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26.

same time by ye weight E in remounting directly, as A E to A H, wherefore Ye weight E to make an equilibrium ought to be to ye weight [[blot or stikethrough?]] b as E A to A H by ye universall principall; and because that ye bowl shall get a little higher than ye point F viz from ye point e it follows that ye weights being in that proportion ye weight b shall descend and elevate ye wieght E, as I have found it confermed by experience for having disposed the arm A C so that it may make an angle of 60 degrees with ye horizontal arm A H K, I have observed that ye weights b being doubled to ye weight E it would make an equilibrium with it when I had stopped to hinder it working, but having given it freedom after I had put a looking glass represented by C G for to hinder its working aside, it was necessary to put ye double weight in E and ye simple in G to make an equilibrium, and also to add a little weight in E. It will be proved by ye same proportions that if ye angle K A C was 48 degrees it would be necessary to make an equilibrium that ye weight E was ye greater in proportion of ye diagonal of a square to its side.  There is not there considered that ye center of ye bowl F is a little at ye side of ye point of support.

  These things being supposed, on may sufficiently well explain ye equilibrium of fluid bodies.
  The lightest, that is to say ye least heavy of fluid bodies is ye flame, but because it is elevated into ye air, and that it is not extended upon ^[[any]] other bodies it cannot make an equilibrium by its weight, but only by its shoc and by its spring.

  The air wch is extended about the earth and water can make an equilibrium by its weight, by its shoc and by it spring with other more gross fluid bodies, and also with firm and hard bodies. ye weight of ye air is proved by ye effects of ye barometer, that is a streight pipe of glass of 2 feet and 1/3 or 3 feet long sealed hermetically at one end it is fitted with quick silver without permitting any air and ye other end is stopt with ye finger and after ye sealed end is turned upermost , ye finger is dipped into mercury put into a vessel Y finger is taken away wch ought to sustain ye mercury in ye pipe, and then part falls into ye vessel, and after some vibrations it is stopped at half in ye pipe at ye height of 27 or 28 inches; but according to ye changes of winds and ye air it mounts sometimes to 28 inches and 1/2 and at other times only to 26 1/2 and ordinarily it is stopped at Paris at 27 inches and about a half.

  Now that elevation of ye Mercury cannot be well explained, but by supposing that ye column of air of ye same largenss as ye inward diameter of ye pipe weighs as much as ye 27 or 28 inches of Mercury elevated in ye pipe, in takeing that column from ye surface of ye mercury wch is in ye vessel to ye extremity of ye highest region of ye air; now if ye barometer is carried to ye top of a mountain or of a very high tower ye hight of ye mercury is seen a little to diminish, and be reduced to 24 or 25 inches, as being then changed with a less quantity of air; and if we descend into caves or very deep mines, is elevated by little and little as being succesively charged with a greater quantity of air.

  The weight of ye air and ye equilibrium wch it makes with water may be known by ye same rules supposing that in a inch of mercury weighs as much near as 13 inches of water as I knew by ye experiments wch I made; for 28 inches of mercury weighs almost as much as 383 inches of water, wch make somewhat less than 32 feet; whence it follows that when ye weight of ye air will make mercury mount 28 inches and some lines, it will make ye water in a pipe of 35 or 40 feet mount to 32 feet, and that when it is elevated to but 27 1/2 inches ye water ought to be elevated but to 31 feet or near, wch is found to confirm to some experiments wch I have made at ye observatory in ye following manner.  I caused Mr Hubin to make a pipe of glass of 40 feet high wch was fitted to a hollow peice of wood, to ye end that it might not be broken in ye handling, it was of 5 or 6 peices wch he soddered in ye great hall of ye observatory, and one of ye ends was elevated to ye top of ye platform thrô ye hole wch is there wch answers perpendicularly to a hollow place of atop of ye [[?core or ?cove]]; it descended by little and little into that hollow and was made fast by tying to iron in many places then having been filled with water after ye lower most end was stopped, there was applyed to ye top a glass stopple wch might exactly stop ye pipe and there is put moreover a bladder for ye better sealing; a small vessel was likewise filled with water, wch was below ye other end so that it might be immerged in ye water, and after it was unstopped, ye water falling descending to about 12 feet, but there went out so many bubles of

Transcription Notes:
mandc: It is difficult sometimes to tell the difference between upper and lower case letters. You can refer to another translation where there are clearer diagrams. The subject here is found in Figure 13 on page 94 of this book [Desaguliers, John Theophilus translation: http://echo.mpiwg-berlin.mpg.de/ECHOdocuView?url=/permanent/library/QERNH1MN/pageimg&start=11&pn=17&mode=imagepath In the Desaguliers translation the 48 degrees on this page is shown as 45 degrees.