General and physical chemistry
Journal of the Chemical Society Abstracts
Astrophys. J., 1919, 49, 42---47) .-Thc. region investigated extended frobm 9000 to 30,000 A., and was found to contain some fifty measurable lines. The experimental arrangement was the same as that previously described (Randall, A., 1910(Randall, A., , ii, 1014. The slit of the collirnat-or and the thermopile were a t first approtxiniately 0.2 mm. wide, and covered a region in the neighbourhood of l p of about G A. and a t 3 p of aboutl 3.7 A. Later the entire spectrum was examined with a slit
... xamined with a slit 0.5 m m . wide, and a very appreciable number of weaker lines were found and measured. No systematic differences between the values of wave-lengths measured with the slits of different width were noted. The material used iii the major part of the work was ingot iron (99.8% Fe), the largest single impurity being copper, approximately 0.04%. Electrolytic iron also was used. No lines due to impurities in either were observed. The iron was placed in a boring in the positive carbon (1.9 cni.), the hole being as large as the carbon would permit. The carbons showed several infra-red potassium lines and also two others, the approximate values of which are 11,439 A. and 10,692 A. The origin of these lines is not known. The current used was in general greater than 60 amps. Tables of wave-lengths are given in Angstrom units, as measured in air according t o the Rowland scale. The relative intensities of the lines were estimated from the galvanometer deflexions. F o r the region between 0 . 8 ,~ and 1 p the photographic method is more sensitive than the bolometric, but beyond 1 ,U the latter becomes increasingly the more sensitive. 1919, 49, 54-60. Compare preceding abstract) .-The experimental arrangement and methods were the same as those for the iron spectrum. With the exception of manganese, which volatilised readily and gave a comparatively steady arc, the metals were very similar t o iron in their action i n the arc. Nickel and cobalt produced possibly an even mare uncertain arc than iron. The strongest lines were given by manganese. The materials used were " p u r e " metals of commerce. No lines due to any of the impurities likely to be found were actually observed. The currents used were 60-80 amps. The spect.rum of each m&al was in general searched twice, once with narrow slits and once with double widtLh slits. A number of the lines in the tables are multiples of strong lines of short-wavelengths. It is thought, however, that i n each case it has been established that the higher order line of short wave-length is superposed by a line of long wave-length of the first order.