470 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



passes to the engine, and, by means of an electro-magnet, 

 presses upon a lever which opens the steam whistle, thus 

 making it virtually automatic. 3 A, April 11, 1874, 454. 



CHECKING UNCOUPLED CARS ON A DOWN GRADE. 



A portable stand was constructed for this purpose by Se- 

 mann, cut in the form of a quadrant, prolonged into tongues 

 about four feet long, resting upon the rails. When the sig- 

 nal is given that a car has become detached, the road-watcher 

 places this on the track, with the tongues toward the car, 

 the fore wheels of which run over the tongues into the curved 

 recess, and push the apparatus along the track ; and the slid- 

 ing of the tongues and the stopping of the wheels soon check 

 the car. 6 0, January 22, 1874, 38. 



A NEW STEAMBOAT PROPELLER. 



A new propeller for steamers has lately been introduced by 

 Dr. Collis Brown, which differs materially from the screw pro- 

 peller at present in use, resembling, when at rest, the letter 

 X, and claimed to possess many advantages over its prede- 

 cessors. These are stated to be absence of vibration ; reduc- 

 tion of wear and tear to machinery; ready adaptability to any 

 screw steamship; and facility of checking a ship's way, with 

 the power of driving her full speed astern in a few seconds 

 on reversal, as well as giving considerable increase of speed 

 and effecting a great saving of coal. During a trial with the 

 steam-yacht Lapwing, under a pressure of fifty-eight pounds 

 of steam, with a consumption of eighty-one pounds of coal 

 per hour, the propeller made 220 revolutions per minute, with 

 the tide slack, and the furnace burning hard steam coal ; the 

 measured mile being run in five minutes. 3 A, December 27, 

 1873,804. 



HEATING POWER OF WEATHERED CINDERS. 



The efforts at utilizing cinders for building purposes have 

 not succeeded very well; and attempts to burn them have 

 also been unsuccessful, on account of the melting slag which 

 chokes the draft in a short time. According to a communi- 

 cation to the Westphalia Engineers' Association by Chary, 

 when condensed air is passed over glowing cinders in a fur- 

 nace the carbonic oxide formed affords a flame several feet 



