Department of Marine Biology, and. (Dr. Tubbe's own idea) a row of laboratories, which visiting foreign scientists were invited to use as their own. A Belgian biologist and a Portuguese bio-chemist were occupying guest laboratories now, and once, Martin thrilled to learn, Gustav Sondelius had been here.
Then Martin saw the Berkeley-Saunders centrifuge.
The principle of the centrifuge is that of the cream-separator. It collects as sediment the solids scattered through a liquid, such as bacteria in a solution. Most centrifuges are hand-or water-power contrivances the size of a large cocktail-shaker but this noble implement was four feet across, electrically driven, the central bowl enclosed in armor plate fastened with levers like a submarine hatch, the whole mounted on a cement pillar.
Holabird explained, "They're only three of these in existence. They're made by Berkeley-Saunders in England. You know the normal speed, even for a good centrifuge, is about four thousand revolutions a minute. This does twenty thousand a minute—fastest in the world. Eh?"
"Jove, they do give you the stuff to work with!" gloated Martin." (He really did, under Holabird's handsome influence, say Jove, not Gosh.)
"Yes, McGurk and Tubbs are the most generous men in the scientific world. I think you'll find it very pleasant to be here, Doctor."
"I know I will—shall. And Jove, it's awfully nice of you to take me around this way."
"Can't you see how much I'm enjoying my chance to display my knowledge? There's no form of egotism so agreeable and so safe as being a cicerone. But we still have the real wonder of the Institute for to behold, Doctor. Down this way."
The real wonder of the Institute had nothing visible to do with science. It was the Hall, in which lunched the staff, and in which occasional scientific dinners were given, with Mrs. McGurk as hostess. Martin gasped and his head went back as his glance ran from glistening floor to black and gold ceiling. The Hall rose the full height of the two floors of the Institute. Clinging to the soaring wall, above the dais on which lunched the Director and the seven heads of department, was a carved musicians'-gallery. Against the oak panel-
