with such a device, as most of the smoke is made so early in the morning that a fireman could not see whether or not his stack is smoking, although he took the trouble to go out and look. Moreover, many of these plants are located in basements, making it impracticable for a fireman to see his stack, and unless there is some provision for his information he will not know whether the means taken are keeping down smoke.

The Salt Lake City smoke cloud is unique in smoke-abatement work and hovers over the city so long because of the unusually low wind velocity during the winter. Ordinarily smoke made before daylight in the average city is entirely dissipated before business hours, but in Salt Lake City the large volumes of early morning smoke form the basis of the smoke nuisance throughout the remainder of the day.

If this initial smoke cloud is eliminated, a decided improvement in atmospheric conditions will be noted at once and a condition brought about similar to that noticed on Sunday morning when industrial smoke is at a minimum and in the valley there is only a light haze, for which the residences will be mainly responsible. It will then be easy to concentrate on the remaining classes of smokers to reduce them to a minimum, as is done in the usual smoke-abatement work throughout the daylight hours in other cities.

FUEL SURVEY

In connection with the investigation a fuel survey was made to determine the amount of coal burned in Salt Lake City, the amount burned by different classes of fuel users, the source of the coal, and its characteristics. The amount of coal used by the different classes of fuel consumers, except that used for heating residences and for cooking, was found from answers to questions sent to all coal consumers. The information obtained is given in Table 7.

TABLE 7.-Coal consumption of Salt Lake City, winter 1918-19

The coal consumed by residences was determined in a house-tohouse canvass by the Boy Scouts. This canvass also included a tabulation of domestic heating and cooking equipment. The form following is for such data.

The coal consumed was distributed over the entire year by months. (See Table 8.) All the information concerning coal consumption, with the exception of that for residences, was supplied by months. To distribute the residence consumption by months it was necessary to make some calculations. The coal consumed by plants operated for heating purposes only was distributed by percentage for each month of the year, and it was assumed that the residences which use coal principally for heating would use fuel in the same ratio, so the residence coal was distributed throughout the year in the ratio used for heating plants.

TABLE 8.-Distribution of coal consumption for Salt Lake City, 1919-20, tons

TABLE 8.-Distribution of coal consumption for Salt Lake City, etc.-Continued

67, 804. 10 57, 925. 00 54, 058. 80 39, 107.30 27, 852. 70 23, 398. 15 513, 202.00

CONSUMPTION OF FUEL OIL

A very minor quantity of fuel oil is consumed in Salt Lake City and during the year of the survey amounted to only 1,927,560 gallons. (See Table 9.)

TABLE 9.-Utah oil consumed in Salt Lake City, winter of 1918-19, gallons

The amount of coke consumed in the city was also determined. It was very small-3,470 tons for residences and about 8,000 tons at the plant of the Utah Gas & Coke Co.; the remainder of the coke produced was shipped out of the city.

SOURCE AND CHARACTERISTICS OF COAL

The source of the coal supplying the city market was found by questionnaires sent to all operators who supply that market. The tonnages given were tabulated for five different coals. (See Table 10.) The coals were classified as to the locality from which they came. Those from the same locality have about the same characteristics. Carbon and Emery County coals came from the groun

95813°-26-2

of mines in southwestern Carbon and northwestern Emery County. Spring Canyon coals include all those mined in Spring Canyon. Carbon County coals include those mined in Carbon County with the exception of those classed separately above. The Grand County coals are mined in Grand County. All Wyoming coals were grouped into one class.

TABLE 10.-Total coal consigned to Salt Lake City from July 1, 1918, to June 30, 1919, exclusive of railroad coal

The characteristics of the coal delivered and used in Salt Lake City were determined from a series of samples taken from railway cars and storage piles in the yards of retail dealers. Many analyses of Utah coals are available in Bureau of Mines publications;1 some of these are analyses of mine samples and can only be used as checks. The samples taken were sent to the Pittsburgh laboratory of the bureau for analysis. Table 11 gives the analysis of this series of samples.

TABLE 11.-Analyses of coals on Salt Lake City market

0016

Egg size, domestic equipment

tests.

1.0 2.52 43. 90 47.08 6.50 5. 64 73. 22 1.46 12.74 .44 13,214

1 Pope, G. S., Analyses of Coals Purchased by the Government During the Fiscal Years 1908-1915: Bull. 119, Bureau of Mines, 1916, 118 pp. Snyder, N. H., Analyses of Samples of Delivered Coal Collected from July 1, 1915, to Jan. 1, 1922: Bull. 230, Bureau of Mines, 1923, 174 pp. Analyses of Utah Coals; Tech. Paper 345, 1925, 90 pp.

TABLE 11.-Analyses of coals on Salt Lake City market-Continued

Western coals are generally high in moisture, high in volatile, and high in ash, with a correspondingly low B. t. u. value. Many such coals are rather difficult to burn and are inferior to eastern coals. There are large deposits of lignites and coals of lignite types in the West. Utah coals, however, offer marked contrast to most western coals. Analyses show them to be low in moisture, low in ash, and with a high B. t. u. value, a high percentage of volatile matter, and an extremely low sulphur content. These characteristics make a coal easily burned in all types of furnaces, easily ignited, and free burning, with a minimum production of clinker.

With respect to smokiness, the most pronounced characteristic of Utah coal is its volatile content. In general the higher the volatile matter in coal the more smoke the coal makes when burned, because it is difficult to supply enough air or oxygen to burn the volatile matter