610 Dr. H. Geiger and Mr. E. Marsden on the Laws of 



Table II. 

 Variation of Scattering with Angle. (Collected results.) 



I. 



Augle of 



deflexion, 



0. 



II. 

 1 



III. IV. 



Silver. 



V. VI. 



GrOLD. 



sin 4 (p/'S 



Number of 



scintil- 

 lations, N. 



N 



; Number of 



scintil- 

 lations, N. 



N 



sin 4 <p/2' 



sin 4 0/2' 



o 

 150 . , 

 135 

 120 

 105 



75 



60 ... 



45 



37-5 



! 30 ., 



22-5 



i 15 . . . 



30 



I 22-5 



15 



10 



7-5 

 5 , 



1-15 

 1-38 

 1-79 

 2-53 

 7-25 

 16-0 

 46-6 

 93-7 

 223 

 690 

 3445 



223 



690 



3445 



17330 



54650 



276300 



22-2 

 27-4 

 33-0 

 47-3 

 136 

 320 

 989 

 1760 

 5260 

 20300 

 105400 



5-3 



16-6 

 93-0 

 508 

 1710 



19-3 

 19-8 

 18-4 

 18-7 

 18-8 

 200 

 21-2 

 18-8 

 23-6 

 29-4 

 30-6 



0-024 

 0024 

 0-027 

 0029 

 0031 



33-1 

 430 

 51-9 

 69-5 

 211 

 477 

 1435 

 3300 

 7800 

 27300 

 132000 



3-1 

 8-4 



48-2 

 200 

 607 

 3320 



28-8 

 31-2 

 29-0 

 27-5 

 29-1 

 29-8 

 30-8 

 35-3 

 35-0 

 39-6 

 38-4 



0-014 



0-012 



0014 



00115 



0011 



0012 



angles <f> between the direction of the beam and the direction 

 in which the scattered a particles were counted. Gol. II. 



gives the values of . . , , - In Cols. III. and V. the 

 471 sm 4 <p/2 



numbers of scintillations are entered which were observed for 

 the silver and gold respectively. Corrections are made for 

 the decay of the emanation, for the natural effect, and for 

 change of diaphragm. For the smaller angles corrections 

 have been applied (in no case exceeding 20 per cent.) owing 

 to the fact that the beam of a particles was of finite dimen- 

 sions and not negligible compared with the angle of deflexion. 

 These corrections were calculated from geometrical con- 

 siderations. In Cols. IY. and VI. the ratios of the numbers 



of scintillations to . , . ,^ are entered. It will be seen that 



sin 



42 



in both sets the values are approximately constant. The 

 deviations are somewhat systematic, the ratio increasing 

 with decreasing angle. However, any slight asymmetry in 

 the apparatus and other causes would affect the results in a 

 systematic way so that, fitting on the two sets of observations 

 and considering the enormous variation in the numbers of 

 scattered particles, from .1 to 250,000, the deviations from con- 

 stancy of the ratio are probably well within the experimental 



