tion of the right of fishery on a particular coast has sometimes been the occasion of involving the most powerful nations in expensive wars: for these fisheries, at the same time that they are a source of immense riches to individuals, constitute as it were a nursery for the hardiest race of sailors; and thus become of the highest importance in a national point of view.

CHAP. X.

Adaptation of the external World to the Exercise of the Intellectual Faculties of Man.

SECT. I.

On the Rise and Progress of Human Knowledge. IN the preceding part of this treatise the physical character and condition of man were first considered; and, afterwards, the adaptation of external nature to the supply of his bodily wants. It remains for us to consider the adaptation of the various objects of the material world to the exercise of his intellectual faculties..

But, in contemplating the connexion which exists between the external world and the exercise of the mind of man, who shall attempt to describe the nature and boundaries of that yet unmeasured plain of knowledge, in which man is constantly either intellectually expatiating, or practically exerting himself? who, without wandering into the mazes of metaphysical speculation-always amusing in the pursuit, but never,

T

perhaps, satisfactory in the result-who shall develope the obscure steps by which science first finds access to the mind? In reflecting indeed on the state of civilized society during its earlier periods, there is nothing more wonderful in the intellectual history of mankind, than the skilful management of many processes in the arts, the true nature of which was not understood till ages and ages afterwards. Thus, although zinc was scarcely known as a distinct metal till about a century since; and, almost within the same period, one of its commonest ores, calamine, was held in so little estimation in Great Britain that it was frequently used merely as ballast for shipping, (Watson's Essays, vol. iv. p. 6.); yet that same ore was used before the time of Aristotle for the purpose of making brass, and to that purpose is principally applied at the present day. The process also of making wine was known in the earliest periods of history; although the principles on which it is produced were not well understood till a few years since.

Another remarkable fact in the history of human science, which, though frequently observed, has not yet been explained, is the occasional arrest of its progress at a point immediately bordering on discoveries which did not take place till many ages subsequently". This

u The substance of the following note, though not directly illustrative of the subject now under consideration, is not irrele

may be affirmed, in a certain sense at least, with respect to glass: for this substance, though very early discovered, hardly came into general use for ordinary purposes till comparatively a very late period. But a more remarkable instance occurs with respect to the art of printing: and whoever looks at the stereotype stamps, as they may be called, which have been discovered at Herculaneum, and other places, will be disposed to allow that the embryo of the art of printing died, as it were, in the birth*.

vant to it; and is sufficiently curious in itself to justify its introduction to the notice of the reader.

In Dr. Thomson's Annals of Philosophy for 1817, p. 149, is an account of a paper read at the Royal Society, relative to some experiments made on torpedoes at Rochelle, in which it is stated that, where torpedoes abound, boys are in the habit of playing the following trick to those who are not in the secret. They persuade the ignorant boy to pour water in a continued stream upon the torpedo; and the consequence is, that an electrical shock is conveyed, along the stream, to the body of the boy.

Plutarch notices the same fact in almost the same terms. "It

"is affirmed by those," he says, "who have often made the ex"periment, that, in pouring water on a live torpedo, the hand of "the person who is pouring the water will be sensible of a shock, "which has apparently been conveyed through the water to his "hand." Ἔνιοι δὲ ἱστοροῦσι, πεῖραν αὐτῆς ἐπιπλέον λαμβάνοντες, αν ἐκπέσῃ ζῶσα (Νάρκη, the Torpedo), κατασκεδαννύντες ὕδωρ ἄνωθεν, αἰσθάνεσθαι τοῦ πάθους ἀνατρέχοντος ἐπὶ τὴν χεῖρα, καὶ τὴν ἁφὴν ἀμβλύνοντος, ὡς ἔοικε, διὰ τοῦ ὕδατος τρεπομένου καὶ προπεπονθότος.

PLUT. MORALIA, Oxon. 4to, 1797, tom. iv. p. 643, 644. x A very interesting conjectural account of the origin and progress of the arts, and of social life, occurs in the last part of the fifth book of Lucretius.

In order that the external world may be fitted to the just exercise of our intellectual faculties, it is evidently necessary that its phenomena should be presented to our senses with a certain degree of regularity. This is a condition so obvious to a mind capable of reflection, that wẻ find it inculcated, almost in the same terms, by two writers of the most opposite views as to the causes of those phenomena. Thus Lucretius asserts, that the sun and moon, by the constant returns of their light and by the regularity of their course, afford to mankind an assurance that day and night, and the various seasons of the year, will recur not only in a definite order, but also for definite periods of duration. And thus also, but in language and imagery more elevated, and with a sublime acknowledgment of the cause, as well as a declaration of the fact, the author of the 19th Psalm affirms, that "the "heavens declare the glory of God, and the "firmament sheweth his handywork. Day unto day uttereth speech, and night unto night "sheweth knowledge.

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But it is also necessary to the just exercise of our intellectual faculties, that the senses of men in general should be similarly affected, when acted on by the same causes: for otherwise there would be no stability in our knowledge, as derived from these its most fertile sources.

y Lib. V. 971-979, and 1435-1438.

And though, from a peculiarity in original constitution, or from the effect of disease, the sensations of particular individuals may differ, not only in degree but in kind, from those of the world at large; the error is of no moment, since it may at once be corrected by a reference to the common sense of mankind.

If any one should too curiously object that there can be no direct proof of a similarity of impression, from the same object, on the senses of men in general; it might be answered, that neither is there any direct proof to the contrary : while we have many antecedent reasons for believing that there really is such a similarity of impression. The structure for instance of the several organs, of taste, smell, hearing, and sight, is essentially the same in all individuals; and the functions of those organs may therefore be presumed to be the same: and from the similarity of the natural expression of disgust, which peculiar odours and flavours usually excite in numerous individuals, it cannot be reasonably doubted that their respective senses are similarly affected by those agents.

If, again, any one should further object that we can have no absolutely firm ground for a reliance on the senses themselves, it might fairly be answered, that although, from the time of Pyrrho to that of Berkeley, there have been always speculative sceptics with respect to the