Of Hydraulk Enghm. $3

and A qi and these heights measured upon the scale S will be 64.3, 76.6,

86.6, 94.0, and 98.55 which express the pressares at A in all theseelevations, considering the pressure iri the upright pipe AB as 100.

Because it may be of use to have the lengths of all the sines of aquadrant from o degrees to 90, we have given the foregoing table,fhewing the length of the sine of every degree in such parts as the wholepipe (equal to the radius of the quadrant) contains 1000. Then the sineswill be integral or whole parts in length. But if you fuppofe thelength of the pipe to be divided only into 100 equal parts, the lastsi gure of each part or sine must be cut off as a decimal 5 and then thofewhich remain at the lest hand of this feparation will be integral orwhole parts.

Thus, if the radius of the quadrant (supposed to be equal to thelength of the pip e AC) be divided into 1000 equal parts, and theelevation be 45 degrees, the sine of that elevation will be equal to 707of these parts: but if the radius be divided only into 100 equal parts,the fame sine will be only 70.7 or 70/- of these parts. For, as 1000is to 707, so is 100 to 70.7.

As it is of great importance to ali engine-makers, to know whatquantity and weight of water will be contained in an upright roündpipe of a given diameter and height 5 so äs by kriowing what weightis to be raised, they may proportion their engines to the force whichthey can afford to work them 5 we finali subjoin tables shewing thenumber of cubic inches of water contained in an upright pipe of around bore, of any diameter from one inch to six and a half ; and ofany height from one foot to two hundred: together with the weightof the said number of cubic inches, both in troy and avoirdupoise ounces.

The number of cubic inches divided by 23 r, will reduce the waterto gallons in wine measure; and divided by 282, will reduce it tothe measure of ale gallons. Also, the troy ounces divided by 12, \kdllreduce the weight to troy pounds; and the avoirdupoise ounces dividedby 16, will reduce the weight to avoirdupoise pounds.

And here I must repeat it again, that the weight or pressure of thewater acting against the power that works the engine, must always beestimated according to the perpendicular height to which it is to beraised, without any regard to the length of the conduct-pipe, when ithas an oblique position; and as if the diameter of that pipe were justequal to the diameter of that part of the pump in which the pistonworks. Thus, by the following tables, the pressure of the water,against an engine whbfe pump is of a 4- inch bore, and the perpen-dicular height of the water in the'conduct-pipe is 80 feet, will be equal

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