407837 400 ~ @ 0 TOTAL RADIATION N m o Z 8 e -w > ert ~~ ‘Appears to be the principal origin. Theoi ies which propose that the carbon skeleons of furfuryl alcohol and maltol of ‘heared milk derive from carbon atoms (2 to 6 and 1 to 6, respectively, in the ‘glucose moiety of lactose remain attractive in light of these findings (/0)}. S. Patron ae ey R. J. Frrpsr Department of Dairy Science, Pennsylvania State University, University Park References and Notes 1, 2. 3. 4. 5. 6. 7. 8. 9. 10. §. Patten and R. J. Fiipse, J. Dairy Sci, 36. 766 (1953). S. Patton, ibid. 38, 457 (1955). , ibid, 33, 904 (1950). F, E. Potter and 8S. Patton, ibid. 39, 978 (1956); H. C. Sherman, Ind. Eng. Chem. 2, 24 (1910); J. Brand, Ber, deut. chem. Ges. 27, 806 (1894). §. Patton, f. Dairy Sei, 33. 102 (1950). According to I. A, Gould, [f. Dairy Sei, 28. 379 (1945)], 80 to 85 percent of the total volatile acid of heated milk is formic acid. O, L. Osburn, H. G. Wood, C. H. Werkman, Ind. Eng. Chem. Anal. Ed. 5, 247 (1933). C. K. Claycomb, T. T. Hutchens, J, T. Van Bruggen, Nucleones 7, 38 (1950). [Isolated only as its naphthyl urethane. Authorized for publication as paper No. 2134 in the journal series of the Pennsylvania Agricultural Experiment Station. “ 1 300 mr Eos nun ay. 2- 7oo t 0 . Oo a| 913 8 sla oe a ® - - per yr} = m a. ve! 3 200- ¢5 0 S © A ment Lpaatne, garth, » v0 @®@ - wm ~_ - Cv oO —_— os ho ec So : — i - § 5 @ [trae ; e £2E So @ x bh © 2 \ <9 |! 5 86 §Oo o3 £ io a - - - o © o 3 e £ oO a w wo @o e|3 z= 2\3 a |2 ¢ tal oO wo o wo e ww o 3 a Ssa lUéX r aq}oo “) LOCAL GAMMA RAYS Soo 2 8 = o (Local¢ Gosmie} 3 z a O23 ©o Z £ Ze‘ me, 8 March 1957 100 , Gamma Rays from Local Radioactive Sources There is considerable interest at the present time concerning the possible ceffects of man-made radiations on man himself. Because one source of these radiations is of world-wide extent, the interest has also become world-wide. Although considerable literature nowexists on the subject of man-made radioactive contamination, on the one hand, and on the biological effects of radiation, on the other, the actual importance of the first as far as the second is concerned has often been obscure, It is thought desirable at this time to present some independent experimental data that will allowindividuals to reach their own conclusions. As early as 1928, R. A. Millikan be- came interested in the gamma rays emitted by local radioactive materials in the soil and rock at: various localities in order to determine the effect of these radiations on the cosmic-ray measure- ments in which he was primarily interested. These measurements extended from California into the Rocky Moun- tain area and on up to Churchill, Manitoba (1). They probably represent a unique series of measurements, since they were made before man-made contamination became widespread. An ionization chamber measures directly the quantity of interest as far as the biological effects of gamma rays are 1088 cv Man-made Contamination O — we ee —_— ee ree Fig. 1. “‘Noise level” of gamma rays and cosmic rays in the Western Hemisphere. Abscissas roughly increase with increase of distance from Pasadena. The amount of man-made contamination is taken from the National Academy of Sciences report, Biological Effects of Atomic Radiation (7). As is stated in that report, ... U.S. residents have, on the ce average, been receiving from fall-out over the past five years a dose which, if weapons testing were continued at the same rate, is estimated to produce a total 30-year dose of about 0.1 roentgen” (an average of 3 mr per year). concerned, and this is the instrument here employed. One of the instruments Millikan made and calibrated is still in good condition after 26 years and is very convenient to use. A recent redetermination of the absolute value of the calibra- tion (2) agrees with Millikan’s value to 0.3 percent. In this survey, Millikan’s instrument has been used for some of the measurements, and a more modern jonization chamber (3) for others. The two give essentially the same answer. Both were used unshielded in the measure- ments reported here. In Fig. 1, most of the values taken during the years have been entered. The ordinates are in milliroentgens {mr} per year, To convert into ion pairs per cubic 3 centimeter, per second in | atmosphere of air, divide the ordinates by 15. The various stations are plotted as abscissas with the same increment from one to the other. Roughly, the stations get farther from Pasadena with increase in abscissa. The chief reason for plotting in this manner was to bring out the variability of ‘ radioactivity from one station and region to another. Measurements were madeof the total radiation at a given station; then the known contribution from cosmic rays (4) was subtracted to get the effect of the gamma rays from local! radiation only. In the Rocky Mountain region, the local radiation is high, presumably because of the Seay ; which is known to SCIENCE, VOL. 125