pipe 4 inches in diameter that leads to the burners. (See fig. 81.) The burners are of special design, and were made by the company's workmen. Steam for atomizing the oil is supplied to the burners at normal load of 200 lbs., through a -inch hole, but

on a heavy load the steam is by-passed through a 2-inch hole. The plant originally was equipped with 27 boilers, but with the installation of a new 15,000-kilowatt turbine in July, 1919, four of the original boilers were removed and eight 822 horsepower vertical water tube boilers were installed. There are four fuel oil pumps and four oil heaters in the boiler room. (See fig. 82.)

In December, 1908, a 9,000 kilowatt turbine was installed in the Oakland steam plant of the Pacific Gas & Electric Company,

FIG. 82. Boiler Room Showing Piping for Oil Burners in California Electric Plant.

but in 1911 it was deemed advisable to further protect the consumers of the company by installing a sister unit of greater capacity to meet any emergency that might arise, so in 1911 a 12,000 kilowatt vertical turbine was installed. This new turbine is supplied with steam from four 773-horsepower water tube boilers of the Parker type, each boiler containing 366 four-inch tubes 20 feet long, heating surface 7,734 square feet and grade surface 48 square feet.

The turbine can be operated in parallel with the main transmission lines of the company or separately on the Oakland load. The arrangement of the plant is such that extension can be made

TABLE 22.-EVAPORATIVE TEST OF OIL-FIRED BOILER AT ELECTRIC PLANT.

CHAPTER XIV

FUEL OIL IN THE SUGAR INDUSTRY

Although sucrose or cane sugar (C_H„ ...) is found in many plant, its extraction is often unprofitable because it is masally found in association with other substances. Only a comparatively small quantity of the sucrose will crystallize if dextrin, glucose, "invert sugar," or dissolved mineral salts are present in considerable quantities. Sugar is obtained commercially from various sources, the most important of which are sugar cane. sugar beet, sugar maple and the date palm. Although the sorghum plant contains considerable sugar it has not been possible to obtain from it a satisfactorily crystallized product, even after much experimentation, because its sugar content varies and in addition it contains a large percentage of gums and dextrin. As a commercial product, in the peculiar flavor of maple sugar lies its only value. When maple sugar is refined it cannot be distinguished from ordinary cane sugar, because it loses the maple sugar taste. Date palm sugar is shipped for refining and is produced in India as a low-grade crude sugar, where it is known as "jaggary."

Practically all commercial sucrose is obtained from the sugar cane and the sugar beet. A warm and moist climate is necessary for the growth of the sugar cane and there must be periods. of hot and dry weather. Sugar cane is a member of the grass family and it is propagated by budding. A plant and several shoots are produced from each bud and these shoots form cane clumps. The height of the stalks varies; some being only four or five feet high, while some attain the height of twenty-five feet.

Practically all of the supply of sugar comes from Louisiana, Brazil, the West Indies, the Sandwich Islands, the Philippine Islands, Java, and Mexico. The climate suitable for sugar cane is not suitable for sugar beets, which require a temperate climate. Germany, France, and the United States raise great quantities of sugar beets.

In the growing cane plant, as is the case with many fruits, it is not until the plant reaches maturity that sucrose is secreted.

After the juice is squeezed from the ripe cane its analysis is about as follows:

The actual yield of sugar, however, is not equal to the analysis, because ordinarily 16 to 20% of the juice cannot be extracted from the waste cane pulp, which is called "begasse." The mineral salts can be decreased in the mature cane if the soil in which it grows is plentifully limed, because the lime precipitates salts deposited by surface water and the decomposition of the soil. The preparation of raw sugar from the cane is divided into four operations:

(1) Extraction of the juice.

(2) Clarification of the juice.

(3) Evaporation of the juice to crystallization.

(4) Separation of the crystals from the liquor.

In the field the leaves are stripped from the cane and the

stripped cane is taken to the mill, where it is crushed and all of the juice extracted which it is possible to squeeze out. A great deal of the sugar is lost if fermentation begins, and consequently the crushing must be done very soon after the cane is cut. The crushing mills are very simple and are made up of two or three horizontal rolls having a diameter of 30 to 60 inches (see fig. 83). The axes of the rolls are parallel and the bearings of the rolls are adjustable. If the mill contains three rolls, the cane passes between the top roll and the first bottom roll and then between the top and the second bottom rolls. The second bottom roll is set nearer to the top roll than is the first, so that the crushing is done in two stages. The cane is ordinarily passed through two or three of these crushing mills and about sixty to seventy percent of the juice is extracted. In Louisiana shredder machines are used which consist of toothed wheels that revolve at different