This is a chance in a thousand.'

'I wonder if I might?' said Estelle, looking at Marjorie.

It was a great temptation. It did seem such a pity to lose this
opportunity; a chance, as Alan said, which might never occur again:
though the children knew they were doing wrong, curiosity began to
overcome them.

'I don't think it would be right,' answered Marjorie, with decision. 'We
can see all we want from here.'

'I'm sure we can't,' said George, excitedly. 'Look at that dark corner.
We don't know what is in there, but there is something, I'm sure.'

'Well, Marjorie,' said Alan, 'if you don't want to come in, don't. But
you need not spoil sport for all the rest of us. You and I will go in,
Estelle, and Marjorie can keep guard outside.'

'I wish I knew if I might!' cried Estelle, clasping her hands on the top
of her head, and dancing up and down in despair. I really and truly
believe Auntie only meant I was not to go in alone. Don't you think so,
Marjorie?'

'No, I don't,' returned her cousin, quietly.

'What on earth does it matter?' cried Alan, impatiently. 'We are losing
all our time and we shall have Peet or somebody down upon us in a
minute. Come on, Estelle.'

But love for Aunt Betty still acted as a restraint, and though she put
her foot on the threshold, she did not step over.

'I would like to--I would like to,' she exclaimed, torn between her
conscience and her wishes, 'if---- '

She broke off, for Georgie was screaming in terror, 'The door--the door!
Look at the door!'

(_Continued on page 47._)

[Illustration: "Alan made the first attempt to push the door open."]

[Illustration: "It became necessary to descend the shaft."]

MARVELS OF MAN'S MAKING.

II.--THE SEVERN TUNNEL.

[Illustration]

If you were bound from England to some town in South Wales, it was very
awkward to have to leave your train on the banks of the Severn and make
a voyage of more than two miles in a slow ferry-boat before you could
take another train on the opposite shore. The Severn tides, too, were so
erratic that there was never any knowing when the ferry-boat would be
able to start. But that was what people had to put up with forty years
ago. So the Great Western Railway Company, in 1871, decided to go under
the fickle waters, as they found it so troublesome to go over them. A
study of the bottom of the river made it clear that the tunnel they
intended to make would have to slope downwards considerably from b