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The Tropenas Process for Steel Castings. BY THEEDITOR. Foundry, 17, 237 ; Eng. Min. I., 70, 761.-The paper contains a brief description of the Tropenas process with illustrations of converter and of castings. Influence of Copper in Retarding Corrosion of Soft Steel and Wrought Iron. BY F. H. WILLIAMS. Eng. SOC.Western Pa., 26, 231, through Iron Age, 66, 16.-The experiments described were carried out in order to show what effects small additions of copper would have in retarding the corrosive effect of moisture on soft steel and wrought iron. For this purpose the specimens were cut and filed to the same dimensions, weighed, suspended on a frame, dipped together into water, and then left to hang in the air until dry. This treatment was repeated several times a day for a month, until the oxide-scale formed showed a tendency to peel off. The specimens were freed from oxide and then weighed. I n the table below are given the percentage losses : L O S S FROM
ATMOSPHERIC CORROSION. Loss in weight. Per cent.
A-Soft B-Soft C -Soft D-Soft
....................... .... ..... ....
Bessemer steel Bessemer steel with 0.078 copper.. Bessemer steel with 0.145 copper Bessemer steel with 0.263 copper..
1.85 0.89 0.75
0.74
STEELAND WROUGHTIRON. in weight. Per cent.
1,oss
.......................... ..................... .....................
Soft Bessemer steel 1.65 Wrought iron, sample I . . 0.76 Wrought iron, sample 2 . . 0.80 Wrought iron, sample 3 ...................... 0.87 Wrought iron, sample 4 (containing 0.393 per cent. copper). 0.53
..............................
They show that both soft Bessemer steel and wrought iron resist corrosion much better when they contain some copper than when they do not.
GEOLOGICAL AND MINERALOGICAL CHEnISTRY. W. 0 .
CROSBY,
REVIEWER.
On the Constitution of Barytocelestites. BY C. W. VOLNEY. J. A m . Chent. SOC.,21, 386-388.-Although previous work had discredited the existence of a true barium-strontium sulphate, showing only barites containing a trace of strontium or celestites containing a trace of barium, the author finds this mineral from eastern Ontario to yield : BaSO,, 30.850, and SrSO,, 70.010. A previous analysis by the author had given : BaSO,, 39.850, and
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Review of Aniericuit Chemical Research.
SrSO,, 58.200. These results correspond very closely to the formulas (BaSr,) (SO,), and (BaSr,) (SO,),. These two types of barytocelestites have distinct habits of crystallization which remain to be investigated.
Analysis of Emery from Virginia. BY W. W.MILLER,JR. A m . Chenz. ],, 2 2 , 212-213.-The emery occurs in a heavy ledge near Whittle's, on the line of the Southern Railroad, in Pittsylvania County. I t is described as a black, crystalline mass, magnetic, polar, with specific gravity 4.205, and hardness 8. The analysis shows : alumina, j6.74 ; ferric oxide, 15.50 ; ferrous oxide, 20.77 ; silica, 0.68 ; titanicoxide, 1.86 ; soda, 3.95. T h e ferrous oxide, in excess of that required to Iorni magnetite, i5 supposed to be present as hercynite, FeAl,O, ; and the soda is considered to take the place of ferrous oxide in forming additional hercynite, thus greatly reducing the amount of alumina which can exist as corundum. T h e large amount of hercynite reduces the erosive power and makes the mixture of no d u e as emery. Examination of a Sandstone from Augusta County, Virginia. BY IT.W.MILLER,J R . Ant. Chem. ]., 2 2 , 216-217.This sandstone is a disintegrated quartzite, occurring in the vicinity of Basic City, and found to be valuable for ballast and road metal. The analysis shows large proportions of alumina and alkalies, indicating partially kaolinized feldspar. which is regarded as explaining the packing of the material in use. Analysis of Smithsonite from Arkansas. BY W. W.MILJ R . Ant. Clzeiiz. ]., 22, 218--21g.-The smithsonite from the Morning Star Mine, in Searcy County, is the usual botryoidal variety, and encloses layers of zinc blende from which, probably, it has been derived. The analysis shows it to be nearly pure, but with a little cadmium, copper and iron replacing zinc. LER,
On the Interpretation of Mineral Analyses : a Criticism of Recent Articles on the Constitution of Tourmaline. BY S. L. PENFIELD.A m . ] . S C ~160, . ~ 19-32. C. H. W A K R E NR , EVIEWEK.
