Paolo shrugged his shoulders with magnificent indifference. "You might slip and fall from a topsail yard, you might get a hernia, a roundshot might knock your head off the next time we go into action ..."

"Agreed, sir," Jackson said amiably, "but that's not to say I'm going to jump off a topsail yard deliberately, get a hernia, or stand and invite the enemy to knock my head off with a roundshot. When you play around with these mortars, though, you light the fuse in the shell, and if someone's made a mistake in the length or anything, it makes a big bang you never hear!"

"How heavy the shell?" Rossi inquired.

Paolo ran his finger down the page of the notebook, turned over the page and then said: "The gunner says this is about the same as the British 10-inch. And . . ." The tip of his tongue was protruding with the concentration. ". . . Ah, yes. 'Weight of shell when fired' - Mama Mia! It is ninety-three pounds - nearly a hundredweight! That's the hollow cast-iron ball and the powder inside."

"How much powder in it?"

"Only seven pounds."

"Seven?" exclaimed Rossi. "Why, that is nothing!"

Jackson said: "It doesn't need much to blast the shell casing into thousands of pieces. It's these splinters that do the damage."

" 'ow far will it toss a shell, then?" Stafford asked, peering down the bore like a farmer inspecting a horse's teeth.

"Wait," Paolo said, consulting the notebook. "It depends on the amount of powder in the charge. That's obvious, but as far as I can see, it's easier to use more or less powder than to change the elevation of the gun."

Stafford slapped the side of the mortar. "I should fink so; must weigh a ton!"

"One and a half," Paolo said, having just found some details in a neatly-written table. "Ah, here we are. First you must understand about the shell. It is round as you know, but it is cast so that it has the two carrying handles and the filling and fuse hole at the top." He read on a moment and said: "You might well ask why the shell falls the right way up - with the fuse at the top, because it might fall upside down and break off the fuse."

"We might well ask, sir," Rossi agreed politely. "Why does it fall with the fuse upside down?"

"No, no," Paolo said patiently. "Why it falls with the fuse uppermost."

"Yes," Rossi said, having lost track of the conversation, "that is most interesting, sir. But how lights the fuse, then?"

Paolo looked up in surprise and lost his place in the notebook as Stafford and Jackson started laughing. "Why the laughing?"

"We were waiting to hear why the shell falls the right way up after it's been fired, sir," Jackson said.

"Ah, yes. Well, although the shell casing looks like a circular ball from the outside, in fact the bottom is much thicker, and therefore heavier, so it drops first."

"Ah," Rossi said. "I was going to ask you about that, signor. But supposing you fire the shell and bang, it falls in the enemy fort with the fuse at the top and burning; what stops the enemy throwing a bucket of water at it and putting out the fuse?"

"Wait," Paolo said, "let me read more. There must be a reason why that will not work."

"I can fink o' one good reason," Stafford said emphatically. " 'oo'd be daft enough to walk up to a smoking shell with a bucket o' water? Not me! I'd duck down art of the way."

There were two or three minutes' silence while Paolo read through the pages, occasionally grunting to indicate an interesting point, but saying nothing, obviously absorbed by the mental picture of a shell lying in the castle courtyard with smoking fuse.

"Here we are," he exclaimed triumphantly. "The fuse burns at the rate of an inch in four seconds and forty-eight parts."

"Forty-eight parts of what?" Stafford asked.

Paolo looked appealingly at Jackson, who shrugged his shoulders. "Of a second, sir? Most likely a second is divided into a hundred parts. It's the sort of thing they do," he added darkly, knowing the unreliability of the Board of Ordnance.

"Well, it's not very long, is it... about half a second. Anyway, you know how long the shell takes to land, so you cut the fuse to the ..."

"How do you know how long it takes?" Rossi asked.

"Accidente! You have it here in the tables!" Paolo said crossly. "Now just listen. Just suppose your target is 680 yards away. You elevate the mortar to forty-five degrees. Then you put in a charge of one pound of powder; then you cut the fuse to burst ten seconds after you fire the mortar."

"Why ten seconds?" Rossi persisted.

"Mama mia, Rossi! Because it takes ten seconds for the shell to fly through the air and land on a target 680 yards away. That means it's no good having a bucket of water."

"Who cuts the fuse?" Jackson asked.

Paolo had just reached the page giving details of the fuse. "The fuse," he said, like a priest reading a liturgy, "is a conical tube made of beech, willow or some other dry wood. It is open at the top and at the pointed end. So it is filled with a mixture of sulphur, saltpetre and mealed powder - yes," he said quickly, anticipating Rossi's question, "obviously you keep a finger over the hole in the pointed end while you're doing it. Then each end - each hole, in other words - is covered with a composition of tallow and beeswax or pitch, to keep out the damp. When the fuse is put into the shell, the little end is cut off or opened, but the big end is left closed until just before firing.

"So, starting at the beginning, the shell itself is loaded with powder through the fuse hole in the casing. Then the fuse is inserted so that an inch and a half comes out beyond the fuse hole. Protrudes, it means," he explained, proud of his English. "You must make sure there is nothing to prevent the fire from the fuse exploding the powder in the shell - make sure the little end is clear, in other words.

"So there you are," he said proudly, closing the notebook.

"Is all right if the enemy is 680 yards away," Rossi grumbled. "But suppose he is più distante?And the mortar, she is not even loaded yet."

"Ah, yes," Paolo said cheerfully, turning back to the middle pages of the notebook. "Now, we know about the shell and the fuse. Now we have to hurl it at the enemy so that it bursts at his feet." He waved a hand dramatically and slapped the wooden bed.

"Their feet," Jackson said.

"Yes, their feet. First we put in the charge. Now," he said hurriedly, to forestall Rossi, "we will work on an elevation of forty-five degrees. Note that, forty-five degrees. Then we vary the charge to suit the range. The amount of powder can be critical - for example, one pound four ounces of powder gives us 892 yards and yet only another eight ounces gives us an extra 300 yards. I'll choose a straightforward one," he said with a sharp look at Rossi. "Here we are: three pounds of powder gives us a range of 1,945 yards and the time of flight - the time it takes the shell to land after it's been fired, Rossi - is twenty-one seconds and ten parts."

"The fuse in the shell," Rossi said casually, hoping he had now caught out the young midshipman, for a Genovese should always be able to get the better of a Tuscan. "How long should that be so we burst at the enemy's feet?"

Paolo ran his finger across the table. "Four inches and seventy parts."

^Parts of what?"

'Seventy parts of a hundred parts of an inch," Paolo said triumphantly.

"What is the maximum range?" Jackson asked.

"Well, the maximum given in another table for a 10-inch mortar with a different elevation is 3,821 yards, using a twelve-pound charge. The shell takes exactly half a minute to land . . ."

"I wonder if this bed -" Jackson pointed to the one on which the mortar was mounted "would take the recoil from a twelve-pound charge?"

"We do not have to worry about that," Paolo said firmly. "We are learning about mortars in general. So we have the shell filled and the fuse filled. Now we must load the mortar. First we put in the powder charge after carefully measuring it, and then a wad. We beat that down hard with the rammer - that is most important: it is underlined here. Then we put in the shell, holding it with the two handles at the top - which of course means the fuse is uppermost.