Col. William Ayrault Jackson was born in the city of Schenectady, N.Y., on the 29th day of March, 1832. His father, Isaac W. Jackson, was then Professor of Mathematics in Union College, of which he was a graduate, a position he has held uninterruptedly to the present time.

William was the eldest of the family. He fitted for college at home, under the instruction of his father, and entered at the early age of fifteen the Freshman Class of Union, at the commencement of the academic year in 1847.

During his collegiate career, he displayed marked and brilliant talents in various departments, and by the exhibition of the frank and generous qualities, which were characteristic of him, made among the under graduates of his time many and warm friends. He then more particularly won distinction as a forcible adn elegant extempore speaker, and skillful debater. In these accomplishments he was acknowledged to be without a rival among his college cotemporaries, and they were at a later period exercised with effect on the wider field of political discussion.

He graduated with honor in the summer of 1851, and during the succeeding year remained at home, devoting his attention to the study of general literature, and giving some of his time to study of the law that being the profession which he had chosen. Previous however, to his regular entry upon his legal studies, and during the year 1852, he spent some omnths with an uncle, Mr. I. C. Chesbrough, a civil engineer, and at that time engaged upon the survey of the Albany and Susquehanna Rail Road. In December, 1852, he removed to the city of Albany, with some of the most prominent and influential familes in which he was nearly connected, and entered the office of Marcus T. Reynolds, Esq. He also, about the same time, attended a course of lectures at the Albany Law School. He was admitted to the bar on the 10th of April, 1853, and immediately commenced the practice of his profession in Albany, which was his residence until his death.

Soon after the commencement of his legal career, he formed a partnership with his cousin, Frederick Townsend, Esq., an accomplished gentleman, since so favorably known as Adjutant General of the State during the whole of Gov. King's and a part of Gov. Morgan's administration, who as Colonel of the 3d Regiment of New York Volunteers distinguished himself by his brilliant gallantry at the battle of Big Bethel, and is now a Major in the United States Infantry. They were associated during the whole of Colonel Jackson's connection with the law. For a short period, during the year 1857, Alfred Conkling, formerly United States Distric Judge of the Northern Distirct of New York, was professionally conencted with them, under the firm name of Conkling, Townsend & Jackson. On the 1st of May, 1858, their business association with Judge Conkling having previously terminated, they took as a partner Richard M. Strong, Esq., and the firm name was changed to Townsend, Jackson & Strong. This partnership continued until the stirring national events of the spring of 1861 turned the thoughts of all from peaceful pursuits to arms, when Col. Jackson, who had been at the commencement of that year appointed and now held the office of Inspector General of the State, relinquished the profession to which he had been bred, and engaged in the defence of government, in the great struggle inaugurated by the attack upon the fall of Fort Sumpter.

Before proceeding to the mention of Col. Jackson's brief but honorable military career, we pause to say a few words of the character and talents which he displayed during the time of his practice at the bar. Possessed of a singularly handsome person, with frank and genial manners, having a bold and energetic character, and a quick penetrating intellect, being an agreeable speaker and vigorous writer, he fast made friends and admirers, and soon acquired a prominent and influential position at the capital of the state. Well grounded in the principles of the law, and prompt  in the dispatch of business, he obtained a very considerable professional practice. Always taking a deep interest in politics, state and national, and mingling freely and on intimate terms during almost the whole of this period with the most distinguished politcal leaders, he soon became appreciated as a man of ability, and a brilliant and effective speaker. His politcal views being in accordance with those of the Republican party, he early took that side, and in the campaigns of 1856, 1858 and 1860, rendered valuable services with his pen, and on the stump, to that organization. In 1858, indeed, he made quite an extended tour, and addressed numerous large assemblies in the western part of the state.

When, therefore, in the spring of 1861 he embraced with characteristic ardor the career of arms, he had acquired a high position in his profession and in society, and was making himself felt and his influence appreciable to a degree unusual in one so young.

No reasons then for so complete a change in the plan and pursuits of his life existed, other than a generous patriotism and an honorable ambition to win the praise of honest men by his sacrifices for and services to his country.

Successful in raising a regiment whose superior in material was not to be found in the state, he originally intended to take the position of Lieutenant-Colonel, devolving its command upon an army officer of experience. His plans failed in that respect, and after much hesitation and doubt from a consciousness of his inexperience, he was finally prevailed upon to accept the Colonelcy. On the 18th of June, 1861, he received his commission as Colonel of this, the 18th Regiment of New York Volunteers, with the rank from May 13th, 1861. From the breaking out of the war in April to the time he received his commission, he had been arduously engaged as Inspector-General of the State in aidinng the Governor in the organization of its forces, and hence by close application had acquired military knowledge which was of value to him in his new position.

