SAPONITE (Nicklès). For a more extended description of this silicate noticed in the Suppl. VII, see Ann. de Chimie, [3], Ivi, 46.

At the

Saualpite.-A synonym for a variety of zoisite from the Saualp in Carinthia. SCHEELITE [p. 347].-F. A. Genth has found scheelite at the Bangle Mine in Cabarras Co., and also at Flowe mine, Mecklenburgh Co., North Carolina. former place it occurs in granular masses three-fourths of an inch in diameter; it has a pale yellowish-brown color, and a distinct octahedral cleavage. Composition (this Jour., [2], xxviii, 252):

The variety from Flowe mine was observed in crystals, in one case a modification of the octahedron 1, truncated by 1-i,-crystal about three-tenths of an inch in length; another specimen, half this size, had an orange color and was a combination of the planes and i-i.

Another variety from Flowe mine, forming what Dr. Genth calls rhombic tungstate of lime, occurs in small indistinct crystals-the largest one-quarter of an inch long. Each crystal has a nucleus of wolfram, and the following planes are given: I, i-i, -i, 1, and 1-7; cleavage could not be observed. Dr. Genth does not believe these crystals to be pseudomorphs, and suggests that tungstate of lime is dimorphous, a conclusion which, though extremely interesting, we hesitate to accept until the subject has been more fully investigated.

SERPENTINE.-Observations on the crystalline structure of serpentine by Websky in Zeit. d. deutschen geol. Gesellsch., x, 277.

SMITHSONITE [p. 447, I, III, VII].-For analyses of zinc ores from Arkansas by Dr. Elderhorst see First Geological Report of Arkansas, pp. 147–155.

SODALITE [p. 229, II, VI].—J. P. Kimball has published a description and analysis of sodalite, from an erratic block of compact syenite at Salem, Mass. (this Jour., [2], xxix, 67). The mineral was associated with elæolite, orthoclase, biotite, zircon, and albite (?) Occurs in crystalline, sub-translucent masses; cleavage indistinct; lustre greasy; color lavender-blue. Sp. gr. on three specimens 2.294, 2·303, 2·314. Chemical composition:

Calculating the chlorine to exist as chlorid of sodium we have:

4.57 6.99 99.76

corresponding very closely to the analyses of the sodalite from Litchfield in Maine by Whitney (Min., anal. 5, 6). Dr. Kimball remarks that the sodalite from both Litchfield and Salem, is found in erratic blocks, but the absence of cancrinite as an associating mineral in the Salem specimens, would seem to favor their being derived from different sources.

STROYMEYERITE [p. 48].-Prof. W. J. Taylor has described and analyzed a variety of stroymeyerite occurring at Copiapo in Chile (Proc. Acad. Nat. Sci. Phila., Nov. 1859). It is found in small six-sided trimetric crystals not larger than one-eighth of an inch in diameter. Its hardness is 2.5-3. Lustre metallic; color dark steelgray; streak nearly black and shining. Sectile, crystals brittle. It occurs in barytes in small cavities associated with quartz crystals, and upon the latter are implanted the crystals of stroymeyrite, together with small crystals of pyrargyrite. Analysis gave:

S

16.35

Ag 69.59

Cu 11.12

Fe

2.86 = 99.92

This composition differs materially from the published analyses of stroymeyerite, although not more than the analyses of specimens from different localities vary

from each other. Eu and Ag appear to replace each other in this mineral in all proportions. The formula is (Eu, Ag, Fe)S.

TALKOID, Naumann (Mineralogie, 5te, Aufl. 255).—The sparry crystalline talc from Presnitz described by Scheerer (Pogg. Ann., lxxiv, 321, this Jour., [2], xiv, 39) has been named talkoid by Naumann. It is snow white and broadly foliated occurs with magnetite at Presnitz. Sp. gr. 2:48. Composition, according to Scheerer and Richter:

for which Naumann gives the formula Mg3Ïi+É.

TANTALITE [p. 351, III-VI].-A. E. Nordenskiöld has analyzed tantalite from a new locality at Björtboda in Finland (Pogg. Ann., cvii, 374):

Ta 83.79

Sn 1.78

Fe 13.42

Mn

1.63 * 100-62

the oxygen ratio between the bases and the metallic acids is 1:4.83, most nearly resembling the composition of the Tammela tantalite.

TENNANTITE [p. 84, II].-Vom Rath has published the following analyses of tennantite from Cornwall (Verhandl. d. naturhist. Ver. d. Rheinlande u. Westphalens, xv, s. lxxii, in Kopp's Jahresbericht f. 1858, 680):

No. 1a is the direct result of the analysis-the mineral was associated with black oxyd of copper, and assuming the amount of this substance to be seven per cent, and averaging the analysis to one hundred, gives the result as in No. 16. Analysis No. 2 was by Baumert. According to v. Rath, the ratio between the metallic sulphids and the sulphid of arsenic in tennantite is 5:4, while the analogous ratio in tetrahedrite is 4: 3.

