On page 29, this Vol. " Scientific American," we briefly reviewed a pamphlet by R. S. Cul-loh, late Metal Refiner at the Mint at Philadelphia, now of Princeton, N. J. An answer to that pamphlet has been published and is now before ua, by the present Melter and Refiner, James C, Booth. The pamphlet is a letter to our now ex-President Fillmore, and we have been requested to peruse, and notice it, and in courtesy we will d o so. The letter of Prof. Booth, is remarkably temperate in language and we like the spirit which pervades it. . The historical origin of the transaction in question may be thus briefly stated from Prot. Booth's publication. Prof. McCulloh was melter and refiner at the U. S. Mint, at Philadelphia, for some time prior to Dec, 1849 ; before which period he had invented a new process for refining gold, in regard to which he took the preliminary step fora patent with-in-a few days after his accounts at the Mint had been closed. He was succeeded in his office by Prof. Booth, who, in attempts to im-prove the methods actually in use, lell, as he says, upon one which turned out to be the same with that earlier invented by Prof. Me- j C, and which, though characterized by remarkable facility in the earlier stages, presented extreme difficulty in the lamination, afterwards, of the gold refined by it. Prof. Booth was thus induced to devise another pro- j cess, for which, in August, he, in conjunction with Prof. Morfit,now of Baltimore, also took out a patent. As neither of the processes had been experimentally tried on a sufficiently large scale, and as the parties, up to this time "at least, appear to havehad mutual confidence in one another's lermag, -ilul!, .i. &jef they concluded to join their interests in the two patents, inad subsequently procured an appropriation from Congress of $25000 for the purchase of that one which, upon fair trial at the Mint in Philadelphia, should prove to be the better. The experiments for determining this question were made in the last part oi 1850 and first month of 1851, under the instructions of the then Director ot the mint (Dr. R. M. Patterson) and by Prof. Booth, who, haviflg succeeded in overcoming the brit-tleness of the metal that had before resulted under the McCulloh process, recommended that process tor adoption at the Philadelphia Mint, where the establishment was ample and regular, and the other—the Booth and Morfit process—for adoption in California as being the cheapest and most flexible and best adapted for extemporized and less extensive mints. But so far, these experimental tests related to the quality of the metal and the quantity of it that could be refined in a given time. And belore the recommendation of the McC. process was adopted,the Director ordered that another very important particular—the relative waste of gold, under the several processes,—should be observed. These observations are stated to have been in fact made by the Director himself and to have proved unfavorable, by showing a greater waste in the McCulloh than in the old or Mint process, with this result before him, in spite of the recommendation of Prof..Booth, in other respects Dr. Patterson disapproved the introduction of the McC. process into the Mint. Prof. McC. was naturally dissatisfied with this issue, proposed and with the consent of Prof. B. procured a dissolution ot the partnership which had existed in the two patents; and founded upon the circumstances attending the events which we have thus briefly sketched, grave complaints and charges against Prof. B. in particular. These charges were formally laid in the Treasury Department, from which they were duly referred, in the latter part of 1851, to the then Director of the Mint . —Dr. Eckert, snecessor to Dr. Pattersonfor L investigation. The Director reported then backas unsustained. Subsequently,the Trea sury Department authorized Prof. McC. to ap ply his process himself within the walls o the Mint at Philadelphia, as he did, on Apri 1, 1852, upon about a quarter million of gold but in result showing more waste than the or dinary Mint process, the Director disapprove! the introduction of the new method. To thi; disapproval, Prot. McC. takes exception; am in a printed letter to Mr. Corwin, in August 1852, states his exceptions and renews th( charges against Prot. B. We understand th( pamphlet of Prof. B. is a reply to the origina and to the renewed charges. The charges thus replied to may be assembled in three groups; according to their purely personal, their official and their mixed cha racter. To the first of these belongs the allegatior of disingenuousness at the time of the formation of the partnership. Prof. B. declares thai he assented to the partnership originally at Prof. Culloh's suggestion and acquiesced in its dissolution at Prof. McC.'s request.The second group of charges are those which affect the official relation and standing of the Melter ?nd Refiner at the Mint, and amount to a general allegation of unskilful-ness and neglect of duty. Without taking up the minute and particular answers of Prof. B.. which we have not room to enumerate, it ii sufficient to say that he refers to the evidence of two successive Directors of the Mint. On this point, Prof. B.'s pamphlet lurnishes some very interesting statistics, which of course we accept as authentic and reliable. From these we have reduced the following table of depo-sites of Gold at the U. S. Mint per month. McCulloh Refiner-Least amount. Greatest. Average. 1849 . . . 30,000 793,000 404.200 Booth Refiner— 1849 . . . 747,000 1,669,000 1,208,000 1850 . . 1,005,000 4,579,000 3,660,750 1851 . . 