"How did it happen?" Blake wanted to know.
Curtis told him of the incident and related in bitter terms how he had gone down and found the sphere.
"Maybe I sound callous about Harben's death, but it was his own fault. I wouldn't have minded him killing himself or getting himself killed - but he had to do it with my sphere!"
"Who was the other man?" Blake demanded.
"A man called Linwood - Jim Linwood. I never met him. He was an assistant Harben hired while I was away. Some bum mechanic who used to hang around the waterfront cafйs."
"That's all you know about him?"
"That's all I want to know. All I want to do is get my sphere back before the water rusts too much of the equipment away."
"You're going to bring her up?"
"As soon as the salvage equipment arrives from the States."
"When will that be?"
"Tomorrow, I hope."
"You mentioned water damaging the sphere - was the sphere holed?"
Curtis nodded. "Yes - a small, jagged hole near where the cable was. It looks as though some explosive caused it - blew the cable apart and sunk the sphere."
"You're sure it was explosive?"
"I'm not sure of anything. For all I know the men may be right. They say it was a sea monster, for Pete's sake."
"A sea monster?" Blake frowned. "That's a bit far-fetched, isn't it?"
Curtis eyed him evenly and shrugged. "Who knows? Strange things have been found in the lower ocean. Dead fins and tentacles, five hundred times bigger than any known beast have been washed up on the beaches before now. Fragments of bone and scales the size of dinner plates… We don't know what lives at the bottom of the Tanangas Trench, Mr. Blake. I've spent years of my life and thousands of dollars trying to find out!"
As Blake frowned throughtfully at this theory, Curtis went on: "Listen - I'm not saying it was a prehistoric monster but stranger things have happened. All the evidence suggests that even well-known sea-creatures - whales and dophins - may have brains not so different from our own. It's not impossible that some form of higher intelligence lurks down there unknown - the point is we really don't know!"
Blake said thoughtfully: "And if it were true-"
"If it were true it would explain what otherwise remains insoluble - who killed Harben and how did Linwood disappear!"
"You're sure there's no way Linwood could have killed Harben - and then got out of the bathysphere?" Blake asked.
"Impossible!" said Curtis. "Harben was more than seven hundred feet down before he suddenly started screaming for help. No man could have got out at that depth. It isn't just a question of surviving - he could never have got the hatch of the sphere closed again!"
Curtis glanced towards two nearby Indians who were members of his crew. He lowered his voice.
"In any case, Harben's cries for help gave no indication he'd been stabbed. He screamed out because he'd seen something - something uncanny and terrifying, something he called horrible and disgusting - outside the sphere! Then contact was severed and the sphere sank."
Blake nodded grimly as he digested these facts. Whatever the ultimate explanation of the mystery, it seemed an inescapable certainty that both Harben and Linwood were dead.
Just then two men came up on deck and walked towards the detective and biologist.
They both wore fedora hats and highly-polished tan shoes; light-weight grey suits and pastel coloured ties.
They were obviously the two FBI men Curtis had mentioned earlier.
One was lean and looked as though he had been carved out of rock. There wasn't an ounce of surplus fat on him. His skin was swarthy and he was obviously an emigrй from the south of the US border - a Mexican. He walked delicately, like a girl, but there was nothing feminine about him for all that.
Probably the FBI had recruited him because he spoke Spanish. His companion was taller, beefier, with cynical grey eyes.
As they approached, the Mexican confronted the biologist and jerked a thumb at Blake. "Who's this?"
"My name's Blake," the detective spoke up with an edge on his voice.
"Didn't the local cops tell you this ship's off limits to the Press?"
"Mr. Blake isn't a newsman," Professor Curtis put in. "He's an insurance investigator."
"Okay, we'll handle this," the Mexican told him.
To Blake's surprise, Curtis merely nodded to the FBI man and moved off! He went about his work leaving Blake to face the questioners alone.
"I think we'll maybe ask you some questions, Mr. Blake," said the Mexican.
Blake smiled easily. "By all means, Mr. -"
"Navarro. Lieutenant Navarro. This is my colleague, Lieutenant Kellaher, FBI."
"How can I help you?" Blake inquired.
"What are you doing aboard this ship?" demanded the beefy man, Kellaher.
"I'm a private investigator," Blake produced one of his professional cards. "I'm here to represent a client in London."
The two men examined the card suspiciously. "British, huh?" Kellaher looked at him. "Investigating what?"
"Trying to trace a seaman who's needed as a witness in an arson case. We heard he'd signed on with the Gorgon…"
"What name?"
"Harben," Blake said evenly. "Jules Harben."
The two men looked at each other. They both looked at Blake.
The Mexican said grimley: "Come into the cabin."
Inside the cabin, stacked high with electronic equipment, diving gear, winch meters and air regulators, and Sonar, the underwater radar, Blake realised what the loss of the sphere really meant to Curtis. Without it, most of the other equipment was useless.
He seated himself casually upon a small table and said: "Very well, Lieutenant Navarro, what do you want to know?"
"Who you're working for?" demanded the Mexican.
Blake paused. He studied the coal-black eyes of the fierce Mexican and said slowly: "I'd like to see your means of identification."
The Mexican glowered. "We'll ask the questions!" He snarled. "We're agents of the Federal Government and this is a United States ship!"
Blake said slowly: "This ship is moored in Maliban territorial waters - and outside the American jurisdiction. I'm not obliged to answer your questions."
The Mexican's face turned ugly but the man called Kellaher intervened smoothly. "The man's right. Mr. Blake is not obliged to answer us…" He addressed Blake. "All we are asking for is a little friendly co-operation, Mr. Blake. We have reason to believe that Jules Harben was murdered by communist agents who are plotting to overthrow the Maliban Government. If you know something about Harben we may be able to exchange information… as between friendly allies, huh…"
Blake thought grimly that it would be a poor exchange. The suggestion was also an unorthodox one, to say the least. Craille's security regulations did not permit him to do arbitrary deals with foreign agents - even FBI agents; but in any case the detective wasn't convinced that these two men were actually from the FBI.
He said: "I know nothing about that. I'm just a private detective visiting Maliba to represent various clients in London. I was trying to find Harben for the Amethyst Insurance Company."
Kellaher turned to Navarro with a shrug. "Could be true, Navarro."
The Mexican looked suspicious. "Who else are you working for?"
"Sir Gordon Sellingham, the sugar magnate. I've been commissioned to trace his son Peter."
"Peter Sellingham?" Kellaher frowned.
"You've heard of him?" Blake asked.
"Sure. He used to hang around the skid-row area. Tried to look the part of a hobo, but it didn't come off. Stuck a pair of shades on his nose and played at Secret Agent X. Sure, I hard of him."