Devices

Spy Cameras. To spy upon factories whose chimneys spew smoke in violation of municipal ordinances, President Harvey N. Davis of Stevens Institute of Technology last week recommended a long range camera which automatically registers on a long film a picture of everything in its purview, every 30 seconds for eight hours. Shrewd pryers at once thought of many another use for such a device.

Turtle. At Canton, Mo., Mississippi river town quite like those which ingenious Huckleberry Finn knew, a snapping turtle paddled out of a sewer. To its tail was tied a cord. A man hauled at the cord until its end appeared. To that end was tied a rope. The man hauled at that rope and soon a scraper came dragging through the sewer. Thus Cantonese ingeniously cleanse their clogged conduits.

Herring Hearer. Rear-Admiral Henry P. Douglas of England's navy last week revealed a cunning adaptation of the microphone used to detect the proximity of submarines during the War. Fifteen British steam trawlers use such microphones to hear the soughing of hurried schools of herring.

Electrolytic Iron Pipes. A way of making iron pipes cheaper than the usual casting process has been developed by Colin G. Fink, professor of electrochemistry at Columbia. He dissolves crude iron in acid and gets an electrolyte. Into the liquid he immerses a steel cylinder. Through cylinder and electrolyte an electric current goes. Pure iron breaks out of the electrolyte and adheres to the steel cylinder until by such electroplating an iron pipe is formed. Professor Fink avers that his electrolytic pipe is as strong as a cast pipe./-

/- He has also developed chromium plating.