Then he wound up his magnetic detector and sent an answering challenge into the ether.

Everyone will have to walk through a magnetic detector.

Then there is the magnetic detector.

In the Marconi system of the present time there are many forms of coherers, also the magnetic detector and other variations of the original apparatus.

After a few minutes we heard from our magnetic detector the faint sound of the S signals, and then we broke into a great cheer.

With one of Marconi's magnetic detectors signals from Cape Cod were read at Poldhu.

We do this by magnetic detectors, which report instantly the conjunction of the positive and negative.

If we were born with magnetic detectors, the compass would never have been invented because we wouldn't ever need one.