ON four occasions lately in the presence of a number of skilled experimentalists I have asked the question—How would you pick up from a floor, with a smooth cork carpet covering, a quantity of mercury which had been dropped and broken up into innumerable globules—I added on each occasion that I thought it likely that any laboratory boy would know but that no professor would. Not once have I received an adequate answer. I have only asked one laboratory attendant, but he was no wiser than his professor. I specify the nature of the floor covering because a Turkey carpet qr floor boards with intervening spaces and nail holes are not suitable. The smooth cork carpet is the best floor covering for laboratories other than metallurgical and for lecture tables, and is in common use for these purposes. The question, therefore, touches jnost of us. Well, the answer is, sprinkle lightly the area which the globules have reached with drops of water from a wash bottle. Then with a squeegee or the straight edge of a piece of strawboard sweep the wetted globules of mercury together. If dry the process is hopeless, they continue to run away and are essentially elusive, but once wet they are tamed, they have the brake on and will not run, and however small they may be they seem to love one another and all cling together in a mass. Then with the same tool or a smaller one sweep them into a small dust-pan made of thin celluloid or even card. The floor is then cleared of all the mercury. Do it.