THE ASSASSINATON.
Additional Details of the Lamentable Event.
Washington, Saturday, April 15.

The assassin of President Lincoln left behind him his hat and a spur. The hat was picked up in the President's box and has been identified by parties to whom it has been shown as the one belonging to the suspected man, and accurately described as the one belonging to the suspected man by other parties, not allowed to see it before describing it.

The spur was dropped upon the stage, and that also has been identified as the one procured at a stable where the same man hired a horse in the evening.

Two gentlemen who went to the Secretary of War to apprize him of the attack on Mr. Lincoln met at the residence of the former a man muffled in a cloak, who, when accosted by them, hastened away.

It had been Mr. Stanton's intention to accompany Mr. Lincoln to the theatre and occupy the same box, but the press of business prevented.

It therefore seems evident that the aim of the plotters was to paralyze the country by at once striking down the head, the heart and the arm of the country.

As soon as the dreadful events were announced in the streets, Superintendent Richards, and his assistants, were at work to discover the assassin.

In a few moments the telegraph had aroused the whole police force of the city. Maj. Wallach and several members of the City Government were soon on the spot and every precaution was taken to preserve order and quiet in the city.

Every street in Washington was patrolled at the request of Mr. Richards.

Gen. Augur sent horses to mount the police.

Every road leading out of Washington was strongly picketed, and every possible avenue of escape was thoroughly guarded.

Steamboats about to depart down the Potomac were stopped.

The Daily Chronicle says:
"As it is suspected that this conspiracy originated in Maryland, the telegraph flashed the mournful news to Baltimore and all the cavalry was immediately put upon active duty. Every road was picketed and every precaution taken to prevent the escape of the assassin. A preliminary examination was made by Messrs. Richards and his assistants. Several persons were called to testify and the evidence as elicited before an informal tribunal, and not under oath, was conclusive to this point. The murderer of President Lincoln was John Wilkes Booth. His hat was found in the private box, and identified by several persons who had seen him within the last two days, and the spur which he dropped by accident, after he jumped to the stage, was identified as one of those which he had obtained from the stable where he hired his horse.

This man Booth has played more than once at Ford's Theatre, and is, of course, acquainted with its exits and entrances, and the facility with which he escaped behind the scenes is well understood.

The person who assassinated Secretary Seward left behind him a slouched hat and an old rusty navy revolver. The chambers were broken loose from the barrel, as if done by striking. The loads were drawn from the chambers, one being but a rough piece of lead, and the other balls smaller than the chambers, wrapped in paper, as if to keep them from falling out.

CLOSING SCENES.
Particulars of His Lost Moments - Record of
His Condition Before Death - His Death.
Washington, Saturday, April 15 -- 11 o'clock A.M.

The Star Extra says:
"At 7.20 o'clock the President breathed his last, closing his eyes as if falling to sleep, and his countenance assuming an expression of perfect serenity. There were no indications of pain, and it was not known that he died until the gradually decreasing respiration ceased altogether.

Rev. Dr. Gurley, of the New-York-avenue Presbyterian Church, immediately on its being ascertained that life was extinct, knelt at the bedside and offered an impressive prayer, which was responded to by all present.

Dr. Gurley then proceeded to the front parlor, where Mrs. Lincoln, Capt. Robert Lincoln, Mrs. John Hay, the Private Secretary, and others, were waiting, where he again offered a prayer for the consolation of the family.

The following minutes, taken by Dr. Abbott, show the condition of the late President throughout the night:

11:00 o'clock Pulse 44. 11:05 o'clock Pulse 45, and growing weaker. 11:10 o'clock Pulse 45. 11:15 o'clock Pulse 42. 11:20 o'clock Pulse 45; respiration 27 to 29. 11:25 o'clock Pulse 42. 11:32 o'clock Pulse 48, and full. 11:40 o'clock Pulse 45. 11:45 o'clock Pulse 45; respiration 22. 12:00 o'clock Pulse 48; respiration 21 - echmoses both eyes. 12:15 o'clock Pulse 48; respiration 22. 12:30 o'clock Pulse 45. 12:32 o'clock Pulse 60. 12:35 o'clock Pulse 65. 12:40 o'clock Pulse 69; right eye much swollen and echmoses [ecchymosis]. 12:45 o'clock Pulse 70. 12:55 o'clock Pulse 80; struggling motion of arms. 11:00 o'clock Pulse 65; respiration 30. 11:30 o'clock Pulse 95; appearing easier. 11:45 o'clock Pulse 85; very quiet, respiration irregular. Mrs. Lincoln present. 12:30 o'clock President very quiet; pulse 54; respiration 28. 12:52 o'clock Pulse 48; respiration 30. 13:00 o'clock Visited again by Mrs. Lincoln. 13:25 o'clock Respiration 24 and regular. 13:35 o'clock Prayer by Rev. Dr. Gurley. 14:00 o'clock Respiration 26 and regular. 14:15 o'clock Pulse 60; respiration 25. 15:50 o'clock Respiration 28; regular; sleeping. 16:00 o'clock Pulse failing; respiration 28. 16:30 o'clock Still failing and labored breathing. 17:00 o'clock Symptoms of immediate dissolution. 17:22 o'clock Death.

