After having been nearly five years a licentiate, Mr. Welsh was ordained minister of the parish of Crossmichael, on the 22d of March, 1821. His presentation was highly honourable to the patron as well as himself; for while the latter was a Whig, the former was a Tory, and at this time political feeling was near its height; so that the young minister owed his promotion to that superiority of character which he had already acquired, and which the patron showed himself well fitted to appreciate. On entering upon the duties of a country minister, Mr. Welsh had two weighty obstacles to encounter, which would have marred the popularity of most persons thus circumstanced. The first arose from the state of his health, which was always delicate; so that the task of public speaking, so easy to the robust, was with him a work of labour, and often of pain. The other originated in the studious reflective habits he had already found so congenial to his nature, and which could ill brook the daily and hourly demands of common-place parochial business. But the physical obstacles and intellectual predilections were equally sacrificed upon that altar of duty at which he now ministered, and he soon became a most popular and useful preacher, as well as a laborious painstaking minister. On this head, his character is best attested by two of his distinguished co-presbyters, who were at one in their esteem of Mr. Welsh to the close of his life, although the Disruption, that afterwards ensued, rent them asunder in opinions of more vital importance. "I need not tell you," thus writes one of them to his biographer, "that Sir Alexander (Gordon of Greenlaw, the patron, who had presented Mr. Welsh, notwithstanding his political principles) had soon cause to rejoice that he had been guided by the wisdom that is profitable to direct, to do so. Dr. Welsh realized, in every respect, his most sanguine expectations, and was soon admitted by all parties to be the most superior, and efficient, and popular minister that was ever settled in that district of Scotland. I visited him more than once in the manse of Crossmichael; preached to his congregation, and mingled a good deal with his people; and never did I see a minister more beloved, or reigning more absolutely in the affections of his people." "From the time that he came to Galloway," the other thus writes of him, "I had the privilege of close intimacy and uninterrupted friendship with him; and certainly I could fill pages in commendation of his talents—his acuteness of intellect—his grasp of mind—his unwearied zeal in the discharge of his professional duties—the strong hold he had of the affections of his own people—the admiration that his pulpit ministrations met with wherever he appeared in public—the esteem in which he was held by his brethren—and the universal respect that attached to him from the community at large. . . .Notwithstanding all the innate modesty of our excellent friend, it was not possible that, in the most retired retreat, the great vigour of his mind, and the worth of his character as a Christian man and a Christian pastor, could long be hid or confined within the precincts of his immediate locality. It might be predicted of him, from the time of his appearance in public life—perhaps in his earliest days—that he was destined to hold a high place among his professional brethren; and that circumstances would, in the providence of God, occur to bring him into public notice."

Such was his course in the parish of Crossmichael, and such the effect of his labours. Independently, too, of his ministerial duties, in which he was so zealous and successful, Mr. Welsh still continued to be a diligent student, and one of his first, as well as the most distinguished of his literary labours, was his "Life of Dr. Thomas Brown," professor of moral philosophy in the university of Edinburgh, who had been the guide of his early studies, and friend of his more advanced years. This congenial task he undertook not only from grateful affection, but in consequence of the urgent request of Dr. Brown’s friends, who thought that the office could not be intrusted to better hands. It is enough to state respecting the merits of this biographical work, that it was worthy of the man whom it commemorated, as well as a profound and luminous exposition of the ethical and metaphysical principles which he had so eloquently taught as a professor; "and in holding converse," it may be added, in the words of a competent critic—"in holding converse through his memoir with the biographer himself, as well as with its interesting subject, one cannot avoid being infected with a portion of the same earnest and beautiful enthusiasm, which animates so evidently alike the silent inquiries of the master, and kindles the admiration of his accomplished disciple." While engaged in writing this work, the author also resolved, when it was finished, to produce a treatise on Logic, a design, however, which was never executed. In the meantime, his studies were continued, not only among his old, but among new fields of research; and in the latter was political economy, one of the most important, but withal most difficult, of modern sciences. The subject of education, also, as a science, engaged at this time his close attention, from the accident of the well-known Dr. Bell having become one of his neighbours and acquaintances; and in consequence of these inquiries, Mr. Welsh was enabled to turn his knowledge to an excellent practical account in the superintendence of schools, when his sphere of operation was transferred from a small secluded parish to the educational wants of a crowded city.

