O’Sullivan, J.
At its regular session in 1953 the General Assembly enacted Public Act No. 32, purporting to redistrict the senatorial districts of the state. General Statutes, Cum. Sup. 1953, §§ 399c, 400c. The ultimate question in this litigation is whether that enactment is violative of the thirty-first amendment to the state constitution. The amendment, in the form in which it was adopted in 1901 and in which it still remains, is printed in full in the footnote.2
[4]*4The case is here upon a reservation, and the facts stipulated by the parties may be summarized as follows: The General Assembly of 1951 convened on January 3 of that year. During the session, it took no action aimed at altering the state senatorial districts. No redistricting bill was introduced in either house. At that time, according to the figures of the 1950 census, the population of the thirty-six senatorial districts varied from 24,309 in the thirty-first to 122,931 in the fifth. As set up in the 1953 act, the population of the districts ranges from 40,835 in the thirty-first to 73,726 in the sixth.
The seventeenth decennial census of the United States was taken as of April 1,1950. The enumeration started on April 2 and, so far as Connecticut was concerned, was finished by May 1 of that year. It was made by enumerators, to each of whom had been assigned a small district. In addition to making a personal canvass of every household, the enumerators visited hotels and other transient accommodations within their respective districts on April 11 and prepared individual census reports for each person found in the districts on that day whose usual residence was elsewhere. Upon completing their work, the enumerators delivered their returns to field offices, where tabulations were carried out. This field count was completed by the middle of June, 1950, and shortly thereafter the figures for all Connecticut towns were released to and published by the press. Later on, the figures for all cities by wards and voting districts were similarly released and published.
[5]*5About June 25, 1950, the returns for the entire state were shipped to the census office in Philadelphia. These were accompanied by the individual reports of transients found in the state on April 11, 1950. By a method explained in the footnote,3 tabulation of the data appearing on the returns and reports was commenced in Philadelphia in July. The results were recorded on so-called M.C.D. (minor civil division) sheets.4 As a consequence of this tabula[6]*6tion, the determination and the recording of the final figures for all Connecticut towns and for wards and voting districts in the cities were completed prior to October 30,1950.
On the date just mentioned, the director of the census sent to the secretary of commerce a statement showing the total population of the District of Columbia and of each state in the union. On November 2, this information was transmitted to the president and released to the press by the secretary of commerce with the comment: “I am particularly pleased with the speed and accuracy with which the enumeration and final count have been completed. The Bureau finished the job about a month earlier than in 1940.”
Section 18 of the current census act authorizes the director of the census to furnish copies of so much of the population returns as may be requested by state or local officials as well as by private individuals. 46 Stat. 25, 13 U.S.C. § 218. By virtue of this provision, certified copies of the final figures of the 1950 census, broken down to Connecticut towns, wards and voting districts, were obtainable, at a cost of $20, any time after October 30, 1950, by Connecticut state officials and by the 1951 G-eneral Assembly when it convened.
The final population figures of Connecticut towns, which had been computed and recorded on the M.C.D. sheets prior to October 30, 1950, were first released to the press on August 12,1951. This release, which did not cover the figures for city wards and voting [7]*7districts, included an analysis of the Connecticut population under the heading of urban and rural classifications. On November 28, 1951, the bureau of the census published a pamphlet as a preprint of chapter 7 of an eventually to-be-compiled volume 1 of census statistics. Among other data incorporated in the preprint were the final population figures for counties, towns and wards, where a city was divided into wards.
