Volume 35 (1877) (426 pages)

370 MINING AND SCIENTIFIC PRESS {December 15, 1877. {GorRESPONDENCE. It is the desire of the editors of thia journal to he liberal toward all correspondents, and therefore statements and opinions are frequently published, on the authority of the writers, for which we do not assume responsibility, Mechanical Ore Concentration. Enrrors Press:—Mr. F. M. F. Cazin, in replyingto my articleon the Hendy concentrator, takes issue with my views on tbe subject in a sense not aimed at when my invitation for discussion and criticism was made. Such invitation was incorporated with my article, because of a sense of tbe fallability of iudividual opinions on complex subjects and the difficulty of expressing them briefly in such a manner as to be correctly understood by others. The mind, preoccupied by a certain train of thougbt, is prone to pass by unheeded points of importance, and individual experience on any practical operation is never exbaustive in details, no matter how extensive it may be. The hope of getting nearer the truth hy the views of otbers was the main incentive in inviting discussion so ‘‘ paintedly,” and I admit tbat I speculated no little thereby on the extensive theoretical and practical knowledge of which I know Mr. Cazin to be possessed. , That Mr. Cazin did not enter into the details of principles elucidated by me, but devoted so much of his remarks to a generalizing tirade against Mr. Hendy, I regret, for the elucidation of those principles was the main object of my article, as the heading of it indicates. I would have preferred to learn in what details I really am at fault, for in the matter selected by him for particular criticism, we are essentially not at variance, if Mr. Cazin will give my language its full eignificance and if he will view my remarks in the light of my expressions in previous contributions to the PREss. With the defense of Mr, Hendy’s course as an inventor, I have nothing todo. In my opinion, Mr. H. acted wisely in devoting himself to the perfecting of one machine, of whose merits and demerits he had ample practical opportunity to inform himself, aud in leaving to conipetition the successful introduction of others, which have been proved useful under conditions so different, and in localities so remote, that Mr. Hendy could have no sufficient opportunity to assure bimself by independent observation of their excellence. Mr. Hendy has been a successful inventor and has the caution in accepting things new to him which an intelligent inventor's experience ie sure to teach. If Mr. Hendy has naturally been an earnest advocate of his meritorious invention, it does not therefore follow that the latter is to be considered a panacea for all requirements of mechanical ore concentration and that he or anyone else recognizing the merits of his machine therefore rejects such others, ‘‘as for limited action in proper places are far superior and more teliable.” If Mr. Hendy does not recognize the merits of euch other machines for such specified purposes, it, no doubt, is because the peculiar conditions of the art in this country have not given him the opportunity of seeing these claims verified by successful application here. In so far as the article iu question is calculated to foster such one-sided views, it can only do so in the case of inattentive or prejudiced readers, for its whole bent is to circumscribe tbe limits of action most favorable to the working of the Hendy pan, and the very maehines referred to by Mr. Cazin ‘‘for limited action in proper places,” are recommended hy him for such action in such places, as desirable auxiliaries to the operation with the Hendy pan. In this connection I may state that among the many constructions for sand jiggers, Mr. Cazin’s is one of tbe simplest and best, though there are others which will answer the same purpose no less satisfactorily in every respect. As for Mr. Cazin’s classification of machinery, the principles which he sets up for the distinction of good and 6bjectionahle machinery have my full approval, but I insist that his own designations of successful qualities would place the Hendy pan in tbe foremost rank of useful concentrating machines. Its construction is as simple as that of any automatic machine of the same capacity in actual use which can be produced as suitable for the same work, and is sufficient if reasonable and timely attention is paid to it. That its merits are permanent is amply attested by the length of time during which it has been before the mining public and the signal manner in which it has outlived many competitors, also by the fact that many of our most important mills, in which: they have been for years in constant use, retain them and will continue to use them. It does not follow, that hecause the theoretical explanatiou of the action is complex that the practical application is necessarily so, for not every detail of action needs special attention, because many of them combined can be the effect of a leading cause, such as, for instance, speed of motion and volume of pulp, ete. The successful use of any machine requires the presence of a numher of indispensahle couditions, which accounts for the difference of success in the use ofthem. Thenumber of such couditions for the succeseful working of the Hendy pan is not greater than ie the case with any of the machines which Mr. Cazin has described, for I am practically acquainted with the working of every one of them, except his one-plunger jig. I can also assure Mr. Cazin tbat scores of Mr. Hendy’s