Franz Kessler (c. 1580–1650) was a portrait painter,

scholar A scholar is a person who pursues academic and intellectual activities, particularly academics who apply their intellectualism into expertise in an area of study. A scholar can also be an academic, who works as a professor, teacher, or researc ...

inventor An invention is a unique or novel device, method, composition, idea or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an i ...

and

alchemist Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim world ...

living in the

Holy Roman Empire The Holy Roman Empire was a political entity in Western, Central, and Southern Europe that developed during the Early Middle Ages and continued until its dissolution in 1806 during the Napoleonic Wars. From the accession of Otto I in 962 ...

during the 16th and 17th centuries.

Writing

He wrote a number of books and pamphlets: a book on stoves, on making sundials, on using a "sector" or "proportional instrument" (a simple calculator), and on using "

Napier's bones Napier's bones is a manually-operated calculating device created by John Napier of Merchiston, Scotland for the calculation of products and quotients of numbers. The method was based on lattice multiplication, and also called ''rabdology'', a wor ...

" (another calculator) – among other works.

Painting

In the 1620s and 1630s, he was a portrait painter in Cologne, Germany.

Inventions

He wrote a book called ''Unterschiedliche bisshero mehrern Theils Secreta oder verborgene, geheime Kunste'' (Various until now mostly Secreta or hidden, secret arts), which was published in

Oppenheim Oppenheim () is a town in the Mainz-Bingen district of Rhineland-Palatinate, Germany. The town is a well-known wine center, being the home of the German Winegrowing Museum, and is particularly known for the wines from the Oppenheimer Krötenbr ...

in 1616. The first five chapters of this book deal with communicating via a crude Aldis lamp. In the same year he built an improved

diving bell A diving bell is a rigid chamber used to transport divers from the surface to depth and back in open water, usually for the purpose of performing underwater work. The most common types are the open-bottomed wet bell and the closed bell, which c ...

.''Unterschiedliche bishero mehrentheils Secreta oder verborgene geheime Künste. Deren die erste, genannt Ortforschung, dadurch einer dem andern die freye Luft hindurch über Wasser und von sichtbaren zu sichtlichen Orten, alle Heimlichkeiten offenbaren und in kurzer Zeit zu erkennen geben mag. Die andere Wasserharnisch, dadurch jemand etliche Stunden ohne Schaden Leibes und Lebens unter Wasser seyn kann, nach Belieben seyn Vorhaben zu verrichten. Die dritte Lufthosen, mit welchen man wunderlich über See und Wasser nach Wohlgefallen ganz künstlich gehen kann. Sammt beygefügten wohlerdachten Schwimmgürtel, welchen jedermann so wohl bey jetzt benennten Wasserkünsten, als sonst andern Wasserreisen nur Noth zu gebrauchen hätte. Alles ohne Zauberey und Schwarzkunst, den recht göttlich - natürliche Geheimnissen - Liebhabern zu gefallen beschreiben; mit Figuren geziert und erstlich an den Tag gegeben, durch Franz Keßler Conterf. von Wetzlar 1617.''
[Various hitherto mostly Secreta or hidden secret arts. (1) The first of which, called "reconnaissance", whereby one may communicate openly and quickly all secrets to another person through the open air, over water and between places visible to each other. (2) The other, a water harness [i.e., a diving bell that the diver bears on his shoulders via a harness], whereby anyone can be under water for several hours without harm to life and limb, to execute one's plans at will. (3) The third, waders with air-filled floats, with which one can go wondrously across sea and water at one's pleasure quite ingeniously. Together with an attached, well-conceived swimming belt, which anyone would have to use during the above-mentioned water arts as well as during other water-travel (in distress only). All without sorcery and black magic, written to please the truly godly lovers of natural secrets; adorned with illustrations and first brought forth by Franz Keßler, portraitist from Wetzlar in 1617.]
(Oppenheim, (Germany): Hans Dietrich von Bry, 1617). A 1722 edition of this book is available on-line from the state library of Sachsen-Anhalt. Illustrations of Kessler's (1
signaling apparatus
(2
diving bell
and (3
inflatable waders

References

External links

{{DEFAULTSORT:Kessler, Franz 1580s births 1650 deaths 17th-century German scientists German alchemists 17th-century German painters German male painters Artists from Cologne 17th-century alchemists Scientists from Cologne