II. Переведите текст, обращая внимание на значение предложных оборотов:

DIAMOND AND GRAPHITE

Carbon is known in variety of forms; upon examining wood and coal, fat and starch, soap, sugar, and gasoline we find that one element is common to all, namely, carbon.

Diamond and graphite, in spite of their visible dissimilarity, also belong to this group of substances.

When burned, one gram of carbon gives out different amount of heat according to the form used, thus diamond gives 7,805 calories, and graphite – 7,850.

The diamond is distinguished by its natural crystalline form. For ornamental purposes it is “cut” by grinding new faces to give it the artificial form called “brilliant”.

Owing to its hardness, - it is the hardest of familiar substances, - it can be scratched or polished only by means of rubbing with a diamond powder.

The colorless stones and those with special tints are highly valuable; as to the less valuable specimens, due to bad coloration, they are used for grinding, for glass cutting, and on the points of drills.

Diamonds are sold by the carat and the value increases with the size. The largest known specimen weighed 3,032 carats and was evaluated extremely high because of its perfect color.

Graphite is found in Siberia, Cumberland, Brazil, Ceylon and elsewhere. Unlike the diamond, it is quite soft, has a specific gravity of 2.3, and conducts electricity.

Thanks to its conductivity for heat, graphite is used to make crucibles.

As graphite does not interact with chlorine, it is widely used for electrodes instead of conventional conductors in electrochemical industries in cases when chlorine is to be liberated. Graphite is employed also as a lubricant.