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Show 206 'I‘Il l‘lh‘lS .-\ (,‘mnumsnx «w THE ll).\'l7..r\'l‘l().\' BY, AND S'rm'rixu l'owx-zic mm, .\Len.\ l).\l{'l‘l(‘lrl~2.\‘ (n-‘ l‘llrl-ZAH-iN'l‘S .\.\'l) (,'().\ll'()UNDS A methurl (il' determining (lifi'erential dripping powers for last it partieles has been applied in a number (if gases. The results show that web unstable molecules as .\0 "Mil ll_‘,('-.\' .\'(‘ll3 give strietly aililitive stopping powers. The .N'lHIIIViHi‘n' imwein nl' all investigated gases are mastant within one or two per eent for the first 16 mm. of range from polunium. The method used by Gurney. aml by (libsnn aml Gardner, for deter~ mining ~flopping [mwers at the eihl of the range was inveStigateil, an‘l lllmlllit'll in swine iletails. A series «if stopping powers for each of fun!" gases was ul)taine<l. 'l'he I'UltiUH of a lragg ionization enrve bet'ure-‘n the maximum and the last 1.3 min. i\' :q-prnximatel)' a \traight line. if the ionization enrve for an invlix'illual u particle is asunnenl to be a straight line, and if :1 .xtraggling of the r1 partieles given by the well known equation it: 1. e"(EV .. a. V- » (ilerivenl tliem-etie'ill_\' by l‘mlu aiel Fiainin. :n'i testecl experimentally by Irene Curie, Briggs, and otherw is assume-l. the en-l of the Bizigg ll!!ll/.1ill()ll Mine is :n-enraII-ly repriplaeeil. This has been shown by llennlermxi :Hlll by Irene (Varie, 'l'he \‘aiae~ u?" r whit-h they used were Ulvlillllt‘ll from ether eonsideraiinna The inverse prueess. that of linnlinn: (1 frnm the eml of the Bragg innizatinn enrt'e. lia< been useil, and Values ('1' a fur air have been l'l‘lllllll'll by this luroeess which agree with these given by the ntlier inetinnls. This pi'm‘eillll'e is applicable to the sixmy bf straggling in any Mllmiallee ehemieally nen-reaetive. The ionization eurves for nitrie (lellC, uitl'eus oxide, and air were t‘unnrl to give striet proportimmlipv (if their erilinates, while methyl imliwle (lelinitely lines not: so it seems that tliti'erenee in atemie number, an'l not atnmie gmuping, ehangex the shape of the ionization) eurve. |
