of yttrium and cesium are concentrated in the plants. In addition, experiments have been completed on a fift ruthenium. The absorption of ruthenium from nutrient soluti Kidney Bean plants was studied as a function of the rutheni tration and of the acidity of the solution (pH). Observatiohs show that the uptake of ruthenium is dependent upon, but not stri airborne dust. The method has direct application to industfial hygiene preblems involving such measurements and should facilitate tion. Heretofore, the usual’ methods of sampling airborne q heir solu- required analysis of particle size by time-consuming and ta@dious microscopic observations, .The new technique involves collectioy filters which are then dissolved in an organic solvent. fe resultant dust suspension is then analyzed turbidimetrically (in terg concentration of the dust in the sample does not affect thé resultsof the particle-size determination. The turbidimetric methodj gives good accuracy and reproductibility of results. Radiation Instruments Program Fourth Tripartite Conference on Instrumentation Preliminary arrangements have been made between the United States, Canada, and the United Kingdom te hoid a tripartite confe¥ence on instrumentation at Harwell, England, in May 195k. On Oct#ber 15 at Chalk River, Ontario a meeting will be held by the plannigfg committee of representatives from AEC, Chalk River, and Harwell to fstablish an agenda for the conference. Items suggested in preliminary discussions for the sbring ccnference are pile instrumentation, chemical plant instrumentation, tranSistors as applied to nuclear instruments, problems in radiation dosimetry, and new circuit techniques. Specific topics of a [classified nature will be Limited to previously established CommissJon-approved items on instrumentation within the general areas of Health and Safety (Area 2), Isotopes (Area 3), Extraction Chemistry (Area 9), and Low- Power Reactors (Area 9). ; - ARCHIVES