machines are worked in this State and elsewhere hy men who never bad any instruction from Mr. Hendy, and tbat they do the work permanently, persistently, and smoothly, nevertheless. The regulation is not difficult, because it admits of considerable lizense, and the repairs are attended witb no more difficulty tban in the case of any otber automatic concentrating machine. What I claim for the machine, principally, is its financial success under certain conditions, whichis even more marked tban its technical one, for the reasons amply explained in my article. Mr. Cazin can form a conception of this wheu I assure bim that a 40stamp mill, crushing 80 tons ore per 24 bours, and running all the pulp tbrough Hendy’s pans (after amalgamation in the battery and on copper plate outside) requires the services of arly fonr laborers in 24 hours to keep 22 Hendy’s running permanently, persistently, and smootbly; attending at the same time to all regulations and repair, and performing all other work connected therewith. I doubt that the yield could be profitably increased to any considerable extent, and positively assert that no macbinery or combination of machinery which Mr. Cazin has descrihed, could be substituted to do tbe work with same ultimate economy, But all this does not make tbe Hendy a pauacea for all purposes, but merely aspires to do what Mr, Cazin would have us, 7. ¢., giving to each machine ite proper sphere of work. Ihave drawn the limit plainly, suggested the proper substitutes onteits of these limits, and broadly detined my position and claims by the expression: Introducing the treatment for coarse stuff suggested, and perhaps, also that for the finest in the case of rich sulpburets, I will say, tbat of all the concentrating machines at present in successful practical use for wet concentration, either in Europe or America, none will effect the concentration of medium grade sands, under the peculiar conditions presented in our amalgamating stamp mills, with equal ultimate economy, as the Hendy in its present form, when properly used; and none of them can compete with it in the effectual working of unsized and ungraded sand, where systematic concentration, by reason of the uature of the ore, cannot he made the leading consideration in the treatment. Coming to the discussion of those points of my article particularly objected to by Mr. Cazin, I heg leave to say that I fail to see in his exposition a proof that the science of mecbanical ore concentration bas emancipated itself from the nomenclature with which Rittinger more or less labeled, or that tbe search of the intelligent mind for the reason why, the rational elucidation of phenomena seeking cause for effect, the tbeoretical origin of actions, at all interferes with the more important attentiou to practical purposes, or that it holds, or ever will hold, any other relation to it than does theory to practice in any other technical question or pursuit. I must admit, that I cannot fully comprebend Mr, Cazin’s meaning in the paragraph here referred, The attempt to translate the idioms of another language naturally leads to various expressions by different translators. If usage accept ‘‘equal falling” as tbe best definition of the German word ‘‘gleichfaellig,” TI am satisfied, though the English expression may be styled a Germanized one. From tbe first I chose to call the particles so treated “‘graded,” the action “grading,” and the apparatus used thereto “graders,” because the word, in my opinion, presented the briefest expression to indicate the prominent characteristic of the material, etc., to which it was applied. The term ‘ water sizing” has also been used—in some cases simply “sizing.” To this latter expression I object, because the word conveys the idea that eize, or approximate equality of size, is the promiuent characteristic of its action. This term was fouud more applicable to tbe work of graduated sieves, or classification was used synonymously to approach more nearly the nomenclature of Rittinger. In this sense tbe terms are used throughout all my articles on concentratiou, for want of any authoritative English expression for the same purpose. To be a little more explicit, but to avoid a full explanation, as not relevant to the subject. I defined graded ‘‘particles assorted according to their equivalent speed of fall in water.” This expression Mr, Cazin criticises as if reading: According to their equal speed of fall in water. T insist on the use of my words, and emphatically object to the substitution of the word equal for the word equivalent, and if Mr. Cazin has any valuation of the English language he will sustain my ohjection. Not equal speed is the distinction, but such speeds of the particles as are equivalent to the attainment of a certain end or effect, i. e., the sinking of the particles to and below a certain depth within a given time. That I am aware of the differences of initial speed, no one can doubt that reads my article attentively, for on this gronnd, among others, tbe separatiou in the Hendy pan is explained. It is also intimated by mentioning its cause in speaking of fine sand jiggers in my article, ‘Krom vs. Rittinger,” Press 1876, page 2. Moreover, auy one can amply inform himself in the matter by consulting Rittinger’s Appondix I., 1870, page 18. The suhject is there more thoroughly treated than in Mr. Cazin’s treatise in the Minine anp Screntiric Press, May 5th, 1877, and to the iuformation there given hy Rittinger, Mr. Cazin and “‘the trade,” so far as I oan learn, has added nothing