35 



HYDRAULIC ENGINE. 



chines. 



printed at Lyons in 1719. The book is divided inlo three 

 parts, the firft of which contains curious engravings of delicate, 

 Tunieiy. eccentric, fwafli and rofe-work. turnery, the methods of pro- 



ducing which are to be found in Moxon's Mechanic Exercifes, 

 and in other later works on that fubjecl. Upon this part I 

 flidll make no other remark, than by demanding of your 

 correfpondents, whether the oval chuck, or engine for turn- 

 ing ovals, was unknown fo late as the period above fpecified. 

 If Monf. de Serviere had known it, I (houid fuppofe he would 

 have introduced ellipfes among the various figures he has ex- 

 hibited. The fecond part of the work confifts of clocks or 

 Time- pieces. time-pieces, more remarkable for fome Angularity in figure or 

 ftrudure, than any improvement in the art of meafuring time; 

 and, the third part contains models of hydraulic machines, 

 with fome engines for military and other purpofes. Many of 

 Hydraulic ma- the hydraulic machines appear better calculated to be (hewn 

 in a model, than carried into effe6l on a larger fcale, and, 

 among the other engines, I fee nothing which, at the prefent 

 day, would much conduce to the entertainment of your readers, 

 I have, therefore, fent you a drawing of the hydraulic engine 

 exhibited in his 49th plate, and after the defcription, I will 

 mention a few other objedls which have been thought of more 

 modern invention. 



In Plate IV. Fig. 2. A and B reprefent two folid pinions 

 made in wood or raelal, and occupying all the interior fpace 

 of the oval box or chamber C D ; in which they turn freely 

 i n an elliptical and take into each other. The chamber C D is to be well 

 and folidly made, having an openipg below at D, as in the 

 figure, and alfo at E, where the aperture correfponds with the 

 bore of a pipe F, applied and fixed to (he fame. Every other 

 part is well clofed and fecured. Fig. 3,''reprefents the cover 

 or cap. 



This chamber is properly fixed under the water of the well, 

 or ciftern, out of which the fupply is to be obtained, and in 

 this fituation, the elbow or handle G, Fig. I . Plate IV. is fixed 

 on the fquare of the axis A. This handle is conneded with 

 another H, by the iron Aiding piece I, which moves upon 

 the fixed pin K, and obliges its two extremities conftantly 

 to move alike. Whenever therefore the handle H is turned 

 by the firft mover M L, the other arm G muft alfo revolve to- 

 gether with its pinion, and by confequence the other pinion B. 



, Whei 



Hy.^lal.l^c ma- 

 chine defci-ibet 

 It confifts of two 

 pinion worki 



be 



