126 We try to work out some method which will give ua a straight line function because it is difficult to compare curved shapes and we found that by using an intermediate substance such as phogphoroug 32, and plotting a log line relationship, that is of activity transmitted in aluminum for phosphorous versus activity transmitted of your sample, you can obtain a straight line relationship if you have an isotope emitting one Beta particle that is one of a maximum energy Beta, Row, the first slide I have here is the conventional method, This is the phosphorous 32 and this one, The thickness of aluminum versus activity transte mitted in per cent and you see if you come pare two curves like this it would be a visual process just looking at shapes. The second slide is the sane phenomenon plotted on a three logarithmic -- three cycle logarithmic paper and in thie case, the tranemigsion of beryllium ia plotted versus the transmission of Pao for each, for the same absorber and even’ though the Beta points aren't shown, it's a very good straight line, Now, the good part of this method ED