OPTICS. 
G63' 
Of PERSPECTIVE. Plate XVIII, XIX. 
From optics naturally arifes perfpeSiive, all the rules of 
which have their foundation in optics. Tacquet makes 
perfpedlive a part of optics ; but John archbifhop of Can¬ 
terbury, in bis “ Perfpedliva Communis,” calls optics, 
catoptrics, and dioptrics, by the name perjpcclive. 
Perfpedlive is the art of drawing on a plane furface true 
refemblances or pidlures of objedts, as the objedts them- 
felves appear to the eye from any diftance and fituation, 
real or imaginary. 
The art of perfpedlive owes its birth to painting, and 
particularly to that branch of it which was employed in 
the decorations of the theatre, where landfcapes were prin¬ 
cipally introduced, and which would have looked unna¬ 
tural and horrid if the fize of the objedts had not been 
pretty nearly proportioned to their diftance from the eye. 
The ancients muft, therefore, have had confiderable 
knowledge of this art; though the only ancient author 
from whom we can obtain any information relative to its 
antiquity, is Vitruvius; who, in the proem to his feventh 
book, informs us, that Agatharcus, at Athens, was the 
firft who wrote on this fubjedf, on occafion of a play ex¬ 
hibited by Aifchylus, for which he prepared a tragic 
fcene; and that afterwards the principles of the art were 
more diftir.dlly taught in the writings of Democritus and 
Anaxagoras, the dilciples of Agatharcus, which are no 
longer extant. 
The Perfpedlive of Euclid, and of Heliodorus Larifleus, 
contains only fome general elements of optics, that are by 
no means adapted to any particular pradlice ; though they 
furnifh fome materials that might be of iervice in the li¬ 
near perfpedlive of painters. Geminus of Rhodes, who 
was a celebrated mathematician in the time of Cicero, 
hath likewife written on this fubjedt. We may alfo infer, 
that the Roman artifts were acquainted with the rules of 
perfpedlive, from the account which Pliny (Nat. Hill, 
lib. xxxv. cap. 4.) gives of the reprefentations on the 
fcene of thcfe plays given by Claudius Pulcher; by whofe 
appearance, he fays, the crows were fo deceived, that they 
endeavoured to fettle on the fidlitious roofs. However, 
of the theory of this art among the ancients, we know no¬ 
thing; as none of their writings have efcaped the general 
wreck of ancient literature in the dark ages of Europe. 
Perfpedlive muft, without doubt, have been loll, when 
painting and fculpture no longer exifted. Neverthelefs, 
we have reafon to believe that it was pradlifed much later 
in the eaftern empire. 
John Tzetzes, who lived in the twelfth century, fpeaks 
of it as if he was well acquainted with its importance in 
painting and ftatuary; and the Greek painters, w'ho were 
employed by the Venetians and Florentines, in the thir¬ 
teenth century, feem to have brought fome optical know¬ 
ledge with them into Italy : for the difciples of Giotto are 
commended for obferving perfpedlive more regularly than 
any of their predecelfors in the art had done; and they 
lived in the beginning of the fourteenth century. 
The revival of painting in Italy was naturally accom¬ 
panied with a revival of the art of perfpedlive. The firft 
authors who profeliedly laid down rules for this art, were 
Bartolemo Bramantino, of Milan, w'hofe book, entitled 
“ Regole di Perfpedliva, eMifure delle Antichita di Lom¬ 
bardia,” is dated 1440; and Pietro del Borgo, likewife an 
Italian, who was the molt ancient author met with by 
Ignatius Danti, and who is fuppofed to have died in 1443. 
The laft writer fuppofed objedts to be placed beyond a 
tranfparent tablet, and endeavoured to trace the images 
which rays of light, emitted from them, would make upon 
it. His work is not now extant; but Albert Durer con- 
flrudled a machine upon the principles of Borgo, by which 
he could trace the perfpedlive appearance of objecls. 
Leon Battifta Albeati, in 1540, wrote his treatife “ De 
Pidtura,” in which he treats principally of perfpedlive. 
Balthazar Peruzzi, of Sienna, who died in 1536, had dili¬ 
gently fludied the-writings of Borgo ; and his method of 
perfpedtive was publifhed by Serlio in 1450. To him, ft 
is faid, we owe the difcovery of points of diftance, to 
which all lines that make an angle of 45 0 With the ground¬ 
line are drawn. Guido Ubaldi, another Italian, foon after 
difcovered, that all the lines that are parallel to one ano¬ 
ther, if they be inclined to the ground-line, converge to 
fome point in the horizontal line; and that through this 
point alfo, a line drawn from the eye parallel to them 
will pafs. His Perfpedlive was printed at Pefaro in 1600, 
and contained the firft principles of the method afterwards 
difcovered by Dr. Brook Taylor. 
