44 ANNUAL OF SCIENTIFIC DISCOVERY. 



water in the boiler falls below the level of the tube, the latter will become 

 wholly filled with steam and heat up the water pipe, forming steam in it also; 

 the pressure thus produced in the water pipe will extend the diaphragm, raise 

 the throttle lever and permit the pump to inject water into the boiler ; when 

 the water level is restored the tube again fills, in part with water, the press- 

 ure on the diaphragm ceases, and the pump throttle shuts. 



Improvement in Governors for Steam Engines. Ball governors are the kind 

 now almost exclusively used on all stationary steam engines ; they are not 

 adapted to marine purposes, because they always require to stand plumb. In 

 all cases they are comparatively sluggish in their operations; where the 

 driver is required to run fast the old-fashioned governor must be geared to a 

 slow speed, for if it goes beyond a certain velocity it will not operate. And 

 when thus geared, the machinery at times almost has a chance to run away 

 before the governor affects the throttle valve. An ingenious improvement to 

 obviate these difficulties has recently been made by Messrs. J. & E. Arthur, 

 of New Brunswick, N. J. Instead of swinging arms and balls, they use 

 slender elastic springs or ribs, which, when applied to the governor spindle, 

 look to use a homely comparison like the frame of an oyster-balloon 

 stripped of its covering. These ribs are attached at one of their ends to a 

 collar fixed fast on the spindle. The other ends terminate on a sliding collar 

 which connects with the throttle. When rapid motion is communicated to 

 the spindle the elasticity of the ribs is overcome by centrifugal force, and they 

 bulge out in the center; in other words, their poles flatten, just as the earth 

 does in revolving ; the result is that the movable collar slides up or down on 

 the spindle, in conformity with any variation in the speed, and operates the 

 throttle in accordance. It will be evident to any mechanic that this governor 

 will be more sensitive than the ordinary kind, since it may be geared to run 

 at a higher speed than the engine, and thus caused to move the throttle, in 

 case the velocity changes, before the machinery could make even a quarter of 

 a revolution. As a marine governor this improvement seems to be also well 

 suited, since the position in which it is placed, makes no difference with its 

 operation. It is much cheaper in its construction than the ordinary govern- 

 ors. Scientific American. 



Ignition Gas Engine. At the recent fair of the American Institute a large 

 engine, called the "Ignition G-as Engine," was exhibited. The principle on 

 which this engine acts is that of first filling the cylinder to a certain extent 

 with explosive gas, next igniting the gas by an electric spark or otherwise, 

 and allowing the piston to travel to the end of the stroke by the impulse thus 

 obtained. The gas employed may be any combustible one mingled with air. 

 Fairbairn and others, in a report to the British parliament -on coal-mine ex- 

 plosions, stated that one part coal gas, with fifteen of common air, would form 

 a mixture it were possible to explode : but a pamphlet explanatory of this 

 engine informs us that one part in nine is found most economical in practice 

 which is probably the case. The vapor of spirits of turpentine, or its relatives, 

 naphtha, camphene, etc., may be used as well as coal gas for this purpose : 

 and a very ingenious, or rather a complex arrangement of pieces, is provided 

 for attaching the igniter. It appears that hardened cast-iron is thought to be 