TOURMALINE [p. 270, II, IV, VII].-Jenzsch (Pogg. Ann., cviii, 648) has examined a crystal of tourmaline from Elba which he considers to be optically bi-axial. He suggests, from his investigations, that although the tourmaline crystals from Elba and Penig (Saxony) approach very nearly the hexagonal form, that they belong either to the trimetric or monoclinic system-a view previously suggested by Breithaupt's measurements. Breithaupt publishes a preliminary notice in the Berg und Hüttenmannische Zeitung, xix, 93, of a forthcoming monograph on this subject.

TRIPHYLINE [p. 406, 513].-F. Oesten obtained from the analysis of a very pure specimen of triphyline from Bodenmais in Bavaria (Pogg. Ann., cvii, 438):

P Fe Mn Ĉa Mg Li K Na Si

G.-3.545-3561. 44-19 38.21 5.63 0.76 2:39 7.69 0.04 0.74 0.40=10005 This gives the oxygen ratio between the bases and phosphoric acid 15·34: 24-77= 3-09: 5, and the formula, RP, the same as first proposed by Fuchs. Wittstein, in a recent note (Pogg. Ann., cvii, 511), calls attention to the fact that eight years since he published results giving the above formula, and says moreover, that a portion of the iron exists as sesquioxyd. Oesten has since (Pogg. Ann., cviii, 648) published proof that the specimen he examined was entirely unaltered, and that all the iron existed as protoxyd.

TYRITE (?) [I, III, IV].—Potyka (Pogg. Ann., cvii, 590) has analyzed specimens of supposed tyrite from Norway which prove to be a new columbate containing several per cent of potash, and distinct from the tyrite of Forbes. The chemical composition was found to be:

ёь Zr W Sn Pb Ĉu Ỷ Če Fe Ca Mg K H

43.49 0.80 1.35 0.09 0.41 0.35 31.90 3.68 1-12 4.12 1.95 tr. 7.23 371=100-20

The ratio between the metallic acids and bases, exclusive of the water is, as 1:1:04 or R3b. The mineral occurs implanted in red feldspar in small irregular masses having an uneven fracture, but no distinct cleavage. Lustre, sub-metallic; color black, in thin splinters reddish-brown and translucent on the edges; streak reddishbrown; hardness that of apatite (5). Sp. gr. in coarse powder 5124 (16·6° C.). When hot water is poured upon fragments a crepitation or crackling takes place. B.B. with borax gives a reddish-yellow bead while hot, which on cooling becomes yellow; with salt of phosphorus is completely dissolved to a greenish-yellow bead while hot, becoming green on cooling. No reaction for manganese with soda. Treatment with concentrated sulphuric acid gave no reaction for fluorine. [This mineral corresponds in many of its physical and blowpipe characters with the bragite of Forbes (see Suppl. III). Possibly a thorough analysis of authentic specimens of bragite would show them to be very nearly related, if not identical. G. J. B.]

Uranium, silicates of, see Hermann's paper in Jour. f. prakt. Chem., lxxvi, 320. URANONIOBITE (Hermann), see Pitchblende.

URANOCHALCITE, Hermann.-This name has been given by Hermann to a mineral from Joachimsthal (Jour. f. prakt. Chem., lxxvi, 321). It occurs in reniform amorphous masses having a metallic appearance. Fracture compact, and slightly conchoidal, with a feeble metallic lustre; brittle; opaque; color between steel-gray and pinchbeck-brown; streak black. H.-4. Sp. gr. 5.04. Heated in a closed tube the mineral at first gives off water, and then a sublimate of realgar, and finally metallic arsenic, leaving a black residue consisting chiefly of bismuth, uranium, copper, and iron. Treated with nitric acid the mineral is dissolved with separation of sulphur. On evaporation of the solution, silica separates in the gelatinous form. The analysis gave:

S As Cu Ni Fe Si Bi Ü Fe Fe й Ag

5.79 723 10-21 097 2:31 440 36:06 14:41 1195 327 240 tr.=99.00* Hermann writes the formula 5(R4Si+4RSi+10H)+R(ASS). [It is quite improbable that this composition is that of a simple mineral, and until further investigation we may reasonably doubt the homogeneousness of the substance analyzed.—G. J. B.] VANADINITE [p. 362, II-IV].-Kokscharow considers the vanadinite crystals from Beresowsk to be pseudomorphs of pyromorphite. Struve found in the interior of each vanadinite crystal a portion of unaltered pyromorphite. The mean of two analyses gave: РЬСІ Pb Feer V P 71.13 0:43 15.92

2.92

G. 6.863. 9.60 Struve represents this composition by the formula PbCl+Pb(P‡‚V24) or (3Pb3Î +PbCl)+5(3PbV+PbCl).-(Kokscharow, Mat. Min. Russlands, iii, 44).

VIVIANITE p. 415, III, IV].—For an article on the composition and formation of vivianite by Alphonse Gages, see L., E. and D. Phil. Mag., [4], xviii, 182.

