^ibrai'D of the S^wsatm OF COMPARATIVE ZOOLOGY, AT HARVARD COLLEGE, CAMBRIDGE, MASS. The gift of diz. > J^ . J. 0 J^ ■ f- ■.a NOV 27 ]"9] JOURNAL OF THE ELISHA MITCHELL SCIENTIFIC SOCIETY, VOLUME VIII— PART FIRST. JAISTUARY— JUNE:. 1891. POST-OFFICE : CHAPEL HILL, N. C. E. M. UZZELL, STEAM PRINTER AND BINDER. RALEIGH, N. C. l8qi. OFFICERS. 1890-1891. PRESIDENT : George F. Atkinson, Auburn, Ala. VICE-PRESIDENT : F.R. Dancy, A. B Raleigh, N. C. RESIDENT VICE-PRESIDENT: . William Cain, C. E., Chapel Hill. N. C. SECRETARY AND TREASURER : F. P. Venable Chapel Hill. N. C. LIBRARY AND PLACE OF MEETING: CHAPEL HIIvL. N. C. TABLE OF CONTENTS. PAGE. List of Officers -- -- -- 2 Demonstration of the Method of Least Work. William Cain 5 Additions to the Avifauna of North Carolina. J. W. P. Smithwick-- 16 The Alexander Count}- Meteoric Iron. vS. C. H. Bailey .-- 17 Treatment of Zircons in Preparing Zirconium Oxychloride. F. P. Yen able 20 Quantitative Analysis of the Zircon. J. M. Morehead --- 24 Records of Meetings .-- 26 Additions to Exchange List 27 JOURNAL OF THE Elisha Mitchell Scientific Society DEMONSTRATION OF THE METHOD OF LEAST WORK. BY \VM. CAIN, C. E. ; M. AM. SOC. C. E. I. A new method of ascertainino^ the stresses in elastic structures by means of the principle of "Least Work" has been elaborated by Castigliano, in his "Theorie de I'Equilibre des Systemes Elastiques " (Turin, 1879), who claims to have given the first complete demonstration of the theorem of least work, though several authors have touched upon it from 181 8 to the present time. In the ''Transactions of the American Society of Civil Engineers" for April, 1891, the writer published an article entitled "Determination of the Stresses in Elastic Systems by the ]\Iethod of Least Work," in which two new and complete demonstrations of the principle of least work are given, both being founded on the w^ell-known principle of "virtual velocities" of mechanics "applied to framed structures." The following article is an abstract of the briefer demon- stration, given in the article by the writer before men- tioned, and is based on "the theory of deflections," which will first be given. A few preliminary articles on " elastic work" of a bar in tension or compression, "superfluous" 6 JOURNAL OF THE bars in trusses, etc., are added to make the paper suffi- ciently complete in itself; especially as the aim is to make the demonstrations as simple and elementary as possible. 2. If we call a the length of a prismatic bar, tu its cross section, e its modulus of elasticity and k its change of length under the stress a, then, by the fundamental law of elasticity, when the resultant stress j acts along the axis and the limit of elasticity has not been exceeded, we have. (IK a s k = _cs e w a if for brevity. we put, c = . e w If the bar leno^thens or shortens the amount k bv the •;> action of a load P, acting in the direction of its axis, which gradually increases from o to its greatest value P, the stress likewise increases from o to its greatest value j, and at any instant the stress is exactly equal to the load. If in any small interval of time the average stress is s^ whilst the length changes an amount d k, due to a slight increment of load, the work done is s. d k; therefore as the load changes from o to P, the total work done is the limit of the sum, 1 (s. d k) = between the extreme values k ^ o and k = k, correspond- ing to s ^ o, and s = s. . '. The total 7vork of deforniation for ^gradually applied load is, I .^ I k^ I T — I kdk= = _cs2 = — sk.... (2); CO c 2 2 2 or since load P = s, work = \ load X change of length. ELISHA MITCHELL SCIENTIFIC SOCIETY. 7 For a suddenly applied load P, causing a change of length k^ and maximum stress jr, the work of the load is P k\ and since the ?Ar^s?> gradually increases from o to s, the work of deformation, by (2), is \- s k\ and since these are equal s = 2 P, or the maximum stress is double the load; hence by (I) the change of length is double that fo:' a gradually applied load. After a series of oscillations this change ultimately becomes that due to a gradually applied load and s reduces to P. As, in what follows, we are only con- cerned with the ultimate or statical stress, we shall always compute the zvork of deformation of a bar, as for a gradu- ally applied load, by the formula (2), 1 I a — c s- = s- . . . . (3). 2 2 e w 3. Superfluous bars. When the figure of a truss has more lines than are strictly necessary to define its form; i. c, to fix its apices when the length of sides are given in order, the extra sides are said to be ' ^ supetflitous.^^ The relation between the least number of sides w, or the number of '' necessary " bars in a truss and the number of joints or apices ?/, for strictly defining the form of a fig- ure of invariable form, is easily arrived at. Thus for plane figures (which we shall alone consider in this article) assume the position of one side, thus fixing the two apices at its ends. From these apices we can fix another with two new sides, then another with two new sides from two apices previously fixed, and so on; there- fore to each of the (n — 2) joints other than the first two corresponds two sides, so that the total number of neces- sary sides ;;/ = 2 (n — 2) ^1=2 n — 3. If the number of sides exceeds (2 n — 3), the extra number are "super- fluous " to strictly define the form. A less number will give a figure that can change its shape without changing the lengrths of its sides. 8 JOURNAL OF THE It is well known that the laws of statics alone suffice to determine the stresses in any truss, whose pieces are free to move at the joints, when the number of bars is just that necessary to strictly determine the form. When there are superfluous bars or continuous members without free play at the joints, the theory of elasticity must be used to give the additional equations, which, added to those furnished by the ordinary laws of statics alone, give as many equa- tions as unknown stresses, from which the latter are ob- tained by elimination. The theory of ''least work '' offers a direct solution of such problems. It may be observed, if a truss is subjected to such con- ditions^ that more than two joints are fixed in position, that there may be more bars than are strictly necessary to define the form, even when m = 2 n — 3. It is always easy in such cases to ascertain the number of "superfluous bars" by supposing the truss built out from two joints taken as fixed, apex by apex, towards the other fixed joints. The number of bars just sufficient to fix the position of each apex, other than the fixed ones, is easily seen; all other bars are superfluous to this end and must be so treated when applying the method of least work. 4. Derivative of the Work of Deformation with respect to an external force. Deflection. Consider a truss of in- variable form, without superfluous bars, and let a force unity act in the direction of and along the line of action of any external force P. Then when all the original exter- nal forces, such as P, are removed and we have only the force unity acting on the truss, with the corresponding re- actions, if any, call // the stress in any bar due to the force unity in question. Also call the length of this bar «i" the exact amount e w ELISHA MITCHELL SCIENTIFIC SOCIETY. 9 caused by the stress 5 due to all the external forces such as P (the force unity being omitted), and that this elongation alone causes the displacement /\ p^ of force unity in the direction of that force. In applying the principle of vir- tual velocities we have the right to suppose any displace- ment A 1 we choose, and for convenience we take that the bar actually sustains when the truss is fully loaded and not what it would sustain from the force unity. Now assuming ic to be tension, the displacements of the ends of the bar are in the opposite directions to the forces acting, so that the virtual velocity is negative. We shall assume the displacement A p^ to be in the direction of the force unity until otherwise ascertained. We have now by the principle of virtual velocities, I. A p^ — u. A 1 = o; a s .-. A p' = u . e w If u or .V are compressive, it is evident that they must have the minus sign in the above equation. Should A p^ thus become minus in any case, the displacement will be contrary to the direction of the supposed force unity. Continuing thus to find the displacement of force i, due to the change of length of each bar in turn, the other bars remaining unchanged, we have for the total displacement of the force unity, acting in the direction of external force P, the formula, \ e w/ A p = -i u I . . . . (4), the sum extending to all the bars of the truss. But since this displacement is that caused by the actual stresses in all the bars due to the original external forces, it must equal the actual displacement of force P along its direction or the deflection of the truss in the direction of force P. lO JOURNAL OF THE This is a known formula, by means of which the defiec- tion of any truss containing only " necessary " bars in the direction of any given external force or supposed force, can be computed. In using it, strict attention must be paid to the signs of // and a\ plus for tension, minus for compres- sion. We shall now put this formula in a different shape and from it eventually deduce the theory of least work. If we call X the stress (+ for tension, — for compres- sion) in any bar due to all the loads and their correspond- ing.reactions, when P is omitted, we have the stress in any bar, s := X + u P; whence, taking the derivative, since X is entirely inde- pendent of P, ds d P (a s d s \ d I /a s^ \ - — = ^ - (5) e w d P/ d P 2 \e w/ in which it is understood that .v must be replaced by X -f 1 as^ u P. Now b\- eq. (3), represents the elastic work 2 e w of one bar, so that in words (5) shows that if ive express the 7vork of defovuiation of the bars as a fiinction of the ex- ternal forces^ its derivative with respect to one of the forces gives the displacement^ in the direction of the force^ of its point of application. This is called by Castigliano "the principle of the de- rivative of work," or it may be termed the theorem of deflection. If we call the work of deformation of the sys- dF tem, P", it is plain, from the above that when = J p is d P ELISHA MITCHELL SCIENTIFIC SOCIETY. Ii plus, the displacement is in the direction of the force; when minus, in a contrary direction. When two equal forces, directed both toward or both from each other, along the same line (as in the case of the horizontal thrusts of an arch hinged at the abutments), are designated by the same letter P, if we call P and P^ the two forces and F the work d F d F of deformation of the truss, then and give the ac- d P dP^ tual displacements of P and P\ along the directions of the forces; both minus or both plus, according as the motion is opposed to the direction of the force or with it; so that d F d F r gives the total relative displacements of P and d P d Pi F\ In case we can regard the apex, at which either force d F as P^ acts, as fixed, then represents, as usual, the dis- d P placement of one apex with respect to the other. If a truss has siiperjiiious members, we can suppose them removed and that two opposed forces act at either end of each bar, each equal to the final stress in the member and acting in the same direction. Then if we designate bv P and P\ the forces replacing the action of any one bar, at either end, upon the apices, then if F represents the work d F d F of the necessarv bars, \ gives the total relative d P d P^ displacement of the apices. Xow^ as w^e can regard P* = P as a function of P, the total derivative of F with respect to d F d F d P^ d P^ P is \ ; but since P = P\ = i, there- d P d P^ d P d P fore the total derivative of F ivith respect to Pis equal to d F d F + d P d P^ 12 JOURNAL OF THE w'lich, from what precedes, is equal to the total relative displacement of the apices, where P and P' are applied. Hence, in any case, to find the relative displacement of two apices, between which two equal and opposed forces, P and F\ act, we have only to take the total derivative of F with respect to one of the forces P, so that it is not nec- essar}' to designate the two opposed forces by different letters. 