The original constitutional provision for senatorial districting was embodied in the second amendment,5 adopted in 1828. This amendment was in substantially the same form as the thirty-first, save that it authorized fewer districts. During 1829, the state was divided by the General Assembly into senatorial districts. From 183.1 until 1951, with the exception of the redistricting in 1903 required by the express terms of the thirty-first amendment, every act changing the territorial limits of a senatorial district has been enacted in the year immedi[8]*8ately following the year of the decennial census, that is, in 1831, 1841, 1881, 1921 and 1941. During the same period, each General Assembly held in the first year after a census has considered redistricting legislation except the Assemblies of 1891 and 1951. In each of the years in which such legislation was considered, there were available to the General Assembly only the preliminary figures issued by the official charged with taking the census. In 1911 Governor Simeon E. Baldwin procured the final census figures prior to publication and submitted them to the General Assembly. Several of the governors holding office in the first year after a census have called the attention of the General Assembly to the fact that it was proper to redistrict the state and have observed that if it were not done then, it could not be done for another ten years.
From 1903 to 1953, the senatorial districts have been altered twice. In 1921 changes were made in the districts in the city of New Haven, and in 1941 the town of Greenwich was constituted an additional district. Certain other stipulated facts need not be recited at this point but will subsequently be mentioned in discussing the law.
The nine specific questions6 propounded on this reservation can be resolved, as the parties agree, in[9]*9to the following three: (1) Was the seventeenth census of the United States completed, within the meaning of the thirty-first amendment to the state constitution, before the opening of the regular session of the General Assembly in January, 1951? (2) If it was, did the thirty-first amendment preclude the General Assembly of 1953 from enacting redistricting legislation? (3) If the General Assembly of 1953 did in fact have the power to redistrict, did the redistrieting act of 1953 violate the constitutional requirement that each senatorial district shall be composed of contiguous territory?
We begin a discussion of the first of these three questions by observing that, when the constitutionality of a legislative enactment is attacked, we must make every reasonable intendment in favor of its validity. Northeastern Gas Transmission Co. v. Collins, 138 Conn. 582, 586, 87 A.2d 139; Legat v. Adorno, 138 Conn. 134, 145, 83 A.2d 185. On the other [10]*10hand, we must not be blind to the obvious or permit ourselves to be lulled into error by the soothing influence of a mere presumption. If the invalidity of the enactment is evident beyond a reasonable doubt, our duty, delicate as the task may be, is to nullify the statute. Gionfriddo v. Windsor, 137 Conn. 701, 705, 81 A.2d 266; Beach v. Bradstreet, 85 Conn. 344, 349, 82 A. 1030.
The thirty-first amendment (§2) provides that the senatorial districts, after they have once been established, “shall not be altered . . . except at a session of the general assembly next after the completion of a census of the United States.” The initial inquiry which this language naturally suggests is: What is meant by the phrase “the completion of a census”? A census is the official enumeration of the population. Webster’s New International Dictionary (2d Ed.); City of Compton v. Adams, 33 Cal. 2d 596, 597, 203 P.2d 745; City of Huntington v. Cast, 149 Ind. 255, 258, 48 N.E. 1025. In ordinary parlance, the completion of a census refers to the time when an official counting of the people has been finished. But, as used in the thirty-first amendment, the phrase means something more than that. The “census” mentioned in the amendment must of necessity be one showing the figures which are essential for intelligent action on the part of the General Assembly. The mere enumeration of the entire state, without more, is of no help in the enactment of redistricting legislation. The Assembly needs other data if, as provided, it is to make the senatorial districts as nearly equal in population as possible, under the limitation prescribed in the amendment. A census, then, within the thirty-first amendment, is one showing the population figures broken down into counties, towns and wards; and the census is [11]*11completed only when those figures have been released to the public by an official authorized by law to make such publication or when those figures are available for the use of the General Assembly.
This standard for determining when a census has been completed accords with common sense and fulfils the purpose for which the phrase under discussion was incorporated into the amendment. That purpose was not only to establish the time when senatorial redistricting is authorized but also to provide the General Assembly with sufficient data to pass legislation upon the subject, if it desires to do so. The defendant appears to concede this. In his brief he states that “[w]hether or not the census was completed in 1950 in the sense the word is used in the 31st Amendment to our Constitution depends upon whether there was available the information needed to carry out a redistricting of the Senate in this state.” He maintains, however, that such information was not available until November 28, 1951, when the final results of the tabulation of Connecticut counties, towns and wards appeared in a printed booklet issued by the director of the census. The defendant takes this position in spite of the fact, which he readily concedes, that the identical information found in the booklet was, upon the payment of $20, available to Connecticut officials at any time after October 30,1950, and to the General Assembly when it convened in January, 1951.
