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105.

      PART THE FIFTH
   of the conveyance of 
 water, and of ye resistance
        of PIPES

[[line across page]]

        DISCOURS I
  of ye pipes of a conduit

  When ye conduit of water wch furnisheth ye spouts, passeth thrô a long very strait pipe, ye swiftness of ye water is there stopped by ye rubbing of wch I have made experiment in this manner.

  A B C D is a pipe of 6 inches diameter and of 6 foot heigh, ye pipe C E is three inches longe and ye pipe G F one inch.  We made at the points H, I, L, 3 holes that in H was 2 lines, that in I 4 lines, and ye last in L.  In ye other branch F G ye holes K, N, M, were disposed after ye same manner.  According to ye groupings of ye holes in respect of ye nearness of ye pipe

[[image:  Drawing of a reseroir A B  atop a vertical tube F connected to a horizontal tube smaller on the left G D than on the right C E.  Three spouts on the left branch: M N K; and three on the right branch: H I L.]]

A B C D ye pipe A D being full we let go successively ye 3 [[strikethrough]] lines [[/strikethrough]] holes H, I, L ye others remaining always closed, ye spout thrô L was elevated ye height that through I next, and thrô H ye lowest of ye three:  On ye other side M ye great hole spouted ye lowest that of N a little heigher and ye little ones K ye heighest of ye 3 it will not be difficult to know ye reason of these effects if we consider that there goeth much water thrô ye holes L and M, and that to maintain it ye water must be much swifter thrô ye straight pipe than thrô ye large one, wch causeth a considerable rubbing, wch retards ye swiftness of ye water, and hinders its running swift enough to furnish ye passage.  But in ye holes and K as ye swiftness is 18 times less than when ye water goeth thrô L and M, ye rubbing in the straight pipe is not considerable, and doth not sensibly hinder ye spout K more than ye spout H and they mount near as heigh one as ye others:  It follows also that if we diminish ye 2 holes I and N, for example each by a line then ye spout thrô J will mount less heigh than it should and that of N more heigh; because there will be less rubbing in ye channel.  F G wch surpasseth default of ye resistance of ye air, and in ye channel C E that diminution of rubbing shall not be considerable, and ye resistance of 4 lines, this hath confounded many. 

Transcription Notes:
mandc: Reviewed, revised image description, changed J's to I's. Desaguliers' diagram: http://echo.mpiwg-berlin.mpg.de/ECHOdocuView?url=/permanent/library/QERNH1MN/pageimg&viewMode=images&mode=imagepath&pn=283&ww=0.1573&wh=0.2365&wx=0.6153&wy=0.5233