2,818,000 5,577,000 3,977,333 With these results beforejis, which show an amount of work for Prof. B. nearly ten times as great as Prof. McC. was used to—inCorrect in saying to be unprecedented in the annals of minting. It is true that the existence of a large bullion lund might be significantly connected with this silence of depositors, who being paid out of such a fund, directly, the value of their deposits is ascertained by assay and weighing, have no reason tor concern with the subsequent management of what they have deposited and sold. But according to Prof. B.'s statistics, the bullion fund of 1849, in Prof. McCulloh's time, was $1,000,000, when! the average monthly deposit was $404,200 and the ratio, therefore, of the amount kept on hand to meet payments to the amount required to be paid, was very nearly 2i to 1. The same fund now is $4,000,000, and the average monthly deposits as much, showing a ratio of equality between the fund and deposits, or of 1 to 1. This may be plainer in the following account:— In 1849, McCulloh, Refiner, monthly average deposits, 400,000; constant bullion fund, 1,000,000 ; ratio—deposits 1, bullion 2J. In 1851, Booth, Refiner, monthly average deposits, 4,000,000; constant bullion fund, 4,000,000; ratio—deposits 1, bullion 1. It is obvious that, with prompt payments there must be a bullion fund whose amount, other things being equal, must vary in proportion to the amount of deposits in a given time. All that skill can do, is, in the rapid melting and refining of these deposits and the replacement of the bullion fund to lessen this proportion. Whether Prof. B. has reached the utmost limit in this respect, cannot of course be apprised; but under his management progress has been made towards it; and in taking off 60 per cent, of the unfavorable proportion that existed before he certainly cannot be held to manifest want of skill. In another important particular relating to the economy ot his management, and which is of interest to the government, just as the diminution of the bullion fund is, viz,, the waste in the meltings, Prof. B. exhibits a similar improvement, as shown by the following table:— Oz. melted. Oz. wasted. Loss McCulloh, Refiner— 1849 . . . 673,000 239 00035-( Booth, Refiner— 1850 . . 3,000,000 ' 689 -00028-t 1851 . . 2,555,000 635 -000251852 . . 5.074,000 1,247 -00025-The weights have been given here only t( thenearestthousand ounces ; in the pamphle' they are set down to the nearest ounce. Th quantities in the last column result from the exact numbers ; the sign + showing that the quotient is too small, and the sign — that ii too high. They show a diminution of waste effected by Prof. Booth of l-10000th, and a saving of that extent over the results of his predecessor. Had the waste admitted by Prof. McC, during the latter part of his management, been allowed to continue by Prof, B.j the dead loss would have been, up to Aug. 1852, more than 1000 ounces, or upwards ol 18000 dollars, for the saving of which Prof. B. may undoubtedly claim credit. Again, in the earliest practice ot refining gold by the nitric acid process, 3 lbs. of silver were alloyed with 1 lb. of gold, in order to effect the subsequent parting of the latter; from which proportions, the fine gold being a quarter ot the alloy, we still have the term quartation, although it has ceased to be significant. Later improvements allowed the use of 24 lbs. silver to 1 lb. gold, which was the proportion habitually employed by Prof. McCulloh in the U. S. Mint. Prof. B. avers that he requires but 2 lb. silver to 1 lb. gold, thus sparing 1-5 of the silver formerly used. It is probable that, in this respect he has reached the utmost limit of economy; but whether or no he has certainly lessened the room for reproach in thus economizing upon the costly materials required even by his immediate predecessor. The last group of charges to be referred to, affect at once the official and individual character of the party, and include allegation of fraud or clumsiness in the trials made by Prof. ' B., at the Mint, of Prof. McC.'s new process. To us it appears that a charge on this account is not happily nor reasonably made by the rect and positive recommendation of the said process for exclusive employment at the Mint in Philadelphia. Whether the trials, then, were fairly and skillfully or dishonestly and awkwardly made, Prof. McCulloh, inasmuch as he obtained a favorable verdict, is hardly the person to be heard in complaint. Other persons, we ourselves for instance, might ex- press our surprise that so emphatic a recom- mendation should have been given before one of the most important considerations—the waste—had been weighed ; but not the party whose interest was in the way of being sub- served by the premature recommendation. But however this may be it appears thatProt. McC. had and used the opportunity of nearly three months' trial of his own process under his own direction at the Mint, without succeeding in convincing the Director that it is preferable to the one habitually employed. Now, it may be that the Director was unduly difficult to convince, but it is reasonable to say that all defects whatever in Prot. B.'s trials were cured by the actual intervention of the party devising, and therefore most in- terested and best knowing how to carry out his own process. The cause of our remarks has led us'now to the merits of the processes which have given rise to the pamphlet in question; a subject which, in the beginning, we hinted our in- ; tention of not discussing, lor it is our opinion that there are better ways than have j been so far adopted for preventing or quieting j the discords of which we have been treating, and which neither helps science herself nor ker votaries. That it may not be supposed we were using random phrases or dealing in unreflected generalities, we conclude this notice with what seems to us a practical suggestion :—Let a commission of three (or any multiple of three) persons sufficiently distinguished by their knowledge of the subjects, be constituted under the authority of the Treasury Department, whose functions shall be to superintend at some fitting time, and upon a suitable scale at the Philadelphia Mint, : till and fair trials, ot the proposed new pro cesses, so as to set at rest, once and for all the questions that have been raised ; in whose discussion the public can hardly be expected to take interest further than as they affect the vindication and, if requisite, the amelioration of the Mint establishment, whose integrity and judicious administration ought to be, for the credit of the government of our country, above suspicion.