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In a work so extensive as mine, and including so many subjects, it was hardly to be expected that some omissions should not occur; and I should have been sincerely grateful if any critie had pointed them out temperately, and with an appreciation of the nature and the difficulties of my undertaking. But the Edinburgh Reviewer's corrections are made in so captious and hostile a spirit, that I feel little indebted to him, in the few cases in which he is right. I will, however, notice one of the principal of these.

In stating the researches of Alhazen upon Refraction, I think it probable that I have not duly attended to the obligations which that writer had to Ptolemy. If the Arabian derived all his experiments from the Greek, this will confirm an opinion which I have strongly insisted upon-that the Arabians made very few original advances in science. This I shall be pleased to find; for, though I have no such narrow nationality as the Edinburgh Reviewer dreams of, I cannot divest myself of a feeling of European nationality. But I am little disposed, without further inquiry, which requires time, to trust a writer who tells us (p. 132) that "Ptolemy treats the subject of atmospheric refraction with all the science of modern times!" and I may remark, that if the correction be admitted, it will scarcely alter perceptibly the general features of the progress of optical science.

Most of his other corrections I reject. On the subject of the discovery of the law of the sines in refraction, his criticism is erroneous. Snell's law is the law of sines; Descartes had seen Snell's papers; and, from Descartes's habits of mind, I am persuaded that he did borrow the discovery thence.

With regard to the opposition made by Sir David Brewster to Newton's Prismatic Analysis of Light, (p. 136,) I still hold that Newton's discovery is not overturned by any analysis effected by means of absorbing media, the only source of Sir David Brewster's objections.

The critic accuses me (p. 139) of having laid open wounds which have long been closed, in relating the controversies occasioned by the modern optical discoveries. I believe that none of the ingenuous and candid philosophers who have been concerned in these discoveries, will feel that I have done so. I have written of their disputes, as I believe history will speak of them ;-as I have written of the disputes of Newton and Hooke; of Lavoisier and Priestley. I have no doubt that the philosophers whose names are concerned in these questions, will smile at the critic for affecting a soreness on their behalf which they do not feel themselves.

I still hold (Rev., p. 143) that the first place in the History of Physical Optics is due to Young, who made the two great steps of interferences and transverse vibrations. But no admirer of Fresnel has spoken more warmly than I have done of his transcendant merit, though the critic talks of my having "deposed him."

With regard to the merits of the undulatory theory, this is not the place to discuss them; but when the critic denies my assertion that this theory" accounts for, simplifies, and explains the most entangled cases," as gravitation does, I would ask him to refer to the cases of Fresnel's Rhomb, the elliptical polarization of Quartz, the effects of the superposition of the plates of Quartz, Conical Refraction, Newton's Rings by Polarized Light, and other cases which I have noticed in chapter xiii. of the History of Optics, and then tell me if these are not cases as entangled and as fully explained as any in physical astronomy. I fear, however, that I am not likely to convince à critic who thinks himself

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and

entitled to pronounce, not only that "the theory has made many new physical suppositions," but that "it will acquire many more;" whose idea of a theory is displayed by his putting theory in opposition to truth (p. 143).

He blames me (p. 145) for not “ making the most of my favourite science," (referring to my having been formerly Professor of Mineralogy). I never wished to make more of a science on that account. Nor was it possible for me to describe Sir David Brewster as one of the discoverers of the Distinctions of Systems of Crystallization, which the Reviewer appears to wish; or to speak as if the hypothesis of integrant molecules were proved. The merits of that original and inventive philosopher, in confirming, applying, and correcting the above discovery, I have spoken of worthily, I hope, as far as my limits would allow me.

I might go on rejecting the Reviewer's corrections (p. 147). Hutton's geological doctrine was a premature generalization. Leslie's theory of Heat is not deserving of respect. But I do not think it necessary to proceed further in this manner.

Many other objections arise from so complete a mistake of the nature of my work, that it is mere weariness to notice them. How could I encumber a rapid History of the Progress of Speculative Science with the endless list of its applications in the arts! What could I have told of "balloons, and steam-boats, and steam-guns, and gas-illuminations, and locomotive-engines, and rail-ways"? (p. 147). I am compelled to ask concerning these, as I asked concerning every portion of science which I had to incorporate in my narrative, What clear theoretical principle do they establish which I have neglected?

Again, what would have been more absurd than to have quoted all books on similar or related subjects? The Reviewer is discontented (p. 125) because, when I make some observations on the nature of inventive genius in science, I do not refer to a similar passage in Sir David Brewster's Life of Newton; although, as appears to me, the resemblance is of a very general kind. He is angry because I do not quote the historical dissertations of Playfair and Leslie, and Maclaurin's account of Newton's discoveries. These are all valuable works; but to what purpose could I have quoted all historical dissertations on science, or all accounts of Newton's discoveries? I avoided quoting, except what I used as authority.