Ubaldi applied his method to the delineation of the 
fcenes of a theatre; and in this, as far as the pradtice is 
concerned, he was followed by fignor Sabatellini, in his 
“ Pradtica di fabricar Scene,” of which there was a new 
edition at Ravenna in 1638 ; and to this was added a fe- 
• cond book, containing a defcription of the machines ufed 
for producing the fudden changes in the decorations of 
the ftage. 
The writers on perfpedlive are very numerous. The 
following (fome of whom have been already mentioned) 
are the principal, with the dates of their performances, as 
near as can be afcertained. Guido Ubaldi, 1600, Latin 
folio. Bernard Lamy, 1701, 8vo. S’Gravefande, 1711, 8vo. 
tranflated into Englifh by Stone, 1724. Marolois Vrede- 
man Friefe, the Jefuit, 4to. Pozzo, folio. The Jefuit was 
tranflated into Englifh by E. Chambers, 1726. Ozanam’s 
Mathematics contain alfo a treatife on Perfpedtive. Thefe 
are all foreign works. 
The following lift contains all, or nearly all, the Eng¬ 
lifh authors, or their works, that have written on perfpec- 
tive. Humphrey Ditton, 1712, 8vo. Moxon, folio. Brook 
Taylor, two treatifes, one in 1715, and the other in 1719, 
both 8vo. Langley, 1730, 4to. Oakley’s Magazine of 
Architedlure, Perfpedtive, and Sculpture, 1730, folio. 
Halfpenny, 1731. Hamilton’s Stereography, 2 vols. folio, 
1738. Dr. Brook Taylor’s Method of Perfpedtive, by 
Kirby, 1754, letter-prefs 4to. plates folio. Sirigatti, by 
Ware, 1754, folio. Kirby’s Parallel Supprefied. Kirby’s 
Perfpedlive of Architedlure, 1760, large folio. Highmore, 
1765, 4to. Fournier, 1764, 4to. Cowley’s Moveable 
Schemes for illuftrating the Principles of Perfpedtive, 
1763, 4to. Fergufon, 1765, 8vo. Ware’s Complete Body 
of Architedlure contains a treatife on Perfpedlive, 1768, 
folio. Prieftley, 1770, 8vo. Edward Noble, 1771, 8vo. 
Thomas Malton, 1775, folio. Bradberry. Sheraton, in his 
Cabinet and Upholfterer’s Drawing-Book, 4to. Wood of 
Edinburgh, 1797, 8vo. The Painter’s Maulftick, by 
James Malton, 1800,4to. Douglas, 1805, letter-prefsj8vo. 
plates folio. Edw-ards, 1806, 4to. Thomas Noble, fecond 
edition, 1809,410. Wood’s Ledtures, London, fecond edi¬ 
tion, 1809,4to. W. Daniel, 1810, finall 8vo. for children. 
A thin quarto, without the name of the author, the title 
being “ A new Treatife on Perfpedtive, founded on the 
fimplefl Principles,containing univerfal Rules for drawing 
the Reprefentation of any Objedt on a vertical Plane 
1810, thin 4to. D. Creffwell, A.M. 1811, 8vo. Milne, in 
his Elements of Architedlure, 1812, 4to. Mr. Hayter, 
18-'3, 8vo. Befides the above authors and treatifes, are 
Muller, Martin, and Emerfon, who have written odtavo 
treatifes in their mathematical courfes. A thin quarto 
was written by Bardwell, a painter. The Artift’s Repo- 
fitory, publifhed by C. Taylor, Hatton Garden, contains 
alfo an article on perfpedlive. 
But of all the above works, Dr. Brook Taylor’s is the 
mod celebrated, on account of the univerfality of his 
principles in their application to planes and objedts. For, 
though vanifhing points in every pofition were known to 
Guido Ubaldi, and Gravefande not only underflood the 
ufe of vanifhing points, but the ufe of diredtors alfo in the 
reprefentation of a point, anterior to the appearance of 
any thing publifhed by Brook Taylor; Brook Taylor 
has extended his theory not only to vanifhing points, but 
to the vanifhing lines of planes in every fituation, which, 
when once afcertained, the reprefentation of an objedl is 
found by the fame means in each plane, and confequently 
1 with 