But this aside, it is not necessary that the information be published in book form before it becomes officially available. Indeed, there is not even a constitutional provision requiring the figures to be final. While final tabulations tend to greater exactitude than those previously computed, there is no need for the precision of perfection. The results of [12]*12the preliminary counts customarily released by the census bureau, as happened in the case at bar, are ample to afford sufficiently accurate data for an Assembly to proceed to redistrict in an intelligent manner, provided the counts have been broken down into counties, towns and wards. The situation would be vastly different were senatorial districts to be absolutely equal in population. That requirement is not to be found in the amendment. The General Assembly is commanded to equate the districts as nearly as possible. In view of the provisions that each county shall have at least one senator, that no district shall cross county lines and that no town shall be divided unless for the purpose of forming more than one district wholly within such town, equality is impossible. The population in the districts established by the act of 1953 runs from 40,835 to 73,726. If the use of the final figures which were before the 1953 Assembly could bring about no greater equality than that shown by the range of population just noted, the needlessness of requiring final rather than preliminary figures becomes perfectly apparent.
Then again, our acceptance of the defendant’s claim that no census is completed, within the intendment of the thirty-first amendment, until the enumeration has been tabulated by towns and wards into “final” figures would force us into the unhappy holding that each General Assembly which enacted redistricting legislation prior to 1950 did so in violation of law. This conclusion would be inevitable, since every such Assembly acted only on preliminary figures. Indeed, if the redistricting legislation after the 1880 census had had to await the release of “final” figures in pamphlet form by the census director, the first Assembly qualified to act [13]*13would have been that of 1889, because the final figures of the 1880 census were not officially released until 1888. The framers of the constitutional amendments in question would undoubtedly be the first to disclaim a construction of their language which would lead to such an anomalous result.
Furthermore, this claim that the information must be in book form and must be based upon final tabulations is contrary to the construction given for almost 125 years to the phrase “the completion of a census” by the legislative and executive branches of the state government. Those branches have uniformly looked upon the census as completed when the preliminary count was available, and, on every occasion when redistricting was accomplished or considered, such action was taken far in advanee of final publication. Of the many instances of legislative construction referred to in the footnote,7 only one will be mentioned. The first census after the [14]*14adoption of the second amendment (the forerunner of the thirty-first) was taken in 1830. The 1831 session of the General Assembly convened on the first Wednesday of May in that year. That Assembly passed an act which for the first time made a change in the division of the state into senatorial districts. When the Assembly convened, as well as at the time of the passage of the act, only the uncorrected returns of the census were available. It was not until 1832 that the final figures of the 1830 census were first published. In the 1831 General Assembly were undoubtedly many of the legislators who had served in the sessions of 1827 and 1828, when the resolutions leading to the adoption of the second amendment were debated and passed. If the phrase “the completion of a census” embodied in the second amendment was intended to require the final tabulations of the census returns, it is difficult to conceive that those men either overlooked or, worse still, ignored the constitutional mandate they had helped to frame. Water Commissioners v. Curtis, 87 Conn. 506, 511, 89 A. 189. A practical construction placed upon a constitutional provision immediately after its adoption and consistently and repeatedly followed by the executive and legislative branches for over a century thereafter is most persuasive. Ibid. In the case at bar, it furnishes-strong evidence of the meaning to be accorded the phrase. A practice of such duration, while not absolutely binding, is entitled to great regard in determining the true construction of the constitutional provision. State ex rel. Corbett v. South Norwalk, 77 Conn. 257, 264, 58 A. 759. The point need not be further labored other than to invite attention to instances of executive branch construction, some of it by governors who were eminent lawyers and for[15]*15mer members of tbis court, as cited in the footnote.8
Tliat tlie census was completed within the meaning of the thirty-first amendment is likewise supported by the law of other jurisdictions. None of the cases to wifi eh our attention has been called involves a construction of the identical phrase, “the completion [16]*16of a census,” found in our constitutional amendment. The state courts have been usually asked to construe such language as “according to the last census.” In doing so, they referred to the time when a census had been completed and in this manner discussed the matter as though they were in fact construing the phrase “the completion of a census.”
