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74.

below upwards thro ye hole C since ye water goeth swifter in D than in E and so that above is always a little retarded.

[[image:  diagram of L shaped tube and spout of water spouting D vertically from a hole C]] in the base of the L, to height E.]]

  It is found by many experiments that if there should go out 15 pints in a certain time thrô a spout whose hole is 4 lines wch runs from above downwards there would go out but 14 very near when it was made to spout perpendicularly from below upwards, as thô surmounted by a parallel height of water, and that happens particularly in ye moderate heights of ye reservatories for if they are of 20 or 30 feet, ye difference is less sensible because that ye water goeth so swift from above downwards in its beginning, that it makes not any considerable acceleration in ye water of ye spout wch is below ye hole;  because that a drop of water falling acquires but little more swiftness than that of the water wch goeth out thrô a hole when ye surface of ye water is 30 feet above, as hath been explained in ye end of ye 3d edition of ye Treatise of ye Shoc of bodys:

  By these reasons and experiments it is seen that it is difficult to determine wether an inch of water is;  and because that ye [[strikethrough]] distance [[/strikethrough]] dispensing of spouts of water are made ordinarily thrô great heights of ye reservatorys and thrô small holes of Ajutage [[space]] it ought for ye most part to be regulated by experiments of mean holes or of 6 lines or of 4 lines, than by those of an inch entire.  I have took ye middle these experiments of different holes, and as much for ye facility of calculation, as to have a certain measure, and to take away all difficulty.

  I call therefore an inch of water, ye water wch running during the space of one minute gives 14 pints Paris measure, of those wch pass ye brims a little and wch weighs two pounds each.  Ye hole of an inch will give that quantity if ye water is one line above ye hole:  but it must be two lines heigher in ye rest of ye vessel to ye end it may be precisely a line heigh above ye hole.  For ye holes of 6 lines it will suffice that ye water of ye vessel be 7 lines above ye centers.

  That measure so determined is very commodious for calculation, since that in space of one hour ye inch will give 3 muids of Paris, and in 24 hours muids.  Those wch know ye pound less by 7 drachms it would give but 66 muids + 63/72 in 24 hours and these fractions would give much trouble when we would know ye different dispensings of water thrô different Ajutages [[space]] placed at ye bottom of different heights of ye reservatorys.  To confirm this rule ye following experiment was made.

Experiment III

  We took a square vessel containing a cubic foot to ye 12th inch;  but ye last division was of 2 lines from ye bottom to ye top of ye vessel.  Ye water was made to run in by ye means of a vessel, where there was a hole of a circular inch, as hath been described above, ye small plate M was two lines 1/4 heigher than ye top of ye hole, so that near ye top of that hole, ye surface of ye water would remain one line heigh when it was 2 lines heigh in ye rest of ye vessel.  This cubic foot was filled to ye 12th included inch by running water in ye space of 2 minutes and 1/2:  whence it followed that a circular hole so disposed gives gives 14 pints, or 28 pounds of water in a minute, since it give 35 pints in 2 minutes and 1/2.

  By this means is easily known ye inches of water wch a mean fountain gives, or a running rivolet;  for we need but receive ye water in some vessel or place that we can measure and wch holes ye water, and counting what number of minutes or seconds we may say that that running water is of an inch, if it hath given 21 pints of 3 inches, and so in other proportions.

Transcription Notes:
muid - a former French measure of capacity, a method of measuring land in France based on the number of muids of seeds needed to sow the land drachm - a unit of weight formerly used by apothecaries, equivalent to 60 grains or one eighth of an ounce. mandc: Added detail to image. Ajutage: A tube through which is water is discharged; an efflux tube. the ajutage of a fountain. Another example of the translator intending to look up the French word. There seems to be an omission in the ms in this phrase: "and in 24 hours muids." The Desaguliers translation reads: "and in 24 hours 72 barrels [muids]". Image: http://echo.mpiwg-berlin.mpg.de/ECHOdocuView?url=%2Fpermanent%2Flibrary%2FQERNH1MN%2Fpageimg&start=11&mode=imagepath&pn=211&ww=0.0661&wh=0.1547&wx=0.8003&wy=0.7434