From the day, however, that he took command of the 18th he was constant and unwearied in his devotion to and care for his men. Not unwilling to learn, nor unwisely self-confident as were some of the new officers of volunteers at that period, by the industrious application of his quick vigorous mind to the acquisition of a knowledge of the details of his duty, he very soon mastered them.

His Regiment left Albany in June, and proceeding directly to Washington, encamped near the city. Here began his first trial of camp life. The officers under his command were with but very few exceptions with out experience or practical military knowledge, and the men, like almost all the volunteers at that time, owing to the busy brief period that had elapsed since their enlistment, were a mere uniformed mass without drill or discipline, rather than a regiment of soldiers.

To change all this was the determination of the Colonel. He resolved to make it a regiment in truth, and one which should be inferior to none in the field. With this object in view, he was devoted, constant and unwearied, sparing neither body nor mind, but straining every faculty from the tie he arrived at Washington until the disastrous battle of Manassas, and indeed until his death, in his efforts to prefect himself as an officer, and to bring to a high state of discipline the men under his command. In how short a time he, with the earnest and praiseworthy co-operation of his officers, succeeded in doing this; and how well he did succeed, was soon to be shown.

On the 12th of July, in accordance with the general plan of a forward movement into Virginia, his Regiment was ordered across the Potomac and encamped near Alexandria. About the same time it was brigaded with the 16th, 31st and 32d New York Volunteers, forming together the 2d Brigade under the command of Col. Davies of the 16th Regiment.

On the 16th of July, commenced the memorable advance of the army of the Potomac; Col. Jackson's Regiment moved from Alexandria in the afternoon of that day, and, together with the other regiments forming the 2d Brigade, took part in the battle, or rather prolonged skirmish, of the 18th of July. In this, his conduct was gallant and meritorious, and his men behaved with the steadiness of veterans. In the battle of Manassas, on the 21st of July, which resulted so disastrously to our arms, the 2d Brigade were upon the left and constituted the reserve, not taking part in the main battle, fought principally by the right and centre.

It does not, of course, come within the scope of this Memoir to attempt any general description of the events of that terrible and humiliating day. It is sufficient to say that the 18th Regiment, the whole 2d Brigade, and indeed the whole Division, of which it formed a part, behaved with marked gallantry and steadiness. The 2d Brigade, covering Captains Green and Hunt's Batteries during the early part of the day, and with them effectually defeating a formidable attempt of the  enemy's right to flank the left of our line, when later our troops fled in such panic and confusion from the field, was ordered to Centreville to protect the retreat. As to what followed and the conduct of Col. Jackson at this crisis, an extract from the report of Capt. Green, in command of a battery, gives an interesting account; "I chose a position," he says, "on the crest of a hill which, from its shape, gave command of the ground to our left and also of the road along which our Division was retiring. From this position I could perfectly sweep with my fire 180 degrees front, right and left, down a gentle slope. Four regiments were placed as my support, and the force at this point could have stopped double its number. "At this point an unauthorized person gave orders to retreat; I refused the order, but all my supporting regiments but on (Col. Jackson's 18th N.Y.V.), moved off to the rear. Col. Jackson most gallantly offered his Regiment as a support, saying 'that it should remain by me as long as there should be any fighting to be done there.' The above mentioned person again made his appearance at this time and again ordered me to retreat, and ordered Col. Jackson to form column of divisiion on my right and retreat with me as all was lost. The order was of course disregarded and in about two minutes the head of a column of the enemy's cavalry came up at a run, opening out of the woods in beautiful order. I was prepared for it, and the column had not gone more than a hundred yards out of the woods before shells were burst at their head and directly in their midst. They broke in every direction, and no more cavalry came out of the woods."

The 18th, in compliance with orders from the Commanding General, retreated covering Green's Battery; halted for a short time at Fairfax; Col. Jackson ascertaining that the General, despairing of bringing the defeated army to a halt, had himself gone to Washington, it again resumed the retreat and at midday on the 22d took possession of its old camp at Alexandria. This retreat was effected in perfect good order throughout; and on the way back the Colonel was enabled to afford aid to his fellow-townsman, Lieut. Hill of the U.S. Artillery, in bringing off two of the guns of his battery.