For example, a case frequently cited on this subject is Holcomb v. Spikes, 232 S.W. 891 (Tex. Civ. App.). The Texas constitution provided that “counties having 10,000 inhabitants, to be determined by the last preceding census of the United States,” might elect a tax collector. Under the 1910 census, Lubbock County had a population of less than 10,000. On September 30, 1920, the director of the census certified that “according to a preliminary count, subject to correction,” the population of the county was 11,096. On November 2, 1920, Spikes was elected tax collector. Holcomb challenged the legality of the election on the ground that the census of 1910 should govern, since the figures of the 1920 census were not final or complete. The court held (p. 894) that the election of Spikes on the basis of the preliminary count of the 1920 census was valid. To like or analogous effect are Garrett v. Anderson, 144 S.W.2d 971, 973 (Tex. Civ. App.); Herndon v. Excise Board of Garfield County, 147 Okla. 126, 128, 295 P. 223; Excise Board, Washita County v. Lowden, 189 Okla. 286, 287, 116 P.2d 700; State v. Braskamp, 87 Iowa 588, 592, 54 N.W. 532; see also Twin Falls v. Koehler, 63 Idaho 562, 567, 123 P.2d 715. The only case which superficially appears to be opposed to the holding of Holcomb v. Spikes, supra, is Childers v. Duvall, 69 Ark. 336, 338, 63 S.W. 802. The following are clearly distinguishable: Huntington v. Cast, 149 Ind. 255, 48 N.E. 1025; Wolfe v. [17]*17Moorhead, 98 Minn. 113, 107 N.W. 728; Lewis v. Lackawanna County, 200 Pa. 590, 50 A. 162; Greenough v. Town Council of Narragansett, 29 R.I. 380, 71 A. 594.
Thus, on the basis of a construction that serves the purpose for which the phrase “the completion of a census” was incorporated into the second and thirty-first amendments, on the basis of the legislative and executive construction given to the phrase for 125 years, on the basis of the conceded facts, and on the basis of the precedents of other jurisdictions, it is clear that the 1950 census was completed, within the meaning of those amendments, by October 30, 1950.
We now turn to the second of the three questions previously mentioned: If the census was completed in 1950, did the thirty-first amendment preclude the General Assembly of 1953 from enacting redistricting legislation in the form of Public Act No. 32? In maintaining that the question should be answered in the negative, the defendant states his position in this manner: “The General Assembly is vested with the power to alter the senatorial districts when it is found necessary to secure proper equality of population subject to constitutional restrictions. There rests upon the General Assembly the duty to exercise this power for the people of the state. This power is to be exercised at the first session following the federal census and, if not so exercised, continues in ful] force to succeeding sessions until [it is] exercised.” This amounts to saying that, even if the 1951 Assembly was “next after the completion of a census,” the 1953 Assembly could still act because of a continuing duty imposed upon it after the 1951 Assembly failed to consider redistricting legislation. The theory is not applicable, however, to the case [18]*18at bar. To adopt it would require us to find ambiguity where none exists, to warp the language of the thirty-first amendment, to ignore its obvious meaning and the purpose of its framers, and to disregard the practical construction given to it for over a century by both the legislative and executive branches of government.