5. Demonstration of the Theorem of Least Work. Let us suppose that we have a truss of any kind, with superfluous bars numbered n, n -h i, . . . , whilst the (n — i) necessary bars (system N) are numbered consecu- tively, I, 2, ... , (n— i). Let, Xj, X2, . . . Xii_i = stresses in bars i, 2, . . . , (n — i) of a frame supposed to consist of necessary bars alone (system N) subjected to the actual loading. Ui, u,, .... u„_i = stresses in bars i, 2, . . , (n — i) of system N alone, by forces unity acting towards each other from either end of the original position of superfluous bar //, all the superfluous bars being removed. Vi, V2, . . . v„_, = stresses in bars 1,2,..., (n — i) of system N alone, caused by forces unity acting towards each other from the apices of superfluous bar (n i- i), all the superfluous bars being removed. Similarly we proceed for other superfluous bars, if any. The stresses X, //, ?', . . . , can all be found by the laws of statics alone. Now designating the length, cross section and modulus of elasticity of any bar, by <7, zc and ^, re- spectively, with the same subscript as the number of the bar, we have the total elastic work of deformation of all the bars, including the superfluous bars, expressed by G= V2 y I — I ^- ^4 1- 14 ^- . . . , --m e„w„ e„ + iW„4- ELISHA MITCHELL SCIENTIFIC SOCIETY. 13 in which the sum - extends to the necessary bars alone, or bars i, 2, . . . (n — i). In this expression it is under- stood that for j-, the actual stress in any bar, we must sub- stitute expressions of the type, S = X — U Sn -f V S„ -j- I 4- . . . , on supplying the proper subscripts pertaining to the bar considered. The last expression follows at once from the principle of " superposition of effects." On designating by F the elastic work of the necessary bars alone, we have ^iB the sum including only the necessary bars and s being ex- pressed as a function of Su, s„-|- j, . . , as above. We shall next regard the superfluous bars n, n 4- i, . . . , as temporarily removed and replace -their action by two forces for each bar, each equal to the stress in the super- fluous bar and acting towards each other, as all bars are assumed to be in tension until otherwise determined. It has been shown above that treating these forces, s^, Sn-|-i, . . . , as external forces and independent of each other, d F that represents the increase in distance between d s,, the apices at the extremities of bar ;/, the minus sign being used, since the two forces s^, s„, replacing the tension of the bar upon the joints at its ends, act in the opposite di- rection to the displacements. Similarly for the other deflec- tions. Again, since Su is supposed to equal the actual stress in bar ;/ in the complete structure under the loading, d F it follows that must equal the elongation of the bar d Sn ;/ under the stress Sq when all the superfluous bars are in place, since the real change of length of any superfluous 14 JOURNAL OF THE bar 71 is a necessar}' consequence of the real chano^es of length of the necessary bars alone, and it can be found as above, without knowing- the changes of length of the superfluous bars beforehand. The increase in distance between the apices at the extremities of superfluous bar ;/, as determined from "system N," must therefore exactly equal the elongation of bar ;/ under the stress s^ when in place. d F a„ s„ d s„ e„ w, Ml d F a„ s„ or, \ = o (6). d s„ e„ w„ x\ similar expression obtains for each of the supei-fluous bars, so that we always have as many equations as there are superfluous bars. Now each equation of the type above (6), can be found by taking the partial derivatives of the expression for G above, successively with respect to Sj, , s„ -|- ,, . . . , treated as independent of each other^ and placing the results sep- arately equal to zero, so that the equations needed will be of the type, dG dG = o, == o, (7)- d s„ d s„ + , From these equations we find, by elimination, Sji, s„ -f ,, . . . , and then substituting these values in equa- tions of the form, s = X -I- u s„ + V s„ 4- 1 -h . . . , we find all the stresses, s,, S2, . . . s„_i. Theorem of Least Work. Therefore, to deter7n{ne the icnknown stresses^ ive express the ivork of deformation of the zvhole system as a function of the stresses in the bars taken as superfluous^ then treatin^^ these stresses as inde- pendent in the differentiation^ ive express that the ivork of ELISHA MITCHELL SCIENTIFIC SOCIETY. 1 5 the necessary bars and one siiperjiuous bar at a time be a minimum; or preferably^ that tJie worlz of all tJie bars be a minimum^ provided zve asszime the fiction^ that the stresses of the superfluous bars are entirely independent of each other. It is this which constitutes the method of " least work." When there is but one superfluous bar, the true stresses correspond exactly to a minimum of elastic work, but for a greater number of superfluous bars this is not necessarily true, since the stresses in the superfluous bars are functions of each other and not independent, as we assume in form- ing eqs. (7). This consideration has not been pointed out by any previous author, as far as the writer knows. The theorems of " deflection" and " least work" have now both been proved by aid of the method of virtual velocities, which, it is seen, is especially adapted to the object in view, as it leads easily and unmistakably to the theorems, and leaves, no doubt, whatsoever as to the exact interpretation of results. The theorems are easily extended to solid beams, com- posed of molecules, resisting any change of distance apart by forces varying directly as the changes of distance, ac- cording to the law of elasticity first assumed; for such bodies can be treated, therefore, as articulated systems, whence the above theorems directly apply, the unknown stresses between certain molecules taking the place of the stresses in the superfluous bars of the preceding demonstra- tions. The theorems are therefore perfectly general and apply to solid beams, articulated structures, or combina- tions of the two, including structures having certain mem- bers continuous over certain apices ; but it would take us too far in this article to give the most convenient methods of dealing with such composite structures, which may be found, however, partly in the article by the writer in the April, 1 89 1, Transactions Am. Soc. C. E. , and very fully in Castigliano's very exhaustive treatise before mentioned. l6 JOURNAL OF THE ADDITIONS TO THE AVIFAUNA OF NORTH CAROLINA SINCE THE PUBLICATION OF PROF. ATKINSON'S CATALOGUE. BY J. W. P. SMITHWICK. 1. Alca tarda. Razor-billed auk. The head, wing and foot of one of this species were sent to the Department of Agriculture, Washington, D. C, for identification by- Lieut. Foley, U. S. N. It was taken at Lookout Cove on February 15, 1890. Others were seen. (Auk, April, 1890). 2. Branta leiicopsis. Barnacle Goose. ''Has been taken in North Carolina." (Bui. Am. Mus. Nat. His., Vol. I, No. 7, July, 1886; Allen in " Birds of Massachusetts"). 3. Porzana jamaice7isis. Black Rail. Rare summer vis- itor in the middle and western sections. Found breeding in both places. 4. Cohimbigallina passerina. Ground Dove. Accidental summer visitor in the mountain region. So far two speci- mens have been seen and identified. (Cairns). 5. Archibiiteo lagopus sancti-johannis. American Rough- legged Hawk. Seen occasionally in the winter and spring in the west. (Cairns). 6. Strix pratincola. American Barn Owl. One taken at Newport, N. C, by James Moore, Esq., November 7, 1889, and sent to Brimley to mount. 7. Empidonax fiavive)itris. Yellow-bellied Flycatcher. Rare transient in the middle section; one was taken August Ti, 1890, in the mountains. 8. Einpidonax ptLsillns traillii. Fraill's Flycatcher. One was taken in the mountain region in September, 1889. (Cairns). ELISHA MITCHELL SCIENTIFIC SOCIETY. 1 7 9. Otocoris alpestris praticola. Prairie Horned Lark. Rare winter visitor in the middle and western sections. 10. Quisculus qiiisciila cEiieus. Bronzed Grackle. Tol- erably common transient in the mountains. (Cairns). 11. Aimnodranius henslowii. Henslow's Sparrow. One female taken in April, 1890, in the western section. (Cairns). 12. Amviodramiis maritimiis. Seaside Sparrow. One taken by myself, May 15, 1891, in a marsh near Plymouth, N. C. No others w^ere seen. 13. Chondestes grajiimaciis. Lark Sparrow. Rare sum- mev visitor at Raleigh. Breeds. (Brimley). 14. Clivicola riparia. Bank Swallow. Rare transient in the middle and mountain sections. 15. Helmiiithophila bachrnaiti. Bachman's Warbler. Probablv a rare summer visitor. One taken at Raleio^h, April 27, 1891. (Brimley). 16. HelmintJwpJiila leiicobronchialis. Brewster's War- bler. Rare transient at Raleigh, X. C. (Brimley). 17. Dendroica palmanim hypochrysea. Yellow Palm Warbler. Tolerably common transient at Raleigh, N. C. (Brimley). 18. Tiirdus alicicF. Gray-cheeked Thrush. Transient visitor, rare at Raleigh; tolerably common in the west. Saxs Souci, X. C. THE ALEXANDER COUXTY METEORIC IROX BY S. C. H. BAILE\^ About the year 1875, General T. L. Clingman, of Ashe- ville, presented me with a small piece of meteoric iron, concerning which he w^as able to give me little information further than that it had been found some \ears before in l8 JOURNAL OF THE Alexander county, and had been given to him by a Mr. Andrews. The piece was evidently a fragment that had been broken from a larger mass, was rather smoothly rounded upon its broadest surface, and, though wholly de- void of a proper crust, the exterior was quite protected from further oxidation upon that side by the alteration produced from weathering. It did not in any part show any evidence of the pittings common to all classes of me- teorites. Its structure is coarsely granular, or made up of polygonal fragments, lightly adherent, with intervening thin folias of Schreibersite and cracks or veins of iron oxide, cementing the mass together. In some instances the Schreibersite also forms small blocks, with rounded out- lines. The limited area of the surface cut is only sufficient to show that it belongs to the Braunite type of Meunier, or the "Grobe Lamellen of Brezina. " It has a density of 7.635 and its composition, as shown by Venable, is Irou 91-70 Nickel 5.86 Cobalt .63 Phosphorus . 095 Oxygen and loss 1.72 100.00 Where the iron is free from the Schreibersite it cuts eas- ily, takes a good polish, is very light in color, and upon etching it shows neither the Newmann lines nor the figures of Widmanstiidt, but it quickly blackens upon applying the acid, and is very slowly corroded. In grains it is quite malleable, but rather brittle in mass. It is most probable that the fragment in my possession came from near the surface of the main mass, and it may present different con- ditions from the interior portions, which have been pro- tected from the action of the soil or atmosphere. From comparison with examples of the other North Carolina meteoric irons, it is seen to differ essentially from all of ELISHA MITCHELL SCIENTIFIC SOCIETY. 19 them, the only one which it at all resembles being that from "Duel Hill," found in 1873, but several marked dif- ferences are apparent upon direct comparison. \yhile the Alexander county was found some years prior to that from Madison county, the places of find are widely apart, and the densities and analyses do not nearly approximate. This iron does not seem to be especially prone to oxidation, and while it belongs to a class that is not very compact in structure, yet the condition of a part of the surface of this specimen above mentioned would indicate that even when denuded of its natural crust its exterior (unless exposed in a very damp soil) would form a new protective coating of oxide which might preserve the parent mass for many years. Unless it has been so destroyed, the original mass must still be in existence, and as has been the case with other meteorites found in that State, it may now be lying, un- recognized, about some farm building, instead of being where it properly belongs — in the State Cabinet. In a State that has been so favored in the number of its me- teoric falls, it would seem to be natural that its people should be alert to gather and preserve these interesting objects. Professor Venable has recently shown that the authenticated fall within the State bears a strikinorlv lar^e ratio to the entire number of all recorded meteoric falls. The recognition and preservation of the earlier North Caro- lina meteorites is almost exclusively due to the commend- able zeal of General Clingman, and now that the intelligent effort of some of her citizens is directed to the subject it may safely be predicted that the list will soon be much extended. OSCAWANA ON HUDSON, N. Y.. AugUSt I9, 1S9I. 20 JOURNAL OF THE TREx\TMENT OF ZIRCONS IN PREPARING PURE ZIRCONIUM OXYCHLORIDE. BY F. P. VENABLR. Linneniaiin (Sitz. Ber. Kais. Akad. d. Wissens. , Vol. II, 1885, translated in London Chemical News, LII, 233 and 240) has pnblished an acconnt of the "Treatment and Qualitative Composition of Zircons." All previous methods of breaking up the zircon and purifying the zirconia have presented numerous difficulties and proved decidedly un- satisfactory. Having occasion to prepare some of the compounds of zirconium in considerable quantity and of chemical purity I adopted the methods of Linnemann. In the course of my work I have found it advisable to modify the process in several respects, and I make this publication in order that my experience may be available, and perhaps serviceable, to others. In the first place, I have found the mechanical prepara- tion can be simplified. I have used North Carolina zircons and have found it sufficient to pulverize them roughly in an iron mortar and then grrind in an agnate mortar until the powder passed through a 100 mesh sieve. The preliminary exposure during ten days to vapor of hydrofluoric acid and the grinding until the powder passed a silk sieve seemed both unnecessary. The fine powder was repeatedly boiled with strong hydrochloric acid and washed with water. Five hundred grams treated in this way lost seventeen grams, the hydrochloric acid thus dissolving 3.40 per cent, of the whole. The fusions were made in nickel crucibles, which are very much cheaper and less attacked than the silver recommended by Einnemann. The loss comes chiefly EUSHA MITCHELL SCIENTIFIC SOCIETY. 