And that period of transference was not long delayed. It was soon evident, from the superior talents of the minister of Crossmichael, from his love of mental improvement, and from the earnestness with which he prosecuted the work of intellectual acquirement, in a situation where so many minds relapse into mere literary ease and recreation, that he was fitted for a still more important situation than that which he now occupied. Accordingly, a vacancy having occurred in the church of St. David’s, Glasgow, Mr. Welsh, whose reputation was already known, was invited by the town council of Glasgow to occupy the charge. He accepted the offer, and was inducted toward the close of 1827. In this new field he found full scope for his talents, and was quickly distinguished, not only as an eloquent and useful preacher, but a most effective promoter of the interests of education, now become of paramount importance in such an over-crowded manufacturing city. Here also he found that cheering and strengthening intercourse of mind with kindred mind, which forms only an occasional episode in a country manse. He likewise married Miss Hamilton, sister of the Lord Provost, and to all appearance had reached that comfortable termination in which the rest of his days were to be spent in peace. But his health, which had been always delicate, and the weakness of his chest, made the task of preaching to large audiences, and the week-day duties of his office, so laborious and oppressive, that in a few years he would have sunk under them. Happily, however, his labours were not thus prematurely to terminate; and the offer of the chair of church history, in the university of Edinburgh, which he received from government in 1831, came to his relief. This was the boundary to which unconsciously all his past studies had been tending, while the weakly state of his constitution only hastened the crisis. It was more in accordance with his feeling of duty to accept such a charge, for which he had strength enough, than to break down in an office which was growing too much for him. And, even setting this aside, he felt that the great work of training up an efficient ministry was of still higher importance than the ministerial office itself. These inducements were obvious not only to himself, but to his attached congregation; and they freely acquiesced in the parting, although with much sorrow and regret. He therefore left Glasgow, in November, 1831, for his new sphere of action, and received the degree of doctor in divinity from the university, at his departure.

The office into which Dr. Welsh was now inducted, had hitherto, in Scotland, for more than a century, been one of the least distinguished of all our university professorships. This was by no means owing either to the inferior importance of church history as a subject of study, or to any innate dryness and want of interest that belongs to it; on the contrary, we know that it embraces subjects of the highest import, and exhibits the development of the human mind in its strongest and most intense aspects—and is consequently of a more stirring and interesting character in itself, than either the rise and fall of empires, or the record of triumphs and defeats. But Scotland had been so exclusively occupied with her Solemn League and Covenant, that she had found little time to attend to the history of other churches; and even when better days succeeded, those classical and antiquarian studies upon which ecclesiastical history so much depends, had fallen so miserably into abeyance, that the evil seemed to have become incurable. What, indeed, could a student make of the history of the church for at least twelve centuries, when his "small Latin and less Greek" could scarcely suffice to make out the name of a bygone heresy, or decipher the text in the original upon which the controversy was founded? In this state, any one or anything had sufficed as a stop-gap, to fill the vacuum of such a professorship--and it had been filled accordingly. But now a new order of things had succeeded. A more ardent literary spirit had commenced among our students, a wider field of inquiry had been opened, and they could no longer submit to doze over a course of lectures as dark as the dark ages, among which they lingered for months, or listen to a teacher who, perhaps, knew less about the matter than themselves. It will be seen, therefore, that nothing could have been more opportune than the appointment of Dr. Welsh. His clear and vigorous mind, his varied acquirements and extensive reading, had not only furnished him with the requisite stores of knowledge, but given him the power of selecting what was fittest from the mass, arranging it in the most effective form, and expressing it in that perspicuous attractive style which insured attention and stimulated inquiry. And besides all this aptitude, he was so profoundly impressed with the importance of his charge, that he resolved to give himself wholly to its duties; and with this view, he abstained from every engagement, either of literature or public business, that might in any way have allured him from his work. The devout conscientious spirit, too, in which all this was undertaken and carried on, will be manifest from the following memorandum found among his papers. After mentioning what he regarded as shortcomings in the duties of his professorship, and confessing them penitently before the Lord, he adds: "In His strength I now bind myself, during the present session,—

"1. To set apart one hour every Saturday for prayer for my students, and for considering my failures and deficiencies in the past week, with corresponding resolutions of amendment in the succeeding week.

"2. To make it a distinct object daily, praying for assistance to supply the deficiencies and correct the errors mentioned in the preceding page.

"3. To make a study, as opportunity presents, of the passages in Scripture that relate to my duties as a teacher, and to the duties of the young.

"4. To add to my resolutions from time to time, as new light shines.

"5. To read the above at least once a-week—strictly examining myself how far my conduct corresponds, and praying that God may search and try me.

"In looking at a student, ask, how can I do him good, or have I ever done him good?"