WATER [p. 110]-Analysis of water from the Dead Sea, by Dr. F. A. Genth.— Ann. d. Chem. u. Pharm., cx, 240.

WOLFRAM [p. 351, I-IV]-F. A. Genth has published (this Jour., [2], xxviii, 253) an analysis of the wolfram which forms the nucleus of the peculiar tungstate of lime crystals alluded to under scheelite. One crystal showed the planes I, i-i, , and 1-. Sp. gr. 7496 (at 25° C.). Composition: Mn

W 75.79

Sn
tr.

Fe 19.80

5.35

0:32 101.26

corresponding to variety II. (Min., p. 352), having the formula 4FeW+Mn W.

* The original gives 100, but owing to a typographical, or other error the analysis adds up only 99.

WULFENITE [p. 349, II, V]-The massive wulfenite from Garmisch, is a mixture of molybdate of lead, with carbonate of lead and other substances, as shown by Wittstein's analysis (Kopp's Jahresbericht, 1858, 721):

ZINC-BLOOM [p. 460, 513, VII].-Dr. Elderhorst has described a hydrous carbonate of zinc from Marion County, Arkansas, as a new species under the name marionite (First Geol. Rep, Arkansas, p. 153). The chemical composition he found:

[This is identical with analyses 1a, of zinc bloom from Santander in Spain, by Peterson and Voit, published in the last supplement. This analysis gave Zn 731, Č 151, 118. These analysts found that zinc-bloom undergoes a change on exposure to the air, thereby losing both carbonic acid and water. A specimen of la, exposed to the air for three months was found to contain Zn 74-73, Ĉ 13.81, H 11.45. Other analyses by Braun are quoted in the last supplement. Peterson and Voit (Ann. d. Chem. u. Pharm., cviii, 50) give the formula for zinc-bloom Żus, C3, H6, which is the same as that given by Dr. Elderhorst for marionite;—it is an interesting fact that this is also the composition of the precipitate, produced by adding an equivalent of carbonate of soda to a zinc salt at the boiling temperature. Marionite may be considered as zinc-bloom, and the earlier analyses of this species by Smithson and Berthier, are undoubtedly less correct than those of Karsten and the more recent ones by Peterson, Voit, Braun, and Elderhorst.-G. J. B.] Terreil mentions the occurrence of zinc-bloom at Santander in oolitic grains (L'Institut, No. 1347).

ART. XXXIV.-Theoretical Determination of the Dimensions of Donati's Comet; by Prof. W. A. NORTON.

It is proposed in the present article to investigate the dimensions of the great comet of 1858, at certain specified dates, upon the theory developed in this Journal, (vol. xxvi; No 79), and compare the theoretical determinations with the results of observation. Resuming the equation of the approximate orbit of a particle emitted from the nucleus, obtained in the investigation alluded to, viz.

in which the axis of z coincides with the original direction of motion, a denotes the angle of inclination of this initial line of direction to a line perpendicular to the radius-vector, r the radius of the nucleus, p the acceleration due to the repulsive force of the nucleus at its surface, and k the opposite acceleration produced by the sun's repulsion; let us pass to a new system of rectangular axes, x' and z', of which the axis of z' is coincident with the radius-vector of the orbit of the comet. Effecting the transformation of coördinates, reducing, and denot

ing by H the distance of the vertex of the cometary envelope from the nucleus (=), we have

x'2-2H sin 2a. x'=-2H sin 2a cot a.z'.

(2.)

b

2

Let z'=0, and we obtain for the half-breadth of the envelope, =2K; and thence, for the coordinates of the vertex of the K

b

=-=

curve described by the particle, X=

4

K, and Z=h=.tanga.

2

Transferring the coördinates to this point, we get for the equation of the curve, referred to its vertex,

This is the equation of a parabola, of which the parameter, 2p,=2K cot a=4h cot 2a; and the distance from the focus to the

It is also the equation of the curve that would be described by a particle if it were projected from the nucleus with a certain velocity, and subsequently repelled by the sun alone. From which it appears that the path pursued by a particle repelled from the nucleus is very nearly the same, and, for the purposes of the present investigation, may be regarded as the same, as that which would be followed if the particle were simply projected from the nucleus. If we had occasion to trace accurately the trajectory of the particle in the vicinity of the nucleus, another investigation would become necessary. It should also be observed, that in the case of any particle, which, on its return from its excursion toward the sun, comes into proximity to the nucleus, the parabolic projectory becomes materially modified by its repulsive action, and equations (3 and (4) are inapplicable.

We may conclude from the result just obtained that, so far as the form and dimensions of the nebulous envelope are concerned, the theory of a repulsion exerted by the mass of the nucleus does not differ materially from that of the projection of the cometary matter by an instantaneous force from its surface; which, it appears, has been advocated and discussed by Bessel.

=

Other determinations relative to the envelope of the comet may be effected by the following formulas; in which Z the greatest distance attained by a particle, in the initial direction of motion; Y= the actual distance from the nucleus, of the particle when in this extreme position; the angle included between Z and Y; P= the inclination of the tangent drawn to