to go back to robert at the time he was watching the four men in the room on the ground floor of the sanitarium.

our hero saw the certificate signed, and a little later saw dr. remington and his friend arise to depart.

he leaped from the fence and ran around to the front of the grounds, and was just in time to see remington and his companion stalk off in the direction of the nearest street car.

at first he thought to have the pair arrested, but on second thought concluded to wait. he must first have positive proof that mrs. vernon had been brought to the place, and that these men were implicated in the plot against the lady.

"it's one thing to know a truth," thought robert. "it's another thing to prove it. i must wait until i can prove what i suspect."

after the two men had gone the youth walked around to the rear of the institution once more.

some trees hid the upper windows from view, and to get a better sight of these robert climbed one of the trees to the very top.

from this point he could look into several apartments.

the sight in one made his heart sick. on a bed lay an old man, reduced to almost a skeleton. the old man had his fists doubled up, and seemed to be fighting off some imaginary foe.

the next window was dark, and our hero turned to the third.

the sight that met his gaze here startled him. in a chair near the narrow window sat mrs. vernon, while in the center of the apartment stood her graceless nephew.

the conversation between the pair has already been given. robert could not hear what was being said, but he saw every action, and saw that mrs. vernon was pleading to be released.

when frederic vernon went below, our hero slid down the tree and ran once more to the front of the house.

he saw vernon come out and start for the street car line. it was now dark, and he managed to keep quite close to the young man without being discovered.

now that he had seen mrs. vernon, robert's mind was made up as to what he should do.

frederic vernon had to wait several minutes for a car. when it came along he hurried to a forward seat and gave himself up to his thoughts. as before, robert kept on the rear platform.

the center of the city being reached, frederic vernon left the car and took his way to a leading hotel. watching him, robert saw the young man get a key from the night clerk and enter the elevator.

as soon as vernon was out of sight robert entered the hotel office and asked if he might look over the register.

"certainly," answered the clerk.

our hero soon found the entry, "frederic vernon, chicago," and after it the number of his room--643.

"mr. vernon is stopping here, i see," he said to the clerk.

"yes, he just went up to his room. do you want to see him?"

"i won't bother him to-night, thank you," rejoined robert, and walked out.

he felt pretty certain that frederic vernon had retired for the night, but in order to make certain he hung around for the best part of an hour. as vernon did not re-appear he concluded that the young man had gone to bed.

"now to find mr. farley and explain everything to him," said robert.

in looking over the directory he found a long list of people by that name, and of this list three were lawyers.

which of the three could be the man he was after was the question.

"i'll have to go it blind," said our hero to himself, and called a passing hack.

soon he was on his way to the nearest of the three residences of the lawyers who bore the same family name. when he arrived he found a rather tumbled-down looking place. telling the hackman to wait for him, he ran up the steps and rang the bell.

no answer was returned and he rang again. presently an upper window was thrown up, and a head thrust out.

"what's wanted?" asked a deep bass voice.

"i am looking for mr. farley, the lawyer," answered robert.

"all right, i'm your man."

"hardly," thought robert.

"i mean mr. farley who has his office in the phoenix building," he went on, aloud.

"oh!" came the disappointed grunt. "i am not the fellow."

"so i see. will you please tell me where he lives?"

"somewhere out on michigan avenue. i don't remember the number." and with this the upper window was closed with a bang.

"that man doesn't believe in being accommodating," said robert to himself. "however, there is no telling how many times he has been bothered by people looking for other farleys."

he had the address of the farley living on michigan avenue, and told the hackman to drive to it. the distance was covered in quarter of an hour. a sleepy-looking servant answered our hero's summons.

"is mr. farley at home?"

"he is, but he went to bed long ago."

"will you tell him that robert frost is here and wishes to see him on important business?"

"yes, sir."

robert was ushered into a library and the servant went off. soon mr. farley appeared, in dressing gown and slippers.

"why, frost, what brings you here this time of night?" he asked, as he came in.

"i suppose you are surprised, mr. farley, but something quite out of the ordinary has happened, and i want your advice."

"i will assuredly do the best i can for you. what is the trouble?"

"frederic vernon has carried off mrs. vernon and had her placed in an asylum for the insane."

the lawyer emitted a low whistle.

"is it possible!" he ejaculated.

"it is, sir. i hunted for mrs. vernon for several hours, and just located her a little while ago. she is confined in dr. rushwood's sanitarium for the weak-minded, as the institution is called."

"i have heard of the place, and, let me add, dr. rushwood's reputation is none of the best."

"how frederic vernon got her there is still a mystery to me, but she is there, and i am pretty certain that he has got his tool, dr. remington, and another physician to certify that she is insane."

at this announcement the lawyer's face fell.

"in that case we may have considerable trouble in procuring her release."

"but she is no more insane than you or i."

"that is true, and i presume an examination in court will prove the fact."

"i can testify that frederic vernon plotted this whole thing out with dr. remington, and offered the doctor ten thousand dollars for his assistance."

"that will be good evidence in mrs. vernon's favor."

"we can prove, too, that vernon forged his aunt's name to a check for six hundred dollars."

"yes, i know that. i saw the forged check myself."

"and we can prove that he followed her to england and tried to take her life," added robert. and then he told the particulars of the perilous carriage ride along the cliff and of how frederic vernon had been caught by farmer parsons.

"i guess we'll have a pretty clear case against that young man," said mr. farley, after robert had finished.

our hero then told of his following frederic vernon from mrs. vernon's mansion, and of what he had seen while hanging around dr. rushwood's institution.

"we ought to rescue mrs. vernon at once," he concluded. "if we don't frederic vernon may take it into his head to do her harm."

"i think we had better have vernon and dr. remington arrested first," answered the lawyer.

he returned to his room above and donned his street clothing. a little later he and robert were driven to the office of the private detective who had been engaged to hunt up frederic vernon.

"he is around town," said brossom. "i've seen him. he is thick again with that dr. remington." he had learned a few things, but was astonished when robert told his tale.

"why, you ought to be a detective yourself, young man," he cried.

"thanks, but i don't care for the work," was our hero's dry response.

brossom agreed that it would be best to arrest frederic vernon without delay. the arrests of dr. remington and the other physician could then follow.

again the hack was called into service, and they proceeded to the hotel at which frederic vernon had been stopping since his return to the city by the great lakes.

"i will see mr. vernon now, if you please," said robert.

"sorry, but mr. vernon went out about half an hour ago," was the clerk's answer, which filled our hero with dismay.