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sp. gr. =

sp. ht. =

sp. vol. temp. vap. =



specific gravity (gravities)

specific heat(s)

specific volume(s) temperature(s)


In the cross references the first number in clarendon type is the number of the volume; the second number refers to the chapter; and the succeeding number refers to the "§," section. Thus 5. 38, 24 refers to § 24, chapter 38, volume 5.

The oxides, hydrides, halides, sulphides, sulphates, carbonates, nitrates, and phosphates are considered with the basic elements; the other compounds are taken in connection with the acidic element. The double or complex salts in connection with a given element include those associated with elements previously discussed. phosphides, arsenides, etc., are considered in connection with carbon, silicon, titanium, etc. The carbides, silicides, titanides, The intermetallic compounds of a given element include those associated with elements previously considered.

The use of triangular diagrams for representing the properties of three-component systems was suggested by G. G. Stokes (Proc. Roy. Soc., 49. 174, 1891). The method was immediately taken up in many directions and it has proved of great value. With practice it becomes as useful for representing the properties of ternary mixtures as squared paper is for binary mixtures. The principle of triangular diagrams is based on the fact that in an equi. lateral triangle the sum of the perpendicular distances of any point from the three sides is a constant. Given any three substances A, B, and C, the composition of any possible combination of these can be represented by a point in or on the triangle. The apices of the


triangle represent the single components A, B, and C, the sides of the triangle represent binary mixtures of A and B, B and C, or C and A; and points within the triangle ternary mixture. The compositions of the mixtures can be represented in percentages, or referred to unity, 10, etc. In Fig. 1, pure A will be represented by a point at the apex marked A. If 100 be the

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standard of reference, the point A represents 100 per cent. of A and nothing else; mixtures containing 80 per cent. of A are represented by a point on the line 88, 60 per cent. of A by a point on the line 66, etc. Similarly with B and C-Figs. 3 and 2 respectively. Combine Figs. 1, 2, and 3 into one diagram by superposition, and Fig 4 results. Any point in this

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diagram, Fig. 4, thus represents a ternary mixture. For instance, the point M represents a mixture containing 20 per cent. of A, 20 per cent. of B, and 60 per cent. of C.



§ 1. The Discovery of Titanium

IN 1791, W. Gregor 1 studied the black sands of Menacan, near Falmouth, Cornwall, and found some greyish-black granules which were attracted by a magnet. He digested 100 grains of the mineral with hydrochloric acid and obtained an insoluble grey powder, and a soln. which, when treated with aq. ammonia, furnished a precipitate which, on calcination, gave 46 grains of magnetic oxide of iron with traces of manganese oxide. When the grey powder was digested for a long time with hot sulphuric acid, an insoluble residue was obtained, which, after calcination, contained 3 grains of silica. When the yellow sulphuric acid soln. was treated with potash-lye, a white precipitate was obtained which gave on calcination 45 grains of a brownish calx. W. Gregor's analysis of the black sand is therefore

Magnetite 4616


Brownish calx.


41 per cent.

The yellow sulphuric acid soln. was changed to an amethyst or purple colour by the action of metallic zinc, tin, or iron; and to yellow, by tincture of galls. The precipitate itself, in contact with dil. acid, is also coloured purple by contact with zinc; and a reddish-purple slag is obtained when an intimate mixture of the powdered mineral and coal-dust is fused in a crucible. Hence, said W. Gregor:

The extraordinary properties of the sand have led me to believe that it contains a new metallic substance. In order to distinguish this substance from others, I have ventured to suggest a name derived from the neighbourhood-Menacan, Cornwall-where it was found, and therefore I propose to call the metal menacanite.

Three years later, M. H. Klaproth 2 analyzed a specimen of a mineral from Boinik, called Hungarian red schörl. He found this product to be a natural metallic oxide which possessed peculiar properties, and hence, he inferred it to be the calx of a new metal which he called titanium. The name was borrowed from mythology -the Titans," the first sons of the earth "--because, " in order to avoid giving rise to erroneous ideas, it is best to choose a name which means nothing in itself, whenever no name can be found which indicates the peculiar and characteristic properties of a substance." About the same time, 1794, M. H. Klaproth also found that a brown mineral from Passau contained about 33 per cent. of titanium oxide, 33 per cent. of lime, and 33 per cent. of silica, with a trace of manganese. He called this mineral titanite. About 1797, the same observer analyzed the black magnetic sand from Menacan, and found it to contain iron oxide, 51 per cent.; titanium oxide, 42.25 per cent.; silica, 3.5 per cent. ; and manganese oxide, 0.25 per cent. He accordingly suggested that the suspected new element in W. Gregor's mineral--kein anderer sei, als eben der, welcher den hungarischen roten Schorl bildet; namlich Titankalk, so that W. Gregor's new metallic substance is identical with M. H. Klaproth's titanium. M. H. Klaproth's results were confirmed by W. A. Lampadius,3 J. T. Lowitz, and L. N. Vauquelin, but the systematic investigation of purified titanic oxide was made by H. Rose, about 1824. The impure metal was isolated by J. J. Berzelius in 1825, and by F. Wöhler, in 1849; but it




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