The heating as well as the illuminating value of the gas per unit volume is lowered by over-baking, and Dr Bueb gives the following figures as to the heating value of gas obtained from the same coal but by different methods of carbonization: Vertical Retorts, 604 British thermal units per cub.
The municipality owns and operates the waterworks, a natural gas plant, and an electric lighting plant.
In order to make spongy or porous rubber, some material is incorporated which will give off gas or vapour at the vulcanizing temperature, - such as carbonate of ammonia, crystallized alum, and finely ground damp sawdust.
The carburetting of low-power gas by impregnating it with the vapours of volatile hydrocarbons.
The manufacture of great quantities of coke has resulted from the demand for this product in the iron and steel industry and from the abundance of coking coal; the manufacture of glass has been promoted by the supply of glass sand and natural gas in the west of the state; the manufacture of leather by the abundance of hemlock bark; the manufacture of pottery, terra-cotta and fire-clay products by the abundance of raw material; the manufacture of silk and silk goods by the large number of women and girls who came into the state in families of which the men and boys were employed in mining and picking anthracite coal; and in each of these industries as well as in a few others the state has for many years produced a large portion of the country's product.
The railways, lighthouses, gas and waterworks and other concessions and industries were placed in British hands.
In this it passes through four sheets of water, by which it is not only freed from any dust and dirt that may have come over with it from the kiln, but is also cooled to a temperature which permits an air-pump to withdraw the gas from the kiln, through the gas-washer, and force it into the saturators, without overheating.
Hence in the act of solidifying it expels any excess of gas which it has dissolved while liquid, and this gas becomes entangled in the freezing mass, causing gas bubbles or blowholes, as at A and B in fig.
The earliest attempts at enrichment by oil gas consisted in spraying oil upon the red hot mass in the retort during carbonization; Enrich- but experience soon showed that this was not an econo- meat by mical method of working, and that it was far better to oil gas.
Nitrogen peroxide is also prepared by heating lead nitrate and passing the products of decomposition through a tube surrounded by a freezing mixture, when the gas liquefies.