File:Encyclopædia britannica - or, A dictionary of arts, sciences, and miscellaneous literature - constructed on a plan, by which the different sciences and arts are digested into the form of distinct (14579804877).jpg

Identifier: encyclopaediabri03macf (find matches)
Title: Encyclopædia britannica : or, A dictionary of arts, sciences, and miscellaneous literature : constructed on a plan, by which the different sciences and arts are digested into the form of distinct treatises or systems ..
Year: 1797 (1790s)
Authors: MacFarquhar, Colin, ca. 1745-1793 Gleig, George, 1753-1840
Subjects: Encyclopedias and dictionaries
Publisher: Edinburgh : Printed for A. Bell and C. MacFarquhar
Contributing Library: University of California Libraries
Digitizing Sponsor: Internet Archive

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ed on the horizon-tal leg would be 12 inches. But the inconveniencesof frittion are much grt-ater here than in the diagonalbarometer ; and befides, by the leaft accident the mer-cury is apt to be driven out at the open orifice F. The pendant barometer (fig. 4.) confifts of a fingletube, fufpended by a ftring faitened to the end A.This tube is of a conical or tapering figure, the endA being fomewhat lefs than the end B. It is herme-tically fealed at A, and filled with mercury : then willthe mercury fink to its common ftation, and admit ofa length of altitude CD, equal to that in the commonbarometers. But from the conical bore of the tube,the mercury will d-fcend as the air grows lighter, till itreaches its lov.-eft altitude, when the mercury will ftandfrom the lower part of the tube B to E, fo that BEwill be equal to 28 inches: confequently the mercury■vlll, in fuch a tube, move from A to E, or 32 inches,if the tube be five feet, or 60 inches; and therefore til BAROMETER Plat I- XCli
Text Appearing After Image:
■ //W/. !>,>.H.i/liw/i/.^/.-r >r. ; ::-:v :\\r^ rp - . V. i£S^>W - ii- ■ d • • • -^ j • ;. BAR (2 i;«fen^»tr.jl,e fcalc AE Is here ahiivc ten tiini9 greater than in the common barotnctcr : but the fault of this barome- ter is, that the tube bcinjr of a very fmall bore, thefriction will be eonfiderable, anil prevent its mmini;freely ; and if the tube is made of a wider bore, themercury will be apt to fall out. Iig. 5. is an invention of Mr Rowning, bv whichthe fcale of variation may be incrcafed to any length,or even become intinite. A15C is a compound tubeliermctically fcaled at A, and open at C, empty fromA to D, filled with mercuiy from thence to Yi, andfrom thence to E with water. Let GBH be a hori-Konal line ; then it is plain from the nature of theliphon, that all the cjnipouiid fluid contained in thepart from H to G, will be always in ^quililrio withttfelf, be the wcif;ht «t the air what it will, btcaiifethe prelRue at H and (r mull be equal. Whence iencyclopaediabri03macf

Note About Images