All the officers who were present bear testimony to the gallantry of Col. Jackson, and the admirable behavior of his Regiment, throughout that memorable advance towards and retreat from Manassas.

During the whole time he was almost constantly mounted, and he bore up with astoninshing endurance under the most exhausting fatigue. He says himself, in a letter written to a friend on the 23d of July: "from half past two Sunday morning until Monday at midday, we neither slept nor rested. I was in my saddle nearly all the time."

After the battle, the Regiment not sharing in the general demoralization of the troops, remained near Alexandria; shifting its camp occasionally, taking its turn at guard and picket duty, and for a time engaged in building Fort Ward, one of the numerous fortifications erected protect Washington.

When Gen. McClellan, taking command, commenced the reorganization of the Army of the Potomac, the 18th Regiment was placed in Gen. Newton's Brigade and Gen. Franklin's Division.

The devotion and enthusiasm of Col. Jackson, in raising to the highest standard the discipline and morale of his men, did not flag. Until attacked by his last illness, he was hardly ever absent from the camp, and it was an extremely rare thing for him to sleep out of it; and he took eagerly upon his shoulders the thousand constant cares and labors consequent upon a scrupulously conscientious discharge of his duties. In a word, his whole time and energies were employed. In all this, and indeed during the whole of his connection with the Regiment, it is but justice to record, that his efforts were much aided, and the character of the regiment for discipline and efficiency raised, by the steady suport and uniformly gallant conduct of his Lieutenant Colonel (now Colonel), Young, a townsman, and the officer who succeeded him in command.

These wearing anxieties of his responsible position, and the unaccustomed privations and exposures of life in the field, in an unhealthy climate, were unfortunately laying in the constitution of Jackson the foundations of fatal disease. His health, which had been, through life, up to this period, almost perfect, now showed signs of giving way; and during a hurried visit home in August, his friends were alarmed at the inroads made by fatigue and anxiety upon it. Although, for some time after his return to the regiment, he seemed better, he was towards the end of October seized with an illness, which, assuming the form of bilious remittent fever, proved fatal. Prostrated for some days in  his tent, his brother officers were unalbe to induce him to "give up" and seek relief from his official duties, and it was not until his illness assumed a most serious form, that he consented to apply to be removed to Washington. This was done on the 30th of October, and Dr. Stone, one of the most eminent physicians of the city, was then immediately called to his bedside, but it was too late. For a few days, no critical symptoms appeared, and his condition was not considered as imminently dangerous until the 7th of November. Hemorrhage of the bowels, and after wards of the brain, then set in, destroying all hope. On Monday, the 11th of November, a little before six o'clock in the evening, his spirit passed away. His last words were these uttered just before the power of articulation departed, in a strong, deliberate voice, but evidently with great effort: "I do believe in the Lord Jesus Christ, I trust in Him."

The remains of Col. Jackson were taken home for interment. They were escorted to the cars at Washington by his regiment, every member of which expressed a desire to testify his respect for his beloved Colonel. At Albany, they were received by the military of the city, and lay in state.

He was buried at Schenectady on the 14th of November, 1861.

Borne to his last resting place by the friends of his youth whom he loved so well, amid the scenes of his boyhood he sleeps, requiemed by the sighing pines which wave over his grave.

Beautiful and joyous was his youth; bold and vigorous his manhood; his death honorable, nay glorious; for, although he fell not by the sword nor amid the maddening whirl and din of battle, yet by his self-consuming labors and his country's weal, were sown the seeds of that fell disease which was his destroyer.

He was young when he died, but so matured was his charactor, so rich in all manly qualitities, that he seemed to have passed his contemporaries, and to have taken, by a single bound, a high place above them.

The civil war, which he lived to see assume gigantic and fearful proportions, still rages undiminished; the eyes of all men are riveted, not to be turned aside but for an instant, upon that great drama. Act follows act so rapidly that yesterday seems a year ago, and the events of the past float in our remembrance vaguely and uncertainly as last summer's clouds. The tumult and peril of the time forbid to linger long over the tomb of the most loved one, and the mighty flood of public grief and calamity seems to drown all private sorrow. Yet the memory of the departed Jackson remains and will ever remain fresh and vivid in the hearts of the many friends and companions of his lfe. In brighter, happier days in the future, when peace shall again smile upon the land, and time shall have softened the first sharp pangs of their grief, they will speak gently and regretfully but proudly together of the one who is gone, recalling the eagle eye, the noble port, the bright intellect and the generous heart of him summoned so early, but who so well ran his brief race on earth.