"Can you tell whether there is any of it here?" asked Harold.

"Very easily, with a little fire," answered Robert. "AIR THAT WILL NOT SUPPORT FLAME, WILL NOT SUPPORT LIFE.'

They stuck a splinter of rich pine in the cleft end of a pole, and, lighting it by a match, let it softly down the well. To Harold's astonishment the flame was extinguished as suddenly as if it had been dipped in water, before it had gone half way to the bottom.

66

Stop, let us try that experiment again," said he.

They tried it repeatedly, and with the same result, except that the heavy poisonous air below being stirred by the pole, had become somewhat mingled with the pure air above, and the flame was not extinguished quite so suddenly as at first; it burnt more and more dimly as it descended, and then went out.

"I do believe there is something there," said he at last, "and I certainly shall not go down, as I intended. But how am I to get my knife?"

"By using father's magnet, which is a strong one," replied Robert, "let us go and ask him for it."

On relating the circumstances to Dr. Gordon, he said, "You have made a most fortunate

escape, Harold. Had you descended that well, filled as it is with carbonic acid gas, you would have become suddenly sick and faint, and would probably have fallen senseless before you could have called for help. Make it a rule never to descend such a place without first trying the purity of its air, as you did just now."

"But can we not get that bad air out," asked Harold.

"Yes, by various means, and some of them very easy," replied his uncle. "One is by exploding gunpowder as far down as possible; another is by lowering down and drawing up many times a thickly leaved bush, so as to pump out the foul air, or at least to mix it largely with the pure. But your knife can be obtained without all that trouble. Robert, can you not put him upon a plan?"

"I have already mentioned it, and we have come to ask if you will not let us have your magnet," replied Robert. "But," continued he smilingly, "I do not think that we shall have any need this time for the looking-glass."

Harold looked from one to the other for an explanation, and his uncle said:

"Last year Robert dropped his knife down a well, as you did, and proposed to recover it by means of a strong magnet tied to a string. But

the well was deep and very dark, and after fishing a long time in vain, he came to me for help. I made him bring a large looking-glass from the house, and by means of it reflected such a body of sun-light down the well that we could plainly see his knife at the bottom, stowed away in a corner. The magnet was strong enough to bring it safely to the top. You also may try the experiment."

With thanks, Harold took the offered magnet, tied it to a string, and soon recovered his knife.

CHAPTER V.

RILEY-A THUNDERSTORM-ASCERTAINING THE DIS

TANCE OF OBJECTS BY SOUND-SECURITY AGAINST LIGHTNING-MEANS OF RECOVERING LIFE FROM APPARENT DEATH BY LIGHTNING.

A FEW days after this incident another visitor was seen coming from Fort Brooke. This person was not a horseman, but some one in a boat, who seemed even from a distance to possess singular dexterity in the use of the paddle. His boat glided over the smooth surface of the bay as if propelled less by his exertions than by his will. Dr. Gordon viewed him through the spy glass, and soon decided him to be an Indian, who was probably bringing something to sell.

It so turned out. He was a half-breed, by the name of Riley, who frequently visited the fort with venison and turkeys to sell, and who on the present occasion brought with him in additiɔn a fine green turtle. Major Burke, conceiving that his friends at Bellevue would prize these delicacies more than they at the fort, to whom they were

no longer rarities, had directed the Indian to bring them, with his compliments, to Dr. Gordon.

an

Riley was a fine looking fellow, of about thirty years of age-tall, keen-eyed, straight as arrow, and with a pleasing open countenance. He brought a note from the fort, recommending him for honesty and faithfulness.

Dr. Gordon was so much pleased with his general appearance, that he engaged him to return the following week with another supply of game, and prepared to remain several days, ir. case he should be needed in raising the timbers of the new house.

Toward the close of the week, the weather gave indications of a change. A heavy looking cloud rose slowly from the west, and came towards them, muttering and growling in great anger. It was a tropical thunder-storm. The distant growls were soon converted into peals. The flashes increased rapidly in number and intensity, and became terrific. Mary and Frank nestled close to their father; and even stout-hearted Harold looked grave, as though he did not feel quite so comfortable as usual.

"That flash was uncommonly keen," Robert remarked, with an unsteady voice. "Do you not think, father, it was very near?"

Instead of replying, his father appeared to be busy counting; and when the crash of thunder