21 in the cracking of the crucibles during the cooling after fu- sion. The crucibles used measured 10.5 c. m. in diameter by 8 c. m. in height and held a charge of 100 grams zircon, 400 grams sodium hydroxide and 20 grams sodium fluoride. This is one-half the amount of sodium fluoride recom- mended by Linnemann, but proved sufficient. The sodium fluoride should be dried beforehand. The sodium hydroxide is first thoroughly melted and the fluoride then added. The mass should be brought to a fairly high temperature and then the zircon powder added. A rapid evolution of gas follows the introduction of the powder. The mass should be well stirred by means of a nickel stirrer — a narrow^ strip of sheet nickel fastened to a glass rod answers the purpose and keeps the hands beyond the reach of hot alkali occasion- ally thrown out. If the bubbles threaten to rise over the edge temporary removal of the lamp secures their subsidence. The crucible should not be allowed to cool too far, how- ever. Much seems to depend upon carrying through the reaction rapidly at a high temperature. I have at times doubled and even tripled the length of fusion at a lower temperature without securing the thorough breaking up of the zircon secured at a higher temperature. After the first violent boiling a quieter period follows. The end of the reaction is showm by a thickening of the mass and the rising of large bubbles here and there, also sometimes by a fine spitting or spray. In several instances where weights were kept the undissolved or unattacked portion of the zircon powder amounted to less than five per cent. The melted mass was poured out upon pieces of sheet nickel for cooling. After solidifying enough to handle wnth tongs it was broken off" and plunged in a beaker of cold water. Water was also put in the crucible after it had cooled, to dissolve off" the portions adhering to the sides. The water separates the sodium silicate from sodium 22 JOURNAL OF THE zirconate, leaving the latter undissolved. This is dissolved in dilute hydrochloric acid and evaporated several times to dryness with fresh amounts of acid in order to drive off the hydrofluoric acid. The separation b}- means of water is far from perfect, some of the zirconate going into solu- tion, though not enough, usually, to make it worth while to attempt to regain it. There is a good deal of silica left with the undissolved portion. This is separated after evaporation to dryness. The dried mass is reached with dilute hydrochloric acid. There is difficulty sometimes in extracting all of the zirconium chloride in this way. Of course the solution contains large quantities of salt, besides other substances. Zirconium hydroxide is precipitated away from these by ammonium hydroxide, and then thor- oughly washed in large jars by decantation. The crude zirconium hydroxide is next dissolved in strong hot hydro- chloric acid, using as small an amount as possible. This solution is evaporated to dryness and the crude zirconium chloride obtained placed in a large funnel and washed with a mixture of strong hydrochloric acid and four parts of alcohol. This mixture is poured upon the mass in the funnel and allowed slowly to drain through. Some zir- conium chloride is dissolved, but can be recovered by evaporation. The mass in the funnel is left white and fairly pure. To complete the purification this mass is taken an^ repeated!}' crystallized from boiling hydrochloric acid until the acid gives no test for iron, which seems the most persistent among the impurities. I have commonly found it well to repeat this crystallization more than twenty times. The pure oxychloride is gotten in well- formed crys- tals of glistening whiteness. This method of crystallizing from hydrochloric acid, used by Ivinnemann, is the only sat- isfactory one for purifying the zirconium chloride. I have tried the precipitation by hydrogen dioxide, as recom- mended by Bailey, but the consumption of pure dioxide is ELISHA MITCHEI.L SCIENTIFIC SOCIETY. 23 very large and a heavy source of expense, and the pent- oxide or mixed oxides yielded is not nearly so convenient as the chloride for further working with. The method described above is shorter than the tedious and expensive treatment with hydrochloric acid, alcohol and ether. Judging from an attempt at carrying it out on a small scale, the amount of ether required in purifying the prod- uct from a kilo of zircons would be very large indeed. The modifications in the process have throughout the aim of cheapening and shortening Linnemann's process, and were successful in both directions, at least under the conditions under which I worked. A qualitative analysis of the different products obtained while thus decomposing the zircon was made under my direction b}" ]\Ir. John M. Morehead. It differed in sev- eral noteworthy particulars from that made by Linnemann. In the first place, the hydrochloric acid used in the prelimi- nary treatment of the zircon powder extracted a large part of tlie total tin present. Linnemann does not men- tion tin as occurring in this solution. No lithium was dis- covered in any of the solutions, nor any bismuth and zinc. The list of elements found by Mr. Morehead is therefore shorter than Linnemann, who reports sixteen. The list found was sodium, potassium, magnesium, calcium, alu- minium, iron, lead, tin, uranium, erbium, silicon and zir- conium. Undoubtedly a large proportion of these come from foreign matter mixed with the zircons and sifted into the cracks in the crystal, so as not to admit of separation. A number of the rare elements were looked for without finding them. No thorough spectroscopic examination was made, however. Mr. Morehead also made several quantitative determina- tions of the iron, silicon and zirconium, resulting as fol- lows: 24 JOURNAL OF THE Per cent. Zircoiiia 62.82; 62.59; 63.12; 62.80; Percent. Silica ^-- 34.10; 34.20; 33.52; 34.10; Percent. Ferric Oxide 3-29; or, taking- the ineaiLs, Z2O2 = 62.83 SiO^ = 33.98 Fez O3 = 3- 29 100.10 It is not right to calculate the iron as all in the oxidized condition, as much of it comes from the iron mortar and can be easily separated with a magnet. QUANTITATIVE ANALYSIS OF THE ZIRCON. BY J. M. MOREHEAD. In the following analysis it was found most convenient to fuse a portion of the zircon by the Einnemann process, as modified in the preceding article, and from that portion to make the determinations of zirconia and iron. For the silica a second portion was fused with sodium hydroxide, without the use of fluoride. Several other modes of fusion were first tried without satisfactory results. The method recommended by Classen was tried. One gram of the powdered zircon was fused with five grams each of sodium and potassium carbonate. Heating for one and a half hours with the blast lamp failed to effect thor- ough fusion. The cooled mass was leached out with water, acidified with hydrochloric acid and filtered away from the unattacked residue. This process was repeated four times, fusing in each case with the same weights of carbonates. It was then found that out of the original gram of zircon .36 gram remained undissolved. This method was abandoned. ELISHA MITCHELL SCIENTIFIC SOCIETY. 25 The method finally used was to fuse one gram of pow- dered zircon with ten grams of sodium hydroxide in a nickel crucible, the fusion continuing with an ordinary burner for one-half hour, and then with a blast lamp for twenty minutes. The contents were then poured upon a piece of sheet nickel and cooled. During fusion the mass was occasionally stirred with a nickel stirrer, which must be thoroughly dry. The caustic alkali left on the rod rapidly attracts water on cooling. The cooled mass on the sheet nickel is transferred to a beaker of water and the crucible is rinsed into the same. This was acidified with hydrochloric acid, and in one case only was a residue left. This hydrochloric acid solution was evaporated to dr}'ness and the silica determined in the usual way. Treatment with ammonium fluoride and weighing of the residue not volatilized is essential, as a small amount of zirconia was always found with the silica. For the iron the solution freed from silica was made up to a known volume, definite portions withdrawn, and the iron determined by titration with a potassium permanga- nate solution. In determining the zirconia, measured portions of the solutions were taken, rendered nearly alkaline with sodium carbonate (this is best done in the cold solution); sodium acetate was then added and the whole heated to boiling. After boiling ten minutes the main part of the zirconia will be found precipitated. This is filtered out. The filtrate is acidified with acetic acid, again raised to boiling and boiled for twenty-five minutes with sulphuretted hy- drogen bubbling through. The nickel, coming from the crucible, is thus precipitated and is filtered off. The filtrate is acidified with hydrochloric acid and boiled until no fur- ther smell of sulphur dioxide is noticed. Then precipi- tate with ammonium hydroxide, wash thoroughly, dry and ignite. From the weight of this last precipitate must be 26 JOURNAL OF THE subtracted tlie known weight of iron present. The sum of the weights of the first precipitate from the sodium ace- tate, and this last, as corrected, give the amount of zir- conia. The analyses were made from several fusions. The re- sults were as follows: Mean Silica. Zirconia. F( erric Oxide. Total. 34.10 62.82 34.20 33-52 34.10 62.59 63.12 62.80 3-285 3-29 33-98 62.83 3-29 100. 10 RECORDS OF MEETINGS. FIFTY-NINTH MEETING. Person Hall, January 16, 1891. 1. Reservoir Dams. William Cain. 2. Progress in Chemistry. F. P. Venable. SIXTIETH MEETING. Person Hael, F'ebruary 10, 1S91. 3. Vegetable Butter. H. L. Miller. 4. The Welsbach Lamp. J. M. INIorehead. 5. Multiple Telegraphy. J. W. Gore. 6. Koch's Treatment of Tuberculosis. R. H. Whitehead. SIXTY-FIRST MEETING. Person Hale, March 10, 1891. 7. A Geological Trip Into Hyde County. B. E. Shaw. 8. Aluminium. J. V. Lewis. 9. Modern Myths. K. P. Battle. SIXTY-SECOND MEETING. Person Hall, April 21, 1891. 10. The Electric Motor. J. W. Gore. 11. Applications of the Electric Motor. A. H. Patterson. 12. I'hotography in Natural Colors. F. P. Venable. 13. A Brief Sketch of the Pea-nut Plant. Gaston Battle. ELISHA MITCHELL SCIENTIFIC SOCIETY. ADDITIONS TO THE EXCHANGE LIST. ARGENTINE REPUBLIC. National Department of Agriculture. AUSTRIA. Budapest— R. Hungarian Academy of Sciences. Prag — Die Gesellschaft. "Lotos." ENGI.AND. Birmingham — The Philosophical vSociety. BurTON-on-Trent— Natural History Society. FRANCE. Toulouse — La Societe des Sciences Physiques. GERMANY. Rostock — Verein der Freunde der Naturgeschichte in Mecklenburg. ITALY. Bologna— R. Accad. delle Scienza. Brescia — Ateneo di Brescia. Genova — Societa Letture e Conversazioni Scientifiche. " Napoli — Societa di Naturalisti. Pavia — Bolletino Scientifico, R. Univ. di Pa via. LUXEMBOURG. Luxembourg —Verein Luxem burger Naturfreuude. JOURNAL ELiSHA ilTCHELL SCIENTIFIC SOCIETY, VOLUME VIII-PART SECOND. J LILY-DECEMBER, 1891 post-office: CHAPEL HILL, X. C. E. M. EZZELL, STEAM PRINTER AND BINDER RALEIGH, N. C. 1892. OFFICERS. 