THALLIUM, THE NEW METAL.

Lyttelton Times, Volume XX, Issue 1112, 8 July 1863, Page 3

THALLIUM, THE NEW METAL.

The metal is very soft and heavy. Lead scratches it as iron does lead; and the finger-nail makes a deep indentation. A knifie cuts it like cheese. It possesses the remarkable property of welding together while cold, and has extraordinary ductility. Its proper solvent is nitric acid. It marks paper like black-led, and the writing, examined by reflected light, has a golden appearance. This, however, in a few hours fades all but entirely away; the writing, however, being readily restored by a solution of an alkaline sulphide. Its electrical properties have been investigated by Dr. Matthieson. It conducts electricity much in the proportion that lead does; and for a metal of its class is therefore a tolerably good conductor. But its dia-magnetic properties are very remarkable, and in this respect it stands second only to bismuth, the most dia-mag-netic of all substances. It is highly volatile, the metallic fumes flying rapidly off under the ordinary blowpipe. It has the greatest affinity for oxygen, and its actual brightness can only be seen by following the cutting-knife, so rapidly does it tarnish. If the coating of oxide be removed under water, the new surface will remaiu bright for a considerable period immersed in that fluid. Various re-actions of salts of thallium, lead, silver, &c., were shown in proof of its exact metallic nature, and its alliance with the lead class of metals. But the most beautiful experiments exhibited in his lecture by Isr. Crookes next to the exhibition of tile greet!'nqfe itself, was the display, by means of the electric lifeit and three Grove's batteries, of the actual crystal zation of metallic thallium from a solution of |ts sulphi.te. the fern-like fronds formed by 'pfc crystals branching out between the poles of llie battery with surpassing gracefulness and elegauce. In respect to the position of thallium among the elements, Mr. Crookes has well observed that observers/ generally err in regarding natural bodies as so many : links in a perfect chain, and facts are frequently strained in order to make them agree with precon* ceived opinion. In such a group as chlorine, and iodine, there are doubtless three consecutive but most frequently nature should be looked upon i more as a perfect net than as a perfect chain. In - seeking for the chemical relationships of thallium, ■ at first sight it might appear to belong to the group of alkali-metals on account of its forming a readily soluble highly alkaline oxide, as also that it forms an insoluble platino-chloride; but, on the other hand its physical characters, chemical reactions, and high atomic weight, prove incontestably that its true position is close to lead and silver. For the answer to the question—What is its use? we must probably wait until it is procured by the ton at no greater cost than it is now by the ounce; for the practical uses of a body depend and keep pace generally with its abundance. In the form of an alloy, however, its uses may soon possibly be very great, as it readily mixes with many metals, and communicates to them valuable properties.—London Review.