Les Raisons des Forces Mouvantes

Salomon de Caus, 1615

Jean Salomon de Caus (1576-1626) was a French architect and hydraulic engineer, best known for working for the Elector Palatine of Heidelberg. He was born in Normandy into a Protestant and Huguenot family (a religious group of French Protestants who followed the Calvinist tradition of Protestantism), and moved at an early age to Great Britain because of religious conflicts, where he began his education. Later, between 1595 and 1598, Salomon de Caus studied in Italy where he had the opportunity to visit Bernardo Buontalenti's garden at Pratolino in Florence and the Villa d'Este at Tivoli, which gave him inspiration for several gardens and water features.

During the following years, he was working as an engineer and architect in Netherlands, Belgium, England, and Germany. His work in Britain for the Prince of Wales included several places, such as Richmond Palace, Greenwich Park, Wilton House, Somerset House, and Hatfield House. While in Germany, his work focused mainly on Heidelberg Castle with the Elisabethentors and Hortus Palatinus.

It was during his German period that Salomon de Caus published, in 1615, his volume Les Raisons des Forces Mouvantes avec diverses machines tant utiles que plaisantes. It is a treatise on hydraulic, written in French and German and influenced by the texts of Heron of Alexandria. In this work, the author presented and analyzed several hydraulic devices: mechanical fountains, water games, water wheels, mechanisms of hydraulic grottoes, and other automates. As for the structure of the volume, it is divided into three books where he explained the fundamental laws of air, fire, and water, and applied it on the building of the machines. In particular, the first book includes 37 problems on hydraulics, specifying how to use mechanical devices in order to produce sound. The second book discusses 28 designs for grottos and fountains for palaces and gardens. The third and final book deals with organs’ building and includes 17 proposals. Each proposal is structured in two sections, where he outlined the introduction of the invention (propositio) and then the explanation (declaratio). He published a second edition in Paris in 1624, where were included ten problems with corresponding illustrations.

Salomon's treatise is particularly widespread. As far as the Iberian Peninsula is concerned, the volume can be found in its second editions at the National Library (BNP) of Portugal and in Spanish libraries, such as the Royal Palace Library, the Library of the School of Architecture in Madrid, the National Library of Spain (BNE) and the University Library of Navarra (it is significant to point out how, between 1580 and 1640, Spain and Portugal were under the same crown).

After the discovery of the texts from Heron of Alexandria, along with the knowledge of that time, it was possible to provide a better development of the hydraulic mechanisms, in which Salomon’s work had remarkable importance. His influence could be seen, for instance, on the Hellbrunn Palace, near Salzburg in Austria, with mechanical birds singing, grottos with sea creatures, and water games.

Editions & translations

  • The book was first published in Frankfurt, Germany, in 1615.

  • The second edition was published in Paris in 1624.


[1] Morgan, L. (2007). Nature as model. Philadelphia: University of Pennsylvania Press.

[2] Maks, C. (1935). Salomon de Caus 1576-1626. Paris: Imprimerie Jouve & cie.

[3] Munch, A. (1854). Salomon de Caus. Christiania: C. Tønsberg.

[4] Picqué, C. (1879). Salomon de Caux gravant sa médaille (1st ed.). Bruxelles: Gobbaerts.