1890-1891. PRESIDENT: GeorCxE F. Atkinson, ..---- Auburn, Ala. VICE-PRESIDENT: F. B. Dancy, -------- Raleigh, N. C. RESIDENT VICE-PRESIDENT: WiivLiAM Cain. ------- Chapel Hill, N. C. SECRETARY AND TREASURER: F. P. Venable, ------- Chapel Hill, N. C. I.IBRARY AND PLACE OF MEETING: CHAPEL HILL, N. C. TABLE OF CONTEXTS. PAGE. Some Cercosporge From Alabama. George F. Atkinson 33 A North Carolina Catalan or Blomary Forge. H. L. Harris 67 Notes on the Fertility of Physa Heterostropha vSay. W. L. Poteat-- 70 Occurrence of Zirconium. F. P. Venable 74 Magnetic Iron Ores of Ashe County, N. C. H. B. C. Nitze 78 Notes on the Development of Some Sponges. H. V. Wilson 96 The Transition Curve. William Cain 105 The Occurrence of Platinum in North Carolina. F. P. Venable 123 Treasurer's Report 129 Council Meeting 130 Records of Meetings - 130 X V JL-i \^ ^^ 1 JOURNAL OF THE Elislia Mitchell Scientific Society, SOME CERCOSPOR.^ FROM ALABAMA. BY GEO. F. ATKINvSOX. The genu.s Cercospora Fres. conipri.ses a great number of specie.s of leaf fungi producing effects in their hosts fre- quently termed, in common parlance, "blight," or "leaf blight." The species are all probably more or less para- sitic, varying in different degrees of intensity, as obligate parasites, from the forms occurring in dying parts of leaves, languid leaves, upon plants physiologically diseased or of low vitality, induced sometimes by overcrowding and thus preventing necessary circulation of air among the parts or entrance of sunlight; at other times through imperfect assimilation caused by defective drainage, careless prepa- ration and care of the soil, so that the unfavorable physical condition of the soil prevents proper nutrition; by impov- erished soil which predisposes the plant to a hastened and unnatural maturity: to perhaps a few cases of a more viru- lent nature where quite healthy plants are injured from their attacks. The nature of this parasitism, in general as above described, would suggest to the thoughtful and progress- ive cultivator of the soil the necessary remedy in each case. 34 JOURNAL OF THE The genus belongs to one of the great groups of fungi known as the HypJioiiiycctes. Its members, along with many others, are sometimes termed "imperfect fungi," because they are not autoiwnious; i. e.^ they represent, as is supposed, not complete individuals in themselves, but only a transitory form, or stage, of a polymorphic fungus, the perfect condition of the individual being some species of SphcereUa or other ascomycetous fungus. Thus they stand only as the conidial stage of more or less complex life cycles. It is quite probable that in this respect they are analogous to other conidial forms, of the nature of which we have more positive knowledge, for example the Powdery mildews (^nw_/^//^^). Downy mildews (Peronosporeae), etc., so that the conidial stage can reproduce itself successively for several generations without the intervention of the per- fect, or ascigerous, stage. Therefore there is not a true, or strictly obligate, alternation of generations such as obtains in the Muscinc(S^ Filices^ etc. In but few of the species has the perfect stage been dis- covered. The writer has given an account of the perfect stage of Cercospora gossypina in the Bulletin of the Torrey Botanical Club, Vol. XVIII, p. 300 {SphcereUa gossypina Atkinson). Pammel (Bulletin No. 13, Iowa Agr. Exp. Sta., May, 1891) is of the opinion that Cet^cospora angidata^ on currants and gooseberries, is connected with SphcFrella Grossularice^ and that Septoria Ribis is also connected with the same perfect fungus. If this should be con- firmed, then we have here a Cercospora forming one of the stages of a trimorphic fungus possessing conidial, sper- mogonial, and ascigerous stages. Cercospora arice Fkl. is considered the conidial stage of SpJicercIla cincrascens Fkl., and C. radiata Fkl. of S. Vitlncrue Fkl. (Sacc. Syl. Fung., Vol. I, pp. 493, 503). Probably one reason why the perfect stage of but few has been found lies in the fact that in many cases this stage is only developed after ELISHA MITCHELL SCIENTIFIC SOCIETY. 35 the leaves have fallen to the ground and become more or less disoro^anized or frag^mentarv and the evidences of the Cercospora have disappeared. While the species are not autonomous, and we thus possess only fragmentary evidence, as it were, of the characters of the complete individual, the peculiarities of form, group- ing, markings, color, dimensions and effect upon their hosts are such as to offer comparatively satisfactory data for the systematist to characterize and arrange them. It is fortunate that this is so, because of their parasitic habit it is quite important that we can arrive even approximately at the limitations of the species on the different hosts. It may seem surprising at first, to one unfamiliar with the growth of these forms and the reactionary influence of their hosts, that so many species are at present known, and that the probability is the number will even yet be increased. The specific physiological differences of the various hosts as w^ell as the structural variations of their leaves, the differences in texture, thickness, and the varying powder which the different species possess through their vital processes to resist the growth of the parasite, all exert a powerful influence upon its form and characteristics. Here we have the coincidence of several quite effective agencies, all which tend to produce variations in the parasite. It is quite possible to conceive how during a long period of time a few forms wndely distributed over a great number of hosts have become more and more unlike each other and finally more firmly fixed in the possession of peculiar characteris- tics. This is even more probable when we consider that quite likely during much of this time the hosts themselves have been differentiatino- more and more so that now w^ell- marked specific differences appear in hosts that long ago were alike and harbored the parasite which has kept pace with them in descent. The action of the Cercospora parasite on the host results 36 JOURNAL OF THE in most cases in the death of the affected part of the leaf, producing a marked appearance in contrast with the unaf- fected portions, usually termed a "spot." One or more of these spots occur on a leaf, their form varying from cir- cular to angular, or irregular to very indefinite. In many cases the resulting color changes, due to a partial disorgan- ization of the chlorophyl, to a development of erythrophyl or other coloring substances, gives variety to the circumfer- ence of the diseased areas or to surfaces of the leaf opposite that on which the fungus is located. In a number of cases there are no well defined spots, but the fungus is diffused over small or large areas of leaf surface, giving to those areas the characteristic color peculiar to the species, being roseate in C. effusai^. &C.)K11., ferrugineous in C. lateritia Ell. and Hal., etc. In the case of C. catcnospora Atkin- son the fungus is diffused over large areas of leaf surface and quite injurious, producing a decided "leaf curl." The vegetive portion of the fungus consists for the most part ot colorless mycelium made up of filamentous, septate bodies irregularly interlaced among themselves and the cells on the interior of the diseased portions of the host. These contain protoplasm, they grow by longitudinal extension and division of their end cells and by branching. Further formation of cells probably takes place by the division of older cells. Their nourishment is obtained by absorbing materials from the cells of their host. Following the vegetive condition is the conidial stage. Provision is made for the production of conidia and their easy dissemination by means of specialized fungus threads, or fruiting hyphae, properly conidiophores^ usually termed briefly by systematists Jiyphce, These arise in more or less divergent or compact fascicles, which stand perpendicularly to the leaf surface and project beyond it. In a few cases some of the vegetive threads ramify on the surface of the leaf and produce conidiophores in a diffuse manner. The ELISHA MITCHELL SCIENTIFIC SOCIETY. 37 fascicles, or tufts, of conidiophores arise from a more or less compact fungus body termed a slrorna. This is formed at various points on the vegetive mycelium within the leaf tissue by a lateral growth of certain of the cells together with a conjunction of cells of adjacent threads. In C. Boehmci'icE Pk. this consists of a prominent globose body; from this there are different degrees of compactness and rotundity down to a few closely associated cells which bear only a few conidiophores. The conidiophores themselves vary greatly in length, size, general direction, markings and color. They may be continuous, septate, geniculate, flexuous, toothed, or cylin- drical. The geniculations, the denticulation and much of the flexuous condition is brought about by the manner of growth of the conidiophore while it is bearing conidia. In nearly all the species the conidia are, as termed in some cases, lateral and acrogenous in their production on the conidiophores; /. ' indistinct, or distributed over large areas, fuliginous with olive tinge, subflexuous, denticulate or torulose, longer ones faintly septate and multiguttulate, 50—60 X 3, 5 — 4. Conidia straight or curved, subcylindrical, abruptly tapering at each end or terete, 3 — 10 — septate, multiguttulate, dilutely olive yel- low, 50—70 X 3—4- This is very different from C. 6"<9/<7;// Thiini as shown in Myc. Univ., 270, and also from C. diffusa Bll., specimens of which I have seen, both of those being much stouter and the conidia quite different in texture, easily collapsing, while those of C. rigospora are quite firm. Ellis' diffusa seems to me on comparison 5 66 JOURNAL OF THE identical with Thiimen's Solani. Specimens collected by Langlois, 1322, in Louisiana and marked C. Solani^ agree quite well with Ellis' diffusa and are quite different from my specimens. On leaves of Solanum nigrumi^\ 1225, Auburn, July 5, 1890, i\tkinson. 75. Cercospora catenospora n. sp. Diffused in irregular patches or over large surface of under side of leaves, giving dirty green color. Hyphae fasciculate from stomata of leaf, divergent, 20—30 up to 75 X 5 — 6, septate, nearly cylindrical, often toothed, bearing conidia laterally as well at the apex, olive yellowish, rarely darker and inclined to faint reddish tinge. Conidia lateral and acrogenous, concatenate or single, cylindrical when concatenate and then abruptly tapering each way to small truncate end, terete when single, more rarely slightly clavate, dilutely olive yellowish, often guttulate, 1 — 6 septate, 20 — 100 X 4 — 5. On leaves of Samhiiats canadensis^ 2045, Auburn, August 27, 1 89 1, Atkinson. The leaves are severely injured by the fungus, which causes them to curl and fall, so that in many cases the shrubs are entirely denuded of their leaves. 76. Cercospora Erechtitis n. sp. On dead parts of the leaf Hyphse epiphyllous, fasciculate, reddish brown, geniculate or scarred, in which case hyphro are cylindrical, frequently guttulate, 50 240 X 4. Conidia hyaline, septate and guttulate, 70 — 230 X 3 — 4- On leaves of Erechtites hieracifolia^ 2303, Auburn, November 5, 1891, Duggar. ']']. Cercospora gossypina Cooke. Spots light brown or dirty white, irregular, often bordered by a dark or purple color, frequently without spots appearing on large dead or dying areas of the leaf Hypha? amphigenous, fasciculate, brown, geniculate or toothed, 70-450 X 5—7. ELISHA MITCHELL SCIENTIFIC SOCIETY. 67 Conidia hyaline, few to multiseptate, terete, 70 400 X 3—4- On leaves, bracts and cotyledons of Gossypiiim herba- ceum. 78. Cercospora Liriodendri Ell. & Hark. I have not collected good specimens of this, but my notes read as follows: "Differs from C. Liriodendri (as described) in having conidia 70 long and several times septate." On leaves of Liriodendron Tiilipifera^ 195I1 Auburn, July II, 1 89 1, Newman. 