There were three ways that the Constitution of 1864 provided for revising the Constitution:
1) Amendments could be passed by three-fifths of the members of each house of the General Assembly and then submitted to the people for ratification;
2)  The General Assembly could provide at any time by a two-thirds vote in each house for taking a vote of the people on whether a constitutional convention should be called;
3)  The question was to be posed to the voters at the general election of 1882 and each 20-year interval thereafter asking, "shall there be a convention to revise, alter or amend the constitution."  (No prior legislative approval was required.)  (Article XI, Sec. 3 of 1864 Constitution; Report of the Constitutional Convention Commission 1967, p. 59)

Article XI of 1864 replaces article XI of the Constitution of 1851 which calls for the legislature to pass a law "at its first session immediately succeeding the returns of every census of the United States [ie. every ten years] for  ascertaining, at the next general election of Delegates, the sense of the people of Maryland in regard to the calling a Convention for altering the Constitution..."  (Art. XI, Constitution of 1851).

The Report of the Constitutional Convention Commission 1967, with former governor William Preston Lane, Jr. (who died six months before publication of the report) serving as honorary chairman, H. Vernon Eney serving as chair, and Robert J. Martineau as secretary reported the following on the ten-year provision, p. 45:
"The experience of the reformers [of 1850/51] had made them exceedingly sensitive to the undesirability of leaving the process of constitutional amendment and revision exclusively within the province of the legislature, and they succeeded in including in the new Constitution [of 1851] a provision designed to assure that the people would not be powerless to change their form of government.  In the section setting forth the amendment process, the legislature was required to provide for the taking of the sense of the people as to whether the Constitution should be amended at each session immediately following the publication of a United States census."  The reformers attempted "to include in the Declaration of Rights an article reciting the inalienable right of the people to change their form of government, even by methods not established by the Constitution," and were unsuccessful.  (Report of the Constitutional Convention Commission 1967, p. 45).

At the 1850 Constitutional Convention, the members of the Committee on future Amendments and Revisions of the Constitution were so at odds with their visions for the process of amending the constitution that they submitted two different reports to the convention at large.  The first report was submitted on Thursday, April 3, 1851 by the chair of the committee, A. R. Sollers of Calvert County, by himself, because he could get no other members of the committee to agree with him.  He believed that the constitution should be altered by "passage of a bill by the General Assembly, provided such bills shall be published at least three months before a new election, and shall be confirmed by the General Assembly, after a new election of Delegates in the first session after such new election."  He also believed that a constitutional convention should be called only by the General Assembly passing a bill for that purpose, "provided such bill be published at least three months before a new election, and ... confirmed by the General Assembly after a new election of Delegates in the first session after such new election."  (See Proceedings and Debates of the 1850 Constitutional Convention, Vol. II,  p. 223)

The majority of members of the Committee on future Amendments and Revisions of the Constitution took a view that called for more direct involvement by the voters on the issue.  On Friday, April 4, 1851, James Fitzpatrick of Allegany County, Thomas J. Welch of Baltimore County, John Sappington of Harford County, and John D. Gaither of Frederick County submitted their own report to the convention (see Proceedings and Debates of the 1850 Constitutional Convention, Vol. II, p. 245).  The majority report made on April 4 is the first time I see mention of the 10-year provision.  The report read:  "At the session of the General Assembly next succeeding the return of every census of the United States hereafter to be taken, it shall be the duty of the Legislature to take the sense of the people of Maryland at the next general election of delegates to be held thereafter, for and against a Convention; and if it be ascertained that a majority of the people are in favor of a Convention, the Legislature shall take measures for the election of delegates to and for the assembling of the Convention at the earliest convenient day."