new. Professional theory has therefore not to yield to governing practice, and commou sense is not in favor of the laborer and contrary to tbe scientist, as Mr. Cazin so pointedly pute it, for in this matter they are not at variance; many years bave passed since they were elucidated by tbeory and verified by practical experiment conjointly, this being the basis on which nearly all of Rittinger’s doctrines bave been built up. If any one man ever had superlative ability for elucidating theory in these matters, and at the same time extraordinary facilities for verifying it by ae a ohservation and careful, systematized experimentation, it was Rittinger, and for this reason his opinions are justly considered authoritative. To claim bis views as sole authority, and to consider bis opinions unconditionally correct in all things relating to concentration, even, would be presuming an infallibility which I refuse to recognize as within tbe reach of the buman mind, If Iam not mistakeu in the hints, Mr. Cazin would have me looked upon as a scientific tbeorist in the art of concentration. If this be so, let me aseure Mr. Cazin that I can give him ample reference regarding my yactival experience and ability in this line. As objectionable in my article, Mr, Cazin further cites the expression, “it bas been accepted asan axiom almost iu rational conceutration that sizing or grading of the material is absoJutely nécessary to effect a good separation with any concentrating macbine.” If Iam not mistaken in the weigbt of English words, this is far from being a generality. It does not express that it bas always been, or is, or everywhere has been accepted as an axiom, unconditionally, but almost, to effect a good scparation. As for the example which Mr. Cazin gives to sustain his objection, be might have chosen oue more to tbe point, because of practical importance, by taking the case of separation with quicksilver, instead of referring vaguely* to the use of zine vitriol solution (or another salt solution, susceptible of high density), which latter, for obvious reasons, though serving as iuteresting experiments, have little or no practical value, In writing my article, it was not my aim to branch out on every detail, but I chose to iutimate instead, where not expressed, couditions qualifying, as briefly as possible, by the turn of words, thus paying more attention ‘‘to practical purposes.” If, therefore, the axiom, as Mr. Cazin says, is not a general one—whichI do not claim it to be—it is sufficient for us to have his assurance that ‘‘it is such for all successful apparatuses in actual use,” for these are the ones with which we deal. Cas. C. RuEGER. Benicia, Cal., Dec. 2d, 1877. * Tam very much interested to learn of Mr. Cazin what medium he does refer to, for such an one above 1.59 Sp. gr. (excepting quicksilver) is unkuown to me. Arizona Mines. Epirors Press:—I will not, at the present writing, attempt any detailed account of the mines and mining interests in this Territory, nor say much about any particular property or locality, but give merely such information of a general kind as I havo been ahle to pick up in regardto the condition and prospect of things here since my arrival in June last. There is, as you have no doubt observed, a constant dispositiou among mining men to Compare Arizona with the State of Nevada; A very natural and proper thing to do, considering that they are both great mineral hearing countries, and that of the latter we already possess 2 good deal of practical knowledge. Tbis knowledge of the older we like to apply to the newer region, both as a meaus of avoiding former mistakes and furthering the work of its physical development. In their climate, topography and agricultnral resources the two countries are not widely unlike. Here, as in Nevada, climatic differences depend greatly on altitude, the low lying plateaus, desert plains and river valleys being hot in summer, and free from snow at all seasons, while at greater elevations tbe summer temperature is moderate, eome snow falling in the winter, the summits of the higher mountains heing covered with snow for five or six months in the year, and in a few instanves the whole year round, With these variations, the climate here is, at corresponding altitudes, from five to ten degrees wariner than in most parts of Nevada, there being a considerable area in the southern portion of that State depressed below the sea level, which has an almost tropical climate. Our rainfall occurs mostly during tbe summer months, and. is usually quite heavy. In Nevada they have frequent showers in the summer, confined, chiefly, to the mountains, but the precipitation takes place there mostly in the epring, or in the form of snow during the fall and winter. On an average, a greater amount of water falls here than in that State, and, coming in the summer, is of more benctit to the growing crops. The Topography of Both Countries Ie marked by long chains of nearly parallel mountains, with a generally north and eouth trend, and separated by a seriee of alternating valleys, the latter spreading out often into great plains, and forming the desert lands cbaracteristic of both regions. The most of the mountains consist of high, narrow ridges, though they are eometimes brokeu up, forming a hroad belt of otraggling ranges, or flatten out into vast arid and timberless meeas. We do not find here, however, the tahle mountains proper, such as are seen in certain parts of California, In the more southerly part of Arizona this system of alternating