Abstract: An ammeter apparatus and method of taking current reading includes current inputs receiving a signal from a current source through a suitable gate. A conversion circuit having a preamplifier and an amplifier, in inverted configuration, produce a signed voltage proportional to the current signal. The signed voltage is passed, to both a rectifier and a polarity indicator through another gate. A comparator switches the polarity indicator gate and a third gate upon receipt of a threshold value rectified voltage from the rectifier. The third gate interconnects the rectifier and a charge-retaining element, and a meter outputs a display corresponding to the charge thereon. A fourth gate connects the charge-retaining element to ground in order to discharge the retained charge. A timing circuit with a manual override operates the input gate and the fourth gate, and a timed power supply provides operating voltage for the circuit.

Abstract: A composition and method for testing and evaluating a person's sensitivity to metals, such as mercury and nickel includes an inorganic salt of that metal carried by a mixture of propylene glycol and deionized water. In the case of mercury, a base solution having 5% by weight of mercury chloride in deionized water is mixed with propylene glycol so that the resulting composition has between 0.1% and 2.5% by volume of the base solution. For nickel, between 4% and 7% by weight of nickel sulfate is mixed with a 50-50 mixture of propylene glycol and deionized water. The method includes the steps of measuring first values of the person's vital signs, applying the mercury or nickel composition to the skin by way of a bandage, measuring second values of the vital signs after a lapse of time, and comparing the first and second values.