that he sees the same colours in the drops which are dashed from oars in the sunshine;-and in the spray thrown by a mill wheel;-and in the dew drops which lie on the grass in a meadow on a summer morning;—and if a man takes water in his mouth and projects it on one side into a sunbeam ;-and if in an oil lamp hanging in the air, the rays fall in certain positions upon the surface of the oil; --and in many other ways, are colours produced. We have here a collection of instances, which are almost all examples of the same kind as the phenomenon under consideration; and by the help of a principle collected by induction from these facts, the colours of the rainbow were afterwards really explained.

With regard to the form and other circumstances of the bow he is still more precise. He bids us measure the height of the bow and of the sun, to show that the centre of the bow is exactly opposite to the sun. He explains the circular form of the bow,-its being independent of the form of the cloud, its moving when we move, its flying when we follow,-by its consisting of the reflections from a vast number of minute drops. He does not, indeed, trace the course of the rays through the drop, or account for the precise magnitude which the bow assumes; but he approaches to the verge of this part of the explanation; and must be considered as having given a most happy example of experimental inquiry into nature, at a time when such examples were exceedingly scanty. In this respect, he was more fortunate than Francis Bacon, as we shall hereafter see.

We know but little of the biography of Roger Bacon, but we have every reason to believe that his influence upon his age was not great. He was suspected of magic, and is said to have been put into close confinement in consequence of this charge. In his work he speaks of

Astrology, as a science well worth cultivating. "But,"
says he, "Theologians and Decretists, not being learned
in such matters, and seeing that evil as well as good may
be done, neglect and abhor such things, and reckon them
among Magic Arts." We have already seen, that at the
very time when Bacon was thus raising his voice against
the habit of blindly following authority, and seeking for
all science in Aristotle, Thomas Aquinas was employed
in fashioning Aristotle's tenets into that fixed form in
which they became the great impediment to the progress
of knowledge. It would seem, indeed, that something
of a struggle between the progressive and stationary
powers of the human mind was going on at this time.
Bacon himself says, "Never was there so great an
appearance of wisdom, nor so much exercise of study in
so many Faculties, in so many regions, as for this last
forty years.
Doctors are dispersed everywhere, in every
castle, in every burgh, and especially by the students of
two Orders, (he means the Franciscans and Dominicans,
who were almost the only religious orders that distin-
guished themselves by an application to study †,) which
has not happened except for about forty years. And yet
there was never so much ignorance, so much error." And
in the part of his work which refers to Mathematics, he
says of that study ‡, that it is the door and the key of
the sciences; and that the neglect of it for thirty or
forty years has entirely ruined the studies of the Latins.
According to these statements, some change, disastrous
to the fortunes of science, must have taken place about
1230, soon after the foundation of the Dominican and
Franciscan Orders §. Nor can we doubt that the adoption

#Quoted by Jebb, Pref. to Op. Maj.
Op. Maj., p. 57.

+ MOSHEIM, Hist. iii. 161.

§ MOSHEIM, iii. 161.

of the Aristotelian philosophy by these two Orders, in the form in which the Angelical Doctor had systematized it, was one of the events which most tended to defer, for three centuries, the reform which Roger Bacon urged as a matter of crying necessity in his own time.

CHAPTER VIII.

THE REVIVAL OF PLATONISM.

Causes of Delay in the Advance of Knowledge.-IN the insight possessed by learned men into the method by which truth was to be discovered, the fourteenth and fifteenth centuries went backwards, rather than forwards, from the point which had been reached in the thirteenth. Roger Bacon had urged them to have recourse to experiment; but they returned with additional and exclusive zeal to the more favourite employment of reasoning upon their own conceptions. He had called upon them to look at the world without; but their eyes forthwith turned back upon the world within. In the constant oscillation of the human mind between Ideas and Facts, after having for a moment touched the latter, it seemed to swing back more impetuously to the former. Not only was the philosophy of Aristotle firmly established for a considerable period, but when men began to question its authority, they attempted to set up in its place a philosophy still more purely ideal, that of Plato. It was not till the actual progress of experimental knowledge for some centuries had given it a vast accumulation of force, that it was able to break its way fully into the circle of speculative science. The new Platonist schoolmen had to run their course, the practical discoverers had to prove their merit by their works, the Italian innovators

had to utter their aspirations for a change, before the second Bacon could truly declare that the time for a fundamental reform was at length arrived.

It cannot but seem strange, to any one who attempts to trace the general outline of the intellectual progress of man, and who considers him as under the guidance of a Providential sway, that he should thus be permitted to wander so long in a wilderness of intellectual darkness; and even to turn back, by a perverse caprice as it might seem, when on the very border of the brighter and better land which was his destined inheritance. We do not attempt to solve this difficulty: but such a course of things naturally suggests the thought, that a progress in physical science is not the main object of man's career, in the eyes of the Power who directs the fortunes of our race. We can easily conceive that it may have been necessary to man's general welfare that he should continue to turn his eyes inwards upon his own heart and faculties, till Law and Duty, Religion and Government, Faith and Hope, had been fully incorporated with all the past acquisitions of human intellect; rather than that he should have rushed on into a train of discoveries tending to chain him to the objects and operations of the material world. The systematic Law* and philosophical Theology which acquired their ascendancy in men's minds at the time of which we speak, kept them engaged in a region of speculations which perhaps prepared the way for a profounder and wider civilization, for a more elevated and spiritual character, than might have been possible without such a preparation. The great Italian poet of the fourteenth century speaks with strong admiration of the founders of the system which prevailed in his time.

* Gratian published the Decretals in the twelfth century; and the Canon and Civil Law became a regular study in the universities soon afterwards.

Thomas, Albert, Gratian, Peter Lombard, occupy distinguished places in the Paradise. The first, who is the poet's instructor, says,

Io fui degli agni della santa greggia
Che Domenico mena per cammino
U' ben s'impingua se non si vaneggia.
Questo che m'è a destra piu vicino
Frate e maestro fummi; ed esso Alberto
E di Cologna, ed io Tomas d'Aquino.

Quell' altro fiammeggiar esce del riso
De Grazian, che l'uno et l'altro foro
Ajutò si che piace in Paradiso.

I, then, was of the lambs that Dominic
Leads, for his saintly flock, along the way
Where well they thrive not swoln with vanity.
He nearest on my right hand brother was
And master to me; Albert of Cologne
Is this; and of Aquinum Thomas, I.

That next resplendence issues from the smile
Of Gratian who to either forum lent
Such help as favour wins in Paradise.

It appears probable that neither poetry, nor painting, nor the other arts which require for their perfection a lofty and spiritualized imagination, would have appeared in the noble and beautiful forms which they assumed in the fourteenth and fifteenth century, if men of genius had, at the beginning of that period, made it their main business to discover the laws of nature, and to reduce them to a rigorous scientific form. Yet who can doubt that the absence of these touching and impressive works would have left one of the best and purest parts of man's nature withont its due nutriment and development? It may perhaps be a necessary condition in the progress of man, that the Arts which aim at beauty reach their excellence before the Sciences which seek speculative truth; and if this be so, we inherit, from the middle ages, treasures which may well reconcile us to the delay