On Thursday, April 10, 1851, Sollers moved that the Convention take up his report for consideration (See Proceedings and Debates of the 1850 Constitutional Convention, Vol. II, p. 359).  Mr. Fitzpatrick of Allegany County immediately moved to substitute the wording from the majority report.  Robert J. Brent of Baltimore City moved to substitute wording that would have the governor issue a proclamation in 1860 and every ten years thereafter "giving at least thirty days notice that at the next general election of Delegates, the voters of the State may vote by ballot for or against a Convention... and if a majority of said votes shall be cast against a Convention, the Governor shall make proclamation of such result, but if there shall be found a majority in favor of a Convention, it shall immediately be the duty of the Governor to give at least sixty days notice in the most public manner, of a special election to be held at such time and places within six months thereafter, as he may prescribe, and at such special election, each county and the city of Baltimore shall elect as many Delegates as the said county and city respectively have on joint ballot in the General Assembly, and the Judges of election shall certify full returns of the ballots cast at such special election, to the Secretary of State, and the same shall be counted by the Governor and Secretary of State, and the persons having the highest number of votes in each county and the city of Baltimore, according to the representation herein allowed, shall be declared elected, and the Governor shall immediately make proclamation thereof, and at the game time designate a day for the meeting of said Convention within two months thereafter; and the said Convention shall meet in the Hall of the House of Delegates, or such other place as it may select, and when assembled, the said Convention shall elect such officers as it may deem necessary, and shall be the Judges of elections and qualifications of its members, and shall prepare a new Constitution To be submitted for ratification or rejection, to the qualified voters of the State, and if ratified, to be carried out, in such manner and at such times as the said Convention may provide; and the Treasurer of the State shall pay to the order of the President of said Convention, a compensation of four dollars per diem to each member during the time said Convention shall be in session, and in like manner such expenses as said Convention shall think proper to incur by its orders or resolutions, provided the said Convention shall not sit longer than six months."  Brent's justifcation for getting the governor involved in the process was that "he would trust the Governor sooner than the Legislature, and he would trust him sooner for this reason—that he was elected by the aggregate vote of the people, and was liable to impeachment.  But the Legislature was not liable, and therefore he would not trust a Legislature formed upon a territorial and not a popular basis, for he regarded the present basis as nothing but a mitigation of inequality and injustice." (pp. 362-3)

Debate on the issue ensued.  (See Proceedings and Debates of the 1850 Constitutional Convention, Vol. II, p. 360 and ff).  Those who supported letting the voters decide on amending the constitution were considered "radicals," and "red republicans."  Robert J. Brent of Baltimore City, a "radical," stated that, "The report of the majority proposed to secure the right of the people to hold a Convention, independent of any legislative action.  He regarded this as a most sacred right, and desired a provision engrafted in the Constitution authorising the people [voters] to vote every ten years, as to the propriety of calling a Convention to revise the Constitution."  He believed that the "people [voters] were the proper judges, and let them decide the question at the ballot box."  Brent delineated the basic  difference between the two proposals:  His (along with the majority report) "protects and guarantees, independent of Legislative action, to the people of Maryland this great right, while the other plan [Sollers'] leaves this right dependant on the action of a Legislature, which he [Mr. Brent] was unwilling to trust."  Brent asserted that there was an "anti-reform majority" in the Legislature that made it reluctant to call for a constitutional convention, and that the "great popular right [to change the government] must be protected," so that there needed to be a way for the voters to get around a recalcitrant legislature.  Brent "regarded the engrafting on the Constitution of an article referring all future Conventions to the corruption, or caprice of a Legislature, would be to deprive the people of their rights and their wish, every ten years, to have the Constitution amended, and tie them down, as heretofore, under the despotism of legislative majorities." (p. 362)  For Brent, "referring the subject of Constitutional change to the people every ten years...would be far preferable to leave it for legislative tyranny, or legislative caprice..." (p. 362)
Brent saw the issue as one of "equal rights." [between the voters and the legislature or among the voters of all the counties and Baltimore City?--unclear]. (p. 363)

