The "PREFACE.
XXX
kind. It may be faid, that every Art tends to give the Mind a particular Turn ; and that the only way of maintaining it in its natural Reaitude, is by 'calling in other oppofite ones, by way of Counter-ballance. Thus we find nothing more perverfe and unfufferable than a mere Mathematician, mere Critic, Grammarian, Chy- mift, Poet, Herald, or the like 5 and the proper Difpofition is only to be had from a juft Temperament or Mixture of 'em all. . .
I OWN this is not the way to make a very great progrefs in any Art; but at the fame time it is the only way to hinder our being fpoil'd by any ; and becoming Creatures rather of Homer or Jrijlotle's making, than God's : and receiving our Taftes, Views, Relifhes, at fecond hand, rather than from Nature her felt This, however, is only to be underftood with regard to perfonal Benefit. For no doubt the Publick is better provided for, by the mere Purfuers of particular Arts, than the general Appliers to all: fince each is hereby brought to greater Perfeftion ; and the Mixture and Temperament, wanting in the Individuals, is found in the Whole.
T O conclude, the ultimate View of a Work of this, or any other kind, fhould be, the forming a found Mind, i. e. a Syftem of Perceptions, and Notions agreeing to the Syftem of Things, or in the Relation thereto, intended by its Author. The End of Learning and Study, is not the filling our Heads with other Mens Ideas ; that is an Inrichmerit which may prove for the worfe, if it carry any ill Quality with it : Richnefs is not the chief thing aim'd at ; 'tis only a Circumftance, or Matter of a fecondary Confideration : Soundnefs is the firft. There °are many Manures which the Hulbandman dares not ufe, by reafon they would corrupt the Land, at the fame time they enriched it ; and lay the Foundation of a Difeafe, which would in the End impoverifh, and make it fpend it felf in unprofitable Weeds. A little pure Logic, or Theology, or Chy-
mi'ftry, in fome Peoples Heads, what Mifchief have they not produced ? But it muft be owned,
Mens Heads are not fo foon fill'd : the Memory is not fo tenacious as we imagine ; Ideas are tranfient things, and feldom ftay long enough with us to do us either much good, or harm : Ten to one but what we read to-day, is forgot again to-morrow. And what chiefly makes new Ideas of any fignificancy, is
their extending and enlarging the Mind, and making it more capacious and fufceptible. But neither is this
Enlargement the laft Aim ; but is chiefly of ufe, as it contributes to the increafing our Senfibility, to the ma- king our Faculties more fubtil, and adequate, and giving us a more exquifite Perception of things that occur ; and thus enabling us to judge clearly, pronounce boldly, conclude readily, diftinguifh accurately, and to ap- prehend the manner and Reafons of our Decifions. In which view, feveral things may be ufeful, that are not fo much direft Matters of Knowledge, as fubfervient to the fame End ; for inftance, much of the School Phi- lofophy, which by exercifmg and exciting the Mind, has a kind of collateral tendency to fharpen its Faculties -,
and needs only be read, not retain'd, to produce its Efieft. But neither does the Matter end here : Even this
does not amount to the full and adequate End of Knowledge : This is only improving the Organ j and there muft be fome farther End in fuch Improvement. No Man fharpens his Weapon on the fole Confideration of having it fharp, but to be the fitter for ufe. Briefly, then, our Faculties being only fo many Inlets, whereby, and according to the Meafure whereof, we receive the Intimations of the Creator's Will, or rather, the EffecTs of his Power and Action ; all the Improvements made in 'em, have a tendency to fubjeft us more entirely to his Influence and Direction ; and thus make us confpire, and move more in concert with the reft of his Works, to accomplilh the great End of all things. In which our Happinefs and Perfection confifts ; the Perfection of a fingle Nature, arifing in proportion as it contributes to that of the To" n A~ N.
ERRATA.
IN the Article Angle, Page 97. Column 1. Line ult. for Centre L, read Centre I. Article Mean Anomaly, 1. 10. infert Fig. 64. Article Afymptote of a Logarithmic Curve, infert Fig. 3 3.
Centre of Ofcillztion, 1. II. forDEHB, r. DFHB.
Centripetal Force, 1. 2. for Fig. 24. r. Fig, 25.
Centrobaryc, Corol. VI. for divided into two M D, r. be bifeCied
in D, and for m O, r. in O. Chord, p. 211. col. a. 1.26". for Fig. 7. r. Fig. 6. Circle, p. 221. col. i.I. 27, for DE r. DF, andl. 36. infert Fig. 7. Circumscribing, for Fig. 32. r. Fig.zy.