79. Cercospora Cephalaxthi E. & K. I have sev- eral times collected specimens of this with characteristic spots, but the hypha? and conidia were so poorly developed it was impossible to take any notes worthy of record. On leaves of CepJialanthits occidentalis. A NORTH CAROLINA CATALAN OR BLOMARY FORGE. BY HUNTER L. HARRIS. This forge is situated on Helton Creek, near its union wnth North Fork of New River, in Ashe county. It is remarkable as an example of a process for obtaining iron which is now^ becoming extinct. Briefly, it is the process by which a mass of malleable iron is obtained by heating together in an open hearth a mixture of a pure ore of iron with charcoal, until the carbon monoxide from the char- coal unites w^ith the oxygen of the ore and reduces the ore. There w^ere formerly a number of such forges in that region, but all others have long since disappeared. This forge was built perhaps fifty years ago by John Ballon; w^as rebuilt by W. J. Paisley in 187 1, and has 68 JOURNAL OF THE since been in operation by him, snpplying sufficient bar iron for the local demand for wagon tires, horse-shoes, etc. The plant comprises a two-fire forge, a hammer and an ore crusher, the two latter being operated by separate overshot water-wheels, while the blast for the forge fire is supplied by a third water power arrangement. The forge / y. / "V rio,.\ fro-nt view of forge f\qZ.-)iammer. XIL r~i H f iC\ li Position o^ KommCT. f»o3- Ore CrusViet is an open hearth, rudely built of stone fragments. The tuyere communicating with the blast pipe enters this fire space from one side, and the hearth piece consists of a superannuated hammer head built in with the rock frag- ments. The blower, said to be similar to the Catalan blower, is a large box, placed 8 or lo feet below the water supply, and communicating with it by means of a wooden conduit which enters the blower from above. The blast pipe, also of wood, leads from the upper part of the blower to the tuyere, and near the bottom of the blower at the end is an exit slit for water. When the gate ELISHA MITCHELL SCIENTIFIC SOCIETY. 69 above is opened and the water allowed to enter the blower, air is drawn in with it from openings arranged in the con- duit above. Once in the blower, the water escapes under pressure through the slit, w^hile the air collecting above is forced through the blast pipe and tuyere into the forge hearth. The hammer is a mass of iron, weighing perhaps 600 pounds, and mounted on the end of a beam, the other end of which is pivoted in an upright post. This post is deeply buried and braced with a heavy beam. The anvil is a similar mass of iron fastened in a wooden block, which is buried in the ground. The hammer is raised by wooden cams fixed in the periphery of an iron ring mounted as a drum upon an axle. This axle is also the axle of a small overshot wheel, so that when the wheel is set in motion the drum revolves, and the cams engaging the hammer raise it to the height of ten or twelve inches and allow it to fall upon the anvil. The force of the blow is augmented by a spring beam acting downward upon the hammer as it is released. A similar arrangement of cams set in a drum and operated by a separate water-wheel works the ore crusher. This consists of an iron shod beam of about a hundred pounds weight, standing on end in a strong wooden trough, and having a vertical movement, in guys, of about one foot. The trough has an iron grating in the bottom through which the crushed ore (which has been first roasted) falls, and whence it is raked out. The accompanying figures give dimensions and show mode of operation. Soft ore is washed in an inclined trough by stirring in gentlv flowing; water. About 100 bushels of charcoal is required to run 250 pounds of ore. Each fire will make three loops a day, each loop yielding from 75 to 80 pounds merchantable bar iron. The iron is wagoned over the surrounding country 70 JOURNAL OF THE over a radius of lo or 15 miles, and is much esteemed for its good working qualities. The whole thing is rude in construction and arrangement and is entirely exposed to the weather. The water supply is abundant and no attempt is made to economize in that particular. Suitable ore is found as friable magnetite in the near neighborhood, but the forge is worked only as the demand may arise. NOTES ON THE FERTILITY OF PHYSA HET- EROSTROPHA SAY. BY W. L. POTEAT. In the essay on the "Duration of Life" Weismann remarks that while the length of life of many molluscan species is well known, "any exact knowledge is still want- ing concerning such a necessary point as the degree of their fertility."* Binney remarks of the family Limnseidae, to which our snail belongs: "From the fact of my finding young individuals only in the spring and numerous dead full-grown shells during the late autumn and winter, I pre- sume they arrive at maturity in one season. "f Of Physa heterostropha in particular he says that it deposits eggs the beginning of May. In view of these statements I have thought it perhaps worth while to record in this place some observations made by me in the year 1886. On the 8th of March I collected from a marsh near Wake Forest two specimens of Physa heterostropha Say.t ■^•Heredity, p. 14. tl^and and Fresh-water Shells of N. Amer., p. 23, Vol. VII, Smiths. Misc. Coll. jKindly determined for me later by Dr. Stearnes, of the National Museum at Wash- ington. ELISHA MITCHELL SCIENTIFIC SOCIETY. 7 1 On the 1 6th three thick nidamenta of some forty eggs each were seen loosely attached to the walls of the glass aquarium. A few days later four others had been depos- ited. Up to June 15th the aquarium was examined at intervals nearly every day. iVfter that date it was not seen again until July 12th, when the water was changed. The next day both the snails were dead, probably as the result of the change of water. In the period of four months — say ]\Iarch 12th to July I2i:h — the pair produced 43 nidamenta, w^hich contained, on an estimate certainly not too high, an average of 30 eggs each. So that the number of their offspring for the period mentioned amounted to 1,290. There w^as ho well- marked decline of the reproductive function toward the close of the period, w^hich is perhaps another indication that they came to their death by violence. From March 31st to June 6th inclusive, the pair were observed in coitu as many as 15 times, at hours ranging from 8:30 A. M. to 6:15 P. M., the coitus lasting sometimes but 20 minutes, sometimes more than an hour. The male function was performed alternately by the two snails. The eggs appear to have been laid only during the night.* It was important to determine, if possible, the age at which sexual maturity is attained and reproduction begins. Accordingly, on the 12th of July I took out of the aqua- rium two of the largest of the young snails and put them *It may be mentioned, however, in view of the similarity of the habits of Phj-sa and of Limnceus, that I once observed a specimen of the latter depositing a nidamentum on the glass wall of the aquarium at 2:20 p. m. The work was about half done when it caught my e^-e, and I judge that tv/o minutes were consumed in completing it. The eggs and the protecting jelh- emerged at the same time from under the right side of the shell aperture and at right angles to its margin, the snail moving slowly sidewaj-s in the opposite direction. When the nidamentum was completed, the snail turned slowly round on the glass, made tv.-o or three rather aimless grazing movements of the mouth, and then crawled slowly over the nidamentum in the direction of its longer axis, completely covering it v/ith the foot. That position was maintained but a mo- ment or tv.-o; nevertheless the snail remained near by. When I. lightly touched the nidamentum and the snail at the same time, the latter shrank a little, but immediately proceeded to cover the threatened nest. During the fifteen minutes that I watched further, the snail remained close to the nest — with the view of protecting it ? I thought I detected that the jelly of this one freshly made was somewhat softer than that of an older one near by. 72 JOURNAL OF THE into another aqnarium. They were presnmably members of the first brood, the eggs of which were deposited near ]\Iarch 13th. Their age, reckoning from the time they were hatched, was abont 3)-^ months; size — length of shell, 5 mm. ; length of foot, 6 mm. In tw^o days one of the snails was dead. On the 25th of July another snail of about the same size was introduced from the first aquarium. The next entry in my notes is under date of September nth, when six nidamenta were observed attached to the fibrous roots of a water plant. They were, however, small, containing only from one to four eggs each, showing that the reproductive fuction at that age was feeble. Some of the eggs were already hatched, and the tiny grandchil- dren of my first Physas were going about the aquarium in search of food. Allowing, say, fifteen days for the intra- capsular development of these snails of the third genera- tion, I estimate that the isolated pair of the second genera- tion attained sexual maturity at five months of age. The same day — September nth — in the first aquarium I noticed a confirmation of my observation in the second, namely, the pairing of two of the oldest brood. The maintenance of a species depends on the equilibrium between the forces tending to its destruction and those tending to its preservation. We may embrace the former under the general phrase, adverse external conditions. There are two different ways in which the destructive tendency of these adverse external conditions is opposed. The first is by adaptations of structure and habit. The second is by the production of new individuals to take the place of those that have been overcome. Now, as differ- ent animals exhibit varying degrees of ability to adjust themselves to their environment, so also their reproductive power may be small or great. In estimating this repro- ductive power four factors, as Herbert Spencer points out,* i^Biology, Vol. II, p. 395. ELISHA MITCHEI.L SCIENTIFIC SOCIETY. 73 are to be taken account of, namely, (i) the age at which reproduction commences, (2) the frequency with which broods are produced, (3) the number contained in each brood, and (4) the length of time during which the bring- ing forth of broods continues. Accordingly, for the special case of Physa heterostropha we have the followino- results: 1. Age at which reproduction begins, 5 months. 2. Frequency of broods, i in about 2yV days. 3. Number in each brood, 30 average. 4. Reproductive period, 4 months, March to July. Some addition ought to be made to this actually observed period, inasmuch as the snails had certainly already entered upon it at -the time of their capture, and, further, instead of closing normally, it seems to have been violently inter- rupted. Just how much the period of reproduction is to be extended I have no means of determining, unless the fact that the young snails of the first brood were observed reproducing themselves in September warrants an exten- sion of at least two months, making it six months instead of four. "^ Assuming, then, that the reproductive season extends from March to September, and assuming, further, some- what arbitrarily, that the snail lives but two years, we have, on the basis of facts above mentioned, the followino^ esti- mate of the total number of the offspring of a single pair: At close of first season 1,900 950 pairs at close of second season 1,805,000 Original pair at close of second season 1,900 Total number offspring in two 3'ears 1,808,800 *Packard (Zooloo^-, p. 266) states that the "egg-s of P. heterostropha are laid in the early spring, and three or four weeks later from fifty to sixty embryos with well-formed shells may be found in the capsule." The apparent inference that only a single brood is produced must of course be dismissed. W.AKE Forest College. X. C. 74 JOURNAL OF THE OCCURRENCE OF ZIRCONIUM. BY F. P. VENABLE. Zirconium occurs principally in the form of silicate in the hard, heavy mineral known as zircon. That this mineral was known in very early times is highly probable from the number of localities where it may be found and its striking physical properties. Yet it is dif- ficult to assert positively that Theophrastus referred to it under the name lyncurium, or Pliny under the various terms chrysolithos, melichrysos and crateritis. The evidence for the first is based mainly on the fact that it is spoken of as a material from which to cut cameos. Theophrastus says the lyncurium was used for engraved signets, was electric on friction and was often amber-colored. Whether the ancients distinguished the zircon from other minerals and knew it under any of the above names or not it is certain that intagli of zircon are not at all uncommon among ancient gems. Agricola and Interpe speak of the jacinth. The first mention of the Ceylonese name Jargon seems to be by Cronstedt in 1758. DeLisle in 1783 writes of the "Dia- mant Brut ou Jargon de Ceylon." This name Jargon was long used for the colorless and yellowish and smoky zircons of Ceylon in allusion to the fact that while resembling the diamond in lustre they were comparatively worthless. From this comes the name zircon. The colorless or only slightly smoky kinds seem to have often been sold for inferior diamonds. Brownish, orange and reddish kinds were called distinct- ively hyacinths (topazes and garnets were sometimes called the same\ ELISHA MITCHELL SCIENTIFIC SOCIETY. 