A number of pipetting aids are commercially available which obviate the necessity of filling pipets by oral suction. Most of the commercially available devices involve fitting the pipet into a soft tight fitting bushing and filling by means of either a piston or a rubber bulb. The pipet is then emptied by means of a valve control which permits, it is claimed, a dispensing accuracy of 0.1mL. It is at once apparent that the probable error (10% for a 1 mL. pipet) is considerably greater than is permissible for great precision. In practice these devices are found to be awkward and after a period of use tend to become even more so due to corrosion of the valve and aging of the rubber bushing and rubber bulbs.

The recently developed "n" on "p" type silicon solar cell has been evaluated for application as a high-level gamma radiation dose rate meter. The solar cell ionization current was found to be a linear function of dose rate in a range 10 2 to 10 7 rads per hour. A degradation rate of approximately one per cent per megarad was measured after stabilization with twenty megarads of cobalt-60 gamma radiation. The system has proven to be stable over long periods of time. Temperature dependence corrections have been found to be .0 per cent per degree centigrade between 0 and 60 degree centigrade.

The descriptive parameters of a waveguide with smooth or periodic structure are most easily measured in a waveguide section of suitable length which is transformed into a resonant cavity by placing short circuits at both ends. Measurements of dispersion diagram, phase velocity, group velocity, voltage attenuation coefficient, shunt impedance, field configuration, etc. all involve some form of perturbation technique. The introduction of a perturbing object in a resonant cavity changes the stored electric energy We and magnetic energy Wm by Δwe and ΔWm' resulting in a frequency shift Δf of the resonant frequency f, which is given by the perturbation formula of J. Muller.

The Brookhaven Bubble Chamber Group is developing a Hough-Powell fast analysis system (HPD)1 for bubble chamber photographs. High precision measurements are made with a computer controlled flying spot digitizer. We are currently testing the track selection programs for the system. We have just completed a study of a method for automatic bubble density measurements.

The radiolysis of several polyaromatic compounds which might be used as coolant material in a reactor was investigated using both gamma and reactor radiation. The compounds selected were naphthalene, anthracene, naphthacene, pyrene, phenanthrene, 1, 2 benzanthracene, chrysene, triphenylene, 9, 10 dihydrophenanthrene, phenazine, 7, 8, benzoquinoline and m-phenanthroline, in addition to the uncondensed ring compounds, biphenyl, ortho, meta and para terphenyl and bibenzyl. Gas yields, percentage decomposition, percentage "high boiler" and number average molecular weights were determined. A correlation was found between radiation stability and electron affinity and singlet triplet excitation energies. The most stable compounds were the condensed ring compounds, naphthalene, pyrene, chrysene, phenanthrene and triphenylene.