In this spirit Dr. Welsh entered upon his duties; and perhaps it would be needless to add how distinguished he soon became as a professor of church history. In his hands, a course of teaching hitherto so uninteresting and unprofitable, seemed to start into new life. At the close of each session he sat regularly in the General Assembly, as member for the presbytery of Lochcarron, but without taking an active part in its proceedings, as, from his delicate health, nervous temperament, and constitutional diffidence, he was neither a bold combatant in debate, nor a ready extemporaneous speaker. In the latter capacity, indeed, he jocularly compared himself to a narrow-necked bottle, from which the liquid is hurriedly discharged in jerks and gurgles. In the third session of his professorship (1834) he published a volume of "Sermons on Practical Subjects," which he had preached during his ministry in Crossmiohael and Glasgow; and although they were intended merely for private circulation among the two congregations, they at once went beyond these narrow bounds, and obtained a wide popularity. During the spring and summer of the same year he also went abroad, accompanied by his wife and two children, and resided at Bonn and Heidelberg, besides visiting other places in Germany. This trip, however, instead of being a mere pleasure tour, was undertaken by Dr. Welsh for the purpose of perfecting himself in German, in reference to the advancement of his studies in theology and church history; and to acquaint himself, by personal examination, with the educational system of Prussia, with a view to the introduction of its improvements into that of Scotland. Having now, by frequent re-writing and improvement, brought his course of college lectures to some conformity with his own rigid standard, and having become familiarized with the duties of his chair, Dr. Welsh at length ventured to take a larger share in the general business of the church than he had hitherto attempted. Accordingly, in 1838, he accepted the office of vice-convener of the Colonial Committee, and in 1841, that of convener. This situation, when conscientiously filled, involved an amount of study about the spiritual wants of our colonies, of extensive correspondence, and delicate influential management, as had hitherto daunted the boldest, and made them pause perhaps too often; but in the case of Dr. Welsh, these difficult duties were entered and discharged with the same unflinching zeal which he had so successfully brought to his professorship. He also took a very active and influential share in an important controversy of the day, regarding the monopoly in printing the Bible, which had so long prevailed in Scotland, but was now felt to be an intolerable religious grievance; and on the monopoly being abrogated, and a board of control and revision established for the new editions of the Scriptures, Dr. Welsh was ultimately appointed by government to be secretary of the board. How he occupied this most trying and responsible charge is thus stated by his talented and distinguished biographer: "His fitness was acknowledged by all, and his performance even exceeded the expectations of the country. In the main matter of securing accuracy in the impressions of the Scriptures, complete success may truly be said to have been achieved, and chiefly through his care and knowledge; while the conciliatory manner in which the control exercised by the board was carried into effect, through him, guarded against all cause of discontent on the part of the trade, and soon did away with those jealousies which a little indiscretion might have called into such activity as to have greatly marred the usefulness of the measure. He brought the whole machinery into smooth and efficient working order, and handed it over to his successor in a state that required little more than the ordinary care of seeing that nothing should interfere with the system as he had arranged it."

During this interval, an under-current had been going on in the life of Dr. Welsh, that was soon to assume the entire predominance. We allude to those great church questions that had been agitated from year to year, and were now to end in the DISRUPTION. Upon these questions he had meditated deeply and conscientiously, and at every step had gone along with the evangelical party in the Church of Scotland, and at last had arrived with them at the conclusion, that further concession to the state was impossible; that all state advantages must be foregone by the church, in behalf of those principles that were part and parcel of her very existence. Such was the decision to which the controversy had come in 1842; and upon that memorable year, the decision was to be announced, and the church committed on the issue. At such a solemn period of assize, the high estimation in which Dr. Welsh was held was fully shown by his election to the office of moderator of the General Assembly; and this office, now so fraught with difficulty and deep responsibility, he undertook with fear and trembling. The faithfulness and ability with which he discharged it, is matter of history. Many important measures were passed at the sittings of this Assembly; but the most important of all was the "claim, declaration, and protest," in which the spiritual rights of the church were announced, the assumptions of the civil courts abjured, and the resolution of foregoing all the benefits of an Establishment distinctly declared, unless these rights were recognized, and the encroachments of the civil courts terminated.