Surrounding the death-bed of the President were Secretaries Stanton, Welles, Usher, Attorney General Sprod, Postmaster-General Dennison, M.B. Field, Assistant Secretary of the Treasury, Judge Otto, Assistant Secretary of the Interior, Gen. halleck, Gen. Meigs, Senator Sumner, R.R. Andrews, of New-York; Gen. Todd, of Darotah, John Hay, Private Secretary; Gov. Oglesby, of Illinois; Gen. Farnsworth, Mrs. and Miss Kenney, Miss Harris, Capt. Robert Lincoln, son of the President, and Doctors E.W. Abbott, B.K. Stone, C.D. Gatch, Neal Hall, and Mr. Lieberman. Secretary McCulloch remained with the President until about 5 o'clock, and Chief-Justice Chase after several hours attendance during the night returned early this morning.

Immediately after the President's death a Cabinet meeting was called by Secretary Stanton and held in the room in which the corpse lay. Secretaries Stanton, Welles and Usher, Postmaster-General Dennison, and Attorney-General Speed were present. The results of the conference are as yet unknown.

Removal of the Remains to the Executive
Mansion -- Feeling in the City,
Washington, Saturday, April 15.

The President's body was removed from the private residence opposite Ford's Theatre to the executive mansion this morning at 9:30 o'clock in a hearse, and wrapped in the American flag. It was escorted by a small guard of cavalry, Gen. Auour and other military officers following on foot.

A dense crowd accompanied the remains to the White House, where a military guard excluded the crowd, allowing none but persons of the household and personal friends of the deceased to enter the premises, Senator Yates and Representative Farnsworth being among the number admitted.

The body is being embalmed, with a view to its removal to Illinois.

Flags over the department and throughout the city are at half-mast. Scarcely any business is being transacted anywhere either on private or public account.

Our citizens, without any preconcert whatever, are draping their premises with festoons of mourning.

The bells are tolling mournfully. All is the deepest gloom and sadness. Strong men weep in the streets. The grief is wide-spread and deep and in strange contrast to the joy so lately manifested over our recent military victories.

This is indeed a day of gloom.

Reports prevail that Mr. Frederick W. Seward, who was kindly assisting the nursing of Secretary Seward, received a stab in the back. His shoulder blade prevented the knife or dagger from penetrating into his body. The prospects are that he will recover.

A report is circulated, repeated by almost everybody, that Booth was captured fifteen miles this side of Baltimore. If it be true, as asserted, that the War Department has received such information, it will doubtless be officially promulgated.

The government departments are closed by order, and will be draped with the usual emblems of mourning.

The roads leading to and from the city are guarded by the military, and the utmost circumspection is observed as to all attempting to enter or leave the city.

Autopsy Upon the Body of Abraham Lincoln
Washington. Saturday, April 15.

An autopsy was held this afternoon over the body of President Lincoln by Surgeon-General Barnes and Dr. Stone, assisted by other eminent medical men.

The coffin is of mahogany, is covered with black cloth, and lined with lead, the latter also being covered white satin.

A silver plate upon the coffin over the breast bears the following inscription:

ABRAHAM LINCOLN.
Sixteenth President of the United States.
Born July 12 1809.
Died April 15, 1865.

The remains have been embalmed.

A few locks of hair were removed from the President's head for the family previous to the remains being placed in the coffin.

THE ASSASSINS.
Circumstances Tending to Inculpate G.H. Booth - Description of his Confederate in the Crime.
Washington, Saturday, April 15.

There is no confirmation of the report that the murderer of the President has been arrested.

Among the circumstances tending to fix a participation in the crime on Booth, were letters found in his trunk, one of which, apparently from a lady, suppicated him to desist from the perilous undertaking in which he was about to embark, as the time was inauspicious, the mine not yet being ready to be sprung.

The Extra Intelligencer says: "From the evidence obtained it is rendered highly probable that the man who stabbed Mr. Seward and his sons, is John Surratt, of Prince George County, Maryland. The horse he rode was hired at Naylor's stable, on Fourteenth-street. Surratt is a young man, with light hair and goatee. His father is said to have been postmaster of Prince George County."

About 11 o'clock last night two men crossed the Anacostia Bridge, one of whom gave his name as Booth,a nd the other as Smith. The latter is believed to be John Surratt.

Last night a riderless horse was found, which has been identified by the proprietor of one of the stables previously mentioned as having been hired from his establishment.

