Evening Star Newspaper, December 16, 1936, Page 11

NEW WEIGHT BASE FOR EARTH FOUND! Six Years of Work on Gravity Measurement Sets Figure Lower. BY THOMAS R. HENRY. Finding of a new absolute value for the acceleration of gravity—and hence & new basis for determining the weight of the earth—was announced today at the Bureau of Standards. The result was obtained by six years of work with delicate instru- ments, mostly in an underground vault, by Dr. Paul R. Heyl and Dr. G. 8. Cook. It shows that the speed of a falling body is accelerated 980.08 centimeters per second as it drops to the earth—a value which is lower by two parts in 10,000 than the hith- erto accepted value obtained at Pots- dam, in Germany, 30 years ago. This indicates that the earth is considerably lighter than the weight calculated in the past—but it is only the second step in obtaining an ac- curate figure for the mass of the planet. Dr. Heyl, in a specially con- structed circular hut in the woods near Albemarle street and Connecti- cut avenue, is about to start work on the third step, which will require sev- eral years. Everybody Weighs Less. The result also indicates that the weight of every person on earth is a trifie less—approximately 20,000,000ths less, which is far too minute a dif- ference for any scale—than it would have been considered yesterday. Gravity is the force of attraction | between two bodies, which varies di- rectly as their masses and inversely as the square of their distance apart. Thus, if the weight of any object is accurately known, the weight of any other object could be deduced | from it by the attraction between the two, if it could be measured. It is the force which pulls all falling bodies toward the earth. The falling body, of course, also is pulling the whole earth towards itself, but the relative | mass of the earth is so enormous | that the contrary pull cannot be de- tected. Three Requisites. In order to obtain an accurate | measure of the earth’s weight, Dr. Heyl explains, it is necessary to know three things to fit into the gravita- | tional attractions formula. First is | the actual radius of the earth. Sec- ond is the so-called Newtonian con- stant of gravitation, which Dr. Heyl | refers to as “big G.” Third is the ac- | celeration of gravity—his “little g | the determination of which he has just completed. The earth's radius is known with | considerable precision. value, postulated by Sir Isaac Newton and first determined by the English physicist Cavandish about 150 years ago, was redetermined by Dr. Heyl himself a few years ago. It is ex- tremely small—about 6.670 times 10 | to the minus 8 power. Dr. Heyl| at the conclusion of his work in 1930 found that it was slightly smaller than the accepted value, and immediately started his measurement of “small g.” Square Vault Discarded. He was by no means satisfied, how- ever, with his value for the constant of gravitation. First, the work was carried on in a square vault where there was some variation in the dis- tance between the tortion balance which he used and the walls. The | new laboratory has circular walls, and | 4s far enough removed from Con- | necticut avenue to be away from the | disturbing influence of automobiles | and busses. Moreover, he now has an instrument of much greater precision which, he believes, will make it pos- | sible to carry the determination to | one more decimal point. This rede- termination will be the third step in “weighing the earth.” The earth weighs “small g” divided “big G” times its radius. Dr Heyl's work has been designated #s “the symphony in g minor and | the symphony in G major.” The planet, on the basis of present ealculations, weighs approximately 6,000,000,000,000,000,000,000 tons. Animal Life Negligible. ‘The mass is so great, Dr. Heyl says, that if all the men and all the ani-| mals on earth were suddenly trans- | ported to the moon the loss in weight would be so trifling that it would be impossible to detect it with any existing instruments. The determination of the gravity eonstants, he stresses, has & much more practical importance. For ex- ample, the “small g” which he has Just determined enters into the cal- culation of some of the fundamental eonstants of elecmcny ‘The house- SANTA WANTS ME TO REMIND YOU TO BE SURE TO PUT ELECTRICAL GIFTS | ON YOUR SHOPPING holder actually pays for gravity in his electric light bill, by a roundabout process. . The cost, of course, .is in- finitesimally small, but the differ- ence in values may be of considerable importance in scientific work with electricity. More immediately practical is the use made of the absolute value of gravity in big-scale surveying where the curvature of the earth must be taken into considsration. The pres- THE EVENING. STAR, WASHINGTON, D. C., WEDNESDAY, DECEMBER 16, 1936. ent investigation was undertaken at the request of the Coast and Geodetic Survey. By means of the formula the dis- tance from the center of the earth to the surface can be determined at any particular place. Board Established in 1856. ‘The Mississipp! State Agricultural Board was established in 1856. HOLIDAY LAW HELD NEEDED FOR POLICE Elliott Rules Time Off With Pay for Firemen Also Requires Special Legislation. may be granted time off with pey for having to work on legal holidays and the Saturday half holiday granted to other Government workers, acting Controller General R. N. Elliott ruled yesterday. He held, however, that firemen and policemen are entitled to 26 days |annual leave with pay, not €ounting ‘any legal holidays that might fall 8pecial legislation would be needed | within the periods the men were on before District firemen and policemen | annual leave. Up to now, such legal holidays have been counted as part of the snnual leave of policemen and firemen when they fell within the leave periods, Officials of the departments revealed recently at s meeting of the Presi- dent’'s Committee on PFiscal Relations that additional men would have to be employed if the firemen and police were granted compensatory time off for working a full day on Saturdays. Denominations Co-operate. YORK, Nebr. (#).—The necessity for trimming expenses melted the de- nominational differences between York's First Congregational and Pirst Baptist Churches. Under their merger agreement the Congregationalists will furnish a church building and 60 per cent of the funds, while the Baptists will provide 40 per cent, the parsonage and a preacher. Crowns of Hats Higher, PARIS (P).—New “Mexican” hats in Paris are being made in black felt, with wide, alightly rolled up brims, and towering crowns smaller at the top than at the base. Guiltless of other trimming, they look “perfectly swell” with a Jace-bordered veil draped nonchalantly down front or back. Tal} persons look best in these “tomalf land” types. — Tk x m"‘ SURE OF A CHRISTMAS WELCOME. BEAUTIFUL SATIN Secrete Slips and Silk Gowns The second | [ JRT—————————— N s AR e P F STREET at SEVENTH £ The Slips: HAND-DETAILED She'll finger lovingly * the glorious all-silk fabrie, beautiful as trousseau satin . . . note with the delight the perfect tailoring and smooth fit . . . and compliment you on your taste. 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