The Boy Travellers in The Russian Empire

CHAPTER I.

DEPARTURE FROM VIENNA.--FRANK'S LETTER.--A FAREWELL PROMENADE.--FROM VIENNA TO CRACOW.--THE GREAT SALT-MINE OF WIELICZKA, AND WHAT WAS SEEN THERE.--CHURCHES AND PALACES UNDERGROUND.--VOYAGE ON A SUBTERRANEAN LAKE.

"Here are the passports at last."

"Are you sure they are quite in order for our journey?"

"Yes, entirely so,&quo...