The Rosicrucian Order is a legendary and secretive Order publicly documented in the early 17th century. The Rosicrucian Order is viewed among earlier and many modern Rosicrucianists as an inner worlds Order, composed of great "Adepts." When compared to human beings, the consciousness of these Adepts is said to be like that of demi-gods. This "College of Invisibles" is regarded as the source permanently behind the development of the Rosicrucian movement.

This image is from the 18th century book titled Geheime Figuren der Rosenkreuzer, aus dem 16ten und 17ten Jahrhundert (Secret Symbols of the Rosicrucians from the 16th and 17th Centuries.) The University of Wisconsin Digital Library scanned and posted the entire tome, rich with stunning and cryptic illustrations, on their History of Science and Technology site.
Geheime Figuren der Rosenkreuzer, aus dem 16ten und 17ten Jahrhundert: aus einem alten Mscpt. Zum erstenmal ans Licht gestellt: erstes -[drittes] Heft
(1785-[1788])

The ever excellent University of Wisconsin Digital Library has recently posted 'Geheime Figuren der Rosenkreuzer, aus dem 16ten und 17ten Jahrhundert' ('Secret Symbols of the Rosicrucians from the 16th and 17th Centuries') to their History of Science and Technology subsite. It was published in 1785-1788. There are multiple format page images available (click 'display gallery view').

This 18th century compendium, drew on 17th century alchemical sources such as Adrian von Mynsich, with mystical pieces from Valentin Weigel, and Abraham von Franckenberg's works on Jacob Boehme. It was an important and influential source of Rosicrucian ideas, albeit filtered thtough an 18th century perspective. Geheime Figuren der Rosenkreuzer, aus dem 16ten und 17ten Jahrhundert. Erstes Heft. Aus emem alten Mscpt. zum erstenmal ans Licht gestelit. Altona, 1785. Gedruckt und verlegt von J. D. U. Eckhardt. Zweites Heft. Altona, 1788.

Adam McLean tells us:

"This 18th century compendium, drew on 17th century alchemical sources such as Adrian von Mynsich, with mystical pieces from Valentin Weigel, and Abraham von Franckenberg's works on Jacob Boehme. It was an important and influential source of Rosicrucian ideas, albeit filtered through an 18th century perspective."

Adam has posted translations from a selection of images here.

Sources:
Geheime Figuren der Rosenkreuzer, aus dem 16ten und 17ten Jahrhundert: aus einem alten Mscpt. Zum erstenmal ans Licht gestellt: erstes -[drittes] Heft
(1785-[1788])
http://digital.library.wisc.edu/1711.dl/HistSciTech.GeheimeFiguren
http://en.wikipedia.org/wiki/Rosicrucian
http://www.boingboing.net/2006/11/13/secret_symbols_of_th.html
http://bibliodyssey.blogspot.com/2006/11/secret-rosicrucian-symbols.html
http://www.levity.com/alchemy/secret_s.html