mycLn-rieh lilt rate i> admixed with art 1vated carbon on a continuous basis. T h e carbon is introduced by a measuring mecha,sm which integrates the amount of carbon added with the flow of broth fill r a t e and the streptomycin concentration in t h e filtrate. The introduction of carbon must be very closely controlled, as insufficient carbon results in incomplete adsorption and excess carbon reduces the elation yields. The strcptoinycin-rich carbon is separated from the spent broth by filtration. T h e spent broth has a very high biological oxygen demand, and it is d i s posed of by quadruple effect evaporation followed by inciner.-it ion of the resulting concent rate. Following separation from the spent broth, the rich charcoal adsorbate is washed first with alcohol and then eluted with acid-alcohol so hit ion. T h e acid eluate is neutralized and the streptomycin concentration in soluti'-n has now been increased to 0. lO to O.LV, and con. iderable preliminary purification has taken place. Evapora tion of Neutral El note The neutral eluate is now concentrated to a solution from which the streptomycin
Scaborg Announces Fissionable Neptunium Tla v discovery of a fissionable isotope of neptunium was announced by Glenn T. Seaborg, professor of chemistry at the University of California, at a meeting of the California Section of the AMKRICAX CMJVMICAL SO0-ineh cyclotron at Berkeley, but its fissionable tendency and low fission cross section (2 X 10 2G sq. cm.) were discovered by A. (Jhiorso, D. "W. Osborne, and L. H. Magnusson, work-
can be precipitated by solvents as the crude hvdrochloride and be recovered
ing; with Dr. Seaborg at the iikotallurgical laboratory, University olChicngo. \"p-' 17 is among t h e by-products of p l u 'oniuni production a< the Clinton a n d ITanford plants. Dr. Senborg also reported the d i s covery of a new isotope of plutoniuni-, Pu 241 , and announced the mass n u m bers of the elements, ainericium a n d curium. Pu-' 1 i- produced by a l p h a particle bombardment ofl~- : i \ It h a s a relatively long half-life and
