'Have we any?' Kydd asked.
'Aye, sir. Costs a pretty penny—we keeps it f'r the chase guns only.'
Duckitt was dispatched to find it and Kydd asked Fulton, 'If the explosion is within the sea, will not the water pressing on your, er, container, act t' tamp it like the clay jacket?'
'Coffer. That's what we call 'em,' he replied, distracted. 'Why, yes, I'm supposing it will, but how do I take the measure of an underwater blast, pray?'
Nowhere in Kydd's experience in the Navy had he ever come across explosions occurring beneath the surface. His question, however, seemed to have sparked something in Fulton, for the next trial was with small submersible casks.
'From the boat, if you please.' The match was started and the cask head thumped home, then the whole was allowed to sink on a line to an improvised buoy, nervous oarsmen sparing nothing to make certain the boat was nowhere near the spot.
In a deathly silence all eyes were on the barely ruffled innocent surface of the water. A sub-sea thump was more felt than heard, followed a second later by the bursting upward of a white geyser, which subsided to an ugly, roiling scar in the sea.
'We take it by the height of the splash,' Fulton said defensively, selecting another, larger cask. 'We'll see if this scales up.' There was another tense wait, and once more the plume rose skyward.
'Better!' Fulton said, with relief, lowering his improvised quadrant. Kydd pulled out his pocket watch and consulted it pointedly.
'Don't worry, Mr. Firebrand, I'm satisfied an' will now move forward.'
'So this means—'
At that moment a naval cutter was sighted, making her way prettily towards them. 'A very good morning to you, gentlemen!' Popham said breezily, when he had stepped onto the shore. 'Do I see your new curiosities performing to satisfaction?'
Fulton busied himself obstinately among the apparatus in the arms chest, leaving it to Kydd to answer. 'Mr. Francis is moving forward this day, sir, on account he has achieved satisfaction in the matter of the, er, coffer.'
'Splendid,' Popham said heartily, 'as it will please their lordships to hear.' His tone became more serious. 'The descent on Boulogne has been sanctioned at the highest, and time is now of the essence. Is there anything whatsoever that I might do for your American?'
Kydd detected a note of anxiety and guessed that there was more to the question than had been said, but before he could answer Fulton swung round, his face dark. 'Yes, there is, Mr. Englishman—perhaps you'd keep clear of the works. There's enough to worry on without we have sightseers.'
Popham gave a wintry smile. 'Do tell me your concerns. I'm no stranger to novelties of a mechanical nature, sir,' he encouraged.
Fulton hesitated. 'It's the fault of your committee. Without I have a submarine, how do I attack with a torpedo? If it's agreed that it be done unseen, do they propose I use ships' boats splashing along with oars in full sight of the enemy? Or like the ancient Greeks, by swimmers with a torpedo under each arm?'
'There are other ways of approaching a prey,' Popham responded.
'Flying over it in a balloon?'
'I'm reminded of my service off the coast of the Coromandel. There we encountered nightly the thievery of the native peoples—'
'Captain, I'm very engaged today, If you've—' '—who could approach unseen to within close hail except in the brightest moonlight.'
'Swimming.'
'No, Mr. Francis. In a species of native craft called a catamaran. This has the property that it lies very close to the water, being of two hull forms joined by a central bracing. I'm sanguine it can be made strong enough to deliver your torpedoes.'
'Low in the water?'
'Inches only.'
'Then we have a possibility.'
Fulton looked speculatively at Popham, who hastened to add, 'Leave it to me. I know an amiable shipwright who will be persuaded to produce one immediately for our consideration. In the meanwhile you shall be free to concentrate on your curiosities.'
'It won't do! I calculate we'll need all of thirty minutes, if not the hour, to make our approach by stealth. An' if that's with slowmatch it'll die of suffocation long since.'
'A different kind o' fuse, Toot?'
'There isn't any not using fire, damn it all to hell! If we were going in with a submarine, there'd be none of this.'
Kydd's heart went out to him: to be pressured so and in a situation not of his making was taking its toll. 'Can you not—a mechanical fuse o' sorts?'
Fulton looked up with red-rimmed eyes. 'There's no such. Not even . . . Wait! I have it.' He laughed. 'Why not? Mechanical—an automatic self-igniter.'
He pulled out his notepad and, with hurried strokes, sketched in a gear train and cams, then a striker plate and cocking detent. 'Yes! Does not consume air, and can do its deadly work in secret, deep beneath the waves until it knows its time has come. Then, without warning, heroically sacrifices itself in one hellish detonation.'
Kydd shuddered at the picture but he had to see things through. 'It must be made of brass or some such, else the seawater will turn it to rust in quick time, and that'll cost you not a little.'