mountains and valleye is by no means so well preserved as in northern and f . central Nevada. Here, as tbere, the timber is usually found in the mountains, only cottonwood, mesyuite and willow being met with elsewhere. A greater variety of woods grow here than in the Silver State, and, generally, our timber ie more widely distributed and of a better quality. We have fewer of tbe alkali flate and mud Jakes, and none of the “sinks” that form 2 peculiar feature of that region. In their place, however, we bave the tremendous canyone of the upper Colorado, gorges bardly equaled elsewhere in nature, while we can boast of at least one navigable river skirting our borders. In fact, as regarde Rivers, Springs and Mountain Streams We are able to make a much better sbowing than our northern neighbors. The Colorado, which, after crossing tbe entire northern part of the Territory, forms its whole western border, carries duriug the summer an immense volume of water and is at all times a river of respectable magnitude, being even at its lowest stages navigable for 500 miles or more. After passing 100 miles east of this river the mouutains ahound with running streams, many of them large and never failing, the water always of tbe purest kind, As,a Grazing and Farming Country Arizona is much ahead of Nevada, tbere being bere a large scope of good agricultural land, while tbe grasses are varied in kind, perennial and abundant. For sheep and stock raising this is one of the hest regions west of the Rocky mountains, pasturage being plentiful and tbe climate mild aud healthful. In process of time, our flocks and berds will constitute a sonrce of wealth second only to that afforded by Our Mines, Of which I can in this letter say but little. That we have not in this department of industry been able to make a larger production than has yet been done has not been so much the fault of the mines as of other and extrinsic causes, chief of which has been the lack of means to open them up and outfit them with suitable reduction works. Notwithstanding the food showing of rich ores our mines have made uring the past year, but little outside aid has yet been extended to them. What little money has been invested here has been mostly in tbe purchase of mines, not half a dozen of mills having meantime been brought into the Territory. What we most need just now is a little money to help open up some of the rich ledgee that exist bere. The amount need not be large, as enough ore could iu most cases be taken out, when once tools, supplies and hoisting works were on the ground, to defray current expenses. Without a dime to bis name, the miner, however rich his claims, can do nothing, and these men are always willing to give to parties furnishing money to prospect their lodes a liberal interest therein. If only we could bave the assessments paid on half a dozen unproductive Comstock claims scattered over two or three of the best districts here, it would be pretty sure to reward the investors many hundred fold. What We Want and What We can Do, In the more recent immigration only three classes of men have come to Arizona: The laboring man without means, the speculator, intent on securing any sort of property for gambling purposes, and the capitalist or his agent seeking to buy a valuable mine for a nominal price. Let now the capitalist or his agent come here, and, taking his time, look ahout, and wben he sees anything that suits him act in a epirit of liberality and fairness, and he need not go away witbout getting properties that will turn out satisfactory in the end. He can extract: the ores himself, select his samples and bave them tested by our local assayers, of whom we have here several that stand at the head of their profession. In this town we have a number, all thoroughly competent, some of them being skilled metallurgists and chemists as well. At Picket Post, near the Silver King mine, Prof. Henry Degroot, Jr., has opened an assay office, whereat he is doing a Jarge business, thie being an important mining center where an establishment of the kind was much needed. This young man has become very popular with our mining community, be being not only a capable and trustworthy assayer but possessing in addition that intuitive knowledge of ores tbat enables him to indicate the metbods best suited for their reduction, a faculty that renders bim doubly useful in his calling. Not only can parties have their ores well assayed here, hut they can obtain small lots to be worked, if they desire it, making all required tests on the ground. To men who have cven a little money and thiuk of embarking in mining; this is, above all others, the place to come to. There are more ledges in the Pioneer and Globe districts showing rich ores on the surface than have ever been found in the whole State of Nevada. Parties coming here need not buy these properties outright. They can bond them, buy them conditionally, get them, in fact, on almost any terms they choose to propose, having all the time they want to prospect and open them up. We may not succeed in developing down this way another Comstock. What is even more certain we shall uot spend millions upon millions aud impoverish multitudes of people in looking for ore. If we donot find here lodee that will give vast wealth toa few we shall surely find those tbat will hring moderate enrichment to many, thereby increasing that atahle and well-to-do element that forms the mainstay of every commuuity. A good word from our friends and a little cash from almoet any quarter is what we most want just now.

