That prescient brain! It was Hilda's handwriting.
I tore it open and read: "MY DEAR HUBERT,--I KNOW you will come; I KNOW you will follow me.

So I am leaving this letter at Donald Currie & Co.'s office, giving their agent instructions to hand it to you as soon as you reach Cape Town.
I am quite sure you will track me so far at least; I understand your temperament.

But I beg you, I implore you, to go no further.

You will ruin my plan if you do.

And I still adhere to it.