75 These zircons occur in crystalline rocks, especially in granular limestone, in chloritic and other schists, in gneiss, syenite, and also in granite and sometimes in iron ore beds. Zircon syenite is a coarse syenitic rock containing crystals of zircon along with oligoclase, aegirine, claeolite and epidote. Crystals of zircon are common in most auriferous sands and sometimes are found in volcanic rocks. In Ceylon they are mainly found in the alluvial sands. In the Ural Mountains mainly in the gold regions. In Norway sometimes in syenite, sometimes in the iron mines. Zircons are also found in Transylvania, in Bohemia, in Saxony and in the Tyrol. The occurrence at Expailly, near Le Puy, in France is well known and of especial interest. Fourcroy says ''the hyacinth from Expailly was formerly placed in collections of the Materia Medica to be used in some pharmaceutic compositions." In Auvergne it is found in volcanic tufa. On Vesuvius it occurs with ryacolite in white and blue octahedrons. In Scotland it is found at Seal pay and in Argyleshire. In Ireland with the auriferous sands. In Greenland, in New Granada, and in the gold regions of Australia, it also occurs. Coming now to North America we have a long list of localities. In Maine, at Litchfield, Paris, Mt. Mica, Green- wood, Hebron. In Vermont, at Middlebury. In Connecti- cut, at Norwich and Haddam. In New York, in Essex, Orange, Lewis, St. Lawrence, Warren and other counties. In New Jersey, at Franklin and Trenton. In Pennsylvania, near Reading, in magnetic iron ore; at Easton, in talcose slate. In California, in auriferous gravel in various locali- ties, and in Canada, at several places. Ver}' large crystals weighing as much as fifteen pounds have been found in Renfrew and adjoining counties, but they are so isolated that it would be impossible to obtain a large supph* there. 76 JOURNAL OF THE Opaque green zircons have been found an inch long by one- half inch across in St. lyawrence county, N. Y. , and five black ones of equal size near Franklin, N. J. One of the New York specimens was over four inches in length and is now in the United States National Museum. An interest- ing form of zircon is found near the Pike's Peak road, almost due west from the Cheyenne Mountains, following a vein-like mass of white quartz in granite. The crystals are generally deep reddish brown, pink, or pale honey-yel- low; and a few crystals of deep emerald green are recorded. The largest observed were about one-third inch, but gen- erally they are not more than one-tenth to one-sixth inch in length and would only cut into minute gems. They are, however, perhaps the most beautiful crystals of zircon known, owing to transparency, brilliancy and perfection. The finest gem stones come from Ceylon, Mudger, and New South Wales (Kunz). The chief States for yielding zircons are South and North Carolina. At Anderson, S. C. , the zircon is found loose in the soil and in large quantities. The containing rock is granulite, or gneiss devoid of mica, and according to Ivieber this zircon-granulite corresponds to the zircon-syen- ite of Norway. In North Carolina the zircon is abundant in the gold sands of Burke, McDowell, Polk, Rutherford, Caldwell, Mecklenburg, Nash, Warren and other counties in very minute yellowish brown and brownish white, sometimes amethystine, pink and blue crystals. It is mainly found, however, in large greyish brown crystals on the south side of the Blue Ridge near Green River, in Henderson county. Here, in a few weeks in 1869, General Clingman collected one thousand pounds of crystals. The presence of zircons there was known many years prior to this. The occurrence is mainly on what was known as the Freeman and Jones farms, about two miles distant from one another. The ELISHA MITCHELL SCIENTIFIC SOCIETY. // deposit runs north-east and south-west, and for many miles zircons can be found, but only at the Freeman and Jones mines in sufficient quantities to work. These are situated on a high ridge. The zircons seem as plentiful on the sur- face as lower down. The mines have been worked to about the depth of fifteen feet. Before i860 the zircons were collected from the surface and sold to collectors for about ten dollars a quart. From sixty-five to seventy thousand pounds have since been raised and sold at prices varying from fifteen cents to one dollar per pound. The principal consumers of zircons assure me that there is at present no demand for them, they themselves having a number of tons in stock, all they will need for some years. They are worth about $250 a ton in large lots. At the Green River mines the dirt is placed in rockers and washed, the zircons and grains of magnetic ore sorting- out easily. The latter is separated by means of large mag- nets. The zircons are from the smallest sand to a quarter of a pound in weight. They are somewhat smaller than the zircons from Anderson, S. C. , and easily distinguished from the latter by their form. When zirconium began to be used a few years ago in incandescent lamps, it was thought to be a comparatively rare mineral. The new application and consequent demand caused a search to be instituted which has shown that in realit}' it is widely distributed and in places very abundant. It is to be found in many cases along with titanium, which was to be expected from the chemical relationship existing between the two. Sandberger has observed transparent crystals of zircon in granite of many places; also in gneiss and mica, in diorite and porphyry. Microscopic crystals are widely distributed in the sedimentary rocks, the mate- rial of which has been mainly derived from the older rocks; for example, in the variegated sandstones of the Black For- est, in carboniferous limestones and in the sands of the valley of the Maine. 78 JOURNAL OF THE Thiirach has shown that microscopic zircon is rarely absent from the archaean and sedimentary rocks. It also occnrs in very many ernptive rocks, and it is widely dis- tribnted in basalts and dolerites. Corse reports many localities where it is fonnd in Italy, among them the anriferons sand of Ticino, volcanic sand, and the shore sands of the Tyrrhenian Sea. The world's main supply, however, if the demand increases, must come from the enormous quantities in the Ural Mountains and in Norway, and from the great and easily workable deposits of Green River, N. C. , and Ander- son, S. C. Hitherto it can scarceh' be said to have been mined in more than one locality. Green River, N. C. As to other minerals besides the zircon containing zir- conium, we have a few, but they are rare and apparently exist in small quantities. First there are the altered zircons: Auerbachite, Mala- cone, Cyrtolite, Tachyaphattite, Oerstedite and Bragite. It is also found in Eudialite, Polymignite, Aeschinite and Fergusonite. THE MAGNETIC IRON-ORES OF ASHE COUNTY, N. C* BY H. B. C. NITZE. At a time when the mineral resources of the Southern States are attracting such wide-spread interest and atten- tion, I have thought it appropriate to give a short general description of the iron-ore deposits of a territory concern- =Pul)li,shed in Transactions of the American Institute of Mining- Kngineers. 1892. ELISHA MITCHELL SCIENTIFIC SOCIETY. 79 ins;- which little is as yet known and nothing published, so far as I am aware. The data used here are due to the preliminary examina- tions of the North Carolina Geological Survey, on which work I was engaged during the past summer, and my acknowledgments are due to Professor J. A. Holmes, State Geologist, and Messrs. Harris, Ashe and Lewis, of the sur- vey, for their co-operation in the work; also to Messrs. A. S. McCreath and C. B. White for analyses which they kindly furnished. Other analyses were made by Mr. Charles Baskerville, assistant chemist to the survey, and this may be understood where the name of the chemist is not mentioned. All samples for analysis were dried at 212° F. The accompanying map has been prepared from the revised sheets of the United States Geological Survey by Mr. H. L. Harris, and will be referred to throughout this paper. Ashe county lies in the extreme north-western part of North Carolina, bordering on Tennessee and Virginia; it is drained principally by the north and south forks of New river and their tributaries, and is therefore on the eastern edge of the great Mississippi drainage-basin. The country is exceedingly rugged and mountainous, having an average elevation of about 2,900 feet above sea-level. Jefferson, the county-seat, near the center of the county, is forty-five miles nearly due south from the Norfolk & Western Railroad at Marion, Va., and thirty miles north- west from the Richmond & Danville Railroad at Wilkes- boro, N. C. Geologically the ore-deposits described in this paper are situated in the area of the crvstalline rocks, consistinof chiefly of gneiss, hornblende-schist, and micaceous schists. These iron-ore deposits, owing to their present inaccessi- bility, are practically entirely undeveloped. During the 8o JOURNAL OF THE summer of 1890 considerable private prospecting was car- ried on throughout the county, and much of our knowledge concerning the ore-beds is due to this. Many of the open- ings, however, have caved in to such an extent that but little can be seen at present. More than fifty years ago there were a number of Catalan forges throughout the county, which smelted these ores into a very superior tough iron. One of these now known as Paisley's forge, at the mouth of Helton creek, is still in operation, and made in 1890 from twenty to thirty tons of bar-iron, used locally for wagon-tires, horse-shoes, etc. At present there are no mining operations whatever going on, excepting in a ver}- small superficial way to supply the Helton forge. The territory to be described in this paper, as including the principal ore-deposits of Ashe county, embraces about 150 square miles. The ores are principally magnetites, chemically suitable for the manufacture of Bessemer pig- iron. Some brown hematites and red specular ores are also found; but, although of excellent quality, their quan- tity will hardly place them in the category of economic raw materials. The structure of the magnetic beds is decidedly lenticu- lar, and as such they are distributed over a rather undefina- ble area, though there is some regularity in the direction of their outcrops, which have a general trend north-east and south-west. In the following I shall divide them into three main belts, called according to the local nomenclature: The Bal- lon or River belt, the Red Hill or Poison Branch belt, and the Titaniferous belt. Starting along the north-eastern extremities of these belts I shall describe the openings along the outcrops in regular order towards the south-west. By reference to the accompanying map their locations and relation to each other can be more easily comprehended than from mere description. MAP OF THE PRINCIPAL ORE DEPOSITS of Ashe County, X. C, Scale of Miles: 3 i Names of owners or occupanUi in italics. ■•• Ore-outcrops. S J*rospectiug pits etc. ELISHA MITCHELL SCIENTIFIC SOCIETY. 