Nitrates in Cave Earths. BY HENRYu'.KICHOLS. .] Geol., 9, 236-243.-This is, in the main, a criticism of the theory adGeol., 7, z ) that the nitrates of cave earths vanced by Hess (1. are not derived to any extent from bat guano, as has been formerly supposed, but from the soil above by a leaching process followed by a deposition of the salts on evaporation. T h e chief objections raised by Hess to the old theory may be briefly summarized as follows : I . Bats do not penetrate far into caves, which makes it difficult to account for the presence of salts derived from guano and their uniform distribution in the cares. 2 .
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Cave earths contain little or no organic matter. 3. While the total phosphates in the guano and underlying earth are about equal, the soluble phosphates are much less in the earth. I n criticizing these objections it is shown that bats do penetrate into remote parts of the caves, that in some instances cave earths do contain organic matter, and that the lack of soluble phosphates in the earth is due to a simple reversion of the soluble to an insoluble form. Among other things to which attention is called is the presence of carbonates in the drip waters of the cave and their absence in the cave earths, a fact which Hess’ theory does not account for. I t is thought that the amounts of phosphates and nitrates taken into solution from the soil are too small to account for the amounts found in the earths and that the considerable quantities of soluble salts in the bat guano furnish a more probable source of supply. The author therefore concludes that the old theory agrees with the facts better than the new.
nohawkite. BY JOSEPHW. RICHARDS. A m . J. Sn’., 161, 4 5 7-458 .-Under the name mohawkite a mineral was described by Ledoux (Eng. &fin. J . , Apr. 7 , 1900) to which he assigned the formula (Cu,Ni,Co),As. Later the correctness of his work was called into question by Koenig, who appropriated the name mohawkite for a mineral which he described ( A m .J . Sa‘., Dec., 1900) as having the composition (Cu,Ni,Co),As. A new analysis is reported in the present paper, confirming the correctness of Ledoux’s work and proving the existence of a molecule (Cu,Ni,Co),As. The name Ledouxite is proposed as a name for t h e latter.
On the Origin of the Phenocrysts in the Porphyritic Granites of Georgia. BY THOMAS I,.WATSON.J . Geol., 9, g7--122.-A detailed petrographical study is given of the porphyritic granites of Georgia, within the Piedmont Plateau. The different areas are taken up according to their geographical distribution. The following facts given by the author concerning these rocks are believed to indicate that the phenocrysts (orthoclase) have been formed in place and are not of intratelluric origin : I . The absence of a definite arrangement or orientation among the phenocrysts. 2 . Absence of the phenocrysts from the border zones of t h e granite masses and a gradation peripherally from an interior porphyritic facies into an even-granular granite of coarse texture a n d of the same mineral and chemical composition. 3. The absence of any evidence of magmatic resorption or corrosion of the phenocrysts. 4. The absence of any flow structure. 5. T h e abundant inclusions of all the ground mass constituents, a feature very ch’aracteristicof these porphyritic granites. A table of the chemical analyses of these rocks accompanies the article.
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Review of American Chemical Research.
Mineralogical Notes. BY C. H. WARREK,Am.]. Sn'., 161, 36g-373.-The following minerals are described : Anorthite crystals, occurring as a contact mineral in the limestone a t Franklin Furnace, X. J. ; soda orthoclase crystals of peculiar habit from a phonolite dike, Cripple Creek, Colo. ; iron wolframite crystals from South Dakota ; pseudomorphs of wolframite after scheelite from Trumball, Conn. Studies for Students. BY 0 . C.FARRINGTOS. J . Geal., g, 51-66 ; 174-rgo.--This is a study of meteorites in regard to their chemical and mineralogical composition, their petrographical characteristics, their terrestrial analogies, and to some of the theories relating to their origin.
