258 On the Instrument Makers of Paris* 



the sitting of the 8th of September, in consequence of which 

 the reporter, M. Prony, made his report in the sitting of the 

 15th of the same month; the other members of the Commis- 

 sion were MM. Arago and Breguet. The invention of M. Pec- 

 queur was much praised, as a thing which had already proved 

 its utility ; and the future results of which could not be fore- 

 seen : the Commission therefore proposed that the invention 

 of M. Pecqueur should be received by the Institute to be in- 

 serted in its records ; which was adopted after some discus- 

 sion. 



M. Pecqueur has besides exhibited an ingenious pump which 

 requires very little force to carry water to a prodigious height. 



M. Rieussec junior, the king's watch-maker, No. 1 3, Rue 

 neuve des petits Champs, has exhibited a chronograph, a sort 

 of counter by the touch, which by pressure given to a spring, 

 makes at the same instant a black mark upon the dial-plate 

 whilst it is in rotation. It is this invention which M. Breguet 

 improved by applying it, but in a different manner, to chrono- 

 meters : — a chronograph costs 400 francs. 



M. Peschot the elder, No. 18, Rue des filles St. Thomas, 

 has exhibited an extraordinary sort of clock, already rather 

 common at Paris, and which consists only of a needle on a 

 dial-plate of glass ; for example, a mirror, without any visible 

 mechanism ; this consists in a rotatory weight, contained in 

 a round box applied to the other end of the needle. 



In instruments of astronomy and optics the exhibition pre- 

 sents nothing very remarkable, except the instruments of 

 Gambey, of Lerebours, and of Cauchoix. There are some 

 samples of flint glass from the royal glass-works of St. Louis, 

 near Bitsch, Department de la Mozelle. 



It is said that the Minister of the Interior, M. de Corbieres, 

 has an intention to render France independent of foreigners 

 for flint glass, by making advantageous propositions to M. Gui- 

 naud, established in Switzerland, and known by his produc- 

 tions in that line, to establish himself in France. 



There has also been exhibited a light-house with lenses a. 

 echelon on the plan of M. Fresnel and executed by M. Soleil, 

 the k mechanism of M. Wagner and the lamp with concentric 

 wicks of MM. Arago and Fresnel; the detailed description 

 of such a light-house is to be found in M. Fresnel's memoir 

 on this subject. — It appears beyond doubt that these light- 

 houses with lenses are, as to intensity of light, much superior 

 to those with reflectors : but I believe that the greatest diffi- 

 culty will be to make them quite distinct from each other, 

 especially on a coast where there are many of them. For in 

 making them fixed they lose too much of their advantages, 



unless 



