The assay technique is discussed in detail. The results of three purity determinations are: 94.92 per cent, 100.50 per cent, and 106.9 per cent. The errors present in each determination are stated. The inherent dangers in the present procedure are pointed out, and an improved method is outlined.

From Summary: "An analysis is presented of the effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings with partial-span constant-percent-chord ailerons extending inboard from the wing tip. The geometric variables considered are aspect ratio, taper ratio, aileron span, and aileron chord. The shape of the wing-torsional-stiffness curve is assumed and the twisting moment is considered to result solely from the pressure distribution caused by aileron deflection, so that the necessity of using a successive-approximation method is avoided."

The principal object of this report is to record results of tests made on equipment installed in Room 232 of ``T`` Building and used to prepare bismuth powder for process operations. Another object is to establish the most favorable operating conditions for the equipment and to prepare operating instructions therefor.