this that Mr. Whitney is guilty of such palpable errors in endeavoring to discover examples to illustrate the theories advanced. Still we would be happy if he would show us a vein of attrition, a fissure filled "by fragments of the wall-rock, falling from above, or produced by the friction of the sides against each other." Even if there are such veins they can only be very local, and would belong to the general class of fissure veins. Mr. Whitney has been led away by that over-sorting and systematizing of Weissenbach, which is so peculiar to some German writers, and which leads to the eternal divisions and subdivisions abounding in their works and covering the pages with those categorical distinctions that begin with the Latin numerals and end with the Greek alphabet, after passing through all the intermediate distinctions of numerals and letters of our own. May we inquire, too, why the author, in speaking of veins of infiltration, merely refers to those where lime was in solution? Is it only because Weissenbach also omits all other substances? The latter is excusable, because, as Professor T. Reich himself says in the introductory remarks to the article, that paper was not complete nor ready for publication at the time of his death. Not so Mr. Whitney. A gentleman of his extensive experience should be able to fill out the deficient parts of a theory which he establishes as normal. Can it, then, in this instance, be the author's intention to say, that calcareous matter alone produces the incrustations on the walls of infiltration veins (p. 45)? What becomes of the oxides and salts of iron and copper, and what of the numerous other substances that were brought into the fissures in the shape of solutions and there precipitated? Cotta's able article on metalliferous veins would seem to present more substantial theories than those which Mr. Whitney has embodied in his work; and while Weissenbach's hypotheses refer merely to the secondary action, the filling up of the veins, those of Cotta enter into an explanation of the primary cause of the solution of the materials which now compose the lodes. It is true that Cotta only explains the formation of one species of veins, but it is, perhaps, the most important one of all, and, singular to relate, one which has escaped Mr. Whitney's attention entirely, for it cannot be regarded as a subdivision of those which Mr. Whitney terms "metalliferous veins proper," nor of the segregated veins, which he defines as produced "by the gradual elimination of their component particles from the surrounding formation." To this class he asserts that the auriferous veins of North Carolina belong. Certainly, if the contents of segregated veins are taken from the surrounding country, the nature of the composition must alter with every change in that of the neighboring rock, and yet we could point out many instances where the North Carolina veins penetrate through the slates into the massive crystalline rocks without any essential alteration in the nature of

their contents. Cotta's theory alone seems able to account for the origin of such lodes, and we are more particularly inclined to apply it to the North Carolina, and, indeed, the infinite majority of Southern auriferous lodes, when we consider the following established facts, viz.: that the character of the veins forms a regular and almost universal series of progression, which begins with the ferriferous quartz, passing downwards into iron pyrites, which gradually changes into various sulphurets of copper; that the gold is most abundant above, and, at greater depths, seems to have had time to settle in the uncongealed mass, and thus to disappear from workable levels.

I have not the space here extensively to enter into Professor Cotta's theory, and therefore refer the interested reader to the translation of his article in this and the former number of this journal.

It must be a matter of surprise to every reader to find that Mr. Whitney makes no mention of pipe-veins. Assuredly they are of adequate importance to deserve some attention, and of sufficient interest to merit a description, particularly as some of the richest Southern auriferous lodes belong to this class.

In speaking of the phenomena observed by Mr. Fox in Cornwall, and by Professor Reich in Freiberg, relative to the effects of electric currents in lodes, we were astonished to find that nothing was said of the very remarkable facts that have been observed in connection with gold, for instance the pseudomorphous crystals of gold upon hematite, with the crystallization of iron pyrites, the accumulation of gold around old roots on the backs of veins, which certainly proves the continued agglomeration, if not precipitation of gold. We would not have expected that Mr. Whitney should have offered an explanation based upon observation, for he shows that he cannot have had great experience in auriferous lodes, but we did certainly expect to find some notice of so very remarkable a phenomenon.

On page 87 I see it remarked that, in the process of the formation of auriferous detritus, "the metallic particles, having by far the highest specific gravity, are first deposited and sink to the bottom, while the lighter earthy portions are carried farther." This is a decided mistake. The metallic particles would certainly sink to the bottom of the detritus with a gyratory or perpendicu lar motion, but not so by washing away. According to Mr. Whitney, the black oxide of iron, which is much heavier than sand, would never appear on the surface in the beds of currents, and yet, after every rain, we find it above the sand, where the water flowed. The true explanation is this. At first, when the rocks decompose, the metallic particles may occasionally sink to the bottom. The currents of water, bearing the whole along, will, at all events, first remove the lighter portions and afterwards the metals. When these are deposited anew, the last removed

parts will be uppermost. The water, gradually soaking in, or the wind may, indeed, in some instances, carry the heavier particles down through the sand, but they are not thus originally deposited as Mr. Whitney affirms, and, indeed, he will not be able to point out many cases where the bottom of one and the same deposit is richer, for instance in gold, than the upper parts, except where the size of the gravel is variable, for then the coarser portion will be uppermost, and the gold will be found chiefly upon the surface of the subjacent fine-grained deposit, and, therefore, even in this instance, not beneath the whole. It is the same with the Cornish tin.

On page 91 Mr. Whitney remarks, that he is unable to decide upon the usefulness of certain gold amalgamators. I venture to recommend a visit to some of the gold mines, and have no doubt that a decision would be speedily gained regarding inven tions which have flooded the country with old iron, and will leave a pleasant riddle for futurity, possibly inducing some remote descendant of our race to dwell upon the bloodthirsty propensities of his ancestors, who have bequeathed to him those huge bombshells that make the mineral regions of the South resemble some Titanic battlefield.