Acounts are conflicting as to whether Booth crossed the bridge on horseback or on foot; but as it is believed that he rode across it, it is presumed that he had exchanged his horse.

From information in the possession of the authorities it is evident that the scope of the plot was intended to be much more comprehensive.

The Vice-President and other prominent members of the Administration were particularly inquired for by suspected parties, and their precise localities accurately obtain; but providentially, in their cases, the scheme miscarried.

A boat was at once sent down the Potomac to notify the gunboats on the river of the awful crime, in order that all possible means should be taken for the arrest of the perpetrators.

The most ample precautions have been taken, and it is not believed the culprits will long succeed in evading the overtaking aim of justice.

The second extra of the Evening Star says:

"Col. Ingraham, Provost-Marshal of the defenses north of the Potomac, is engaged in taking testimony today, all of which fixes the assassination upon J. Wilkes Booth.

Judge Olin of the Supreme Court of the District of Columbia, and Justice Miller, are also engaged today, at the Police Headquarters, on Tenth-street, in taking the testimony of a large number of witnesses.

Lieut. Terell,, of Col. Ingraham's staff, last night proceeded to the National Hotel, where Booth had bene stopping, and took possession of his trunk, in which was found a Colonel's military dress-coat, two pairs of handcuffs, two boxes of cartridges and a package of letters, all of which are now in the possession of the military authorities.

One of these letters, bearing the date of Hookstown, Md., seems to implicate Booth. The writer speaks of "the mysterious affair in which you are engaged," and urges Booth to proceed to Richmond, and ascertain the views of the authorities there upon the subject. The writer of the letter endeavors to persuade Booth from carrying his designs into execution at that time, for the reason, as the writer alleges, that the government had its suspicions aroused. The writer of the letter seems to have been implicated with Booth in "the mysterious affair" referred to, as he informs Booth in the letter that he would prefer to express his views verbally; and then goes on to say that he was ot of money, had no clothes, and would be compelled to leave home, as his family were desirous that he should dissolve his connection with Booth. This letter is written on note paper, in a small, neat hand, and simply bears the signature of "Sam" [Sam Arnold].

At the Cabinet meeting yesterday, which lasted over two hours, the future policy of the government toward Virginia was discussed, the best feeling prevailed. It is stated that it was determined to adopt a very liberal policy, as was recommended by the President. It is said that this meeting was the most harmonious held for over two years, the President exhibiting throughout that magnanimity and kindness of heart which has ever characterized his treatment of the rebellious States, and which has been so littly requited on their part.

One of the members of the Cabinet remarked to a friend he met at the door, that "The government was to-day stronger than it had been for three years past."

Washington, Saturday, April 15 -- 3:30 P.M.

Today no one is allowed to leave the city by rail conveyance, or on foot, and the issuing of passes from the Headquarters of the Department of Washington has been suspended by Gen. Auger.

Probable Attempt of the Assassins to Escape Into Canada -- Order from the War Department.
[Circular.]
War Department,
Provost Marshall General's Bureau,
Washington, D.C. -- 9:10 A.M., April 15

It is believed that the assassins of the President and Secretary Seward are attempting to escape to Canada. You will make a careful and thorough examination of all persons attempting to cross from the United States into Canada, and will arrest all suspicious persons. The most vigilant scrutiny on your part, and the force at your disposal, is demanded. A description of the parties supposed to be implicated in the murder will be telegraphed to you today. But in the meantime be active in preventing the crossing of any suspicious persons.

By order of the Secretary of War
N.L. Jeffers, Brevet Brig. Gen.,
Acting Provost-Marshal General.

Mr. Seward and Son.
Secretary Seward will Recover -- Frederick Seward Still Very Low.

Special Dispatch to the New-York Times.

Mr. Seward will recover.

Frederick Seward is still unconscious. He breathes calmly and has an easy pulse. His head is dreadfully confused and lacerated.

An invalid soldier nurse saved Mr. Seward's life.

Gen. Grant's Movements.
Philadelphia, Saturday, April 15.

Gen. Grant arrived in this city late last night on his way to Jersey, but was intercepted on his way to Walnut-street wharf, by a dispatch from the office of the Associated Press, and it is supposed he returned to Washington immediately.

His Return to Washington -- Dispatch from Mrs. Grant,
Burlington, N.J., Saturday, April 15.

Lieut.-Gen. Grant left Burlington for Washington, at 6 o'clock this morning.

Mrs. U.S. Grant.
Washington, Saturday, April 15.

Gen. Grant, who left yesterday for New-Jersey, and who was informed of the assassination as he was leving Philadelphia this morning, arrived here in a special traina about noon, and immediately proceeded to the President's house.

The Theaters.

Dispatches from Boston announce that all the theatres in that city will be closed until further notice.

In this city a movement of the same kind has been inaugurated. Fox's Old Bowery Theatre will be closed this evening.