Hydraulics.

Invention will save at least

60 C ° stC ^ U< ^ es ’ t ^ lat ^’ s new

P e r Cent. in Pit-Coals to work a Fire-Engine.

c ' The Method by which he found how much Steamtj-j- “ be Produced from a given Quantity of Water wasj^ is - He procured a Copper Globe A 12 Inches in0 J amete r, with two Brass Cocks B B opposite to each£ ler > by one of these the Globe was fasten’d to a Pipe'\r ^shich was fix’d to the upper Part of one of the Steamj,® iels (as at N) and was sill’d with Steam by the CockfjP u P°n the other Cock was fixed a small Valve D,Q r J 1 to a Bore of one Inch Diameter ; and C is a Handleto suspend it by.

o r ^' The whole thus fitted weighed 15 Ib. 3 oz. Troy ,V'as'V^' °' z ' dverdupois ; the Capacity or Content

t 0 °ut g 25 cubic Inches. The'Globe being fix’de Steam Vessel, all the'Cocks were turn’d, till theP a ® n g thro’ had sufficiently heated the Globe;

^ti

in.

e ing stopp’d, the Steam condensed, and the AirWhen weigh’d in a very nice Balance, the WeightSte *5 I't Z SL. 2 dwt. so that the whole Quantity ofTt-o^ Was but 2 Penny W eights, or -Q of an OunceWhence 1 Ounce of Water makes 9250. cubic; hes of Steam.

The Globe filled with Water weighed 45 Ib. 7 oz.C 0 5 this, it being fill’d with Steam, and one of theQj o ^ s put under Water, the Water rufh’d into theof -G; 5 and the Cock being again turned, and the Globe\vij- , ater now weighed, the Weight was 44 Ib. 9 oz.Hfiu ducted from the former Weight, gave 14 oz.-,f <Ut ^ow’d that all the Air was nearly excluded, or/j* 3 Vacuum was approached to in the Ratio of 713 toof ti ; ° r the Part possessed by Air was but the Partj e ^Vhole.

G] 0 ^‘ ^ be Air being again thus excluded out of thee by Steam, and both Cocks turn’d, the Globe was■^ Cl gh’d, and the Weight was 12 Ib. iof oz. thenthe Was open’d and the Air let in, upon whichtQgj a e tRfcended, and f an Ounce Averdupois, beingto t be other Scale, restored the Equilibrium,tic T, ^ as therefore the Weight of the Air, or 925 cu-j 2 ' c J es °/ Air v/eigh’d about 220 Grains,

Sf e ' brut it was found above, that the Giobe full ofV/eigh’d only 2 PennyWeight Troy, or 40 Grains;

whence

th

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