ed. "You'd better let Miss McLeod have that
parcel," he added to McKenzie. The youth handed him the parcel, and at
Myra's suggestion Dennis opened it. Topmost among its contents was a
letter addressed to me. Dennis tore it open and read it.

"Miss McLeod is to wear a pair of these glasses until I see her again.
She will be able to see through them fairly well, but she must not
remove them. The consequences might be fatal. The three other pairs
are for you and Burnham, and one extra in case of accidents. It will
also come in handy if you take Hilderman into your confidence. Wear
these glasses when you are in any danger of coming in contact with the
green ray. I have an idea that they will act as a decided protection.
I also enclose one Colt automatic pistol and cartridges, the only
one I could get in the middle of the night. If you decide to ask
Hilderman's help tell him everything. I am sure he will be very useful
to you. Keep your courage up, old man! The best to you all. In
haste.--H.G."

"We're certainly learning something," said Dennis, as he finished.
"Obviously Garnesk is very suspicious of somebody, but it's not
Hilderman. He writes as if he were pretty sure of himself. Probably he
has proved his theory about Hilderman being a Government detective."

"I have a message for Mr. Ewart, sir," the messenger interrupted.

"You had better tell it me," Dennis suggested.

"I'd rather Miss McLeod asked me," McKenzie demurred. "Those were Mr.
Garnesk's instructions. He said 'failing Mr. Ewart, insist on seeing
Miss McLeod.'"

"Very well," laughed Myra. "I quite appreciate your point. May I know
the message?"

"Mr. Ewart was to take no notice whatever of anything Mr. Garnesk said
in his letter about Mr. Hilderman. He was on no account to trust Mr.
Hilderman, but to be very careful not to let him see he was suspected.
The gentlemen were always to wear their glasses whenever they were in
sight of the hut above--Glas.--above Mr. Hilderman's house."

"Whew!" Dennis whistled. "But why didn't he----? Oh, I see. He was
afraid the letter might fall into Hilderman's hands."

"I wonder where Ron can have got to?" Myra mused wistfully.

"We're very much obliged to you for all the trouble you have taken,
Mr. McKenzie," said Dennis. "You've done very well indeed."

"Oh, Mr. Garnesk also said that Miss McLeod was to put on her glasses
by the red light."

"Yes; that's important," Dennis agreed. "We'll go up to the house now,