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ternal Air may Communicate, Between the T\vo Bottoms , without Pe*netrating into the Cavity, AF.

N. Is a stiort Pipe, Soder’d to a Hole in the Cover, AD. So that therebyone may pour 0)1 into the Cavity, AF. and ilop n afccrwards vcryClose with Cork

For the Filling up os this Engine, you muli Stop the Aperture, G. of iheFipe, IG. with a lorg Pin fitted for that purpose; and the Upper End ofthe Fipe, L M. must bc Stopp’d too : then Pour in your Oyl by the Aper-ture, N. which done, this fame Aperture , N. is to be Shut up Exactly, andboth the other to be Opened, viz,. G. and L. Then it will come to pasi,that the Oyl, through the Fipe, IG. will Run and Fili the Vejfel, P- tillrs Superficies be in the fame Level with the Hole, H. and no more, asraight be casily Demonstrated.

Now it is eafy to see that this Lamp is free from ali Inconvcnieneies theLamp of Cardan is Subject to; for

i. The Air doth not get into it by Starts or Gluts, as it doth in Cardan sLamp : But when the Oyl, in PP. bring Wafled by the Flame, comes tohave its Superficies Lower than the Hole, //.the Oyl from the Cavity, AF.runs into PP. Gently, because its Place lest in the Cavity, AF. is casilySupplied by the External Air, which through the Pipe, LM. and theHole, H. gets up into the faid Cavity, A F.

1. When the Air Contained in the Cavity, AF. comes to be Rariffd 'by forne Heat, it Drives out much Oyl, and so is Abte toChoak Cardan iLamp : But in this, the Oyl bring sodriven out gets into theSpace betweenthe Two Bottoms, as well as into the Vejfel, PP. Now the sind Space betweenthe Two Bottoms, by reason of its Largenesi, receiving Twenty or Thirtytimes more Oyl than the VeJJel, PP. it foliows, that the Superficies of theOyl therein Riseth 20 or 30 times Lesi than if all rhe Oyl had been Dri-ven into the faid VeJJel. Therefore when we FiB the Lamp, we muli takeCare that the Pipe, L. may be Well Shut, so that the Air between the twoBottoms, finding no lflue, may keep the Oyl from Filling that Space, which

by that mean°, when the Hole, L. is Open, will be fit to Reccive the OylDriven out by the RarefaQion of the Air in the Cavity, AF.

3. The Oyl being always kept almost at ths fame Distance from theFlame, the Wick will not be Qujckly Confumed.

4. You have the conveniency to put New Oyl into the Lamp, withoutMoving or Extinguilhing the fame .• for you necd but Shut up, G. and L.and pour the Oyl through N. as hath been faid in the Beginning.

2. Let a Lamp, made 2 or ; Inchts Deep, with a Pipe Corning from the ji no tber ,byDT.Bottom, almost as High as theTop of the Veflel, be Fill’d First with Wa- Rdb.st. cure.ter, so High as to cover the Hole of the Pipe at the Bottom ; to the end n ' 3So 'the Oyl may not get in at the Pipe (and so be Lost ••) then let the Oyl be

poured in fo as to Fili the Vejfel almost Brim füll ; which must have a Co-ver pierc’d with fo many Holes as are Design’d to be Wicks. When theVejfel is thus filPd, and the Wicks are Lighted, if Water fall in by Drops atthe Pspe, it will keep the Oyl always at the Same Height, or very near, the

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