Particulars of calls are now passed between trunk centres to a great extent over telegraph circuits superposed upon the trunk lines.
The fibres belong to the same n,orpholcgical category as the parenchyma, various transitions being found between them; thus there may be thin-walled cells of the shape of fibres, or ordinary fibres may be divided into a number of superposed cells.
Settlements belonging to the Stone age, and manufactories of stone implements, burial-grounds of the Bronze epoch, earthen forts and burial-mounds (kurgans) - of this last four different types are known, the earliest belonging to the Bronze period - are superposed, rendering the task of unravelling their several relations one of great difficulty.
These free poles produce a magnetic field which is superposed upon that arising from other sources.
The wire is subject to two superposed magnetizations, the one longitudinal, the other circular, due to the current traversing the wire; the resultant magnetization is consequently in the direction of a screw or spiral round the wire, which will be right-handed or left-handed according as the relation between the two magnetizations is right-handed or left-handed; the magnetic expansion or contraction of the metal along the spiral lines of magnetization produces the Wiedemann twist.