Viewing page 95 of 140

This transcription has been completed. Contact us with corrections.

91.

[[image:  drawing of a conical-shaped vessel E F sitting on a bench with a reverse S-shape tube siphon A B C D running from below the surface of liguid I K I in the vessel and siphon.  There is a marker H on the siphon level with the opening A of the siphon inside the vessel.]]

  Allow ye same manner if there is a syphon as A B D C, wch makes ye water run out of a vessel E F whose surface is I K, through B H D C it will spout through a small hole into H, and if ye syphon was less long, ye spout would be elevated less, heigh from its hole in C:  But when there shall be no more water in ye vessel below A ye pipe will be void from A to B, and when ye height of ye water shall be in B it will spout to I if ye syphon is 5 or 6 lines large and ye hole C small as at 2 lines because then ye swiftness is made by ye height B C [[strikethrough]] and of ye height ? ?  made[[/strikethrough]] and diminisheth always till ye water of ye vessell was below A.

  It seems to be ye weight of ye water wch give ye elevation to ye spout to reduce to an equilibrium and that if we should press ye water wch is near ye hole with a weight equal to that of ye water of ye pipe it would spout as heigh.  See an experiment I made to prove it.

[[image:  drawing of a reversed J-shaped tube A B C (with a D above the bend in the "J") with liquid level E F in the bottom of the "J."]]
  A B is a pipe of glass of an inch and 1/2 large its height D A is a foot ye hole or passage C is 2 lines 1/2, we poured mercury thrô A till ye bottom E F was filled, we afterwards put water gently into ye space C F afterwards we stopped ye hole C with ones finger and filled ye pipe with mercury unto A.  When we took away ye finger from ye hole C ye water E F was elevated to near 12 or 13 feet.  Ye cause of this great elevation is ye specific weight of ye mercury wch is to that of water as 14 to 1.  By consequence 1 foot of mercury in D A will weigh as much as 14 feet of water, which should be in a greater pipe and should produce ye same effect in spouting water thrô C.  And because a reservatory of 14 feet spouts ye water to about 13 foot, a foot of mercury ought to produce ye same effect.  It is no matter whither ye pipe be large or small, provided it be proportioned to ye hole C.

Transcription Notes:
mandc: Reviewed. Amended image descriptions. Changed the J's to I's. Image: http://echo.mpiwg-berlin.mpg.de/ECHOdocuView?url=%2Fpermanent%2Flibrary%2FQERNH1MN%2Fpageimg&mode=imagepath&pn=254&ww=0.1136&wh=0.2179&wx=0.4646&wy=0.3884