8 1 I. THE BALLOU OR RIVER BELT. This, the most easterly of the three ore-belts, crops out along the north fork of New river, and has been opened at several points on the farm of William H. Brown. Opening No. i on the west bank of the river at the falls, about one mile north of Grumpier P. O. , is a large cut, exposing probably 30 feet of ore-material, composed of hornblende, gneiss, and epidote, which is split up at three points by lenticular masses of magnetite. From the con- dition of the exposure it was not possible to determine the true thickness of the ore. An analysis of an average sample from here shows: Per Cent. Silica 27.59 Metallic iron -- 53.99 Sulphur 0.055 Phosphorus -- 0.063 The ore crosses the river north-easterly from here to the property of John C. Plummer, but no openings have been made. Opening No. 2 is located about half a mile west of the river, near Mr. Brown's house. This cut was also partially caved in and filled with water, so that a clear inspection was not practicable. The exposed material shows : 1. About 4 feet of soft decomposed schistose gangue, carrying finely disseminated grains of magnetite ; above this, 2. About 5 feet of decomposed mica-schist and quartz ; and above these, towards the face of the cut, 3. About 12 feet of mixed material containing strips of harder, richer ore, 2 feet and more in thickness. Of the soft ore it has been found by washing that fully 50 per cent, is magnetite, an analysis of which by Mr. A. S. McCreath shows: 7 82 JOURNAL OF THE Per Cent. Silica 2.40 Metallic iron 67.35 Phosphorus 0.028 The unwashed material shows 43.50 per cent, of metal- lic iron. An analysis by Mr. Baskerville of an average sample across the entire bed shows: Per Cent. Silica 5-73 Metallic iron 60.48 Sulphur 0.003 Phosphorus trace. South-westerly the ore crosses the river about one mile from here, and makes its appearance in a very prominent outcrop over the property of N. B. Ballon, known as the "Home Place," on the east side of the river, between the mouths of Helton and Old Field creeks. It recrosses the river, which makes a large bend at this point, about half a mile from here, near Uriah Ballon' s house, and near this second point of crossing some work was done a number of years ago for one of the old forges, showing the approxi- mate thickness of the bed to be 12 feet. The dip is about 37° S. E., and the strike N. 45° E. The ore is a hard, compact, fine-grained magnetite dis- seminated in a gangue of hornblende, epidote, and quartz. Higher up on the hill some small, superficial openings expose several smaller ledges of richer ore, comparatively free from gangue. But it is believed that the following analyses will represent the quality of the ore as it must be mined: I. II. III. Silica 20.79 17-88 Metallic iron 45.50 49.06 50.68 Sulphur 0.002 trace. Phosphorus 0.024 0.018 trace. Analysis I. is by McCreath. II. is from U. S. loth Census Report. III. is by Baskerville. "ELISHA MITCHELL SCIENTIFIC SOCIETY. 83 Towards the south-west the ore crosses and recrosses the -north fork and becomes thinner-bedded. It crops out about one mile from Ballou's on the farm of Dr. Gentry in a high bluff along the east bank of the river, showing a maximum thickness of 2 feet, and apparently pinching out to considerably less than that. An analysis of an average sample taken here shows: Per Cent. Silica --. 16.68 Metallic iron 47-22 Sulphur - -- 0.063 Phosphorus _. trace. There is a second line of outcrop, about half a mile south- east of the above main outcrop, which has been traced from Brown's on the north fork, about half a mile above the river opening at the falls, in a south-westerly direction, crossing the river at Shubal Lunceford's, almost one mile due north from Grumpier P. O., and continuing through Ballou's and Gentry's lands. This has been opened on Lunceford's place, about a quarter of a mile north of the river, exposing a bed of soft, granular ore, disseminated in mica-schist, which measures 13 feet in thickness, and dips 52° S. E. An analvsis of a sample taken across the bed shows: Per Cent. Silica 38.73 Metallic iron 41-36 II. THE RED HILL OR POISON BRANCH BELT. This belt extends from the north-eastern corner of the county in a general south-westerly direction, its several lines of outcrop crossing over Grassy creek, Helton knob. Red Hill, Helton creek, McClure's knob, Old Field, Silas, Piney and Horse creeks, a distance of some ten miles, as far as traced. It lies from two to three miles north-west of the river belt, and approximately parallel to it. 84 JOURNAL OF THE It has been opened at numerous points along its outcrop, beginning at its north-eastern end on the land of Lee Pugh on Ben's branch, about Y^ mile north of New river, where a bed at least several feet in width is exposed, but is not fully uncovered. The ore is a friable magnetite of schis- tose structure. The dip is from 35° to 40° S. E. An analysis of an average sample shows: Per Cent. Silica 22.74 Metallic iron 45-44 Sulphur 0.049 Phosphorus 0.022 About 400 yards S. 40° W. from here the bed has been exposed on the land of John L. Pugh, on the suuimit of a high ridge, by a cut 105 feet long, the south-eastern end of which traverses a bed of soft mixed ore and gangue, reported to be 40 feet thick, while the north-western end cuts through about 30 feet of similar material, though harder. Between the two is a decomposed feldspathic mass, probably a local horse. The cut was partially caved in, so that exact meas- urements could not be taken. The ore is a coarse-granu- lar, friable, manganiferous magnetite, and the gangue is hornblende, epidote, quartz, and feldspar. Several analy- ses show the ore to contain: I. II. Per Cent. Per Cent. Silica 21. II Metallic iron -- 43.17 44-13 Metallic manganese -- 4.62 1.42 Sulphur 0.048 0.126 Phosphorus - 0.006 0.008 I. by Baskerville. II. by C. B. White. The bed is again opened on the properties of W. W. Smith and Noah Dancy, lying successively to the south-west of Pugh's, but the exposures are incomplete and offer no ELISHA MITCHELL SCIENTIFIC SOCIETY. 85 definite data. Several analyses by Mr. C. B. White show the quality of these ores to be: Iron. Phosphorus. Per Cent. Per Cent. "Smith" ore -.. 55-76 0.040 " Daiicy" ore (surface sample) 63.49 0.176 The next notable exposure occurs on the Black prop- erty, on the north-eastern slope of Helton knob, on the waters of Grassy creek, where several old "forge" banks are located, whence the Paisley forge still draws its limited supply. The old openings are now completely fallen in, and nothing can be seen excepting the fact that there seem to be two beds about 30 feet apart, the upper one of which is reported to be 2 feet thick. The ore is soft and decom- posed, in a friable, schistose gangue; and it is on account of this softness that it was particularly prized by the forges. Higher up on the same hill similar float-ore is repeat- edly met with, scattered over the surface, and it seems to cover a large area. About % mile slightly south of west from these old " forge "-openings is a very prominent outcrop of horn- blendic gneiss, at least 40 feet high, containing lenticular masses of hard, compact magnetite, showing a thickness of 3 feet at one point; and about 200 yards S. 60° W. from here, on another ridge, some heavy and exceptionally pure masses of float-ore were observed, indicating the exist- ence of another parallel series of ore-beds. Unfortunately none of the analyses of these ores were completed in time for this paper. The "soft" ore, as used in the Paisley forge, is first washed in an inclined wooden trough by a gently-flowing stream of water; and an analysis by myself of this washed product shows: 86 JOURNAL OF THE Per Cent. Silica II-075 Metallic iron.. 58.930 Sulphur - - 0.068 Phosphorus - 0.033 In explanation of the formation of these deposits of "soft" ore, snch as occur on the Black, Red Hill, and other properties to be described hereafter, it may be said here that all indications go to show that they are undoubt- edly due to the breaking down of the original outcrops of magnetite and magnetic rocks, subsequent to the erosion of the more readily decomposable surrounding strata, and their consequent spreading over large superficial areas of comparatively limited depths. At the same time their replacement may have been so regulated by nature that they still exist in workable deposits, and the original beds might be expected either directly beneath or in close prox- imity to them; but this can only be definitely settled by further exploitation. As shown in several places much of this "soft" ore can be concentrated to a comparatively high-grade material by simple washing alone, and there is no reason why, by means of magnetic concentration, a highly desirable prod- uct should not be obtained. Even the hard ores, high in silica, are susceptible of concentration, after previous crushing by this process ; and at the well-known Cran- berry mines in Mitchell county experiments are being very successfully carried on in this direction. By means of the dipping-needle the ore was traced across the summit of Helton knob, which rises to an alti- tude of 3,410 feet above sea-level. On the south-western slope of Helton knob several small openings on the prop- erty of Joseph Jones expose the ore-bed, but not sufficiently to furnish much definite information. On the western foot-hills of Helton knob, on Robert's branch, a tributary of Helton creek, an opening on David Blevins' land ELISHA MITCHELL SCIENTIFIC SOCIETY. 87 exposes an ore-bed, showing three streaks of ore, respectively 7^, 4^, and 2 feet in thickness, separated by a gneissoid material, probably a local horse. The dip is 40° S. E. The ore is a compact magnetite in a gangue of hornblende and epidote. An analysis of an average sample shows: Per Cent. Silica.- - .-- - -- 29.901 Metallic iron 36.350 vSulphur --. -- 0.038 Phosphorus 0.022 Between here and Helton creek, a distance of about one- quarter of a mile across, is the Red Hill property, over which a number of openings have uncovered a rather in- tricate and distributed ore-formation. The main opening. No. i, is a trench through the comb of the hill, over 200 feet in length, through a decomposed schistose and argillaceous material, carrying almost through- out its entire extent mixed masses of soft ore, hard ore, and crystalline sandy ore, distributed irregularly through the gangue; it is evidently one of the broken-down re- deposits, before alluded to. At the eastern end of the cut some pyrites was mixed with the material. An analysis of an average sample shows: Per Cent. Silica 19-83 Metallic iron 51-55 Sulphur --- 0.137 Phosphorus 0.042 Opening No. 2, about 30 yards W. S. W. from the above, exposes a solid bed of magnetite in epidote and quartz, over five feet thick, dipping south-east. No pyrites was observed here. An analysis shows: Per Cent. Silica 31.26 Metallic iron 36.21 Sulphur 0.07 Phosphorus trace. 88 JOURNAL OF THE Opening No. 3, on the north-west side of the hill, shows a broken bed of ore in a gangne of hornblende and epidote, with concentrations of pyrites at several points. The entire thickness of the bed mnst be over 10 feet. x\n analysis shows: Per Cent. Silica 32.59 Metallic iron --- -.. 36.41 Sulphur 0.20 Phosphorus . ._ - trace. On the immediate northern bank of Helton creek a small opening exposes a broken bed of compact magnetite, irregularly distributed through a gangue of hornblende and gneiss, split by a lens of pyritiferous ore about 5 feet thick. An analysis of a sample taken across the bed shows: Per Cent. Silica -- 41.13 Metallic iron 23.39 Sulphur ._- --- 1.67 Phosphorus --. 0.109 The conclusion is that there are streaks of pyritiferous ore throughout this part of the bed, which increase in sulphur with depth. On the south side of Helton creek the ore crosses over McClure's knob, where a number of openings expose a series of three parallel beds, none of which show over 3 feet in thickness so far as developed. A number of analy- ses of samples taken from some of these openings show: I. II. III. IV. Silica 23.23 22.78 28.78 16.50 Metallic iron 44.87 43.03 42.39 45.87 Sulphur - 0.036 0.02 0.03 0.025 Phosphorus- 0.053 o-^4 0-03 0.904 To the south-west the ore crosses Old Field creek, and has been opened again at the Poison branch bank, on the ELISHA MITCHELL SCIENTIFIC SOCIETY. 89 divide between the waters of Old Field and Silas creeks, where considerable work was at one time done for the old forges. The main opening exposes a bed of magnetite consisting of two parts, the npper one being visible only in the upper end of the cut just below the surface-soil, where it measures about 4^^ inches in thickness of friable crystalline magne- tite, comparatively clean, below which is a bed of argil- laceous schist and clay, of a deep vermilion color, con- taining fine shot ore disseminated through it, probablv forming a more decomposable part of the same bed. Un- fortunately the cut had not been extended far enough in this direction to determine its true thickness. The lower bed is seen some 30 feet below here, at the bottom of the cut, near its mouth. It is partially filled in here, but I have from good authority that its thickness is 6 feet, about 3 feet of which was visible at the time of my visit. It is a hard ore, and the gangue is entirely hornblendic, while in the upper bed it is micaceous. The dip is about 50° S. E. , and the strike X. 40° E. Several analyses of the lower bed show: I. n. III. Silica 12.31 .