978

THE AMERICAN jOJ1RNAL OF P-UBLIC HEALTH

Benzene exerts its-influence as a-fuel; therefore requiring large quantities for admixture, whereas, the substances named are effective in -fractions of a per cent. Lead tetraethyl is a compound in which a molecule of Pb is combined with four molecules of C2H5. The preparation has been put upon the market under the name of " Ethyl Gas " by the General Motors Chemical Company or, more recently, the Ethyl Gasoline Corporation. Midgley and Boyd feel that it will be only a matter of time when all gasoline will be treated with an " anti-knock " material and that automobile engines having higher compression and giving considerably greater mileage per gallon will be used. Foreseeing the possibility of health hazard to garage and motor workers, as well as to users and the general public, the Corporation arranged with the United States Bureau of Mines in the-autumn of 1923 to begin at its Experiment Station in Pittsburgh, a series of extensive investigations on the pharmacology and toxic effects, if any, of ethyl gasoline when used as a motor fuel, and particularly as to the resulting exhaust fumes from motors. Reports on this work are expected within a few weeks, in which the results of animal experimentations, human exposures, the analysis of air, of street drippings, etc., are to be covered. While it is probable that the full safety of the public and others will be demonstrated as the result of these investigations, this method of procedure also illustrates a somewhat new idea in connection with the exploiting of new discoveries to the public, viz., the primary investigation of the public health aspect. As we know, there are now many substances and appliances upon the market which are dangerous to users as well as to the public which unfortunately have not been given this preliminary study.

MEASURING PERSONAL COMFORT WITH THE KATA THERMOMETERPersonal comfort depends largely upon the rate of cooling of the human body. In other words, the temperature, humidity, and velocity of the surrounding air should be within reasonable limits to permit the heat generated within the body to be removed at the same rate. Persons working under uncomfortable conditions are -necessarily inefficient, although through no fault of their own. Modern industry, to produce the best results from workers, now realizes the importance of personal comfort and is installing equipment to control these three factors ?ertaining to human comfort. It has been shown lately that there is no single index of comfort in atmospheric conditions. The mercury thermometer, which until recently was the only instrument used for measuring the physiological effects of atmosphere, is very inadequate for the purpose, as it merely accounts for that part of the body heat lost by radiation and convection, while a great part of the body heat resulting from the metabolic processes within the body is eliminated by means of evaporation from the surface of the body. This lack of a suitable measuring instrument was partly overcome in 1916, when Dr. Leonard Hill, of England, who introduced 'he kata-thermometer, brought out an improved type. This instrument measures its own rate of cooling when its temperature approximates that of the human body, and thus, under favorable conditions of the environment, serves as an index of the rate of cooling of the body itself. The kata-thermometer is a specially constructed alcohol thermometer-having a stem 20 cm. long, and a cylindrical bulb 1.8 cm. in diameter and 2.2 cm. in

ASSOCIATION NEWS

979

length. As the top and bottom of the bulb are hemispherical, its total length. is 4 cm. The stem is graduated in 0.10 F-.;from 95 to 1000, and an enlargement of the bore at the top of the stem serves as a safety reservoir in case of accidental over-heating. In -manipulating the kata-thermometer, the bulb is heated in water until the alcohol rises to the reservoir mentioned, dried, and the time taken for the alcohol to fall from 100 to 950 is measured by a stop-watch. This time is a function of the heat loss from the surface of the kata-thermometer by radiation and convection. While the heat lost is always the same, the rate of loss depends upon the surrounding atmospheric conditions. It is evident therefore, that there exists a definite relation between the time of cooling of the kata-thermometer and the external conditions. The preceding procedure is known as "dry kata" cooling, but if a wet cotton glove be fitted over the bulb, the rate of cooling due to radiation, convection, and evaporation is obtained, and is known as " wet kata " cooling. The rate of cooling due to evaporation is approximately the difference between these two rates. Dry-kata cooling is considered more representative of comfort under conditions not inducing perspiration, and wet-kata cooling under conditions inducing perspiration. Several readings should be made in all observations, whether dry or wet. All kata instruments are calibrated by the maker and their factor is engraved on the stem prefixed by the letter F. This factor divided by the time of cooling gives the cooling power of the atmosphere in millicalories per sq. cm. per sec. According to Hill, comfortable conditions correspond to a dry-kata cooling power of 6 millicalories per sq. cm. per sec. and a wet-kata cooling power of 18 *nillicalories per sq. cm. per sec. The kata-thermometer under ordinary conditions may also be used as an anemometer. The instrument has, its defects, and it is very doubtful whether any single instrument can be designed to serve as an index of human comfort. Apart from the studies made in England and Transvaal, in America a great deal of work has been accomplished along this line by the United States Bureau :f Mines jointly with the American Society of Heating and Ventilating Engineers.

LIST OF MEMBERSProposed for election to the A.P.H.A., August 30 to September 30, inclusive Names of New Members are set in Light Face Type. Names of Sponsors are set in Bold Face Type.AJLABAMAHomer N. Calver, New York, N. Y.

CONNECTICUTLeonard Greesiburg, M.D., New Haven, Conn.

T. E. Tucker, M.D., B.S., Dothan, Alabama. City and County Health Officer.

Robert Jordan, B.S., C.P.H., New Haven, Conn. Instructor in Public Health, Dept. of P. H., Yale University.

CALIFORNIA Arthur S. Baker, M..)., Alhambra, Calif.

Ottilie K. Stocire, R.N., Health Office, Alhambra, Calif. I)irector of Laboratory. Blisabeth MacVeen Se-phro, M.D., L,oq Angeles, Calif. Adele Brown, M.D., Los Angeles, Calif. Deputy County Health Officer, Child Welfare Division.

FLORIDA EArle D. Clawson, D.V.M., West. Palm HBea. Fla. Mary C. Ryan, West Palm Beach, Fla. City Bacteriologist.ILNI ILLINOIS Hugh 0. Jones, M.D., Chicago, 111. Charles K. Stulik, M.D., Chicago, Ill. Super. visor Infant Welfare, Board of Health.