1792-5.]. 16mo, pp. 48; some light spotting and browning, foot cropped at an angle but with no loss of text; stitched as issued (though with later thread?), and unopened; a most appealing copy. A scarce treatise, written on the cusp of the introduction of the metric system into France and seemingly an early dissemination of its arithmetical concepts. It is the work of the blind mathematician Jacques-Gilles Duverny (fl. 1791-1814), who was later to become known as ‘le troubadour aveugle’ after abandoning mathematics in favour of a career writing poetry and song.
This brief pamphlet introduces the reader to the basic arithmetical operators of addition, subtraction, multiplication, and division, and appears to be an early attempt to explain the new proposed decimal system to public. ‘Ainsi les unités du premier ordre eu égard à la place qu'occupent les chiffres sont des unités simples. Celles du second ordre sont des unités de dixaines, parcequ'elles sont composées de dix unités du premier ordre. Celles du troisieme ordre sont des unités de centaines, parce qu'elles sont composées de dix unités du second ordre, et ainsi de suite: care chacun sait ou doit savoir qu'après viennent les milles, les dixaines de mille, centaines de mille, millions, centaines de million, milliards, etc.’ (p. 16).
Reform had been sorely needed in a country where different areas used different systems and differently named units and where the length, weight, volume etc. of a unit could vary depending on the item being weighed or measured. Once the initial committee including such mathematical luminaries as Lagrange, Laplace, Monge and Condorcet, had decided upon the new system to be adopted in 1793, it fell to the members of the L'Agence temporaire des poids et mesures Etienne-François Gattey (1753 - 1819), Adrien Marie Legendre (1752-1833) and Charles-Etienne Coquebert de Montbret (1755-1831) to oversee its implementation and adoption, and for making it presentable to the populace. Legally adopted in 1797, the metric system gradually come to be adopted throughout France, until in 1840 all other measures were outlawed.
Denis Guedj, in Le Mètre du Monde (2000) cites the work, noting that the ‘Agence temporaire des poids et mesures’ had alerted Claude-Antoine Prieur (1763-1832) (one of the leading exponents of the metric system at the time), that ‘As a teacher of the new measurements, you have a rival, a blind man named Duverny, who intends to teach arithmetic and the calculation of the new measurements publicly in the streets. He has already written a small book, of which we are sending you some copies, and this work will be followed by another on decimal calculation. This blind man has greatly interested us; he seems to possess zeal and talent. We have promised to encourage him and have purchased one hundred copies of his little Instruction from him at the price of 1 franc 25 centimes. He will also sell your Instruction in his shop, along with walking sticks and pocket measures that will be entrusted to him by the artisans of the Notre-Dame cloister.’(translation, Guedj, p. 206).
What we know about Duverny comes largely from the present work. He was educated at the Institution des aveugles nés, and was such a good student that he was entrusted to teach his peers, under the title ‘Chef d’atelier’. Along with five other students, he was taken on by a mathematics teacher called Rouiller, and in August 1791, Duverny together with fellow student Honoré-Vincent Viefville, defended their Thèse de mathématiques sur l'arithmétique, la géométrie et l'algèbre, in the presence of Condorcet, secretary of the Academy of Sciences, as noted in the Gazette Nationale ou Le Moniteur Universal (no. 242, Mardi 30 Aout 1791, p. 522). This was subsequently printed by the Veuve Delaguette, of which there is a copy in the BnF. The Gazette encouraged members of the public to attend, to show that the study of mathematics was not beyond the capability of most men, and that the loss of one of the main senses, did not mean that men were less likely or able to apply themselves to the study of abstract sciences.
Duverny goes on to say in his preface that his hope was to emulate that of the blind English mathematician Nicholas Saunderson, ‘fut puissament secondé par le gouvernement Anglais, et qui eut l’honneur de professer les mathématiques et autres sciences à l’université de Cambridge’ (p. 11). A note at the end promises a follow-up, dealing with calculus and a more detailed treatment of the workings of the decimal system: ‘Dans l’ouvrage qui sera suite à celui-ci, qui n’est qu’un essai, je traiterai des opérations dont les nombres complexes sont susceptibes: je traiterai du calcul décimal qui deviendra absolument necessaire par rapport à la nouvelle division des poids et mesures qui par son uniformité pourra par la suite non seulement être en usage dans toute la république française, mais encore dans toute l’europe. Cette adoption ‘leveroit de grandes difficultés dans nos relations commerciales avec les autres peoples’. Despite this promise, we can find no evidence that it was ever published. Rather, Duverny turned to song and poetry, with a collection of songs published (undated) later in the 1790s by Daniel, and, in 1814, the Charte constitutionelle des Français, mise en Vaudevilles, printed ‘chez l'auteur, imp. de Delaguette’.
A wealth of official publications were issued by the agencies and commission on the new system, providing practical explanations and instructions to ensure its implementation, with the present pamphlet revealing that enthusiastic citizens were also keen to disseminate and educate.