The Emission and Transmission of Rontgen Rays . Eepeated reference has been made (p. 134 andelsewhere) to the apparently anomalous behaviour of nickel, and it is here convenientto take up the lately discussed question of its atomic weight. Barkla and Sadler, * * Barkla and Sadler, Phil. 408, Sept., 1907. 140 , KAYE ON THE as mentioned above, claim a higher atomic weightâ61*4âfor nickel than the value58*7 to which chemists give acceptance. The evidence the latter offer for the atomicweights of both nickel and cobalt (59) is so strong, that one hesitates to accept so biga change
The Emission and Transmission of Rontgen Rays . Eepeated reference has been made (p. 134 andelsewhere) to the apparently anomalous behaviour of nickel, and it is here convenientto take up the lately discussed question of its atomic weight. Barkla and Sadler, * * Barkla and Sadler, Phil. 408, Sept., 1907. 140 , KAYE ON THE as mentioned above, claim a higher atomic weightâ61*4âfor nickel than the value58*7 to which chemists give acceptance. The evidence the latter offer for the atomicweights of both nickel and cobalt (59) is so strong, that one hesitates to accept so biga change as Messrs. Barkla and Sadler suggest. Their contention seems to rest onthe following experiment. The secondary Rtintgen radiations from Fe, Ni, Co, Cu,and Zn were cut down by a single screen of each of the following metals:âAl, Fe,Cu, Zn, Ag, Sn, and Pt. The percentage absorptions were plotted against the atomicweights of the radiators, and the points for the same screen were joined by a smoothcurve (fig. 1, p. 410 in their paper). 2 0. COOS,/}**; THICKNESS of FT $Cft££/V Ooi Eig. 9. Pt screen, 20,000 volts. The curves for five of these screens indicate a value about 61*4 for the atomicweight of the nickel radiator; the curves for the other two screens (Cu and Fe) whichexhibit selective transmission are not used. It is noteworthy that four of the fivescreens (Al, Ag, Sn, and Pt) have thicknesses which produce roughly the sameamounts of absorption of the different radiations, so that any anomaly affecting theone screen might perhaps be expected to occur with the other three. The rest of the paper deals mainly with absorption coefficients and data are calculated from results obtained as above, by assuming the homogeneityof the different secondary beamsâa general assumption admitted by the authorsthemselves to be dubious (p. 421). I venture to suggest, on the lines of the results obtained in the present research on EMISSION AND TRANSMISSION OF
Size: 1606px × 1555px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectproceed, bookyear1909
