Young Sherlock Holmes_ Red Leech - Andrew Lane [94]
‘Patched lead ball?’ he asked, staring more closely down the barrels. ‘Ah, yes, the ball is wrapped in paper. That must form a seal.’
‘Waxed paper. Why is that important?’
‘Because it means it’s airtight,’ he said. ‘At least, for a short time. And if it’s airtight, it’s watertight.’
Before Virginia could say anything, Sherlock turned and ran towards the pond, cocking the twin hammers at the back end of the Derringer as he did so. When he got to the edge he dived, hands held out in front of him, Derringer held in his right hand. The water closed over his head: warm and filled with floating motes of dust and vegetation. Sound was suddenly muffled. He kicked with his feet to take him towards the far wall, beneath the balcony.
And there, where he knew it had to be, where deduction had told him it was, was a glass window set into a metal frame. Before any water could leak into the Derringer he placed it flat against the glass.
And pulled both triggers at once.
Somewhere in the back of his mind was the fact, read once and never forgotten, that water was incompressible. No matter how much you squeeze it, water never gets any denser. All that happens is that the pressure you exert gets transferred elsewhere. Such as to whatever the water is touching.
And so when the hammers at the base of the barrels hit the two percussion caps, the fulminate of mercury inside ignited. This caused the sulphur, charcoal and potassium nitrate in the black powder to burn rapidly, producing a huge volume of hot gas. The gas pushed the lead balls along the barrels, burning the paper patches away as it did so. The bullets pushed against the water in the barrels, and the water pushed against the window.
Which cracked and shattered.
The entire contents of the pond poured into the underground room, taking Sherlock with it. He struck out blindly for the corner of the room where the stairs had to be, hoping desperately that Virginia and Matty would realize what he’d done and follow him. Should he have warned them in advance? It hadn’t occurred to him. He’d just followed through on his deductions without realizing that the other two might not understand.
His lungs were burning with the effort of holding his breath, and his heart was thudding within the cage of his ribs. He pulled himself through the murky water with desperate movements of his arms. Suddenly he felt his knuckles brush against the stone edge of a step. He aimed upward and swam as hard as he could.
When his head emerged from the water, level with the bottom of the doorway that led outside, into the sunlight, he took huge gulps of breath one after the other, waiting for his racing heart to slow.
Matty’s head popped out of the water beside him. Virginia was moments behind.
‘You,’ Matty said, breathing hard, ‘are some kind of genius. I don’t know what you did, but you saved us.’
‘Not quite,’ Virginia pointed out breathlessly.
‘What do you mean?’ Matty asked.
‘Sherlock said those things were amphibious.’
The three of them looked at each other for a long moment, then scrambled rapidly out of the water.
The steps to the underground observation room and to the balcony were out of sight of the house. The three of them sat down for a moment to catch their breaths.
‘What now?’ Matty asked. ‘What do we do?’
‘Only thing I can think is that we follow the train tracks back to the last town,’ Sherlock replied. ‘There’ll be a telegraph office there. We can send a message to Virginia’s father. We have to tell him about Balthassar’s Army, and the invasion of Canada.’
‘Ah,’ Matty said, ‘walking.’
‘We could try stealing horses,’ Sherlock pointed out, ‘but we’ll probably be caught. I suspect these people look after their horses, especially if they’re planning an invasion.’
Matty sighed. All right,’ he said, ‘let’s go. We can dry out while we’re walking.’
Staying out of sight of the house, the three of them made their way through Balthassar’s collection of animal pens and cages. Many of them were empty, but Sherlock saw some things in the occupied ones that he would remember for the rest of