Tellurium

“ It has a strong metallic lustre; a moderate flexibility; considerable softness, and feels heavy.
Before the blowpipe it burns with the colour and smell of tellurium, and has the same action with acids. The precipitate by water burns upon charcoal like tellurium ”

“ Tellurium is also a rare substance generally found in combination with gold and silver. It is like bismuth, and is lustrous in appearance. Telluretted hydrogen is horrible as a gas. Tellurium, like selenium, sulphur, and oxygen, combines with two atoms of hydrogen. (Symbol Te, Atomic Weight 129) .
Fig. 393.—Casting plate-glass.
Arsenic, like tellurium, possesses many attributes of a metal, and on the other hand has some resemblance to phosphorus. Arsenic is sometimes found free, but usually combined with metals, and is reduced from the ores by roasting ”

“ Below a red heat it enters into a state of fusion; at a high temperature it becomes converted into a yellow vapour. It burns in air, when strongly heated, with a blue flame having a green rim, and giving off white fumes that have a peculiar odour. When taken internally, even in very minute quantities, tellurium imparts to the breath an offensively powerful odour of garlic. Tellurium dissolves in cold concentrated sulphuric acid, to which it imparts a rich purple-red colour. If the acid solution be diluted with water the tellurium precipitates unchanged. ”

“ A. Gutbier (Ann., 1905, 342, p. 266) by reduction of the dioxide obtained 127.6; Marckwald, by determining the ratio of telluric acid to tellurium dioxide, obtained 126.85; H. B. Baker (Jour. Chem. Soc., 1907, 91, p. 1849) , by determining the ratio of tellurium dioxide to oxygen and by analysis of tellurium tetra bromide, obtained 127.60, and V. Lenher (Jour. Amer. Chem. Soc., 1909, 31, p. 20) , by heating the double salt, TeBr4⋅2KBr, first in chlorine and finally in a current of hydrochloric acid to convert it into potassium chloride, obtained the value 127.55. ”

“ Antimony, bismuth, and arsenic are distinctly metallic as regards lustre, density, and some chemical properties, but are wanting in malleability. The recently discovered tellurium presents greater difficulties, for it has many of the physical properties of metal, and yet all its chemical properties are analogous to those of sulphur and selenium, which have never been regarded as metals. ”

“ The active matter was found to be deposited in the bismuth with tellurium, and he gave the name radiotellurium to this substance. In later work, he showed that the new substance could be chemically separated from tellurium. By treating the residues from 15 tons of Joachimsthal pitchblende, Marckwald (11) finally obtained 3 milligrams of intensely active material—far more active weight for weight than radium. ”

“ G. W. Kahlbaum, of Basle, with great success to potassium, sodium, selenium, tellurium, cadmium, magnesium, bismuth, and thallium, while the experiments with zinc and manganese have so far been unsatisfactory. Judging by spectrum analysis, an extreme degree of purity was obtained. Thus, thirty-five ines disappeared from the spectrum of tellurium, showing, the author believes, the absence of substances which modify the spectrum of the purest metal obtainable by other processes. ”

“ Only two contradictions have been found in nearly forty years. The atomic weights of the elements, iodine and tellurium, should be transposed to make these substances fit into the table, and there is no place for most of the so-called rare elements. The first difficulty will disappear if any one can show that either tellurium or iodine contains an unknown impurity. It must be admitted that the chances of this are not good at present.
We can avoid the difficulty as to the rare earths by considering a group of
Professor DIMITRI MENDELÉEFF them as equivalent to one element. ”

“ He says, that when a circuit of electricity is completed in water by means of two surfaces of tellurium, oxygen is given off at the positive surface, and instead of hydrogen at the negative surface, a brown powder is formed and separated, which he regards as a hydruret of tellurium; and he conceives that the reason why that metal prevents the metallization of potash is, that it has a stronger attraction for hydrogen than that possessed by the alkali. ”