An analysis of both the second and the thirty-first amendments discloses that each sets forth a duty, a power and a prohibition. Thus, the second amendment provides, in language of clear command, that the General Assembly of 1829 “shall divide the state into districts” (italics supplied). This created a positive duty. The amendment then provides that “[t]he districts, when established, shall continue the same until the session” of the 1831 General Assembly, which “shall have the power to alter the same, if found necessary, to preserve proper equality between said districts” (italics supplied). This was a grant of power. Then, as if anticipating such a claim as that now advanced by the defendant, the framers of the amendment concluded with the provision that, “after [1831], said districts shall not be altered, . . . except at any session of the General Assembly next after the completion of a census of the United States . . .” (italics supplied).
In similar manner and in almost identical language, the thirty-first amendment imposes a duty upon the General Assembly of 1903 to divide the state into senatorial districts, grants the General Assembly of 1911 the power to alter them, and prohibits their alteration thereafter “except at a session of the general assembly next after the completion of a census of the United States.”
It was not by sheer accident that each amendment imposed a duty upon the first Assembly following [19]*19the adoption of the amendment, granted a power to the Assembly convening next after the completion of the federal census, and set up a prohibition against action on the part of every other Assembly. The meticulous choice of language and the manner in which the duty, the power, and the prohibition are physically segregated in the phraseology of the amendment lead logically to no other conclusion than that the framers were speaking with studied deliberation and after thorough consideration.
Dealing, as we are, with constitutional amendments, we must assume that infinite care was employed to couch in scrupulously fitting language a proposal aimed at changing the organic law of the state. 1 Cooley, Constitutional Limitations (8th Ed.) p. 125. Undoubtedly this was particularly true because of the contemplated change in the method of electing the state senate, since this was a subject of great concern and of wide discussion during the 1820’s. Under the constitution of 1818, senators had been elected at large. Conn. Const. Art. Ill § 4 (1818). The purpose of the second amendment, the prototype of the thirty-first, was to provide representation in the senate in proportion to the population. The senate was to be composed, under the second amendment, of senators from not less than eight nor more than twenty-four districts and, under the thirty-first, of senators from not less than twenty-four nor more than thirty-six districts. Since changes in the population might make the districts unequal as they were established by the Assemblies of 1829 and 1903, the framers devised the plan of affording to the General Assembly a periodic opportunity to re-examine and redistrict, if found necessary, in order to adjust, as best could be done, existing inequalities. That power was given to the [20]*20Assembly next convening after tbe completion of the census. The amendments recite that the Assembly “shall have the power” to redistrict; they do not provide, as the defendant insists, that the Assembly “shall redistrict” or “shall have the duty” of doing so. The language of the amendments establishes that no duty to redistrict was imposed on those Assemblies convening next after a federal census had been completed.
But, it is urged, if such a General Assembly should fail, as occurred in 1951, to take any action to adjust inequalities in the various districts, grave injustice might be done the people of the state. That is entirely beside the point. We are not passing upon the injustice, if such it was, wrought by the neglect, if any, of the Assembly of 1951 to act. It may be, as was recently pointed out by a committee of distinguished members, including a former chief justice of this court, that the thirty-first amendment should be altered in order to compel redistricting after each federal census.9 Our concern, however, is here limited to the meaning of a constitutional provision and not to the desirability of a constitutional amendment.
[21]*21Accordingly, we conclude that the language of the thirty-first amendment granted a power but imposed no duty to redistrict upon the Assembly of 1951. Once this conclusion is reached, the defendant’s position collapses. Obviously, there could have been no continuing duty in the Assembly of 1953 unless there was an initial duty in the Assembly of 1951.
This conclusion is fortified by two other considerations, to which we briefly refer. In the first place, if the Assembly of 1951 was burdened with a duty to redistrict which it failed to honor, and if a continuing duty was thereafter imposed upon the Assembly of 1953, we would be obliged to hold that the last part of the amendment, creating the prohibition, is mere surplusage. This, of course, cannot be done. Effect must be given to every part of and each word in our constitution, unless there is some clear reason, not here discernible, for not doing so. Williams v. United States, 289 U.S. 553, 573, 53 S. Ct. 751, 77 L. Ed. 1372; 11 Am. Jur. 665; see General Motors Corporation v. Mulquin, 134 Conn. 118, 126, 55 A.2d 732; Fenwick v. Old Saybrook, 133 Conn. 22, 28, 47 A.2d 849.
