a new-confirutted Air- Pump. sry 
“he other barrel is left out of the figure, to fhow fome of the 
parts more diftin&ly ; except Q Q; which is the top of the 
barrel retained and brought down out of its place; to fhow the - 
Xs- Lr that fhuts up the barrel, feparated from the box, 
which contains the collar of leathers. _S fhows one of the holes 
in che plate over which the valve lies, and which is covered by 
Rin the.crofs-piece. VV is the pifton fhowing the valve 
open on the top, which is to prevent labour when the pump 
condenfes. . W X is the ciftern, in which is more diftin&tly 
feen the fhoulder for, the leather which clofes the joint between 
this and the barrel, and alfo the focket in which the oil lies: 
over the leather. Y¥ Z is the condenfing gage, with the ori- 
fice of the tube raifed above the furface of the quick-filver. ee 
is. the collar of leathers, through which the glafs tube moves. 
i is a fimall pipe coming up through the quick-filver to make a 
communication between the valves and the gage. 
_Fig. 4. is a view of the upper farface of the top-plate which 
clofes. the barrel, being foldered into it, fhowing the place of 
the valve over the three {mall holes, one of which only can . be 
feen at S, in fig. 3- 
Plate V. fig. 1. js a perpendi icular ation of the icin 
piece, pipes, valve-pump, cock, &e. at right angles with. ‘the: 
other fection, fig. 3. pl. IV. A Bis the pipe between the-bar- 
rels, as reprefented i in plate IV. The button eis here fcrewed 
ifto the top inftcad uk the gage. C Dis the valve-pump and 
its. -ciftern, 'e the place of the valve under the cap. EF the 
cock, fhowing the duct through it leading. to the atmofphere, 
G H the pipe leading from, it to the ftem of the receiver- plate; 
ih whith is the d I, to {hut i up. the du& when. the plateis. 
ufedas a transferer. KK is the plate. La piece to {hut oe 
