be a good placement. In that case, he should also request the oath that that man should not use the Art except for the salvation of his soul. OnIy then can he be given the secret signs of the philosophers or sages, with their hidden signs and meanings.
1. The Thumb
First look at the thumb on which stands the crown next to the moon, one quarter old. By this is meant saltpetre.
For just as the thumb vigorousry finishes off the hand, saltpetre does in the Art Alchemia, for he is the King and Lord of all salts. He is the miIl through which everything must be ground. His nature ie elsewhere sufficiently described.
2. The Index
The second sign and secret of the philosophers is the STAR with six points, standing above the foremost finger next to the thunb. It is compared to Roman Vitriolo, because no work that is to be perfect can be completed without vitriol; for it is the greatest and strongest salt after saltpetre. His nature is elsewhere sufficiently described.
3. The Middle Finger
The third sign of the philosopher's Hand is the SUN, standing above the third finger. By it, Sal Ammoniac is designated, for apart from saltpetre and vitriol. Do thing more powerful is found than Sal Ammoniac. That is why it is the third secret.
4. The Ring Finger
The fourth sign of the philosophers is the LANTERN, standing above the fourth finger of the Hand, whereby Alumen Roche in indicated; for without alum, no perfect work can be accomprished, because it is reguired for the Red and the White. ft has an astonishing nature and the most subtle Spinitus. It is described elsewhere.
5. The Little Finger
The fifth secret and sign is the KEY of the philosophers, standing above the little finger. Simultaneouely, it is the lock of the Hand. That is why the key is standing on it. By it, common salt is designated, for salt is the Key in this Art.
6. The Middle of the Hand
The sixth secret sign is the FISH.. It stands in the middle of the Hand and signifies Mercury, for without Mercury or the fish, nothing can be done, He is the beginning, the middle and the end, and he is the priest who must marry everything. And he is the male and the seed; he is the water out of which all metals have originated; and he is the principal (factor) of all Arts, and the greatest of all secrets.
7. The Palm
The seventh sign of the philosophers is FIRE. By this Sulphur is indicated. It is the earth and beginning of all metals. It is the female who brings forth the fruit. For no seed can grow unless it be first thrown into fertile soil. Then beautiful fruit will come from it. Thus it also happens that when a pure Mercury joined to a pure Sulphur, it brings forth pure fruit. Thus are man and woman, father and mother, fire and water, seed and
earth. This is sufficient about the seven secret signs of the philosophers. He who understands well this Hand and its signs, and can work with it, will derive joy from it.