Part 3 (2/2)

At 68 Fahr 1800 pounds

At 50 Fahr 1736 pounds

At 32 Fahr 1672 pounds

At 0 Fahr 1558 pounds

At -10 Fahr 1522 pounds

_Chlorate of Potash Method_--In spite of its higher cost and the inferior gas produced, the chlorate of potash en is used to a lias in cylinders

[Illustration: Figure 8--Oxygen froure 8) is arranged to receive about fifteen pounds of chlorate of potash anese dioxide, after which the cylinder is closed with a tight cap, claas or other hted after the cheeneration of gas coh water baths which wash and cool it before storing in a tank connected with the plant

Froas is compressed into portable cylinders at a pressure of about 300 pounds to the square inch for use as required in welding operations

Each pound of chlorate of potash liberates about three cubic feet of oxygen, and taking everything into consideration, the cost of gas produced in this way is several times that of the purer product secured by the liquid air process

These cheer, especially when used with or near the acetylene gas generator, as is sometimes the case with cheap portable outfits Their use should not be tolerated when any other er from accident alone should prohibit the practice except when properly installed and cared for away froases

ACETYLENE

In 1862 a chemist, Woehler, announced the discovery of the preparation of acetylene gas froh temperature a mixture of charcoal with an alloy of zinc and calciuas For nearly thirty years these substances were neglected, with the result that acetylene was practically unknown, and up to 1892 an acetylene flame was seen by very few persons and its possibilities were not dreamed of With the development of the modern electric furnace the possibility of calcium carbide as a commercial product became known

In the above year, Thoineer of Spray, North Carolina, was experi in an attempt to prepare metallic calciu on a mixture of lime and coal tar with about ninety-five horse power The result was a molten mass which became hard and brittle when cool This apparently useless product was discarded and thrown in a nearby streaas was iht and save off quantities of soot The solid as acetylene

Thus, through the incidental study of a by-product, and as the result of an accident, the possibilities in carbide wereof 1895 the first factory in the world for the production of this substance was established by the Willson Aluht together an action takes place which results in the foras and slaked lime

CARBIDE

Calcium carbide is a che dark brown, black or gray with soe It looks like stone and will only burn when heated with oxygen

Calciuth of time if protected froradually affects it until nothing re odor, which is not due to the carbide itself but to the fact that it is being constantly affected by as

This material is not readily dissolved by liquids, but if allowed to come in contact ater, a decoe quantities of gas Carbide is not affected by shock, jarring or age

A pound of absolutely pure carbide will yield five and one-half cubic feet of acetylene Absolute purity cannot be attained coood carbide will produce from four and one-half to five cubic feet for each pound used

Carbide is prepared by fusing lime and carbon in the electric furnace under a heat in excess of 6,000 degrees Fahrenheit Thesethe most difficult to melt that are known Lime is so infusible that it is frequently ehestht because it will stand extreh temperatures

Carbon is the ht electrodes and other electrical appliances that must stand extreme heat Yet these two substances are forced into combination in the h temperature attainable in the electric furnace that causes this combination and not any effect of the electricity other than the heat produced