In several parts of the volume the reader cannot fail to notice a want of distinct and decisive geological nomenclature, which may cause many mistakes and certainly should have been avoided. Thus on page 342, a group is denominated "calcareous." At first I was inclined to think of the cretaceous group, but from the connection it must mean carboniferous limestone.

The general information regarding the localities and respective geological positions of metals, is on the whole well selected, but we could not refrain from observing a want of information concerning their recent occurrence. Had Mr. Whitney's desire been only to state the practically valuable locations of metals, none would have been disposed to make any objection, but there are too many exceptions to acknowledge this rule, and therefore I do not hesitate to say that the author should have known and read the interesting work of Sartorius Von Waltershausen, on the volcanic rocks of Sicily and Iceland (Goettingen, 1853) in which the latter speaks of the occurrence of metals in recent volcanic rocks. On page 8 and 9 of that work, we find manganese, titanium, copper, nickel, chromium, vanadium, zinc, tin, lead and silver, particularly enumerated.

I have already mentioned that the bulk of information in Mr. Whitney's work centres around Lake Superior. Indeed, all his remarks concerning the mineral regions of the United States are concentrated on the North; and, while he gives exact statements of the occurrence of some little metalliferous specimen upon a farm in New England, he furnishes the most meagre accounts of even the most important Southern mines. Being a Southerner myself,

I am better able to enlarge upon the want of exactness in the descriptions of Southern mines, than of those of the North. In no part of Mr. Whitney's work can I find even so much as an announcement of the existence of zinc in East Tennessee, where it occurs so abundantly as calamine and silicate. In North Carolina, nine gold mining lands alone are spoken of, and even of these the information refers far more to the capital of the companies and the market value of the shares, than to the practical worth and geological character of the mines. To obtain a truly valuable and complete knowledge of all the mines of such a country as the United States, would require a lifetime and the intellect of a Humboldt, and therefore is more than we can reasonably demand from one individual, especially when we recollect the unsatisfactory accounts provided for the scientific investigator by the majority of common mining reports. These are addressed to men who are supposed to be aware of many little specialities, which are therefore left unmentioned, but without which the uninitiated will fail to comprehend the whole. In addition to this, they are intended for technical purposes alone, and very rarely contain matter of interest to the geologist; besides, they possess the greatest similarity, and usually end with the words, "your prospects are admirable," or, "few mines admit of the anticipation of happier results." It is well known that many of these reports are made without any underground examination of the mines, and I could relate some very ridiculous occurrences with reference to this. Under these circumstances, the author of the work before us should have confined his remarks to the localities with which he was thoroughly acquainted, or should have visited, at least, the most accessible of other important regions, and he should certainly have availed himself of all the information he could obtain. Yet, while he mentions Mr. Partz's report on the Rhea mine, in North Carolina, he is perfectly silent upon a far more accurate one by the same on the Hale mine, in South Carolina, although this is published in the very same number of this Magazine. I can conceive no cause for such partiality.

A matter which does not add to the value of the work is the manner in which the information, which should be classed under one head, is scattered over distant pages. This is owing to the way in which the author has taken up the subject. It would have been infinitely more convenient to the reader, and would have prevented numerous repetitions in the work, if all the mines of one metal, in the same country, had been placed under one head, especially as there is no index; for it is presumed that such a work is intended as a book of reference, and is not to be perused as one would read a novel.

In pointing out the errors which are most perceptible in Mr. Whitney's work, it is by no means the intention to decry it or regret its publication. As a commercial and statistical work, it

is exceedingly useful and interesting, and contains also most valuable scientific information concerning the mines of Lake Superior, and of different parts of Europe. With all its marked anti-Southern partialities, I must still recommend its perusal, for it is the only work of the kind published; and I close with the fervent wish that it may lead to more comprehensive publications.

ART. III.-THE BLOW-PIPE, AND ITS USE IN CHEMICAL ANALYSIS.-No. V.*

4.-TEST IN THE PLATINA FORCEPS.

AFTER having ascertained, by previous experiments, that the substance under examination is incapable, in a heated state, of acting upon platina, a small piece of it-a splinter-is placed in the forceps and heated in the oxidation flame. Substances which under these circumstances affect platina, should be heated on charcoal; or those that are very fusible, in the eye of the platina wire. This is not only useful as a means of ascertaining the fusibility of a substance, but also to enable us to determine the presence of those substances, which under these circumstances would, more or less, color the blue blow-pipe flame. With some of these the color conveyed is yellow, with others violet, carmine, green, or blue. Plattner, in the work cited, gives the following particulars regarding these effects:

a. YELLOW.-Soda and its salts, when fused on the platina wire, at the point of the blue flame, possess the peculiarity of enlarging the external flaine and giving it an intense reddish-yellow color. An excess of other salts, whose bases would also color the external flame, though not so intensely as soda, does not obliterate this effect. For the reaction on charcoal see No. IV. When small splinters of silicates containing soda are heated and fused in the forceps with the point of the blue flame, the external flame will be more or less enlarged in the same degree as the substance is fusible and corresponding with its contents of soda. The external flame will also be colored reddish-yellow, and this tint will either remain constant or become more intense with continued blowing.

b. VIOLET.-Potash and its salts, when fused on the platina wire in the point of the blue flame, give to the outer flame a distinct violet color, with the exception of borate and phosphate of potash. If, however, such a salt contains even a very small admixture of a soda salt, this reaction will be changed to some

extent.

It is true that near the test a slight violet color will be

*Continued from Vol. III., No. 3, page 268, Mining Mag.