A Practical Treatise of Perspective, on the Principles of Dr. Brook Taylor

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Leigh & S. Sotheby, 1806 - Perspective - 313 pages
 

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Page 3 - A circle is a plane figure contained by one line, which is called the circumference, and is such, that all straight lines drawn from a certain point within the figure to the circumference are equal to one another : 16.
Page 3 - A diameter of a circle is a straight line drawn through the centre, and terminated both ways by the circumference. XVIII. A semicircle is the figure contained by a diameter and the part of the circumference cut off by the diameter. XIX. "A segment of a circle is the figure contained by a straight line, and the circumference it cuts off.
Page 3 - ... OF THE CIRCLE. A circle contains a greater area than any other plane figure bounded by the same length of circumference or outline. A circle is a plane figure contained by one line and is such that all straight lines drawn from a point within the figure to the circumference are equal, and this point is called the center of the circle. A diameter of a circle is a straight line drawn through the center and terminated both ways by the circumference, as AC in Fig.
Page 15 - ... in which they affect the eye of the observer, under varying conditions : in the latter, it enables us to make representations of visible objects that shall affect the eye in the same manner as the objects themselves would, if viewed from a certain fixed point. " Perspective is the art of drawing on a plane the appearances of any figures by the rules of geometry. "In order to understand the principles of this art, we must consider that a picture painted in its utmost degree of perfection, ought...
Page 1 - A straight line, or right line, is that which lies evenly between its extreme points ; or, as defined by Archimedes, it is the shortest distance between two AB points, as A B.
Page ix - ... to thofe who are not acquainted with Geometry ; but to fuch as have received a .mathematical education, and comprehend the eleventh book of Euclid, Dr. Brook Taylor's treatifes are fufficient for the theory, and fuch perfons will require but little afliftance in the practice.
Page ix - Perfpective, but alfo prevent much error in the future works of thofe artifts who have not opportunity to enter deeply into the fcience. The author cannot conclude this preface without obferving, that in the courfe of the work he certainly would have endeavoured to give more copious...
Page 182 - ... a right angle. XXVIII. An obtufe angled triangle, is that which has an obtufe angle. XXIX. An acute angled triangle, is that which has three acute angles. XXX. Of four fided figures, a fquare is that which has all its fides equal, and all its angles right angles.
Page 17 - ... nature belonging to them. But in this book I make no difference between the plane of the horizon, and any other plane...
Page viii - This citcumftance has never before been attended to by writers on thefubject; and therefore it may be hoped, that this will operate as an improvement, and greatly facilitate the...

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