René Grillet de Roven

A great man is always willing to be little.
Ralph Waldo Emerson

In 1673 the Parisian mechanic and watchmaker of King Louis XIV, René Grillet de Roven, published the small (49 pages) book Curiositez mathematiques de l’invention du Sr Grillet horlogeur a Paris. The book describes several different inventions, but most of it is devoted to his Nouvelle machine d’arithmétique. However, the first edition of Grillet’s book (it was an edition of Jean-Baptiste Coignart, printer-bookseller of the King, and was reprinted in 1678) had a miserable fate, as it was seized by the Intendant of Police in Paris, because in his book Grillet described also a mercury barometer, for which he was accused of plagiarism from another Parisian instrument-maker, Hubin.

The book Curiositez mathematiques de l'invention du Sr Grillet horlogeur a Paris of Grillet
The book Curiositez mathematiques de l’invention du Sr Grillet horlogeur a Paris

Five years later, in 1678, the earliest scientific journal published in Europe—the french Le Journal des Sçavans, published a short description (3 pages text and 1 page sketch) of the arithmetical machine of Grillet.

Pages 161 and 162 from Journal des Sçavans, describing the machine of Grillet

Pages 163 and 164 from Journal des Sçavans, describing the machine of Grillet

Page 165 from Journal des Sçavans, describing the machine of Grillet
Pages 161, 162, 163, and 164 from Journal des Sçavans (1678), describing the machine of Grillet

Grillet obviously was so obsessed with keeping his design of the machine a secret, that he does very little to enlighten its mode of operation. After telling his readers that the idea for the machine originated from the rulers of Napier, mentioning that Pascal had invented an admirable machine for doing arithmetic, and that Petit had given us a cylindre artihmetique (the French physicist Pierre Petit created in early 1650s a kind of Napier’s bones engraved on a cylinder), Grillet stated that his device combines the wheels of Pascal with the cylinder of Petit, in order to provide a wonderful machine, which would perform all the arithmetic operations.

The sketch in the book depicts a box with 24 sets of wheels (3 rows by 8 wheels) on the lid. Each wheel consists of several concentric circles, while the bottom of the box contains a set of Napier’s bones, engraved on cylinders, reminiscent of those, described more than 20 years ago by Gaspard Shot. The construction of the machine is rather simple, with no connection between the group of wheels on the lid, which means, that tens carry cannot be performed automatically.

To perform an addition or subtraction on the lid dials, the operator would set up the first number on the upper line of wheels, the second number on the middle line of wheels, and then to perform the operation mentally, setting down the digits of the answer on the lower line of wheels. The wheels would have found theirs main use in adding up the partial products, generated by the set of the cylindrical Napier’s bones, located in the lower part of the machine.

The calculating machine of René Grillet de Roven (© CNAM, Paris)
The Nouvelle machine d’arithmétique of René Grillet de Roven (© CNAM, Paris)

Perhaps the most advanced aspect of Grillet’s machine was its size, as it was small enough to be carried in a (quite big) pocket (however, it was bigger, than the adding machine of Morland). Its dimensions are: 14.5×32.5×5 cm, weight 990 g. Materials used are: wood, cardboard, paper, brass, and glass.

The reason of Grillet’s striving to keep the mode of operation and internal structure of his device as a secret can be understand by the fact that he tried to make money from his machine, exposing it for a fee at fairs, charging a silver coin to see it operate. It is known, that in 1673 the machine was exposed in Paris, at the Cloistre S. Jean de Latran and Quai de l’Horloge, №49. In 1681 the machine was exposed in Amsterdam, Netherlands. Its seems Grillet tried to produce his machine in series and to sell it, but obviously without great market success :-), as only three examples of the device survived to the present day, two in the collection of Musée des Arts et Métiers in Paris, and one in private hands (on the image below you can see the 32.5cm x 14.5cm walnut cased mechanical calculator of Grillet, sold by Christies in 2013 for 119000 USD).

The Nouvelle machine d'arithmétique of René Grillet de Roven
The Nouvelle machine d’arithmétique of René Grillet de Roven

Biography of René Grillet de Roven

Not much is known about Grillet’s personal life. As it is clear from his name (spelled also René Grilliet), he originates from the town of Roven (Rouen), in the northwestern France, the capital city of Normandy, the same town, where in early 1640s Blaise Pascal created the famous Pascaline.

René Grillet’s parents were perhaps Jean Grillet (1605-1675) and Marie-Rosse Grillet. Jean Grillet was a king’s enameler (émailleur ordinaire de la Reyne), known as an author of a book—La Beauté des plus belles dames de la cour, les actions héroyques des plus vaillans hommes dece temps… et plusieurs autres pièces sur divers sujets gaillards et sérieux (Paris, 1648). Jean Grillet was interested in glassware, clocks, instrument making (he invented a thermometer, which was donated to his patron Monseigneur le comte de Montéclair) and all these sorts of curiosities, so obviously René inherited all these interests.

René Grillet became a well known at the time french mechanic, instrument maker and watchmaker, and he used to work for His Royal Highness King Louis XIV. Besides the calculating machine, which is of a particular interest for us, he is known as a maker of several other devices—a hygrometer (anemometer); graphometers; drawing instrument set; protractor, sector and square; set square, with plumb-bob, etc.

Let’s examine the curious history with one of Grillet’s inventions, a double mercury barometer. In early 1673 Hubin (he was an English enameller, who established in Paris in early 1670s as Emailleur ordinaire du Roy, and made thermometers, hygrometers, hidraulic, and air machines), published a pamphlet, in which he accused Grillet in fraud for using the principle of his mercury thermometer, already demonstrated to the French Academy and displayed it on his shop’s window sill. This accusation probably explains why Grillet’s 1673 book Curiositez mathematiques de l’invention du Sr Grillet horlogeur a Paris was seized by the Intendant of Police in Paris. That’s not the whole story however. When some time later the famous Dutch mathematician, astronomer, physicist and horologist Christiaan Huygens presented his newly invented barometer, Grillet complained contra Huygens, stating that he had invented the double barometer two years before Huygens, and that the latter stole the idea from him. Grillet even stressed he had demonstrated his invention during a meeting of the French Academy, which member was Huygens. Huygens however stated that Grillet had in fact shown a barometer to the Academy, but it had nothing particular to it. It seems Hubin was the only honest man in all this confused story, because he mentioned that the idea of putting serpentine tubes on his instrument he borrowed from a professor of Chartres, Laurent Cassegrain, while Grillet and Huygens didn’t give the proper credit to their precursors, trying to get all the glory.

In 1681 Grillet traveled to Amsterdam, Netherlands, where he exposed his calculating machine and instruments. It seems he stayed in Netherlands for several years, working not only as an instrument-maker, but also probably perfecting his printing art there under the care of the skilled Dutch master-printers.

Later in 1680s Grillet probably tried to establish a calico-printing workshop in France, but after the decree of 1686 prohibiting calico-printing in France, he went to try his fortune in England.

In 1690 René Grillet is mentioned to live already in England, where he took patent for painting and printing calicos, and a factory for this purpose was opened in the Old Deer Park at Richmond, near London. It was the first calico-printing factory in England, but Grillet made the mistake to employ mostly Frenchmen and Roman Catholics, which led him into troubles with the local society and English authorities.