“ Many specimens of the tungsten exist without the tellurium, but every piece which has afforded tellurium has also afforded tungsten, and in greater abundance. Even in well defined crystals, both metals have been found in the same crystal, and where the external appearance was homogeneous. In other specimens a difference seems to be apparent, and a proper ore of tellurium appears to be blended with a proper ore of tungsten. This latter ore is the wolfram, composed of oxid of tungsten, or as some choose to say, tungstic oxid combined with iron and manganese. ”

“ Tellurium, te-lū′ri-um, n. an element by some classed as a metal, placed by others among the metalloids, brittle and crystalline, of high metallic lustre, bluish-white in colour, with close analogies to sulphur and selenium.—n. Tel′lurate, a salt of telluric acid.—adjs. Tel′lūretted, combined with tellurium; Tellū′rian, pertaining to the earth.—n. an inhabitant of the earth.—adj. Tellū′ric, pertaining to, or proceeding from, the earth: of or from tellurium.—n. Tel′luride, a compound of tellurium with an electro-positive element.—adjs. ”

“ It is, that although the differences are irregular (e.g. between B = 11 and C = 12 the difference is 1, while between O = 16 and F = 19 the difference is 3) , yet there is no marked displacement in the order of arrangements of the elements, inasmuch as no element has an atomic weight lower than that preceding it in the horizontal line. It was for some time supposed that tellurium and iodine were thus misplaced; and indeed it is even now not quite established that they are not, but the balance of evidence is in favour of tellurium having a lower atomic weight than iodine. ”

“ Hydrogen selenide and telluride are gases like sulphuretted hydrogen, and, like it, are soluble in water, form saline compounds with alkalis, precipitate metallic salts, are obtained by the action of acids on their compounds with metals, &c. Selenium and tellurium, like sulphur, give two normal grades of combination with oxygen, both of an acid character, of which only the forms corresponding to sulphurous anhydride—namely, selenious anhydride, SeO2, and tellurous anhydride, TeO2 [79] —are formed directly. ”

“ The liquid is decanted from the residue, which is washed with hydrochloric acid and hot water, then boiled with aqua regia until the insoluble matter is white. From the aqua regia solution any gold that may be present is precipitated by means of ferrous sulphate, and afterwards zinc is added to precipitate the tellurium. The precipitate on the zinc is washed, dried, and heated to redness, treated with sulphuric acid to remove any silver, and the remaining tellurium is then collected. ”

“ Gibbs, we were withheld from announcing it, because the form of the crystals, the specific gravity, the colour, and perhaps some other characters, were not perfectly accordant with European descriptions, and with the specimens in our possession, which are from Saxony and Cornwall.
During the necessary chemical trials (which have, we trust, established the correctness of the above opinion,) we very unexpectedly discovered in some of the ores of tungsten, proofs of the existence of tellurium. The conclusion was induced by the phenomena, for nothing was farther from our expectations. ”

“ It burns, and also, like sulphuretted hydrogen, precipitates many metals from solutions of their salts. It may be liquefied, the liquid boiling at 0° C., and on further cooling, it solidifies, the solid melting at −48° C. Many tellurides of metals have been examined by C. A. Tibbals (Jour. Amer. Chem. Soc., 1909, 31, p. 902) who obtained the sodium and potassium tellurides by the direct union of their component elements and others from these by precipitation. ”

“ The funnels generally, but not always, radiate from a central globe. We give beryllium (glucinum) as the simplest example (2 on Plate III) , and to this group belong calcium and strontium. The tetrahedron is the form of chromium and molybdenum, but not that of the head of their group, oxygen, which is, like hydrogen, sui generis. These two groups are marked in orthodox chemistry as respectively positive and negative, and are closely allied. Another pair of groups show the same tetrahedral form: magnesium, zinc and cadmium, positive; sulphur, selenium and tellurium, negative. ”