-- Metallic iron 56.05 56.00 50.77 Sulphur ._ - 0.05 0.076 Phosphorus 0.071 0.013 0.016 Titauic acid-- trace. I. by McCreath. II. by C. B. White. III. from L'. S. loth Census Report. Not over 100 feet south-west from here another old opening exposes the same bed 25 feet lower. In a south-westerly direction the ore has been traced to Silas Creek, but no openings of importance have been made. Some 2 miles S. W. from Poison branch bank a bed 8 90 JOURNAL OF THE of soft schistose ore has been opened on the land of John Parsons, on Little Grapevine creek. The opening is a very narrow and shallow one. It shows not less than 3 feet of ore, but the bed is not fully exposed. Less than half a mile north-west from here, on Douglas Blevin's land, an opening on the top of a high ridge exposes another ore-bed at least 8 feet thick. The ore is extremely hard, in a gangue of hornblende gneiss. The dip is 45° S. E. About half a mile south-west from here, on Piney creek, i^ miles above its mouth, at Ballou's mill, a large bed of manganiferous magnetite has been uncovered. The ore is very coarse-granular in a matrix of brownish-black manga- nese oxide. It is exceptionally pure and practically free from gangue throughout its entire extent. The upper part of the bed shows Gyi feet of solid hard ore, beneath which is about I foot of soft manganiferous ore. The bed is proba- bly even thicker than this, as its full extent has not been uncovered. Several analyses show it to contain: I. n. III. IV. Silica 3.20 0.800 10.64 0.614 Metallic iron 65.40 65.65 39.35 65.090 Metallic mauganese 2.58 3.83 9.63 3.98 Sulphur. 0.0069 Phosphorus o.oii 0.004 0.022 0,019 I. by C. B. White. II. "Hard" ore by McCreath. III. " Soft" ore by McCreath. IV. "Hard" ore by C. Baskerville. Crossing Piney creek, the same bed has been uncovered about half a mile S. W. from here, on the land of Rob- ert Francis, where a slope, 20 feet deep, exposes 10 feet of soft manganiferous ore on the outcrop, pinching out to considerably less than this at the face of the slope. Throughout this soft material are scattered grains of hard magnetite. There is evidentlv a roll or fold in the ELISHA MITCHELL SCIENTIFIC SOCIETY. 91 bed at this point, the dip being abnormally 20° north of east, and the strike N. 34° W. The foot-wall is a decom- posed feldspathic material. The ore carries an excessive amount of hydroscopic moisture. Analyses of the natural and dried ore, by Mr. A. S. McCreath, show: Natural Ore. Dried at 212° F. Silica 3-49^ 6.090 Metallic iron 27.236 47-450 Metallic manganese 5.224 9.102 Phosphorus 0.058 o. T02 Moisture at 212° F. 42.600 About half a mile due west from here, a bed of very hard, compact, crystalline magnetite has been opened at two points, differing 100 feet in elevation, on Jacob Stewart's land near the summit of Turkey knob. The gangue is hornblende and quartz. The openings were filled in, but the ore was reported to be 5 feet thick. An analysis by Mr. White shows: Per Cent. Metallic iron 63.501 Phosphorus 0.006 Titanic acid-- trace. The ore has been traced half a mile north-east from here to the William Hamm place. About three-quarters of a mile south-w^est from the Francis opening, on the waters of Old Field creek, a tribu- tary of Horse creek, a number of openings on the south- w^estern spur of Turkey knob, on the land of Joseph Gray- beal, have exposed a bed of magnetic ore, which was w^orked a number of years ago for some of the old forges. One of these old openings shows a great deal of soft, mixed shot-ore disseminated in decomposed schist, with a streak of manganiferous earth in the front part of the opening. The main opening is a cut about 50 feet long, exposing two beds of ore, respectively 4 and 18 feet thick, separated by a horse of clay. The 4 feet of ore in the front part of 92 JOURNAL OF THE the cut showed some very compact, solid magnetite. The ore in the upper part of the cut was mixed with horn- blende gangue. Between these two openings some man- ganiferous float-ore was observed, resembling very much that at the Piney creek and Francis openings. Several analyses of the Graybeal ore show: I. II. • III. Silica 6.85 Metallic iron 63.55 67.18 64.04 Sulphur trace. Phosphorus trace. 0.010 0.009 I. by Baskerville. II. by White. III. from U. S. loth Census Report. On Horse creek, about one mile above its mouth, a bed of magnetite, precisely similar to that at Piney creek, has been opened. It is a coarse-granular magnetite dissemi- nated in a manganiferous matrix, which decomposes on long exposure into a soft, rich shot-ore. The opening is in the shape of an under-cut in the side of a hill, into which it extends perhaps 20 feet as a slope, the lower part of which was filled with water, preventing a close examina- tion. As far as exposed, the thickness of the ore is at least 6 feet, the lower 2 feet being the harder. Analyses show: I. II. Silica - 4.12 1.96 Metallic iron 64.58 62.48 Metallic manganese --.... 2.21 3.66 Phosphorus o.oii 0.019 I. by White. II. by Baskerville. Over one mile south-west from here the ore-body rises over 500 feet above the level of Horse creek, on Hampton knob, over which it has been traced for considerable distance by the dipping-needle. But none of the openings give any idea of the size of the bed. Several analyses from the locality show: ELISHA MITCHELL SCIENTIFIC SOCIETY. 93 I. II. Silica 9.66 Metallic iron 61.58 65.63 Sulphur --- 0.06 Phosphorus trace. 0.029 I. by Baskerville. II. by White. III. THE TITAXIFEROUS BELT. Starting- at the northern edge of the county, on the Virginia line, on the waters of Little Helton creek, this, the most north-westerly ore-belt of importance in x\she county, has been traced in a south-westerly direction, crossing Helton creek near Sturgill P. O., a distance of some 2}^ miles. It lies, approximately, 3 miles north- west of the Red Hill belt, and parallel to it. On the property of William Young, 150 yards west of the Jeiferson-Marion road, and about % line south of Virginia State-line, a very heavy outcrop of magnetite extends east and west along the crest of a ridge, with a width of at least 25 feet. There are no openings here, but all indications point to the existence of a large deposit. The ore is a coarse-granular, compact magnetite, practically free from gangue. It is titaniferous, and has a bright silvery luster. An analysis by McCreath shows it to contain : Per Cent. Silica • 4.35 Metallic iron -.. 52.85 Phosphorus 0.013 Titanic acid — 8.800 This outcrop is traced for over 150 yards in a westerly direction across Shippy branch, where it is opened on the McCarter place, showing a bed from 9 to 12 feet thick, dipping almost vertically. The local magnetic variation was 11° W. An analvsis bv McCreath shows: 94 JOURNAL OF THE Per Cent. vSilica 5.37 Metallic iron - 5^-75 Phosphorus - — . .. .. . 0.018 Titanic acid . 9.17 The bed is again uncovered, about 350 yards west from here, in front of Mr. McCarter's house, by a shallow cut showing about three feet of ore; but the bed is not fully exposed. About half a mile farther south-west, an opening on the Bauguess place shows 5 feet of ore, having a reddish streak, an analysis of which by myself shows 4.80 per cent, of titanic acid. The next notable opening, about one mile south-west from here, on Wallen's creek, a tributary of Helton creek, on the Pennington place, exposes a bed 8 feet thick, an analysis of which by McCreath shows: Per Cent. Silica . -- 5.07 Metallic iron .- --- 52.45 riiosphorus — 0.022 Titanic acid ._. 911 About half a mile north of Sturgill P. O. , on the waters of Helton creek, on the Kirby place, a broken bed of hard, fine-gained magnetite of steel-gray color has been uncov- ered. Its extent could not be determined from the condi- tion of the opening, but its thickness appears to be not less that 15 feet. I am indebted to Mr. A. S. McCreath for the informa- tion that these titaniferous ores carry a small amount of chromium, and an average analysis of a number of samples shows 0.480 per cent, of chromium. This concludes a description of the location and some of the economic features of the principal ore-deposits of Ashe county; and it is hoped that this region may become an important source of ore-supply in the near future. ELISHA MITCHELL SCIENTIFIC SOCIETY. 95 In. general, the quality of these ores is good; low in sulphur, and below the Bessemer limit in phosphorus. The mined material will, in many cases, be high in silica, but there is no reason why, by means of magnetic concentration, a high grade product should not be obtained. The titaniferous belt is by far the most persistent, and shows a large quantity of ore, but the percentage of titanic acid condemns this material for blast-furnace use, at least in competion with iron-ores less difficult to smelt to pig- iron. There is little doubt that there are valuable, workable beds of ore throughout the other two belts, such as at Ballou's, Piney creek, Graybeal's, Horse creek, etc., but it will require much more extensive exploitation to define their true extent. Other beds of ore have been uncovered throughout the county, but they are rather out of the range of what is con- sidered to be the principal ore-region. Such are, for instance, a bed of magnetite 9 feet thick, on the Ben Greer place, on the waters of Little Horse creek; and a belt of brown hematite along the north-western slopes of Phoenix and Three Top mountains, which is sup- posed to be a secondary formation, and of little importance as compared with the magnetic ores. Nearly all of these ore-deposits, being situated on tribu- taries of the north fork of Xew river, w^ould be accessible to a railroad built up that stream, which is a very feasible project. XoTE BY THE SECRETARY.— Comments or criticisms upon all papers, whether private corrections of t3pographical or other errors, or communications tor publication as "Discussion," or independent papers on the same or a related subject, are earnestly- invited. 96 JOURNAL OF THE NOTES ON THE DEVELOPMENT OF SOME SPONGES.* BY HENRY V. WILSON. The following notes deal with the genmuile develop- ment of Esperella fibrexilis (n. sp.) and Tcdania Briicei (n. sp.), to which are added a few observations on the ^^ ^ = >< length of spiral SEL .... (11). From this we have, since for flat arcs, LD = LE nearly, LE = y2 SEL, or point E is nearly at middle of spiral. The distance CD = q between SY and the circular curve, may then be regarded as the offset at the middle of the transition curve from circular curve to tangent SY. By aid of (9) above we can deduce two more useful formulas: 20 N ^ = (12), D° 20 N^ N^ = .9 =r (13). D° From eq. (3) we have, developing sin (as^) by a well- known formula, dx = ds (as- — \ (as^f + -^ (as'^f — , etc. ) ; whence integrating and noting that the constant is zero, since x := 0 when s ^ o^ and placing for brevity a for its equivalent as^ (eq. 2), we have, a' a' X = sa{% \ , etc.) (14). 42 1320 Developing dy = ds cos {as^} we deduce similarly, a^ a' a' y = ^{^ \ f-, etc. ) (15). 10 216 9360 no JOURNAL OF THE From [S) a = ; hence '3 = i (299-99) = 60, etc. ; X, = \ (.06) = .01, x^ = I (.47) = .09, .r, = i (1.57) = .31, etc. Il6 JOURNAL OF THE Having computed all the ordinates for the eight stations, measure the successive values of y along SY from S and the corresponding ordinates or offsets x, at right angles to SY, until all the stations are located. 2. By deflection angles. The method is similar to that of running in a circular curve with transit and chain. Example. Let ^ = 25, N =: 7. Deflect from tangent SY, with transit at S, successively, Ai = 2\ A, = 8', A3 = 18', A4 = 32^ A5 = 50^ Ag = I°I2', A7 = i°38' and measure S i = 25 feet, 12 = 25 feet, and so on, to fix the stations i, 2, 3, etc. The degree of the circular curve connecting at station 7 Z 980 is, D° = - = = 5°.6 - 5°36^ N M rO r^ ON C^ NO V V ^ V V, V ~i. "v ^ V -r q t^ r^ ■^ ^ ^ 00 Tj- ■Tf 00 NO 00 "* '^ CC NO oo 0 00 rO V? lO CO O CO <-l lO CO CN CN CO r^ CO iTS rO NO o O 0 o 0 0 0 o o 0 0 rO CN CO O) ol NO NO lO NO NO t^ J^ CO ON O CN) CO '^ to rO (N X oo •<^ \o o cr ON V V V V V V V V, ,^ ^ V ~v V o ■^ »o CO '^ CO ^ •^ CO ^ 00 '^ •<^ CO NO 00 Tt 8 0 CO "^ CNJ rl- ^ lO CO M O o o d lo (N (N o 0 o O o o o o 0 o o o o CS ON P4 Q -1- i? "* LO uo NO NO t^ CO ON O o rO CN ^ NO " i ' ON ~o~ 00 ON o O 1 V *^ V V V V V ^ V V ^ V ro (N . NO S3 NO -* VD 2! CN NO ^ NO r) 0) . O lO ■"^ -" o o CN) >0) . lO o O^ O o o o o NO l-H M CO CO CN o CO i lO - » n: u