not a capital excellence. In painting, in mufic, in poetry, in eloquence, it is often neceffary to exprefs the paffions and affections of the foul: they can be expreffed only by the person whose fenfibility of heart enables him to conceive the paffion with vivacity, to catch it as by infection, and whose imagination immediately receives an impulse from it, and pours in the ideas of the proper characters of the several paffions, of those effects, imitable in the particular art, by which each paffion naturally fhows itself. Every artist muft often excite the paffions: they are excited chiefly by being well expressed: they are excited alfo by ftrong representations of their objects and their causes; but it is the fancy, excited by the lively conception of the paffion, running into the fame thoughts which the paffion, if really working, would fuggeft, and placing the artist in the fituation in which he would then be, that puts it in his power to imagine, and confequently to represent, its causes and its objects in a way' proper for infufing it into others (9).

(g) Summa enim (quantum ego quidem fentio) circa movendos affectus in hoc pofita eft, ut moveamur ipu.-Nec incendit nifi ignis, nec madefcimus nifi humore: nec res ulla dat alteri colorem, quem ipfa non habet. Primum eft igitur, ut-aficiamur antequam afficere conemur. At quomodo fet

In these feveral ways, brightness and pene-. tration, a genius for the arts and a genius for the sciences, arise from a difference in the turn and conftruction of the imagination.

SECT. III.

How the two Kinds of Genius differ in refpect of the Affiftance which they derive from Memory.

OTH in genius for the arts, and in ge

BOTH

nius for science, imagination is affifted by memory, operating in fubordination to it, and operating continually along with it. But it is not, in these two kinds, affifted equally. by memory, nor affifted by the fame species, of memory.

ut afficiamur? Neque enim funt motus in noftra poteftate, Tentabo etiam de hoc dicere. Quas Parracias Græci vocant, nos fane vifiones appellemus: per quas imagines rerum abfentium ita repræfentantur animo, ut eas cernere oculis, ac præfentes habere videamur: has quifquis bene conceperit, is erit in affectibus potentiffimus. Hunc quidem dicunt infanacutis, qui fibi res, voces, actus, fecundum verum optime finget:* quod quidem nobis volentibus facile continget.-Infequetur inryum, quæ a Cicerone illuftratio et evidentia nominatur: que non tam dicere videtur, quam oftendere; et affectus non aliter quam fi rebus ipfis interimus, fequentur. QUINT. Infi. Orat. lib. vi. cap. 3. Sed cum fint alii veri affectas, alii fiētï' et imitati,-hi carent natura, ideoque in his primum eft bene affici, et concipere imagines rerum, et tanquam veris moveri. Ibid. lib. xi. cap. 3.

IN

In scientifical invention, memory is exerted in a much greater degree, and its affiftance is more indifpenfably neceffary than in the arts, All the experiments, all the obfervations,^all the principles, employed in philosophical investigations, must be fuch as have been actually obferved or afcertained, and are exactly remembered, else they can be of no use for establishing a just theory, Memory must attcft the phenomena as really observed, and the principles as already verified, and produce a full conviction of their having been obferved and verified, else the philofopher would never think of applying them to the fupport of his theory. Phenomena not experienced, but imagined, could lead to none but chimerical conclufions. At one time electricians imagined that they faw in their experiments the power of electricity affected by the colours of bodies, and light bodies performing a regular motion from west to east round an electrified ball (a) : had these facts been taken for granted, and, conclufions deduced from them, the conclufions must have been altogether fanciful. Often indeed men can in fome degree imagine beforehand what will be the result of an experiment, or what the appearances which it

(a) PRIESTLY'S Hiftory of Electricity, Part I. per.

will difclofe; nay, cannot reftrain themselves from conjectures concerning this. But it is only intimate acquaintance with the subject, extensive knowlege of the laws of nature, accurate remembrance of the appearances which have attended analogous experiments, difcernment of the variation of circumftances in the experiment propofed, and judgment of the probable confequences of that variation, that can enable them to conjecture right. Some of Bacon's anticipations, and many of Newton's conjectures in his queries, were just, and have been fince established by actual trials. But if, without thefe requifites, by the mere force of imagination, a perfon venture to guess in this manner, he will almost certainly guess wrong; and, if he proceed to reafon from it, will produce a fantastical hypothefis. Scarce any man can poffels the requifites mentioned, in fo great a degree, as to render it safe for him to build upon the fuppofed refult, without first bringing it to actual trial, and making himself certain of the fact. Even when a man may naturally think that he has the best foundation for his conje&ure, the refult may, on trial, turn out not only different, but direaly oppofite. When all the experiments at that time made feemed to fhow, that the

elearical

electrical fire is contained in the glass itself, · and when it was known that the earth or a floor draws off this fire from a globe or tube in which it has been excited, it was natural to conjecture that the electrical power would be strengthened by preventing its. being thus drawn off, by supporting the macl ajne and the operator on fome fubftance which is not a conductor of electricity; the conjecture was formed by feveral electricians, and was in the highest degree plaufible: but when, they made the trial, the very reverse of their expectation happened, the power was very much weakened; and this unlooked for effect led fome of them to correct the fpecious error which had occafioned their conjecture, to conclude that the electric fire is only collected, not produced, in the glass by friction, and to discover the twofold electricity, the positive and the negative (b). Facts imagined, or rashly taken for granted, have produced numbeṛrless errors in fcience. All the facts on which true science can be built, muft be exhibited by memory; the operation by which they are immediately applied, is recollection. This recollection is indeed under the influence of a

(6) PRIESTLY'S Hift. of Elearicity, Part I per. vii. and per. viii. fect. 3.

piercing