SAFETY AT SEA 174 SAFETY AT SEA length be carried that metallic gauze, which may be looked on as a series of very short square tubes arranged side by side, completely arrests the passage of flame in explosive mixtures. The first lamp which would safely burn in an explosive mixture of gas and air was contrived in 1813 by Dr. W. Reid Clanny of Sunderland. Into this lamp DAVY SAFETY LAMP fresh air was blown through water, and heated air escaped through water by means of a recurved tube. Such a lamp was unfit for ordinary use. George Ste- phenson invented a safety lamp which was tried at the Killingworth pits in 1815. Both Clanny and Stephenson ap- plied wire gauze cylinders to their lamps after Davy's came into use, or at least after a communication about it had been made to the Royal Society in 1815. Por- table electric lamps are now in general favor, but they give no warning of gas, and in mines much affected by gases the oil-safety lamp is in use. SAFETY AT SEA. The principal dangers to life at sea are connected with stranding, foundering, collision and fire. These dangers are being reduced year by year through improvements in the design, construction and equipment of ships and through inventions and im- provements in the conditions of naviga- tion, many of which are revolutionary in their nature. Radio telegraphy is finding what is perhaps its most beneficent ap- plication, in communication at sea, where a ship in distress can now give notice of its danger to other ships and to shore stations hundreds of miles away; and a very recent development makes it pos- sible for a ship hastening to her assis- tance, to locate her not only by reports of her latitude and longitude but by the direction from which her signals are com- ing. The same invention which makes this possible, — the "Radio-direction Find- er" — makes it possible also for shore sta- tions to guide a ship at sea and in a fog as accurately toward the entrance of the harbor she is seeking as if the lights and buoys of the entrance were plainly visible. A similar device for determining accu- rately the direction of sound, makes it possible for ships in a fog to locate and avoid each other, thus enormously re- ducing what is perhaps the most serious of all dangers at sea, collision in a fog. It is even proposed today to lay a wire along the bottom of a channel and, by sending through it a current of electricity, to enable a ship to follow the channel perfectly, no matter how tortuous it may be; and this in the thickest fog and with the helmsman blindfolded. The service of weather observation and report is improving steadily and both its sources of information and the area cov- ered by its warnings are being greatly extended. Dangerous storms are located almost at their origin and tracked not only day by day but hour by hour, notices being sent broadcast through the air pre- dicting their future movements with such accuracy that they are easily avoided by ships which can afford the time to give them a wide berth. The latest plan of the United States weather service is to main- tain a number of small vessels during the hurricane season, in the Caribbean Sea, where most of the Atlantic tropical storms have their origin, to study these storms by actually seeking them and accompany- ing them on their course. In spite of all that has been done and all that can be done to reduce the dan- gers of the sea, disasters still occur and will continue to occur; and the- problem of minimizing their effects is receiving more attention than was ever devoted to it in days when the dangers were far greater than at present and disasters far more frequent. The details of construction of ships and especially of ships carrying passen- gers, are prescribed by laws enforced by careful inspection which begins with the building of the ship and follows it
