1313.] Account of a New Hydraulic Machine. 413 



by M. Mannoury. The one which we have at present to describe 

 is not less worthy of attention. 



M. Mannoury not having yet given a name to his new ma- 

 chine, we shall venture to call it a danaide. as this name seems 

 proper to give a first conception of the mechanism of the ma- 

 chine, which in fact is nothing else than a trough into which the 

 water is continually running from above, while as great a quan- 

 tity runs out by a hole at the bottom. But the danaide of M. 

 Mannoury is more fortunate than that of the daughters of the 

 King of Argus ; because it is more ingenious. He has contrived 

 to give his trough a rotatory motion, to prevent by its centrifugal 

 force the too great rapidity of the escape of the water : so that 

 if the secrets of M. Mannoury should ever make their way into 

 Tartarus, he will have the glory of alleviating the labours im- 

 posed for so many ages upon these unfortunate princesses. 



The model, by means of which M. Mannoury exhibited his 

 experiments to us, consists principally, as has Tbeen said, of a 

 trough, the bottom of which has a hole in its centre. This 

 trough is cylindrical, and nearly as high as it is broad, and is 

 made of tin plate. It is fixed to a vertical axis of iron, which 

 passes through the middle of the hole in the bottom, leaving a 

 vacant space all around, through which the water escapes as it 

 flows into the trough. This axis turns with the trough upon a 

 pivot, and is fixed above to a collar. 



The object of M. Mannoury was, that the water flowing into 

 the trough from above with a certain quantity of vis viva, should 

 communicate the whole of it to the solid parts of the machine, 

 to be employed afterwards in producing some useful effect ; 

 always excepting the small quantity of force necessary to enable 

 the water to escape by the oiifice below. He obtains his object 

 in the following manner. 



To the axis of the trough, and within it, there is fixed a 

 drum, likewise of tin plate, concentric with the trough, and 

 c!o<=e above and below. This drum, which turns round with the 

 trough, fills almost the whole of its solid contents : there is 

 merely a small space between the two, not exceeding 1*5 inch. 

 This spHce exists likewise between the bottom of tfle trough and 

 the drum, but it is in that place less, and is divided into several 

 compartments by diaphragms proceeding from the circumference 

 to the central hole in the bottom of the trough. These dia- 

 phragms do not exist between the sides of the drum and the 

 trough, and the compartments at the bottom communicate with 

 this annular space. 



The water comes from a reservoir above by one or two pipes, 

 and makes its way inlo this annular space between the trough 

 and drum. The bottom of these pipes corresponds with the 



