Scientist of the Day - Daniel Bernoulli
Title page with engraved vignette, Hydrodynamica: sive de viribus et motibus fluidorum commentarii, by Daniel Benoulli, 1738 (Linda Hall Library)
Daniel Bernoulli, a Swiss mathematician, died Mar. 17, 1782, at the age of 82. He was born on Feb. 8, 1700, in the Netherlands, but his family was Swiss, and ordinarily lived in Basel. The Bernoulli family had more distinguished mathematicians than most small countries, 11 of them in all, spread over four generations. Daniel was third-generation, grandson of Nicolaus, nephew of Jacob, son of Johann. Surprisingly, father Johann picked Daniel to be the businessman of the family, which Daniel consistently resisted. He became a mathematician in spite of his father, and secured a position in St. Petersburg, where he managed to join forces with Leonhard Euler from 1727 to 1733. That was a brain trust.
Portrait of Daniel Bernoulli, oil on canvas, by Peter Portner, 1720-25, Basel Historical Museum (Wikimedia commons)
While in St. Petersburg (he left in 1733), Daniel completed a book on hydrodynamics, the physics of the forces exerted by and on fluids, which was eventually published in 1738. Indeed, Daniel coined the word “hydrodynamics” and used it for the title of his book (first image). We have a copy in our history of science collections, once part of the library of the American Academy of Arts and Sciences (the pencilled “+” on the title page tells us that), and like many of those books, acquired in 1946, it was immediately swaddled in a red buckram binding that is unfortunate. But the inside is perfectly fine.
Engraved title-page vignette, by I. M. Weis, Hydrodynamica: sive de viribus et motibus fluidorum commentarii, by Daniel Benoulli, 1738 (Linda Hall Library)
Bernoulli’s Hydrodynamica is best known for revealing Bernoulli's principle, which says that when a moving fluid increases its speed, the lateral (sidewise) pressure is reduced. This very important principle of physics predicts that if you make a fluid move faster, by say pushing air over the rounded top of an airplane wing, then it will exert less pressure than the slower moving air on the bottom of the wing, and voila! – you will have liftoff. The same principle explains why, if you narrow the passage in a carburetor though which air from the intake is rushing, it will draw fuel from the fuel chamber. Bernoulli’s principle is a very useful one in our modern age.
One interesting aspect of the story is that Bernoulli's father, Johann, a great mathematician himself, but not such a great father, got wind of what his son was doing, wrote his own book on the subject, called Hydraulica, and pre-dated the first part to make it appear it was published in 1732, well before the Hydrodynamica. Competition in the mathematical world is bad enough without being cut off at the knees by your own father. Daniel wrote a long and rather bitter letter to Euler, explaining what had happened and lamenting the fact that his father had tried to rob him of ten years of work.
First page of Sectio Prima, with engraved headpiece, Hydrodynamica: sive de viribus et motibus fluidorum commentarii, by Daniel Benoulli, 1738 (Linda Hall Library)
The large engraved vignette on the title page of Bernoulli's book is also of interest (first and third images). In the 17th century, a title-page vignette like this was usually a printer's mark and had nothing to do with the subject matter of the book. In the 18th century, this changed, so that title-page vignettes began to function like frontispieces or engraved title pages. This is certainly true here, as most of the elements – Archimedean screws, waterwheels, fountains – certainly fall within the purview of hydrodynamics. The artist who drew the title-page vignette, I. M. Weis, also provided a headpiece for section 1 of the book with many of the same elements, but made more intimate by the inclusion of two putti as lab assistants (fourth and fifth images).
Engraved headpiece, by I. M. Weis, with a putto turning an Archimedes’ screw, Hydrodynamica: sive de viribus et motibus fluidorum commentarii, by Daniel Benoulli, pag, e 11738 (Linda Hall Library)
Wikipedia reproduces a title page for the 1738 Hydrodynamica, where the letterpress is identical to ours, but the vignette – printed separately, on a different press – was accidentally exchanged for the headpiece. Mistakes like this happened a lot, when everything was done by hand, and all copper plates looked alike to the printer.
After returning to Basel in 1734, Daniel had to start out teaching botany, which was certainly a misuse of resources, but he moved up to physiology, and eventually to physics and natural philosophy, after the death of his father in 1746 (with whom he never did reconcile, although apparently he tried). He won ten prizes from the Paris Academy of Sciences in their annual competitions, which was an unusual series of achievements. When he died in 1782, he was buried, like many if not all of the Bernoullis, in Peterskirche in Basel. I could not find a wall plaque of Daniel in the church, although there must be one.
William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor emeritus, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to ashworthw@umkc.edu.
