The encyclopdia britannica; a dictionary of arts, sciences, literature and general information . once com-pletely round, making a = area measured by thewheel is by formula (i), lw+(W-lc)2Tr. To this the areaof the circle irr* must be added,so that now ; i P=lw+(U-lc)2T+Tr,orj \ i„: p=ipf c, yiiere C = (iZMc)2T+Tr»*-is-a-constaiit,: ^ it depends on the^ifiieiiaonsi of the; iiistriimentaltJiSA This ebnstantis givenwith each instalment.;! Anislers altimeters aremade either with a rod ?35 Q^ ftied jlehgthj which gives the areatherefore in terms of a fixedunit,, say inj^iuafemches, or else th
The encyclopdia britannica; a dictionary of arts, sciences, literature and general information . once com-pletely round, making a = area measured by thewheel is by formula (i), lw+(W-lc)2Tr. To this the areaof the circle irr* must be added,so that now ; i P=lw+(U-lc)2T+Tr,orj \ i„: p=ipf c, yiiere C = (iZMc)2T+Tr»*-is-a-constaiit,: ^ it depends on the^ifiieiiaonsi of the; iiistriimentaltJiSA This ebnstantis givenwith each instalment.;! Anislers altimeters aremade either with a rod ?35 Q^ ftied jlehgthj which gives the areatherefore in terms of a fixedunit,, say inj^iuafemches, or else therod can be moved in a sleeve 1^ ^hicli thCaJmpQ is hinged (fig. 13).This makes it possible to change the iunit7«, Which is proportionalto I. / , / H- ? .i\ . In the planimeters describpdth^ recording or integrating apparatusis a smooth wheel rolling on/th4^paper!oron some other has described anotfee^t recorder; viz. a lyhiEel with a sharpedge. This will_ roll on t^e/paper Bttrfiot slip. Let the rod QTcarry with it an aJWi-CD perpendicular to it. Let ^there bp-fiJcSiited. it, the roll will measure the area independent of the posltiolnof theaxis OX, as will be seen by drawing a figure; The cone may withadvantage be replaced:by a horizontal disk, with its centre at V;this allows of y being negative. It may be noticed at, once thatthe roll of the wheel gives at every moment the area AATQ; It will therefore allow of registering a set of values,of j ydx for any values of x, and thus of tabulating the •S^alues of any indefiniteintegral. In this it differs from Amslers planimeter. Planimetersof this type were first invented in 1814 by thte Bavarian engineerHermann, who, however, published nothing. They were reinventedby Prof. Tito Gonnella of Florence in 1824, and by the Swisfe engineerOppikofer, and improved by Ernst in Paris, the astronomer Hansenin Gotha, and others (?ee HettriiA, British Association Report, 1894).But-all-were driven out. of the field by Amsler
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
