FROM time to time accounts appear of experiments on new kinds of steel which have been undertaken with the object of determining the most suitable material from which to construct a permanent magnet.

The mechanism that reads and writes magnetic tape as it moves past. Quality tape recorders have three heads: play (read), record (write) and erase. Many consumer products have only two: one that plays ...

A small length of magnetic tape adhered to credit cards, badges, permits, passes and tokens. The tape is read by magnetic stripe readers incorporated into ATMs, identification readers and payment ...