This issue is composed of the following stories and articles, some of which go unattributed on the table of contents:

POPULAR SCIENTIFIC ARTICLES

LETTERS NOW SENT BY RADIO—Front Cover From a painting by Howard V. Brown

EDITORIAL By H. Gernsback

AMERICA'S FAST MINE LAYERS By Graser Schornstheimer, Naval Expert

BOY SINGS SIX OCTAVES By Eric. D. Walrond

A MOTOR-DRIVEN PARACHUTE By Eric D. Walrond

ELECTRICITY'S MONUMENT By H. Gernsback

BLUE AND YELLOW LIGHT HAVE SAME SPEED IN SPACE A MONUMENT TO INVENTOR OF TELEPHONE

A SUB-CONSCIOUS MURDERER By Nellie E. Gardner

AIRPLANE WRITES WORDS IN SMOKE

DR. HACKENSAW'S SECRETS—No. 9, THE SECRET TELEVISION By Clement Fezandié

POPULAR ASTRONOMY—A REMARKABLE DOUBLE STAR SYSTEM By Isabel M. Lewis, M.A. of the U.S. Naval Observatory, Washington, D.C.

UNUSUAL METHODS OF OBTAINING MOTION By E. R. Caley

RADIO TYPEWRITER HERE—WITH OFFICIAL NAVAL PHOTOS OF APPARATUS By H. Winfield Secor

CAPTIVE PLEASURE AIRPLANE

POISONOUS SNAKES, SNAKE POISONS, AND THEIR ANTIDOTES By Dr. Ernest Bade

LABORATORY TO DETERMINE ATOMIC WEIGHTS Translated by Dr. T O'Connor Sloane

NEW TALKING "MOVIE" PROCESS By Edwin Haynes

PREVENTING DUST EXPLOSIONS By Joseph H. Kraus

FLICKERLESS MOVIES SILHOUETTE MOVIES NOW HELICOPTER COMPLETES FIRST FLIGHT

ANIMAL MONSTERS IN MINIATURE By Dr. Ernest Bade

SCIENTIFIC PROBLEMS AND PUZZLES—No. 2 OF THE SERIES By Ernest K. Chapin

MOTOR HINTS—$50.00 IN PRIZES

PRACTICAL CHEMICAL EXPERIMENTS By Prof. Floyd L. Darrow

EXPERIMENTAL ELECTRO-CHEMISTRY By Raymond B. Wailes

A CUPROUS OXIDE PHOTO-ELECTRIC CELL By Raymond B. Wailes

EXPERIMENTS WITH SPARK OIL AUTOMATIC CLOTHES REEL PRINT WITH LINOLEUM

HOW-TO-MAKE-IT DEPARTMENT—$30.00 IN PRIZES

WRINKLES, RECIPES AND FORMULAS Edited by S. Gersnback

RADIO AND THE TELHARMONIUM By Robert Stewart Sutliffe

"MOVIE" EXPLAINS RADIO By H. Winfield Secor

THE SUPER-REGENERATIVE AUDION CIRCUIT By Robert E. Lacault

DR. DE FOREST SOLVES "TALKING MOVIE" PROBLEM

"WBAY"—LATEST NEW YORK BROADCASTING STATION By A. P. Peck

NEW FILAMENT COMPRESSION RHEOSTAT

RADIO FOR THE BEGINNER By Armstrong Perry

RADIO BROADCAST RADIO ORACLE LATEST PATENTS THE ORACLE—QUESTION AND ANSWER BOX

NO ELECTRICITY OF FRICTION By Elihu Thomson

The Broadcast Chorus of a Million Marmots

PATENT ADVICE Edited by Joesph H. Kraus