## The Elements of Euclid: With Dissertations Intended to Assist and Encourage a Critical Examination of These Elements as the Most Effectual Means of Establishing a Juster Taste Upon Mathematical Subjects Than that which at Present Prevails |

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... of being rational creatures . And fuch dif- courfes have generally ended in your urging me to the execution of this plan ; the

... of being rational creatures . And fuch dif- courfes have generally ended in your urging me to the execution of this plan ; the

**first**part of which I here beg leave to present to you . I have had fufficient leave ( ii ) Page 2

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**first**condemned to an examination of particulars . And even when we take up with the systems of others , it is requifite that we have laid in a fufficient ftock of materials to enable us readily to comprehend any very general doctrine ... Page 3

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**first**discovered , as many have been apt to imagine . Now here is the difficulty ; a fcientific book ought to contain knowledge in that compact form ; in which every one would chuse to take a review of it , after he has made himself ... Page 5

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**first**com- mon notion ; because they are all equal to the fame length , viz . the distance between the extreme points of his compaffes . But it is carefully to be obferved that this is not to be made the fubject of a tranfient reflexion ... Page 6

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**first**nothing , then gradually increasing until it disappears when the legs become one straight line . This incli- nation is a quantity , though not a tangible substance , but this the reader will do well to convince himself of ; and ...### Other editions - View all

The Elements of Euclid: With Dissertations Intended to Assist and Encourage ... James Williamson,James Euclid No preview available - 2016 |

### Common terms and phrases

ABCD alfo alſo angle ABC angle BAC angle contained angle equal apply itſelf bafe baſe BC is equal Book certainly circle ABC circumference common notion confequences conft conftruction cut in halves demonftrated deſcribed diſtance drawn equal angles equiangular equilateral equimultiples Euclid exceed faid fame manner fame multiple fame parallels fame ratio fame reaſon fecond fegment fhall fides fimilar fince firſt fome fquare ftraight line BC fuch fuppofe fuppofition given rectilineal given ſtraight line Gnomon greater hath himſelf impoffible infcribed joined lefs leſs let the ftraight magnitudes moſt muſt neceffary parallelogram PROP propofition proportionals purpoſe reader reaſon rectangle contained rectilineal figure remaining angle remaining fides right angles ſame ſay ſhall ſhould ſome ſquare ſtraight line AB ſubject ſuch ſuppoſe taken theſe thoſe tiple triangle ABC underſtand uſe Wherefore becauſe

### Popular passages

Page 3 - Let it be granted that a straight line may be drawn from any one point to any other point.

Page 47 - If there be two straight lines, one of which is divided into any number of parts, the rectangle contained by the two straight lines is equal to the rectangles contained by the undivided line, and the several parts of the divided line. Let...

Page 68 - If a straight line drawn through the centre of a circle bisect a straight line in it which does not pass through the centre, it shall cut it at right angles : and if it cut it at right angles, it shall bisect it.

Page 45 - ABG ; (vi. 1.) therefore the triangle ABC has to the triangle ABG the duplicate ratio of that which BC has to EF: but the triangle ABG is equal to the triangle DEF; therefore also the triangle ABC has to the triangle DEF the duplicate ratio of that which BC has to EF. Therefore similar triangles, &c.

Page 15 - When a straight line set up on a straight line makes the adjacent angles equal to one another, each of the equal angles is right, and the straight line standing on the other is called a perpendicular to that on which it stands.

Page 86 - When you have proved that the three angles of every triangle are equal to two right angles...

Page 88 - EA : and because AD is equal to DC, and DE common to the triangles ADE, CDE, the two sides AD, DE are equal to the two CD, DE, each to each ; and the angle ADE is equal to the angle CDE, for each of them is a right angle ; therefore the base AE is equal (4.

Page 42 - If four straight lines be proportionals, the rectangle contained by the extremes is equal to the rectangle contained by the means ; And if the rectangle contained by the extremes be equal to the rectangle contained by the means, the four straight lines are proportionals. Let the four straight lines, AB, CD, E, F, be proportionals, viz.

Page 109 - Draw two diameters AC, BD of the circle ABCD, at right angles to one another; and through the points A, B. C, D, draw (17.

Page 8 - GB is equal to E, and CK to F ; therefore AB is the same multiple of E, that KH is of F: But AB...