Commutation, I.3. after Earth infert atS, and for .Fi^^, t.Fig.zS. Compares, for GemanCompajfes r. German Compajfes. Composition of Motion, 1. 17. for as far as ee t r. as far as c e . Conchilis, 1. 7. for EE r. EF. Cone, p. 300. col. 1. 1. 13. fox Diameter of its Bafe, r. Diameters
of its Bafes. Contacl, 1. 15. for cats r. touches. Crepufculum, p. 344. 1. penult, for Sum of, r. Sun's, and p. 34^.
1. 2. and 3. for, P Z the Elevation of the Pole P R, r. P Z the
Complement of the Elevation, 5cc, Curve, p. 361. col. 2. 1.26", and 59. for Tab.Analyfis r. Tab.Geom. Cycloid, 1. 4. for Tab. Analyfis r. Tab. Geometry. Declinator, I. a 5. fox Centre E, r. Centre F. Defigning t 1. 10. for Fig. 9. r. Fig, 15, Diagonal, 1. 77. for B S, r. B E. Horizontal Dial, 1. 9. for Meridian Line B, r. Meridian Line A B j
and I.16. for DC, r. DE, and I.12. for a EQd H, r. ab cdU. Eaft Dial, 1- II. for AC, r, D C. Primary Dial, 1. 20. for EE, r, E F. Line of" Diflance, for Fig. 10, and 11. r. Tig. 12, Divifion'm Lines, infert Tab. Geometry, Fig. 17. Eccentric, for Fig, 11. r. Fig. 1.
Equation, p.53^ . col. 1.I.1 5. for given Pofition, r. given in P 'option. Flying, 1. io. for Temporal Mufclss r. Pecloral Mufcles. Geocentric Latitude, 1. 11. for, eT§ r. et $. Latus Tranpverfum, for Fig.*,, x. Fig.i. and for GLRO r. DLRO. Logijlic Spiral, for Fig. 11. r. Fig. 22.
Article Concave Mirror, Law II. after F infert Fig. 34 *;
Paracentric Motion of Impetus, for Fig. 25. r. Fig. 24. and dele T. Paracentric Solicitation of Gravity, dele Fig. 16.
Paralla x of Longitude, for Fig. 28. r. Fig.zy. Parallax of
Afcenfion, for 29. r. 18. Parallelogram, Ll7.for Fig.$9<** Fig.41. andl. 19. forCHr.CD.'
Particula Exfors, for Augment r. Argument.
Perfyeffive of a Triangle, 1, 14. for fince a, b, and are the Appear- ances, r, fince a, b, and c are the Appearances.
Inclined Plane, Law IX. after A C infert Fig.<,^. and in the Corol. of the fame Law infert F'tg.6o. and inLaw XIII. for BAK r. FG.
ProjeclUe, Law III. after defcribe a Parabola dele in a Medium uniformly reftfihzg.
Pump, Artie. Structure of a Forcing Pump, I. 1. for in a Cylinder r. a Cylinder,
Pyramid, 1. 70. for D F r. D E.
Sinical Quadrant, 1. 2. infert Fig. 18.
Quadrature of the Ellipfis, 1. 2. for Circle, r. Curve.
Reclangle, 1. 22. for Fig. 41. r. Fig, 61.
Rectification of a Parabola, for Conjugate Axes r. 'Conjugate Se- miax.es ; and after Hyperbolic Space, add CQ^M A.
Rectification of the Cycloid, 1. I. infert Fig. 27.
Reduction of a Figure, 1. II. for Fig. 64. r. Fig. 6<$.
Refrailion, 1. 9. for B, r. F.
Retrogradation of the Sun, 1. 2. for A N, r. A M.
Rhomb, Article I. infert Fig. 19.
Screw, Art. IV. for to be applied inK, r. to be applied in D.
Sculpture in Marble, after another Plummet like that of the Model 3 infert Tab, Mifcellany, Fig. 2.
Secant, 1. 4. for Circle B, r. Circlein B.
Sector, p. 45. col. 1. I.41. for Lines r. Sines.
Sine, p. 8 1. col. 1. 1. 6 3, for the Arch E F C, c. the Arch's C.
S/Be-Complement, 1. 2. for A E, r. A H.
Solid Angle, I. 3. for Fig. 30. r. Fig. 31.
Star, p. 122. col. 2. 1. 20. for Fig. 3 I. r. Fig. 7. and 1. 24. for the Star C defcribing an equal Arch CDH, r. the Star D defcribing an Arch equal to C D H.
Triangle, p. 142. col. a. I.41. for AC, r. B C.
N. B. The figures relating to each Art are placed fronting the Name of the refpecfive Art, m the Body of the Book ; and are refer'd to under that Title : as, Tab. Architecture, Tab. Geo-,, metry 3 &c. — To each Figure is alfb annexed t he Word for whofe Exemplification it firves : So that the Reader may either go from the Word to the Figure, which exemplifies it \ or back-\^ wards t from the Figure^ to the Word which explains it.
