“Listen, Gene,” the chemist put in suddenly, “I’m worried about the ammonium. I haven’t tested its plating abilities and those are the most important things, you know. What if Staples comes, and we find that all we have is pigeon milk.” “Hmm,” Taylor stroked his chin, “you’re right there. But I’ll tell you what we can do. Before Staples comes, let’s plate something--a spoon, suppose--for our own satisfaction.” “It’s really very annoying,” Sills complained fretfully. “If it weren’t for these troublesome hooligans, we wouldn’t have to proceed in this slipshod and unscientific manner.” “Well, let’s eat dinner first.” * * * * * After the mid-day meal, they began. The apparatus was set up in feverish haste. In a cubic vat, a foot each way, a saturated solution of Ammonaline was poured. An old, battered spoon was the cathode and a mass of ammonium amalgam (separated from the rest of the solution by a perforated glass partition) was the anode. Three batteries in series provided the current. Sills explained animatedly, “It works on the same principle as ordinary copper plating. The ammonium ion, once the electric current is run through, is attracted to the cathode, which is the spoon. Ordinarily it would break up, being unstable, but this is not the case when it is dissolved in Ammonaline. This Ammonaline is itself very slightly ionized and oxygen is given off at the anode. “This much I know from theory. Let us see what happens in practice.” He closed the key while Taylor watched with breathless interest. For a moment, no effect was visible. Taylor looked disappointed. Then Sills grasped his sleeve. “See!” he hissed. “Watch the anode!” Sure enough, bubbles of gas were slowly forming upon the spongy ammonium amalgam. They shifted their attention to the spoon. Gradually, they noticed a change. The metallic appearance became dulled, the silver color slowly losing its whiteness. A layer of distinct, if dull, yellow was being built up. For fifteen minutes, the current ran and then Sills broke the circuit with a contented sigh. “It plates perfectly,” he said. “Good! Take it out! Let’s see it!” “What?” Sills was aghast. “Take it out! Why, that’s pure ammonium. If I were to expose it to ordinary air, the water vapor would dissolve it to NH₄OH in no time. We can’t do that.” He dragged a rather bulky piece of apparatus to the table. “This,” he said, “is a compressed-air container. I run it through calcium chloride dryers and then bubble the perfectly dry oxygen (safely diluted with four times its own volume of nitrogen) directly into the solvent.” He introduced the nozzle into the solution just beneath the spoon and turned on a slow stream of air. It worked like magic. With almost lightning speed, the yellow coating began to glitter and gleam, to shine with almost ethereal beauty.