64 ANNUAL OF SCIENTIFIC DISCOVERY. 



Rotary motion is given to the valve by a vertical shaft, on -which there 

 is a pinion that is worked by a cog-wheel on the shaft of the engine. 

 The two bearing surfaces are ground steam-tight, and an outer casing 

 serves to confine the steam, as in the common slide valve. The advan- 

 tages said to be gained by this arrangement are the diminution of 

 friction and a more ready means of cutting off the steam and of revers- 

 ing the engine. As the rotary valve has a continuous slow motion, 

 the inconvenience and friction occasioned by the rapid reciprocating 

 action of the slide valve is avoided. Among other advantages of this 

 contrivance it is stated that it costs less, is less liable to get out of order, 

 and occupies less room. 



BRISTOL'S ROTARY ENGINE. 



This rotary engine, invented by Richard C. Bristol, of Chicago, 

 and exhibited at the New York Crystal Palace, is very simple in all 

 its parts, and it embraces features which remove many objections to 

 the heretofore economical working of such steam motors. The descrip- 

 tion of the rotary engine to which these improvements relate, consists 

 of an outer fixed annular case with open ends, and an inner wheel so 

 fitted to it as to close its ends and leave a channel or steam way within 

 it, outside of the wheel, the outer case having one or more abutments 

 which project from its inside and fit to the periphery of the wheel, the 

 latter having sliders or wing pistons, upon which the steam acts for 

 the purpose of giving rotation to the wheel, by admitting the steam 

 between the sliders and the abutments spoken of. 



The outer case is so supported that it is capable of yielding in any 

 direction necessary to enable it to preserve, at all times, the proper 

 position in relation to the wheel inside and the working parts of it, 

 notwithstanding any inequality of their wear, or any other cause which 

 might induce them to work out of line. 



The sliders are pushed out against the concave face of the annular 

 case by means of small pistons attached to them and acted upon by the 

 steam, but only at such times as the sliders or wings are acted upon 

 themselves by the steam, the pressure of the said pistons ceasing as 

 soon as the exhausting commences at the back of the sliders to which 

 they are attached, and before the withdrawal of the latter to pass the 

 abutments, so that no resistance is offered to their withdrawal or back 

 stroke. 



This engine cuts off the steam at any point desired ; the packing 

 consists of adjustable metal rings, and is not liable to wear uneven or 

 quickly, as the friction is small. Scientific American. 



NEW BOILER FEEDER. 



The nature of this invention, by Aaron Arnold, of Troy, N. Y.> 

 consists in having a small hollow closed metallic vessel, which is hung 

 on a balance outside of the boiler, and has communication at the top 

 with the steam, and at the bottom with the water of the boiler, and is 