370 MINING AND SCIENTIFIC PRESS {December 15, 1877. {GorRESPONDENCE. It is the desire of the editors of thia journal to he liberal toward all correspondents, and therefore statements and opinions are frequently published, on the authority of the writers, for which we do not assume responsibility, Mechanical Ore Concentration. Enrrors Press:—Mr. F. M. F. Cazin, in replyingto my articleon the Hendy concentrator, takes issue with my views on tbe subject in a sense not aimed at when my invitation for discussion and criticism was made. Such invitation was incorporated with my article, because of a sense of tbe fallability of iudividual opinions on complex subjects and the difficulty of expressing them briefly in such a manner as to be correctly understood by others. The mind, preoccupied by a certain train of thougbt, is prone to pass by unheeded points of importance, and individual experience on any practical operation is never exbaustive in details, no matter how extensive it may be. The hope of getting nearer the truth hy the views of otbers was the main incentive in inviting discussion so ‘‘ paintedly,” and I admit tbat I speculated no little thereby on the extensive theoretical and practical knowledge of which I know Mr. Cazin to be possessed. , That Mr. Cazin did not enter into the details of principles elucidated by me, but devoted so much of his remarks to a generalizing tirade against Mr. Hendy, I regret, for the elucidation of those principles was the main object of my article, as the heading of it indicates. I would have preferred to learn in what details I really am at fault, for in the matter selected by him for particular criticism, we are essentially not at variance, if Mr. Cazin will give my language its full eignificance and if he will view my remarks in the light of my expressions in previous contributions to the PREss. With the defense of Mr, Hendy’s course as an inventor, I have nothing todo. In my opinion, Mr. H. acted wisely in devoting himself to the perfecting of one machine, of whose merits and demerits he had ample practical opportunity to inform himself, aud in leaving to conipetition the successful introduction of others, which have been proved useful under conditions so different, and in localities so remote, that Mr. Hendy could have no sufficient opportunity to assure bimself by independent observation of their excellence. Mr. Hendy has been a successful inventor and has the caution in accepting things new to him which an intelligent inventor's experience ie sure to teach. If Mr. Hendy has naturally been an earnest advocate of his meritorious invention, it does not therefore follow that the latter is to be considered a panacea for all requirements of mechanical ore concentration and that he or anyone else recognizing the merits of his machine therefore rejects such others, ‘‘as for limited action in proper places are far superior and more teliable.” If Mr. Hendy does not recognize the merits of euch other machines for such specified purposes, it, no doubt, is because the peculiar conditions of the art in this country have not given him the opportunity of seeing these claims verified by successful application here. In so far as the article iu question is calculated to foster such one-sided views, it can only do so in the case of inattentive or prejudiced readers, for its whole bent is to circumscribe tbe limits of action most favorable to the working of the Hendy pan, and the very maehines referred to by Mr. Cazin ‘‘for limited action in proper places,” are recommended hy him for such action in such places, as desirable auxiliaries to the operation with the Hendy pan. In this connection I may state that among the many constructions for sand jiggers, Mr. Cazin’s is one of tbe simplest and best, though there are others which will answer the same purpose no less satisfactorily in every respect. As for Mr. Cazin’s classification of machinery, the principles which he sets up for the distinction of good and 6bjectionahle machinery have my full approval, but I insist that his own designations of successful qualities would place the Hendy pan in tbe foremost rank of useful concentrating machines. Its construction is as simple as that of any automatic machine of the same capacity in actual use which can be produced as suitable for the same work, and is sufficient if reasonable and timely attention is paid to it. That its merits are permanent is amply attested by the length of time during which it has been before the mining public and the signal manner in which it has outlived many competitors, also by the fact that many of our most important mills, in which: they have been for years in constant use, retain them and will continue to use them. It does not follow, that hecause the theoretical explanatiou of the action is complex that the practical application is necessarily so, for not every detail of action needs special attention, because many of them combined can be the effect of a leading cause, such as, for instance, speed of motion and volume of pulp, ete. The successful use of any machine requires the presence of a numher of indispensahle couditions, which accounts for the difference of success in the use ofthem. Thenumber of such couditions for the succeseful working of the Hendy pan is not greater than ie the case with any of the machines which Mr. Cazin has described, for I am practically acquainted with the working of every one of them, except his one-plunger jig. I can also assure Mr. Cazin tbat scores of Mr. Hendy’s machines are