Brook Taylor

“John Mason Good, Olinthus Gregory, Newton Bosworth, "Taylor (Dr. Brook)" in Pantologia: A New Cyclopaedia, Comprehending a Complete Series of Essays, Treatises, and Systems, Alphabetically Arranged; with a General Dictionary of Arts, Sciences and Words (1813) Vol.11”

“Brook Taylor, New Principles of Linear Perspective (1749)”

“Charles Knight, ed., "Taylor, Brook," Biography: Or, Third Division of "The English Encyclopedia" Vol.5, p.927”

“I am spared the necessity of closing this biographical sketch with a prolix detail of his character: in the best acceptation of duties relative to each situation of life in which he was engaged, his own writings and the writings of those who best knew him, prove him to have been the finished Christian, gentleman, and scholar.”

“Brook Taylor... in his Methodus Incrementorum Directa et Inversa (1715), sought to clarify the ideas of the calculus but limited himself to algebraic functions and algebraic differential equations. ...Taylor's exposition, based on what we would call finite differences, failed to obtain many backers because it was arithmetical in nature when the British were trying to tie the calculus to geometry or to the physical notion of velocity.”

“The theory of perspective was taught in painting schools from the sixteenth century onward according to principles laid down by the masters... However, their treatises on perspective had on the whole been precept, rule, and ad hoc procedure; they lacked a solid mathematical basis. In the period from 1500 to 1600 artists and subsequently mathematicians put the subject on a satisfactory deductive basis, and it passed from quasi-empirical art to a true science. Definitive works on perspective were written much later by eighteenth-century mathematicians Brook Taylor and J. H. Lambert.”

“Drawing continued to be his favourite amusement to his latest hour; and it is not improbable that his valuable life was shortened by the sedentary habits which this amusement, succeeding his severer studies, occasioned.”

“[I]t may not be amiss to set down here two Approximations I have formerly hit upon. The one is a Series of Terms for expressing the Root of any Quadratick Equation; and the other is a particular Method of Approximating in the invention of Logarithms, which has no occasion for any of the Transcendental Methods, and is expeditious enough for making the Tables without much trouble.”

“Hence if y be the Root of any Expression formed of y and known Quantities, and supposed equal to nothing, and z be a part of y, and x be formed of z and the known Quantities, in the same manner as the Expression made equal to nothing is formed of y; and let y be equal to z + v; the difference v will be found by Extracting the Root of this expression {{center/s}}x + \frac {\dot{x}v}{1} + \frac {\ddot{x} v^2}{1 \cdot 2} + ... etc. = 0.{{center/e}}”

“z and x being two flowing Quantities (whose Relation... may be exprest by any Equation...) by [the aforesaid] Corollary, while z by flowing uniformly becomes z+v, x will become{{center/s}}x + \frac {\dot{x}}{1 \cdot \dot{z}}v + \frac {\ddot{x}}{1 \cdot 2 \cdot \dot{z}^2}v^2 +... etc. or{{center/e}}”

“In doing this he makes use of a Table of Products (...he calls Speculum Analyticum,) by which he computes the Coefficients in the new Equation for finding the Difference mentioned. This Table, I observed, was formed in the same Manner from the Equation propos'd, as the {{w|Fluxion}}s are, taking the Root sought for the only flowing Quantity, its Fluxion for Unity, and after every Operation dividing the Product successively by the Numbers 1, 2, 3, 4, etc.”

“Dr. Halley..., has publish'd a... compendious and useful Method of extracting the Roots of affected Equations of the common Form, in Numbers. This Method proceeds by assuming the Root desired nearly true... (...by a Geometrical Construction, or by some other convenient way) and correcting the Assumption by comparing the Difference between the true Root and the assumed, by means of a new Equation whose Root is that Difference, and which he shews how to form from the Equation proposed, by Substitution of the Value of the Root sought, partly in known and partly in unknown Terms.”

“The Book it self is so short, that I need not detain the Reader any longer in the Preface...”

“There may be regular Methods also invented for teaching the Doctrine of Light and Shadow; and other Particulars relating to the Practical Part of Painting, may be improved and digested into proper Methods... But I only hint at these... recommending them to the Masters of the Art to reflect and improve upon.”

“[[w:Opticks|[T]he Theory]] I have endeavour'd to explain in the Appendix, from Sir Isaac Newton, may be of very great use to Learners.”

“[H]e should be instructed in the Theory of the Colours; that he should learn... their particular Properties... Relations, and... Effects that are produced by their Mixture; and that he should be made well acquainted with the Nature of the several material Colours... used in Painting.”

“Nothing ought to be more familiar to a Painter than Perspective; for it is the only thing that can make the Judgment correct, and will help the Fancy to invent with ten times the ease that it could do without it.”

“When he is sufficiently perfect in these, I would have him learn Perspective. And when he has made some progress in this, so as to have prepared his Judgment with the right Notions of the Alterations that Figures must undergo, when they come to be drawn on a Flat, he may then be put to Drawing by View, and be exercised in this along with Perspective, till he comes to be sufficiently perfect in both.”

“[T]he Method which ought to be follow'd in instructing a Scholar in the Executive Part of Painting; ...first have him learn the most common Effections of Practical Geometry, and the first Elements of Plain Geometry, and common Arithmetic.”

“I would recommend it to the Masters of the Art Painting... to establish a better Method for the Education of their Scholars, and to begin their Instructions with the Technical Parts of Painting, before they let them loose to follow the Inventions of their own uncultivated Imaginations.”