“ The fact is that where the telluride is rich it is a good thing to have, the same as rich quartz or ironstone, and where it is poor it is no better than either of these matrices. The one great fact about the Kalgoorlie belt is that the telluride ores are very rich in gold, and, judging by present indications, likely to remain so. The lodes are strong, and mostly well defined, while the effects of hydrothermal action which they exhibit afford the best and most reliable indications of their permanency. ”

“ Thallium, as we shall afterwards see and as was observed on its discovery, has much kinship with lead and mercury, but some of its properties appertain to lithium and potassium. Naturally, where it is impossible to make measurements one is reluctantly obliged to limit oneself to approximate comparisons, founded on apparent signs which are not distinct and are wanting in exactitude. But in the elements there is one accurately measurable property, which is subject to no doubt—namely, that property which is expressed in their atomic weights. ”

“ That telluride ores in themselves are exceptionally rich is well known, but that they are invariably an indication of continuity in depth, and of increased richness of the ores, is far from being the case, and only harm can come from hasty generalisation. ”

“ In the variety of teredo described by us, we have never observed the formation of two openings surrounded by calcareous matter, situated side by side, like an eight placed sidewise, ∞, [2] and serving as a passage for the siphons, as described by Deshayes.
The calcareous tube, once formed, constitutes for each teredo his own abode, where he isolates himself from his companions, and has nothing to fear from their close proximity. ”

“ When the pieces of wood treated with oil of paraffine were taken from the water in 1862, after a sojourn of more than two years, or rather during three summers, traces of the teredo were found in the pieces of oak, but not on those of red fir; but when examined in November, 1863, fully-developed teredos were found everywhere, in the fir as well as in the oak, in the pieces whose surfaces had been removed by the adze, but not more than in those which had not been submitted to any examination. ”

“ The results of these experiments strongly convinced the commission that no exterior application of any nature whatever, or modification of the surface merely, would give any efficacious guarantee of protection against the teredo. Even supposing that one or another of these means would prevent the young teredos from attaching themselves to the wood, yet the constant friction of the water or ice, or any accident, might break the surface of the wood sufficiently to give access to the teredo. ”

“ When the cylindrical tube d has been extracted from the wood, a shell is seen at the larger extremity, composed of two pieces, as shown at c. In like manner, a piece of fossil wood (a, fig. 14.) [p.24] has been perforated by an animal of a kindred but extinct genus, called Teredina by Lamarck. The calcareous tube of this mollusk was united and as it were soldered on to the valves of the shell (b) , which therefore cannot be detached from the tube, like the valves of the recent Teredo. The wood in this fossil specimen is now converted into a stony mass, a mixture of clay and lime ”

“ It is no less curious than wonderful to observe the mysterious instinct which apparently regulates the mechanical skill of the teredo, its own body supplying it with an implement of such admirable consistency and adaptation as to enable it to excavate a habitation for itself, so accurately formed that to a casual observer it would appear a mystery how so perfect a circle could be produced. It is only on examination that the raised and hollow parts of the wood become visible, and explain, in some degree, the auger-shaped contrivance that has been used for the purpose of perforating. ”

“ If we sprinkle thallium salt in the flame the green line of that element will be visible in the spectrum. If we take the lamp away and place a lime light or a piece of white-hot iron in front of the slit we shall get a brilliant continuous spectrum not crossed by any lines, either bright or dark. Insert now the alcohol-sodium-thallium lamp between the lime light and the slit, and the observer will see the two sodium lines and one thallium line in the same places as before, but as dark lines on a background of bright continuous spectrum, as: illustrated in the lower of the two spectra. ”

“ Fossil terredines of great antiquity have been found near Southend; also pieces of petrified wood from the greensand, near Lyme and Sidmouth, bored by ancient species of teredo; also from Bath, and from Doulting, near Shepton Mallet, specimens of oolite, with petrified corallines in it, pierced by boring shells.
It is said that this worm is a native of India, and that it was introduced to Holland some 200 years ago, from whence it has spread through the ports of northern Europe.
The Teredo navalis [17] is very destructive to harbour works and piling. ”