The youth, clad in khaki-coloured overalls and a pilot’s cap, made straight for the open door of the shed. There he set his suit-case on the ground, and stepping in, recoiled before the acrid smell that saluted his nostrils. He gave a little cough, but the man stooping over a bench that ran along one of the walls neither looked up, nor in any way signified that he was aware of a visitor. He was a tall, fair man, spectacled, slightly bald, clean shaven, dressed in garments apparently of india-rubber. The bench was covered with crucibles, retorts, blow-pipes, test tubes, Bunsen burners, and sundry other pieces of scientific apparatus, and on the shelf above it stood an array of glass bottles and porcelain jars. It was into such a jar that the man was now gazing. "Hullo, Pickles!" said the newcomer, coughing again. "What a frightful stink!" The man lifted his head, looked vacantly through his spectacles for a moment, then bent again over the jar, from which he took a small portion of a yellowish substance on the end of a scalpel. Placing this in a glass bowl, he poured on it a little liquid from one of the glass bottles, stirred it with a glass rod, and watched. A smell of ammonia combined with decayed fish mingled with the other odours in the air, causing the visitor to choke again. "Beautiful!" murmured the experimenter. He then poured some of the solution into another vessel and gazed at it with the rapt vision of an enthusiast. Ted Burton leant against the doorpost. He knew that it was useless to interrupt his friend until the experiment was concluded. But becoming impatient as the minutes passed, he took out a cigarette, and was about to strike a match. Then, however, at a sudden recollection of his surroundings, he slipped out into the open air, taking great gulps as if to clear his throat of the sickening fumes, and proceeded to light his cigarette in ease of mind. By and by a cheery voice hailed him from the interior. "That you, Teddy?" "If you’ve quite finished," said Burton, putting his head in at the door, after he had first flung away his half-smoked cigarette. "Glad to see you, my dear fellow. I say, will you do something for me? You came in your machine, of course." "Of course. What is it? It’s about lunch-time, you know." "Is it? But it won’t take you long. I’ve run out of picric acid, and can’t get on. Just fly over to Chatham, will you, and bring some back with you. You’ll get it at Wells’s in the High Street: you’ll be there and back in half an hour or so." "Can’t you wait till after lunch?" "Well, I can, but it will be a nuisance. You see, the whole experiment is hung up for want of the stuff." "Oh, very well. By the way, you’ve done it at last, I see." "Done what?" "Pulled off the phenosulphonitro-something-or-other that you’ve been working at I don’t know how long." "How on earth did you know?" inquired his friend with an air of surprise and chagrin.