The slot-doorbell, introduced into the Netherlands but a short time ago, has swiftly become a best seller. Instead of ringing the house bell one drops a Dutch cent into the slot and it goes “Bong!”

A slot-doorbell—that was what frugal Dutch huisfrouwen were having carpenters install last week beside their furiously polished brass doorknobs.

The slot-doorbell, introduced into The Netherlands but a short time ago, has swiftly become a best seller. Instead of ringing the house bell one drops a Dutch cent* into the slot…