of second sight), particularly after the specimen of gross plagiarisms already so clearly made out, in respect to his paper of September 12, 1839, and which he so evidently shrinks from refuting.

Mr. Spencer entirely misunderstands me in my concluding remarks. All I meant to convey was, that in any future notice of the history of electrography, in a premeditated electrical treatise, I should acknowledge only Mr. Jordan as the discoverer, and not Mr. Spencer, as has hitherto most mistakenly and unjustly, though I am sure very unknowingly, been done by every preceding writer. And Mr. Spencer, much as he plumes himself

dishes." "What is on the table you spoke of?" "Papers full of scribbles." Mr. Spencer's own share in the business was such as might well make his "hands full," and the Liverpool Phreno-Mesmeric Society are fortunate in having such an advocate as Mr. Spencer, over all whose performances there presides the semblance of an imposing genius. One illustrative example of Mr. Spencer's experiments must close this note. "After being in the adjoining room (he says, Mrs. Todd being in the clairvoyant state in another apartment) some minutes, perfectly still, I put my thumb to the tip of the nose, and extended the fingers outwards, in the most approved manner, and as we frequently see enacted by the clown in the ring. I remained in this dignified attitude for some time. I then returned to the other apartment, and requested to know what I had been doing, the parties present having been instructed to question her during my absence. I was answered by some tittering, but Mr. Todd said that she was no doubt exhausted by the length of the experiments, and they could not get her to answer what I had been doing." The whole of this verbose paper is nothing more than a tedious enumeration of vulgar commonplace experiments, which are made the medium for conveying, first, to a learned scientific body, and afterwards to the public, the highest order of phenomena affecting the animal economy; yet he most unsatisfactorily winds up by confessing, "I have no theory to offer."

on a happier fate, will nevertheless find that his sun has set, and that whatever of honour can attach to being the inventor of the electrographic process, will hereafter be unhesitatingly awarded to Mr. Jordan. Palmam qui meruit ferat.

In connexion with the subject of the invention of electrography, I think the following extract will prove interesting, from a paper "On the Effects of a Battery charged with Sulphate of Copper," by Warren De la Rue, in the London and Edinburgh Philosophical Magazine for 1836. He says, "The zink plate is always partially covered with a coating of copper, which, however, is not detrimental to the power of the battery; the copper-plate is also covered with a coating of metallic copper, which is continually being deposited; and so perfect is the sheet of copper thus formed, that, on being stripped off, it has the polish, and even a counterpart of every scratch, of the plate on which it is deposited." Mr. De la Rue makes this remark incidentally, and I only offer it here as a proof how near others have trenched on the discovery of a useful application to the arts of that very deposited copper, which was a result unfavourable to the action of the battery. Mr. Jordan was the first to direct attention to a useful and ornamental adaptation of this property, peculiar to the action of sustaining batteries, literally bringing good out of evil-for it was before always a desideratum to get rid of this detrimental deposit.

[To this communication, Mr. Robertson, the Editor, appended the following observations:

"We cannot blame Mr. Dircks for not subscribing to the terms which Mr. Spencer wishes to have conceded to him before entering on his vindication from the charge of misappropriation which has been brought against him. Mr. Spencer is in no condition to stipulate terms. The charge has been made, and it is for him to answer it, or not, as he pleases-it is his own affair. If he do not, the public will know what conclusion to draw. We fear that, as it is, any denial he may now make will come all too late to prevent impressions very much to his prejudice. It was an easy thing to say, 'When I claimed the English invention of electrography, I knew nothing of Mr. Jordan's letter; I had never seen it, never read it, never heard of it;' and if he could say so truly and sincerely, we cannot understand why he should have deferred doing so for a single instant. Mr. Spencer has written two pretty long letters to us on the subject since the charge was brought against him, but we have looked in them in vain (much to our regret) for any such distinct disavowal as this. People do not ordinarily take time to consider whether they have been guilty of such offences as that imputed in the present case. It would not have taken Mr. Spencer a hundreth part of the pains to say the few words we have suggested, which he has taken to evade, or at least postpone the saying of them.-ED. M. M."]

F

CONTRIBUTION TOWARDS A HISTORY

OF

ELECTRO-METALLURGY.

(CONTINUED.)

HAVING in my former paper alluded to my meeting with Mr. Jordan, I shall here introduce the letter he addressed to the Editor of the Mechanics' Magazine, it being so confirmatory of all I had stated, independent of any previous personal acquaintance:

"SIR-The very flattering manner in which my claims in connexion with the discovery of electro-metallurgy have been recognized in your pages, demands from me a grateful acknowledgment. When my communication of May 22, 1839, appeared in your Magazine, it was submitted to public consideration to avert, as far as possible, a loss of precedence impending on further delay in its publication, coupled with the conviction, that if worthy of attention it would receive it in the end. Although it would be untrue to deny that disappoint

ment was felt at the neglect it met with, yet, to have murmured at the tardiness of public judgment would have been a step without immediate object. Reflecting also, that in whatever light my letter may have been viewed, nothing advanced therein had been disputed, I determined to remain silent on the matter, and wait the arousing of public attention by other hands—a consummation which I foresaw must, in some way or other, ultimately take place. The expectation has been realized, and I have been indulged with the accession of a vigorous advocate in one of your ablest correspondents, whose contributions to a "History of Electro-metallurgy" have set the matter in a much clearer light than I feel myself qualified to have done. Whatever may be the relation of this gentleman with other individuals mentioned in his paper, with myself it is purely impersonal. The comprehensive exposition of Mr. Dircks appears to have been dictated solely by an impartial spirit, and a just perception of the merits of the case with a view of eliciting truth. In return for his valuable exertions in my cause, I beg to express my sincere thanks.

"It may be necessary to mention here, that at the time of the publication of the second Contribution,' &c., its author was personally unknown to me; but that in consequence of a conversation with Mr. Brown, librarian to the Mechanics' Institution, I was induced to open a communication with Mr. Dircks, which led to an interview with that gentleman, February 28.