worked in this State and elsewhere hy men who never bad any instruction from Mr. Hendy, and tbat they do the work permanently, persistently, and smoothly, nevertheless. The regulation is not difficult, because it admits of considerable lizense, and the repairs are attended witb no more difficulty tban in the case of any otber automatic concentrating machine. What I claim for the machine, principally, is its financial success under certain conditions, whichis even more marked tban its technical one, for the reasons amply explained in my article. Mr. Cazin can form a conception of this wheu I assure bim that a 40stamp mill, crushing 80 tons ore per 24 bours, and running all the pulp tbrough Hendy’s pans (after amalgamation in the battery and on copper plate outside) requires the services of arly fonr laborers in 24 hours to keep 22 Hendy’s running permanently, persistently, and smootbly; attending at the same time to all regulations and repair, and performing all other work connected therewith. I doubt that the yield could be profitably increased to any considerable extent, and positively assert that no macbinery or combination of machinery which Mr. Cazin has descrihed, could be substituted to do tbe work with same ultimate economy, But all this does not make tbe Hendy a pauacea for all purposes, but merely aspires to do what Mr, Cazin would have us, 7. ¢., giving to each machine ite proper sphere of work. Ihave drawn the limit plainly, suggested the proper substitutes onteits of these limits, and broadly detined my position and claims by the expression: Introducing the treatment for coarse stuff suggested, and perhaps, also that for the finest in the case of rich sulpburets, I will say, tbat of all the concentrating machines at present in successful practical use for wet concentration, either in Europe or America, none will effect the concentration of medium grade sands, under the peculiar conditions presented in our amalgamating stamp mills, with equal ultimate economy, as the Hendy in its present form, when properly used; and none of them can compete with it in the effectual working of unsized and ungraded sand, where systematic concentration, by reason of the uature of the ore, cannot he made the leading consideration in the treatment. Coming to the discussion of those points of my article particularly objected to by Mr. Cazin, I heg leave to say that I fail to see in his exposition a proof that the science of mecbanical ore concentration bas emancipated itself from the nomenclature with which Rittinger more or less labeled, or that tbe search of the intelligent mind for the reason why, the rational elucidation of phenomena seeking cause for effect, the tbeoretical origin of actions, at all interferes with the more important attentiou to practical purposes, or that it holds, or ever will hold, any other relation to it than does theory to practice in any other technical question or pursuit. I must admit, that I cannot fully comprebend Mr, Cazin’s meaning in the paragraph here referred, The attempt to translate the idioms of another language naturally leads to various expressions by different translators. If usage accept ‘‘equal falling” as tbe best definition of the German word ‘‘gleichfaellig,” TI am satisfied, though the English expression may be styled a Germanized one. From tbe first I chose to call the particles so treated “‘graded,” the action “grading,” and the apparatus used thereto “graders,” because the word, in my opinion, presented the briefest expression to indicate the prominent characteristic of the material, etc., to which it was applied. The term ‘ water sizing” has also been used—in some cases simply “sizing.” To this latter expression I object, because the word conveys the idea that eize, or approximate equality of size, is the promiuent characteristic of its action. This term was fouud more applicable to tbe work of graduated sieves, or classification was used synonymously to approach more nearly the nomenclature of Rittinger. In this sense tbe terms are used throughout all my articles on concentratiou, for want of any authoritative English expression for the same purpose. To be a little more explicit, but to avoid a full explanation, as not relevant to the subject. I defined graded ‘‘particles assorted according to their equivalent speed of fall in water.” This expression Mr, Cazin criticises as if reading: According to their equal speed of fall in water. T insist on the use of my words, and emphatically object to the substitution of the word equal for the word equivalent, and if Mr. Cazin has any valuation of the English language he will sustain my ohjection. Not equal speed is the distinction, but such speeds of the particles as are equivalent to the attainment of a certain end or effect, i. e., the sinking of the particles to and below a certain depth within a given time. That I am aware of the differences of initial speed, no one can doubt that reads my article attentively, for on this gronnd, among others, tbe separatiou in the Hendy pan is explained. It is also intimated by mentioning its cause in speaking of fine sand jiggers in my article, ‘Krom vs. Rittinger,” Press 1876, page 2. Moreover, auy one can amply inform himself in the matter by consulting Rittinger’s Appondix I., 1870, page 18. The suhject is there more thoroughly treated than in Mr. Cazin’s treatise in the Minine anp Screntiric Press, May 5th, 1877, and to the iuformation there given hy Rittinger, Mr. Cazin and “‘the trade,” so far as I oan learn, has added nothing new.

