HAUTEFEUILLE, JEAN DE, is French mechanician, was born at Orldans, March 20, 1647. His father, who was a baker, being Recta ' tomed to supply with bread the master of the house at which the Duchess of Bouillon then resided, prevailed upon this person to recom mend the youth to thu notice of that lady. The duchess having con sented to see him, an interview took place, when the lady was so well satisfied with the young man that she engaged to pay the expense of his education; and, ou his entering into the ecclesiaatical state, she retained him in her service. He never after quitted his benefactress, who conferred upon him several benefices, and at her death she bequeathed to him a pension.
'she Abb6 Hautefeuille, such was his designation, devoted himself to the atudy of subjects connected with physical science, and to the construction or improvement of instruments; but he is distinguished chiefly by the claims which he advanced in 1675 to the honour of having invented a spriug-belauce for watchee. This contrivance con stated of a straight spring of steel which he applied so that it served to regulate the movements. About the same time liuygliena invented for the like purpose, a spring, which he made of a spirat form : it hap pened however that Hauteleuiile had communicated his invention to the Acadenne des Sciences of l'aria in the preceding year ; therefore when Iluyghens applied to the French Goverunieut to be allowed the exclusive privilege of using it, he was opposed by Hautefeuille, and ho subsequently withdrew his application. It is remarkable that Dr. Hooke bad, about the year 1655, iuvented a balance-spring fur watches, but he spent several years iu improving his escapement, and his watches were not made public till about the same year that the inventions of Hautefeuille and Huyghens were in use in Paris.
The other inventions, or rather projects of Jlautefeuillo are numerous, but few of them appear to have been brought to perfection.
He published iu 1692, at Maria, a work entitled •Itecueil des Ouvragen de al. de Hautefeuille,' which contains an explanation of tho effects of speaking-trumpets; au account of a pendulum Mock in which the weight was to be raised by the action of the atmosphere; a method of raising water by meaua of fired gunpowder; and an account of aouse improvements hi telescopes iu which the field of view was to he increased by means of a concave mirror; also some observations on machines fur raising water; a description of a pump which was to act without friction ; and au account of is contrivance tor mounting teles copes of great length.
riautefeuillo published a method of defining the declination of a maguetio needle) (16a3); an account of a leagued') balance (1702); with accounts of a microtnelrical microscope, and of an instrument for observing the altitudes of celestial bodice. linable published, iu 1719, a work entitled 'Nouveau Syet6me du Flux et Reflux de la Mer,' in which the phenomena of the tidos aro made to depend upon a parti cular motion which he ascribes to the earth ; but the beat of his works is his ' Dissertation sur la Cause de l'Echo,' which had been read before the Academy of Bordeaux in 1718, and was published in that city in 1741.
Hautefeuille appears to have been in haste CO publish his ideas as soon as they arose in his mind, without waiting to put them to the test of experiment ; and consequently most of his projects are crude conceptions which have not led to any object of practical utility. The opinion entertained of him by his countrymen is manifest from the fact, that he was never admitted a member of the Academie des Sciences, though ho ardently desired that honour. He died October 18, 1724, being then seventy-seven years of age.