The slope down which they ventured was covered with loose sand. At each step the treacherous soil slid beneath them. It was a mad and highly reprehensible undertaking. Nevertheless down they went--further and further. The kind heart of the Senator felt a pang at every step. His voice sounded mournfully through the rolling smoke that burst through a million crevices, and at times hid the adventurers from view. But down they went. Sometimes they slid fearfully. Then they would wait and cautiously look around. Sometimes the vapors covered them with such dense folds that they had to cover their faces. "If they ain't dashed to pieces they'll be suffocated--sure!" cried the Senator, starting up, and unable to control his feelings. "I can't stand this," he muttered, and he too stepped down. The guides looked on in horror. "Your blood will be on your own heads!" they cried. As the Senator descended the smoke entered his eyes, month, and nostrils, making him cough and sneeze fearfully. The sand slid; the heat under the surface pained his feet; every step made it worse. However, he kept on bravely. At length he reached the spot where the others were standing. [Illustration: The Descent Of Vesuvius.] At the foot of the declivity was an angular rock which jutted out for about twelve feet. It was about six feet wide. Its sides went down precipitously. The Senator walked painfully to where they were standing. It was a fearful scene. All around arose the sides of the crater, black and rocky, perpendicular on all sides, except the small slope down which they had just descended--a vast and gloomy circumference. But the most terrific sight lay beneath.