Another year rolled on, and the General Assembly again met; but it could only meet for the final departure of such as still adhered to the protest of the former year—for the State had determined not to yield. All things were therefore in readiness for the meditated disruption, and nothing remained but to seize the proper moment to announce it. This was the trying duty of Dr. Welsh, as moderator of the former Assembly; and to be performed while he was labouring under the depression of that wasting disease which at no distant period brought him to the grave. But calmly and with an unaltered step he went through the preliminary duties of that great movement; and on Wednesday, the day previous to the opening of the Assembly, he signed the protest of his brethren, and afterwards dined, according to established rule, with the commissioner, to whom he announced the purposes of the morrow. On Thursday, he preached before the commissioner and a crowded auditory upon the text, "Let every one be fully persuaded in his own mind;" and after this solemn note of preparation, he repaired with the brilliant cortege and throng of divines to St. Andrew’s Church, and opened the Assembly with prayer. This duty ended, the promised moment had come. While all were hushed with painful expectation, the pale sickness-worn face of Dr. Welsh was for the last time turned to the commissioner’s throne, and in a voice that was soft and slow, but firm and articulate, he thus announced the final purpose of his brethren: "According to the usual form of procedure, this is the time for making up the roll; but, in consequence of certain proceedings affecting our rights and privileges--proceedings which have been sanctioned by her Majesty’s government, and by the legislature of the country; and more especially, in respect that there has been an infringement on the liberties of our constitution, so that we could not now constitute this court without a violation of the terms of the union between church and state in this land, as now authoritatively declared, I must protest against our proceeding further. The reasons that have led me to this conclusion, are fully set forth in the document which I hold in my hand, and which, with permission of the house, I shall now proceed to read." He then read the protest; and after bowing to the throne, he left the chair of office, and proceeded to the door, followed by Dr. Chalmers, Dr. Gordon, and the fathers of this momentous secession. Thus the departure commenced; a long array succeeded; and the procession slowly wound its way to Tanfield, where a large hall had been hastily fitted up in expectation of the emergency; and there, a new General Assembly was constituted, by the new—or shall we say—by the old and long-forgotten, but now regenerated Church of Scotland.

Amidst the many sacrifices that were made on this occasion by the ministers of the newly constituted Free Church of Scotland—sacrifices which even their enemies will acknowledge were neither few nor trivial—those of Dr. Welsh were of no ordinary importance. In attaining to the professorship of church history in the university of Edinburgh, he had reached an office all but the highest to which a Scottish ecclesiastic could aspire. It was besides so admirably suited to all his past acquirements, and now matured intellectual habits, that perhaps no other could have been found over the whole range of Scotland so completely adapted to his likings. And yet, this he knew from the beginning that he must forego, as soon as he abandoned the state patronage of the Establishment. In addition to his chair, he held the office of Secretary to the Board for the publication of the Bible, an office that yielded him a revenue of £500 per annum; but this comfortable independence, so rare among the scanty endowments of our national church, must also be sacrificed as well as his professorship. Both offices were quickly reclaimed by the state, as he had anticipated from the beginning. All this would have been enough, and even more than enough, for a bold and brave man in the full strength of manhood, and still eager for enterprise: but in the case of Dr. Welsh the fire of life was well nigh exhausted; a mortal disease was silently and slowly, but securely drying up the fountain-head of his existence; and he had arrived at that state in which every effort is weariness and pain, while tranquillity is prized as the greatest of blessings. And yet he abandoned all, and braced himself anew for fresh action, so that the rest of his brief life was full of exertion and bustle. The chief department that fell to his share was that of Education in connection with the Free Church; and his valuable services in the erection of schools and the establishment of a college, will continue of themselves to endear his memory to the scholars of future generations. Of this new college, which commenced its labours immediately after the Disruption, for the training of an efficient ministry, Dr. Welsh was professor in ecclesiastical history, while Dr. Chalmers held the office of principal. Dr. Welsh also became editor of the "North British Review," and by his able management contributed to raise that periodical to the high literary standing which it quickly obtained. In 1844 he also published his "Elements of Church History" in one volume, which was intended to be the first of a series extending to six or seven volumes, that should carry down the history of the church to the close of the sixteenth century. But his labours had already approached their close; and his inability to continue his college prelections at the close of the year, was the last of many warnings which he had lately received that his departure was at hand, and might probably be in a single moment. The disease under which he laboured was one of those complaints of the heart, now so prevalent, but still so little understood, that often make sickness so painful and death so sudden. And thus it was with Dr. Welsh. He had retired to Camis Eskin, on the banks of the Clyde, but without finding relief, and on the 24th of April, 1845, his troubles were closed. A passage of Scripture had been read to him, which he turned into a fervent prayer, and as soon as it was ended he stretched out his arms, and instantly expired.