A diffusion method that requires less labor than distillation methods was developed for preparing soil KCl extracts for 15NH+4 and 15NO‐3 analyses. The procedure is ideal for preparing samples having low N mass (50–200 µg N) with no cross contamination. The method uses 140 mL disposable specimen containers to hold the sample, and 7‐mm diam, disks of acidified GF/D glass fiber filter paper on stainless steel wire as the acid trap. Devarda's alloy and MgO are used as the reductant and base respectively. Complete diffusion for 40 to 60 mL of sample takes 6 d at room temperature with no shaking. Paired t‐tests comparing analyses of soil extracts of varying 15N enrichment by this method and steam distillation showed no significant difference (p = 0.64). Use of KHSO4 as the trapping acid allows the paper disks to be placed in a Sn capsule and analyzed by direct combustion mass spectrometry. Alternately, H2SO4 can be used and the disks analyzed by an automated NaOBr method. The disks can be easily dried in a desiccator over H2SO4 and mailed for 15N analysis by service laboratories.

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The temperature dependency of the coefficient of viscosity relative to its value at 283°K has been determined for hydrogen, helium, argon, and nitrogen at atmospheric pressure. The method used is a variation of the usual capillary viscometry scheme in that no attempt is made to obtain absolute viscosity values. The measurements provide the ratio of the viscosity of a gas at temperature T to its viscosity at the reference temperature, 283°K. The value of T ranges from 1100°K to 2150°K and is measured by a disappearing filament pyrometer. In this relative method there is cancellation of most noncontrolled experimental variables so that the measurements are of high reproducibility, ±0.1%, and apparently accuracy, ±0.4%, is limited only by the uncertainties in the international temperature scale in the optical pyrometer range. These results are higher by 3%-8% compared with the results of previous workers. However, extrapolation of lower-temperature viscosity measurements by Kestin and Leidenfrost, and more recently by DiPippo, gives excellent agreement with the values reported here.

We present preliminary results of a search for anomalously heavy isotopes of certain light elements using an eloclrostatic charged particle spectrometer in conjunction with the M_P tandem accelerator facility at the Nuclear Structare Research Laboratory of the University of Rochester. New limits for the existence of anomalous, heavy isotopes (100-10,000 amu) in ordinary, terrestrial Li, Be, B and F samples and enriched H 2, C 13, and O TM samples are reposed.

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