MECHANICS AND USEFUL AKTS. 133 



pressure of the gas in the pipes. An increased pressure of the gas in the 

 pipes and chamber raises the valves, and contracts the opening, a diminished 

 pressure causes the valve to drop, and the opening to be enlarged. 



In a patent granted during the past year to Palmer and "Woodruff, of New 

 Haven, Conn., for gas-regulators, the apparatus has two cylinders, one ar- 

 ranged within the other, and having communication all round the bottom, 

 making them equivalent to an inverted syphon. There is a space between 

 the two constituting an air-chamber, having communication with the atmos- 

 phere through two small tubes at the top. The interior of one cylinder is the 

 gas-chamber. This chamber is always filled with gas, and the pressure is the 

 same as in the pipe. The valves of the inlet and outlet tubes are conical, and 

 close downward ; they are attached to a rod which has a float on it, resting 

 on the water in the lower part of the gas-chamber. The gas and air-chambers 

 are filled with water to such a height as to give the valves a full opening 

 when the burners are all open and the pressure lowest. As the pressure in 

 the pipe tends to increase by pressure on the main, acting on the inlet, or by 

 shutting off some of the burners, acting on the outlet, the pressure in the 

 gas-chamber increases, and acts on the surface of the water, depressing its 

 level, and forcing it into the air-chamber, when the float of the valves falls, 

 and contracts the gas-openings. When the pressure of the gas diminishes, 

 the contrary effect is produced, and thus the pressure in the pipe which sup- 

 plies the burners is rendered uniform. 



WEIGHT OF COAL. 



A recent decision of the United States Circuit Court of Philadelphia es- 

 tablishes the weight of a ton of coal at 2,240 Ibs., instead of 2,000 Ibs. The 

 judge ruled that a company of grocers might as well meet and agree to reduce 

 the number of ounces in a pound, and make the smaller number the standard 

 of a pound for their customers, as for coal-dealers to agree that the weight of 

 a ton shall be 2.000, and furnish that amount to their customers. 



DEDEEICK'S IMPROVED HAY-PRESS. 



A curious fact in relation to rail-road economy has recently been stated, 

 namely, that there are at present more horses employed hi connection with 

 the different rail-road companies in New York City, than were used twenty 

 years ago upon all the stage routes directly leading to the city. This greatly 

 increased number of horses within New York has also occasioned the con- 

 sumption of a vast additional amount of hay, nearly all of which is brought to 

 market ha a pressed and baled condition. This in turn creating an additional 

 necessity, has required a better and more efficient form off hay-press than was 

 formerly used. An old-fashioned hay-press required a separate and entire 

 building for its accommodation, and was an expensive and inconvenient ma- 

 chine. This has, however, been superseded by a press invented by Mr. Levi 

 Dederick of Albany, N. Y., which appears to combine all the advantages de- 

 sired. The main improvements in this press relate to the arrangement of the 