The Reviewer has accused me of injustice, because I have joined together the names of Sir Charles Bell and Mr. Mayo, in mentioning the discovery of the distinction of nerves of sensation and of volition. As this passage has excited some scruple in other persons as well as the Reviewer, I have revised the original works in which this discovery is stated, and have reconsidered the subject. The details of the history of the discovery I have given in the Medical Gazette for December 30, 1837; and taking these into account, the result of the best judgment I can use, as there stated, is this:-"That no injustice was committed by joining Mr. Mayo's name to that of Sir Charles Bell, as I did; but that this is not to be understood to imply that they had equal shares in the discovery. If I should have occasion to reproduce this part of my history, I should wish to describe the discovery as having been made by Sir Charles Bell, Mr. Mayo, and M. Magendie; the two latter physiologists having corrected and completed the researches of the former." I will add, that if any other apparent injustice in my History can be pointed out, I am equally ready to re-examine the subject, and, if I have been mistaken, to take the earliest opportunity of correcting my error.

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There is one accusation contained in the Review which I can hardly bring myself to notice seriously, although it is urged over and over again with extraordinary vehemence :-"the generalization which he has most successfully pursued is that of grossly neglecting the claims of the philosophers and authors of Scotland." (p. 147.) So extravagant an example of sensitiveness to supposed neglect in the leading periodical of Scotland might perhaps be safely left to the laughter of the public. But I have the happiness to have many valued friends of that country, and I should grieve that, even for a moment, any of them should admit the thought, that I am not fully sensible how much British science and literature owe to the admirable intellectual character and mental discipline which prevail in that part of the island. I will, therefore, beg them to refer to what I have said of Sir David Brewster, Professor Forbes, Mr. Robert Brown, Mr. Lyell, Sir Thomas Brisbane, Leslie, Black, Robison, Watt, Napier, the Gregorys, Munros, Hunters, and other philosophers of that country, and to judge whether they see traces of any such narrowness of view as the critic, out of the largeness of his own mind, has devised for me."

With regard to the excellent and accomplished lady whose name the critic has thought fit to introduce into his pages, in reference to the same subject, (p. 148,) I will only say, that if I had employed my office of historian for the purpose of complimenting her with a place among discoverers in astronomy, whatever others might have thought of such a step, I am persuaded that her clear sense and genuine modesty would have disapproved of the introduction of such a passage into my work.

When the Edinburgh Reviewer talks of national prejudices, it is whimsical enough that it should never have occurred to him to suspect himself. Yet I am sure that I shall have the assent of every man of real science and literature with me, when I say, that nothing short of the most blind and bigoted prejudice could have led him to speak of the University of Cambridge, at the present day, as "the cloisters of antiquated institutions, through whose iron bars the light of knowledge and liberty has not been able to penetrate.” (p. 150.) This wretched rant is the echo of a slavish tradition, handed down from the brighter and prouder days of the Edinburgh Review. That work, at all periods, has spoken of the English Universities with equal bigotry and ignorance; and the shallow and vulgar conceit thus generated, which tarnished some of the fairest pages of the better scientific critics of its former times, is well fitted to make it contemptible, now that it has no longer any such to boast of.

The critic finally charges me with want of sympathy for men of science. I shall only reply, that I believe him to be the only man who, after reading my work, would make the accusation. He, however, thinks that such a history should conclude by a prayer that nations should extend their bounty and their patents of nobility to men of science. (p. 114.) He would have the chivalry of science incorporated by the state and patronised by the sovereign. (p. 151.) I have not the smallest objection to his using his privileges as a reviewer in order to effect such a purpose; but I must beg to be allowed to preserve my history of the past and my prospect of the future, pure from the vapours which such prayers and aspirations engender.

I am, dear Sir, yours, very faithfully

W. WHEWELL.

N. B. This letter is a repetition of one written in October last, with an alteration of the paragraph respecting Sir C. Bell and Mr. Mayo.

ERRATA IN VOL. I.

Page 42, line 16, for inscribed, read invented.

126, line 1, &c., read

CHORUS OF CLOUDS.

The Moon by us to you her greeting sends,
But bids us say that she's an ill-used moon,
And takes it much amiss that you should still

Shuffle her days and turn them topsy-turvey;

And that the gods (who know their feast-days well,)
By your false count are sent home supperless,

And scold and storm at her for your neglect.

Note. This passage is supposed by the commentators to be intended as a satire upon those who had introduced the cycle of Meton at Athens, which had been done a few years before "The Clouds" was acted.

Page 146, note 44 Acronical, read Acronycal (åкpovvкíos, happening at the extremity of the night).

181, bottom line, for somewhat, read somehow.
245, note, line 7, for audentes, read rudentes.

246, line 11, read of Caius.

271, note, line 2, for essus, read fessus.

273, line 3 from bottom, for compounds, read compends.
274, line 5 from bottom, for Pachymeus read Pachymerus.

291, line 11, for τετραχτὺν, read τετρακτὺν.

301, line 1, for astronom. read Astrorum.

413, line 7, for Malo ne, read Malo me.

ཐ?

LONDON:

JOHN W. PARKER,

WEST STRAND.