CONTRIBUTION
FROM THE
MASSACHUSETTS INSTITUTE OF TECHNOLOGY. ]
REVIEW OF AMERICAN CHEMICAL RESEARCH. VOL.
v.
No. 8.
ARTHURA . NOYES,Editor. REVIEWERS : Analytical Chemistry, H. P. Talbot and W. H. Walker; ’Biological Chemistry, A. G. Woodman ; Carbohydrates, G. W. Rolfe ; General Chemistry, A. A. Noyes ; Geological and Mineralogical C h e n istry, W. 0. Crosby and M. L. F u l l e r ; Inorganic Chemistry, Henry Fay ; Metallurgical Chemistry and Assaying, H. 0. Hofman ; Organic Chemistry, J. F. Norris ; Physical Chemistry, H. M. Goodwin ; Sanitary Chemistry, E. H. Richards; Technical Chemistry, A. H. Gill and F. H. Thorp.
GEOLOGICAL AND MINERALOGICAL CHEMISTRY. Y I. FULLFR,R E V I E W ~ R .
Geology of Certain Counties of Iowa. BY A. G. LEONARD, SAMUEL CALVIN,AND H. FOSTER BAIN. Iowa Geol. Sumley, A n n . Rep,, 8 , 51-366.-The physiography, stratigraphy, and geological structure of each county is described, and a discussion is given of the economic products, accompanied by a number of analyses. Properties a n d Tests of Iowa Building Stones. BY H. FosBAIN. Iowa Geol. Survey, Ann. Rep., 8 , 367-416.
TER
On t h e Phenocrysts of Intrusive Igneous Rocks. BY I,. V. PIRSSON. Am. J . Sci., 157. 271-28o.-The objections to the hypothesis of an intratelluric origin of the phenocrysts are discussed, and evidence pointing to an origin by crystallization “in
place” is presented. T h e supposed manner in which the development takes place is as follows : As the temperature of an intruded aqueous magma falls, centers of crystallization are set u p , the intervals of crystallization of the component minerals becoming progressively shorter as the magma becomes viscous from the escape of the water-vapor. T h u s , while the earlier, or ferro-magnesian, components may reach considerable size, the crystals of the later components are comparatively small. I n the case of recurrent phenocrysts it is supposed that the most abundant components teiid to set up centers of crystallization before their normal periods, the rest of the process continuing as before.
74
Review of Americaz Chemical Researck.
On the Occurrence, Origin, and Chemical Composition of Chromite. BY J . H. PKATT. - 4 m . J . Sci., 157,281--286.-The usual mode of occurrence of the chromite of S o r t h Carolina is in the form of rounded masses of varying proportions in the peridotite near its contact with the inclosing gneiss. I t s basic character is an indication of its insolubility in the peridotite magma ; hence it would have been among the first of t h e minerals to solidify. I t s relation to the inclosing rock confirms this view. With two exceptions, all analyses known show the presence of magnesium and aluminum, and the author concludes t h a t chromite is really a combination of the three isomorphous molecules, FeO.Cr,O,, MgO.Cr,O,, and MgO.Al,O,. The MgO.AI,O, is represented by the mineral spinel, and the discovery of MgO.Cr,O, a s a definite mineral may be expected. Some Rock-forming Biotites and Amphiboles. BY H. W. h BY \v. F.~ H I L L E B R~ A S D , H. 3 ~ . STOKES, ~ AND WILLIAM VALENTINE. Alii. 1.sei., 157, zg4-298.-The paper includes descriptions and very complete analyses of biotite from granite, quartz-monzonite, and gneiss from the Sierra Nevada region, and of the amphibole of gabbro and quartzmonzonite from the same locality. Complete analyses of most of the rocks are also given. T h e n-ork was executed in t h e laboratory of the U. s. Geol. Survey, the object being to furnish a basis for calculating the molecular composition of the rocks in question.
TURNER.L
On the Occurrence of Paleotrochis in Volcanic Rocks in Mexico. BY HENRY S. WILLIAMS. Am. J . SL-i,,157, 335-336. -More or less regularly striated biconical forms resembling t h e supposed coral Paleotrochis of Enimons was found by Alfred Dug& in the volcanic rocks of an old eroded cone northeast of Guanajuato in the Santa Rosa Mountains. T h e explanation is suggested that in the upward passage of superheated siliceous waters through the rock a point might be reached where a sudden loosening of the texture would permit a rapid upward radiation of the heat, while below the point the temperature would remain nearly constant for long periods. Deposition would t a k e piace wherever a cavity existed, but the supply of silica mould be furnished only as it was abstracted by solidification. I t is considered that the cavity would be increased in size by t h e the accretion-surface would increase crystallization, and that with the lengthening of the cone by the separation of the apices of the cones, consolidation taking place a t the point of meeting of the solidified silica with the water, and the water reaching that point slowly.” “
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Geological and Mineralogical Chemistry.