The conservative position was represented by A. R. Sollers of Calvert County and Thomas F. Bowie of Prince George's County.  Bowie saw the ten-year provision as too restricting on the legislature and too forceful on the voters.  He believed that the legislature should be able to amend the constitution whenever "circumstances required and justified such a proceeding," and that "there should not be a constitutional injunction requiring the people at particular periods of time, to meet together to change their organic law, whether it required amendment or not"... and whether the voters "desired it or not."  Sollers "objected to the eternal periodical question of reform."  Every ten years, it seemed, that Maryland was to be excited from one end to the other, and all kinds of passions and prejudices were to be appealed to, and consequently, as a matter of course, we might expect new and extraordinary changes. That was what he disliked and abhored."  Apparently there had been a "long struggle" just to get the 1850 Convention called by the legislature, and the conservatives did not want to spend a lot of time (six months or longer) "tinkering" over the constitution every ten years.  Sollers accused Brent of showing "that the political party to which he belonged, was not content with the power they
already possessed, but even grasped at more, with that cormorant-like rapacity, (laughter,) which seemed to be unappeasible and insatiable." (p. 363)  Sollers "did not want this question of reform agitated every ten years, and disturbing the whole State from one end of it to the other." (p. 363)  Sollers also pointed out that voter turn-out tended to be about one-third of all eligible voters, and that it was possible that a constitutional convention could be called with only a small majority of those voting for it.  Sollers suggested that a future Constitution could "be ratified by less than a majority of all the votes in Maryland, he would ask gentlemen of this Convention, whether this would be in accordance with the great principles of our republican institutions." (p. 364)  Sollers stated that "he desired above all things, a fixed and stable government." (p. 364)

On the question of the ten-year time span:  (p.  362)
"Mr. BRENT thought that the political waters should be moved periodically by fresh agitations; he would say that whenever old dynasties had become rotten and decayed, he was willing to see them changed. 
Mr. SOLLERS [replied] (in his seat.) Why not every ten years?
Mr. BRENT. Yes!  oftener, if the people willed it.  He would be in favor of overhauling the Constitution frequently to meet the progressive wants of the age."

Mr. Brent then demanded a vote on his proposal and it was voted down.  (See p. 365 for a list of those who voted for and against Brent's proposal.)  The convention then considered the majority report submitted by James Fitzpatrick of Allegany County.  Thomas F. Bowie said that Fitzpatrick's proposal was "unnecessary, expensive, and not at all required." (p. 365)  Francis Thomas of Frederick County stated that "He went heart and hand in favor of the proposition for taking the sense of the people periodically, whether in ten or twenty years—but he preferred ten; but he greatly preferred to make the Legislature the agents, that they might pars all the laws required for the execution of such a trust." (p. 366)  Here is where the debate ended for Thursday, April 10, 1851.

Debate on the issue of constitutional amendments resumed on Friday, April 11, 1851.  Ezekiel Forman Chambers of Kent County stated that, "The great cause and clamor was caused, as he believed, not by the defects of the existing Constitution, but by the fact that no provision was made for giving the people the opportunity of reviewing it.  There was a great deal in "fashion" in this as in matters of minor importance.   Conventions to amend the Constitution had been held, every where almost, in the different States of the Union—they were the fashion of the day, he might say the passion of the day—and the people were told, very truly told, they had as much control over the government in Maryland, as the people in New York, Virginia, and elsewhere, had over theirs." (p. 368)

...more 1850 debate to follow

In 1864, the "argument was made by those opposed to constitutional revision that the combination of Article XI of the 1851 Constitution and of Article I of the 1851 Declaration of Rights prohibited the taking of a vote of the people on the question of calling a constitutional convention in any year other than that immediately following a United States census.  See Myers, The Maryland Constitution of 1864, at 63 ("The Johns Hopkins University Studies in Historical and Political Science," Vol. 19, Nos. 8-9, 1901).  This clearly was not the intent of the framers of the provisions, since they desired to open, rather than close, opportunities to revise the Constitution. Nevertheless, a similar argument, founded upon an amendment provision in the 1864 Constitution much like Article XI of the 1851 Constitution, was made by opponents of constitutional revision in 1867.  See Perlman, Debates of the Maryland Constitution Convention of 1867, at 9-13 (1923).  Although the suit in which this argument was made was dismissed by the Court of Appeals, the dismissal was based on procedural grounds, and the merits of the argument were not passed upon.  See id. at 13-27." (Report of the Constitutional Convention Commission 1967, pp. 45-46.)
 

The 1850 Committee on future Amendments and Revisions of the Constitution—
A. R. Sollers of Calvert County, chair
James Fitzpatrick of Allegany County
Thomas J. Welch of Baltimore County
John Sappington of Harford County
John D. Gaither of Frederick County

The 1864 Committee to report future Amendments and Revisions of the Constitution—
Robert W. Todd of Caroline County
William H. Mace of Baltimore County
Twiford S. Noble of Caroline County
Andrew Annan of Frederick County
George M. McComas of Harford County
Alward Johnson of Dorchester County
John Lee of Queen Anne's County