Professional theory has therefore not to yield to governing practice, and commou sense is not in favor of the laborer and contrary to tbe scientist, as Mr. Cazin so pointedly pute it, for in this matter they are not at variance; many years bave passed since they were elucidated by tbeory and verified by practical experiment conjointly, this being the basis on which nearly all of Rittinger’s doctrines bave been built up. If any one man ever had superlative ability for elucidating theory in these matters, and at the same time extraordinary facilities for verifying it by ae a ohservation and careful, systematized experimentation, it was Rittinger, and for this reason his opinions are justly considered authoritative. To claim bis views as sole authority, and to consider bis opinions unconditionally correct in all things relating to concentration, even, would be presuming an infallibility which I refuse to recognize as within tbe reach of the buman mind, If Iam not mistakeu in the hints, Mr. Cazin would have me looked upon as a scientific tbeorist in the art of concentration. If this be so, let me aseure Mr. Cazin that I can give him ample reference regarding my yactival experience and ability in this line. As objectionable in my article, Mr, Cazin further cites the expression, “it bas been accepted asan axiom almost iu rational conceutration that sizing or grading of the material is absoJutely nécessary to effect a good separation with any concentrating macbine.” If Iam not mistaken in the weigbt of English words, this is far from being a generality. It does not express that it bas always been, or is, or everywhere has been accepted as an axiom, unconditionally, but almost, to effect a good scparation. As for the example which Mr. Cazin gives to sustain his objection, be might have chosen oue more to tbe point, because of practical importance, by taking the case of separation with quicksilver, instead of referring vaguely* to the use of zine vitriol solution (or another salt solution, susceptible of high density), which latter, for obvious reasons, though serving as iuteresting experiments, have little or no practical value, In writing my article, it was not my aim to branch out on every detail, but I chose to iutimate instead, where not expressed, couditions qualifying, as briefly as possible, by the turn of words, thus paying more attention ‘‘to practical purposes.” If, therefore, the axiom, as Mr. Cazin says, is not a general one—whichI do not claim it to be—it is sufficient for us to have his assurance that ‘‘it is such for all successful apparatuses in actual use,” for these are the ones with which we deal. Cas. C. RuEGER. Benicia, Cal., Dec. 2d, 1877. * Tam very much interested to learn of Mr. Cazin what medium he does refer to, for such an one above 1.59 Sp. gr. (excepting quicksilver) is unkuown to me. Arizona Mines. Epirors Press:—I will not, at the present writing, attempt any detailed account of the mines and mining interests in this Territory, nor say much about any particular property or locality, but give merely such information of a general kind as I havo been ahle to pick up in regardto the condition and prospect of things here since my arrival in June last. There is, as you have no doubt observed, a constant dispositiou among mining men to Compare Arizona with the State of Nevada; A very natural and proper thing to do, considering that they are both great mineral hearing countries, and that of the latter we already possess 2 good deal of practical knowledge. Tbis knowledge of the older we like to apply to the newer region, both as a meaus of avoiding former mistakes and furthering the work of its physical development. In their climate, topography and agricultnral resources the two countries are not widely unlike. Here, as in Nevada, climatic differences depend greatly on altitude, the low lying plateaus, desert plains and river valleys being hot in summer, and free from snow at all seasons, while at greater elevations tbe summer temperature is moderate, eome snow falling in the winter, the summits of the higher mountains heing covered with snow for five or six months in the year, and in a few instanves the whole year round, With these variations, the climate here is, at corresponding altitudes, from five to ten degrees wariner than in most parts of Nevada, there being a considerable area in the southern portion of that State depressed below the sea level, which has an almost tropical climate. Our rainfall occurs mostly during tbe summer months, and. is usually quite heavy. In Nevada they have frequent showers in the summer, confined, chiefly, to the mountains, but the precipitation takes place there mostly in the epring, or in the form of snow during the fall and winter. On an average, a greater amount of water falls here than in that State, and, coming in the summer, is of more benctit to the growing crops. The Topography of Both Countries Ie marked by long chains of nearly parallel mountains, with a generally north and eouth trend, and separated by a seriee of alternating valleys, the latter spreading out often into great plains, and forming the desert lands cbaracteristic of both regions. The most of the mountains consist of high, narrow ridges, though they are eometimes brokeu up, forming a hroad belt of otraggling ranges, or flatten out into vast arid and timberless meeas. We do not find here, however, the tahle mountains proper, such as are seen in certain parts of California, In the more southerly part of Arizona this system of alternating mountains and