MAJESTY, the following Treatise, on the science and practice of Perspective.

That Your MAJESTY may long be enabled to continue to the Arts, that patronage and protection, under which they have hitherto flourished; and may thence derive the satisfaction which must result from private gratitude and public esteem; is the humble, but ardent wish of

Your MAJESTY'S

Most dutiful and devoted

Subject and Servant,

Edward Edward's.

PREFACE,

ALTHOUGH various treatifes on the science of Perspective have been written, fome of which have great excellence, yet it may with truth be afferted, that not one of them is calculated to be useful, or even intelligible, to fuch artists as are not acquainted with Geometry, yet wish to gain a knowledge of the science, fufficient to qualify them to conduct their works upon true principles. The defects which destroy the utility of thofe treatifes will be clearly demonftrated, by arranging them in two claffes, and then confidering each under its fpecific character. In the firft clafs are thofe which, by their examples, appear clear and inftructive at the firft view, but when examined are found deficient in fcience and theory, and are even wanting in the explanation of the few principles which they contain. Such are the defects of the works of Maralois, the treatife commonly called The Jefuit's Perspective, and of Pozzo.

In the fecond clafs are thofe treatifes which are the best, and contain the truest principles of the science; but are so mathematical in their structure, and confequently fo abftrufe to those who are not verfed in the Elements of Euclid, that they contain no examples of forms or figures in Perspective, and confequently have nothing that can invite the eye of a practical artift to examine their principles.

Such

Such are the difadvantages attending the elegant work published by Dr. Brook Taylor, of Cambridge, first in the year 1715, and again, with improvements, in 1719. The fame inconveniencies attend the treatife by Mr. Hamilton, which, added to its magnitude, deters the artift from its perufal, rather than invites him to study the fcience it contains.

There is alfo another work that has infinite merit, written by T. Malton, fenior, and published in 1775; which contains fome excellent and masterly examples: but he has deftroyed their utility by entangling the vanishing points, and croffing the diagram in fo confufed a manner, that it is almoft impoffible for a young practitioner to trace and diftinguish the different figures.

These faults, which are too frequent in books of inftruction, have arifen from two caufes; the firft is, that the authors of them, though perfect masters of the science on which they wrote, had not acquired the art of explaining it to those who are unacquainted with it; they feem alfo to have forgotten, that thofe who would inftruct, muft defcend to that language for explanation, and apply thofe figures for illuftration, which are suitable to the powers and comprehenfion of their pupil, rather than to the display of their own science and abilities.

The second caufe of the defects before mentioned arifes from the following circumstance; which is, that excepting Pozzo and Highmore, there is no author who has written on the subject of Perfpective, that can be confidered as a painter; confequently they were deficient in the knowledge of the forms of objects, and thereby unable to apply their science to the ufes required by the artist.

Having experienced and confidered the disadvantages before mentioned, the author prefumed to think that a work might be produced, better calculated than any one that has hitherto appeared, for the fervice of thofe artists who have neither time nor refolution fufficient to investigate the fcience of Perfpective, under its prefent obfcurities and

and difficulties. Whether the following treatise, which he has attempted in conformity to his idea, will answer the end propofed, must be left to the reader to determine.

The arrangement of the work is as follows:

As a preliminary apparatus, a selection of definitions and problems in geometry is given, all of which are abfolutely neceffary to be understood by those who mean to practise Perspective; they are inferted not to increase the size of the volume, but that the student may not be compelled to feek for other books, before he can make use of this.

After the Geometry follows the Perspective, which is divided into fix fections;

The first is introductory, and contains all the terms that are employed in the practice, together with their definitions, illustrated by proper examples; the difference between the center of the picture and point of fight is defined; and the various pofitions in which objects may be difpofed to the picture: it alfo contains the rudiments of practice for lines, parallel and perpendicular, to the picture.

The fecond fection contains inftructions, with examples for drawing objects, the fronts and fides of which are parallel and perpendicular to the picture.

The third section treats of objects, the fronts of which are inclined to the picture.

In the fourth fection are examples, with inftructions for delineating objects, when the planes or faces of which they are compofed are inclined both to the picture and to the horizon.

It must be observed, that the aforenamed fections contain all the practical principles neceffary for the delineation of objects in Perfpective, however their different planes may be difpofed to the eye of the fpectator.

The

The fifth fection treats of fhadows, in which the author has attempted to explain the leading principles of that part of the fcience in the cleareft manner he was able; but whatever his fuccefs may have been, it must not be expected that this part can be clear and eafy to thofe who do not well understand the preceding fections of the work; therefore the ftudent muft make himfelf mafter of thofe, before he attempts fhadows.

The fixth and laft fection contains methods for facilitating operations in difficult cafes, as alfo fome theoretic inftructions, together with obfervations by way of praxis; all of which will be found extremely useful to the ftudent.

In the technical language of the fcience, the terms adopted by Dr. Brook Taylor are united with thofe employed by the old writers on Perfpective, by which means it is expected that the ftudy of the fcience will be facilitated to those who chufe to refer to the works of that great mafter and his principal fucceffors.

The plates contain a felection of useful and familiar examples, fuch as are moft generally wanted in the common courfe of practice, yet fuch as will include all the pofitions in which objects may be placed to the picture or spectator; omitting the inclined picture, for which the ftudent is referred to the fenior Malton, Hamilton, &c.

Moft of the examples are drawn to a feale, the ufe of which is explained in the first section, and applied in most of the following. This circumftance has never before been attended to by writers on the fubject; and therefore it may be hoped, that this will operate as an improvement, and greatly facilitate the study of the science in its practical part but the reader muft obferve, that the author does not mean to offer any new method of procefs, founded on any fuperior theory of the fcience; he only wishes to teach the readieft mode of practice, directed by the principles of Dr. Brook Taylor, whofe writings