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Origin of Paleotrochis. BY J. S. DILLER. Am. 1. Sci., 157, 337.-342.-.4 summary of the reviews of previous writers, and descriptions of both the macroscopic and microscopic characters of specimens from Mexico (see preceding review), and from the SanChristian Gold Mine of North Carolina are given in some detail. I n both cases the Paleotrochisoccurred in igneous rock, the analysis of the North Carolina type, which is given in full, indicating a rhyolite. T h e more perfect Paleotrochis are coniposed of granular quartz and were deposited within the more or less elongated spherulites with which the rock abounds, but whether this deposition followed soon after that of the spherulites in the course of consolidation, or took place in hollow spherulites (lithophysae’), or were the result of subsequent alteration, is not clear. T h e biconical forms suggest that they may have originated as two spherulitic sectors, of which the apices were the centers from which the growth started. On the Association of Argillaceous Rocks with Quartz Veins in the Region of Diamantina, Brazil. BY ORVILLEA. DERBY. Am. J . Sci., 157, 343-3 j6.-’I’he paper discusses in detail the characters and probable origin of certain more or less strongly decomposed rocks of the Diamantina district. An exhaustive analysis of a cyanitic schist from the region in question, made by W. F. Hillebrand, is included. Goldschmidtite, a New Mineral. BY WILLIAM H. HOBBS. A m . J . Sci., 157, 357-364.-The new mineral, to which the name of goldschmidtite has been given by the author, is a brittle, silver-white substance, having a hardness of about 2 and a specific gravity of 8.6. I t is found in the form of minute columnar monoclinic crystals attached to the chalcedonic coatings of the fragments of a brecciated igneous rock of the acid type occurring a t the Gold Dollar Mine, Arequa Gulch, Cripple Creek. T h e analysis shows the presence of 31.41 per cent. of gold, 8.90 per cent. silver, and 59.64 per cent. tellurium, corresponding to the formula Au,AgTe,, and giving it a position intermediate between calaverite and sylvanite. Twenty-two crystal forms were recognized, ten of which are also recognized in sylvanite, to which the new mineral is most closely allied.
On a Hydromica from New Jersey. BY F. W. CLARKEAND N. H. DARTON. ,4m.J . Sci., 157, 365-366.-This goldenbronze mineral, which differs widely from any hitherto-described mica, is found mainly a s thin coatings in veins of calcite adjacent to the diabase wall rock a t Rocky Hill, N. J. T h e analysis indicates an orthosilicate of the formula ( K H ) e8(MgFe),4(A1Fe) 6 1 (SiO,) 8,.28H,0,
Review of American Chemical Research.
76
pointing to a mixture ,of muscovitic (R”‘(SiO,),R’,) and phlogopitic (R”’(SiO,),R”,H,,gH,O) molecules in the ratio of 9 to 5 .
METALLURGICAL CHEMISTRY. H. 0 H O F X 4 V . R F \ ’ I E W E R
Porous Castings and Occluded Gases. /. A m . fioundqvnen’s Assoc., 6, 18.-The paper discusses the effects of hydrogen and sulphur dioxide in castings of brasses and bronzes and of carbon monoxide in castings of steel and suggests some inethods for getting rid of occluded gases. Phosphor Bronze-a Description of Its Characteristics and Methods of Manufacture. BY L. S. SMITH. A m . Eng. and R. R. 73, 147-149.-The author distinguishes high tensile bronze, the alloy of copper, t i n , and phosphorus, and bearing bronze, the above alloy to which lead has been added. H e g i r e s a brief history of the manufacture, the compositions and specifications of the alloys, discusses the action of phosphorus in bronze, the foundry treatment of the alloy, and the method of introducing the phosphorus.
I.,
The Progress of Metallography in 1898. BY -4. SXUT’EUK. The Mefallographist, 2, 1-8. The ilicrostructure of Bearing iletals. BY G. H. CLABIER. two leading requirements of bearing alloys, v i z . , good antifriction and good bearing qualities, depend not only upoii the chemical composition b u t also upon the structure of the alloy. T h e author discusses three whitemetal alloys (having the composition, Pb, 80.00 ; S n , 4.75 ; S b , 15.00; Bi, 0.25 : P b , 7 0 . 0 0 ; S n , I O ; S b , 2 0 : and Sn, 8 0 . 0 0 ; S b , 10.00; Cu, IO.OO),miscellaneous alloys (with over 60 p e r cent. of copper, the rest consisting of Zn, S n , P b , S b , e t c . ) , a copper-tin alloy (composed of 7 parts Cu to one part S n once used In railroad cars, but now abandoned), and phosphor bronze (Cu, 78.72 ; P b , 9.89 ; S n , 10.58 ; P , 1.04, which, after remelting, gave C u , 80.39 ; P b , 8.35 ; S n , 10.40 ; P,0 . 8 7 ) , with copper-tin-lead alloys, the last two being commonly used for locomotire journal bearings.
J . Franklin I n s f . , 146, 138-153.-The
A Study of the Microstructure of Bronzes. BY A. E. OUTER]. Franklin I n s f . , 147, 18-31.-The author having examined microscopically a large number of specimens of bronze cut from small castings found that the appearance of t h e etched surfaces varied greatly with the length of time that they had been exposed to the acid and suggests that a uniform system should be adopted so as to permit satisfactory comparisons. BRIDGE, J R .
