“The Sergeant said it!” cried Betteredge.  “From first to last, sir, the Sergeant said she had got a memorandum of the hiding-place.  And here it is!  Lord save us, Mr. Franklin, here is the secret that puzzled everybody, from the great Cuff downwards, ready and waiting, as one may say, to show itself to you!  It’s the ebb now, sir, as anybody may see for themselves.  How long will it be till the turn of the tide?” He looked up, and observed a lad at work, at some little distance from us, mending a net.  “Tammie Bright!” he shouted at the top of his voice.

“I hear you!” Tammie shouted back.

“When’s the turn of the tide?”

“In an hour’s time.”

We both looked at our watches.

“We can go round by the coast, Mr. Franklin,” said Betteredge; “and get to the quicksand in that way with plenty of time to spare.  What do you say, sir?”

“Come along!”

On our way to the Shivering Sand, I applied to Betteredge to revive my memory of events (as affecting Rosanna Spearman) at the period of Sergeant Cuff’s inquiry.  With my old friend’s help, I soon had the succession of circumstances clearly registered in my mind.  Rosanna’s journey to Frizinghall, when the whole household believed her to be ill in her own room—­Rosanna’s mysterious employment of the night-time with her door locked, and her candle burning till the morning—­Rosanna’s suspicious purchase of the japanned tin case, and the two dog’s chains from Mrs. Yolland—­the Sergeant’s positive conviction that Rosanna had hidden something at the Shivering Sand, and the Sergeant’s absolute ignorance as to what that something might be—­all these strange results of the abortive inquiry into the loss of the Moonstone were clearly present to me again, when we reached the quicksand, and walked out together on the low ledge of rocks called the South Spit.

With Betteredge’s help, I soon stood in the right position to see the Beacon and the Coast-guard flagstaff in a line together.  Following the memorandum as our guide, we next laid my stick in the necessary direction, as neatly as we could, on the uneven surface of the rocks.  And then we looked at our watches once more.

It wanted nearly twenty minutes yet of the turn of the tide.  I suggested waiting through this interval on the beach, instead of on the wet and slippery surface of the rocks.  Having reached the dry sand, I prepared to sit down; and, greatly to my surprise, Betteredge prepared to leave me.

“What are you going away for?” I asked.

“Look at the letter again, sir, and you will see.”

A glance at the letter reminded me that I was charged, when I made my discovery, to make it alone.

“It’s hard enough for me to leave you, at such a time as this,” said Betteredge.  “But she died a dreadful death, poor soul—­and I feel a kind of call on me, Mr. Franklin, to humour that fancy of hers.  Besides,” he added, confidentially, “there’s nothing in the letter against your letting out the secret afterwards.  I’ll hang about in the fir plantation, and wait till you pick me up.  Don’t be longer than you can help, sir.  The detective-fever isn’t an easy disease to deal with, under these circumstances.”