valleye is by no means so well preserved as in northern and f . central Nevada. Here, as tbere, the timber is usually found in the mountains, only cottonwood, mesyuite and willow being met with elsewhere. A greater variety of woods grow here than in the Silver State, and, generally, our timber ie more widely distributed and of a better quality. We have fewer of tbe alkali flate and mud Jakes, and none of the “sinks” that form 2 peculiar feature of that region. In their place, however, we bave the tremendous canyone of the upper Colorado, gorges bardly equaled elsewhere in nature, while we can boast of at least one navigable river skirting our borders. In fact, as regarde Rivers, Springs and Mountain Streams We are able to make a much better sbowing than our northern neighbors. The Colorado, which, after crossing tbe entire northern part of the Territory, forms its whole western border, carries duriug the summer an immense volume of water and is at all times a river of respectable magnitude, being even at its lowest stages navigable for 500 miles or more. After passing 100 miles east of this river the mouutains ahound with running streams, many of them large and never failing, the water always of tbe purest kind, As,a Grazing and Farming Country Arizona is much ahead of Nevada, tbere being bere a large scope of good agricultural land, while tbe grasses are varied in kind, perennial and abundant. For sheep and stock raising this is one of the hest regions west of the Rocky mountains, pasturage being plentiful and tbe climate mild aud healthful. In process of time, our flocks and berds will constitute a sonrce of wealth second only to that afforded by Our Mines, Of which I can in this letter say but little. That we have not in this department of industry been able to make a larger production than has yet been done has not been so much the fault of the mines as of other and extrinsic causes, chief of which has been the lack of means to open them up and outfit them with suitable reduction works. Notwithstanding the food showing of rich ores our mines have made uring the past year, but little outside aid has yet been extended to them. What little money has been invested here has been mostly in tbe purchase of mines, not half a dozen of mills having meantime been brought into the Territory. What we most need just now is a little money to help open up some of the rich ledgee that exist bere. The amount need not be large, as enough ore could iu most cases be taken out, when once tools, supplies and hoisting works were on the ground, to defray current expenses. Without a dime to bis name, the miner, however rich his claims, can do nothing, and these men are always willing to give to parties furnishing money to prospect their lodes a liberal interest therein. If only we could bave the assessments paid on half a dozen unproductive Comstock claims scattered over two or three of the best districts here, it would be pretty sure to reward the investors many hundred fold. What We Want and What We can Do, In the more recent immigration only three classes of men have come to Arizona: The laboring man without means, the speculator, intent on securing any sort of property for gambling purposes, and the capitalist or his agent seeking to buy a valuable mine for a nominal price. Let now the capitalist or his agent come here, and, taking his time, look ahout, and wben he sees anything that suits him act in a epirit of liberality and fairness, and he need not go away witbout getting properties that will turn out satisfactory in the end. He can extract: the ores himself, select his samples and bave them tested by our local assayers, of whom we have here several that stand at the head of their profession. In this town we have a number, all thoroughly competent, some of them being skilled metallurgists and chemists as well. At Picket Post, near the Silver King mine, Prof. Henry Degroot, Jr., has opened an assay office, whereat he is doing a Jarge business, thie being an important mining center where an establishment of the kind was much needed. This young man has become very popular with our mining community, be being not only a capable and trustworthy assayer but possessing in addition that intuitive knowledge of ores tbat enables him to indicate the metbods best suited for their reduction, a faculty that renders bim doubly useful in his calling. Not only can parties have their ores well assayed here, hut they can obtain small lots to be worked, if they desire it, making all required tests on the ground. To men who have cven a little money and thiuk of embarking in mining; this is, above all others, the place to come to. There are more ledges in the Pioneer and Globe districts showing rich ores on the surface than have ever been found in the whole State of Nevada. Parties coming here need not buy these properties outright. They can bond them, buy them conditionally, get them, in fact, on almost any terms they choose to propose, having all the time they want to prospect and open them up. We may not succeed in developing down this way another Comstock. What is even more certain we shall uot spend millions upon millions aud impoverish multitudes of people in looking for ore. If we donot find here lodee that will give vast wealth toa few we shall surely find those tbat will hring moderate enrichment to many, thereby increasing that atahle and well-to-do element that forms the mainstay of every commuuity. A good word from our friends and a little cash from almoet any quarter is what we most want just now.