In the second place, the legislative and executive departments have, until 1953, unvaryingly construed the second and the thirty-first amendments as limiting redistricting to the first Assembly convened after the completion of the census. Examples of this construction will be found in the footnote.10 As was stated above, in discussing the first question, as to the completion of the census, this time-honored [22]*22construction points forcibly to tbe true meaning which the framers of the amendments intended each to have. Water Commissioners v. Curtis, 87 Conn. 506, 511, 89 A. 189; State ex rel. Corbett v. South Norwalk, 77 Conn. 257, 264, 58 A. 759; 1 Cooley, Constitutional Limitations (8th Ed.) p. 144 et seq.
It ivas not until January, 1953, that the theory of a continuing duty appears to have ever been mentioned by any official in connection Avith the construction of either amendment. The theory was advanced by the attorney general in a letter addressed to the governor’s office. Apparently on the basis of this letter, the General Assembly of 1953, in enacting Public Act No. 32, devoted the first section to the legislative findings, purpose and policy.11 Cum. Sup. [23]*231953, § 399c. Strangely enough, the legislative pronouncement, incorporated in the first section of the act, that a “continuing duty” rested upon the Assembly of 1953 tends to support a construction of the amendments quite to the contrary of the one promulgated in the public act. For, if the continuing duty existed in 1953, it has always existed. A constitutional provision cannot mean one thing today and, through the application of some newly devised theory, a different thing fifty years hence. 1 Cooley, op. cit., p. 123. To adopt the defendant’s theory would require us to attribute to the framers of the second amendment an intention to create a continuing duty. If we take that ground, then we must also attribute to them an intellectual inability to express themselves in adequate language to accomplish that result — and this we refuse to do. The long lapse of time and the unnecessary incorporation into the enactment of 1953 of a legal conclusion as to a “continuing duty” in the face of a uniform construction to the contrary by former Assemblies for over a century speak eloquently of the futility of attempting to establish, by legislative fiat, a constitutional duty when none has ever before been claimed to have existed. The declaration in § 1 of Public Act No. 32 that a continuing duty has been created by the thirty-first amendment has, under the circumstances, no effect upon the established and proper construction of the amendment.
The defendant has cited several cases in other [24]*24jurisdictions to support his theory of a continuing duty. The language of the thirty-first amendment is so unique that those cases have little, if any, value. Our amendment is unique in two respects: first, it contains no language of command other than that directed to the year 1903 but is, on the other hand, expressed in language of absolute prohibition; and secondly, the inclusion of the words “if found necessary” emphasizes the absence of a duty. None of the following eases cited by the defendant or discovered by us construes a constitutional provision in which there is a prohibition and no command, or a constitutional provision including language equivalent to the words “if found necessary.” In re Legislative Apportionment, 12 Colo. 186, 21 P. 480; People ex rel. Mooney v. Hutchinson, 172 Ill. 486, 50 N.E. 599; Denney v. State ex rel. Basler, 144 Ind. 503, 42 N.E. 929; Opinion of the Justices, 254 Mass. 617, 151 N.E. 680; W.R. Reynolds & Co. v. Secretary of State, 238 Mich. 552, 213 N.W. 707; State ex rel. Meighen v. Weatherill, 125 Minn. 336, 147 N.W. 105; State ex rel. Gordon v. Becker, 329 Mo. 1053, 49 S.W.2d 146; Botti v. McGovern, 97 N.J.L. 353, 118 A. 107; Matter of Reynolds, 202 N.Y. 430, 96 N.E. 87; Jones v. Freeman, 193 Okla. 554, 146 P.2d 564; Noecker v. Woods, 259 Pa. 160, 102 A. 507; Opinion of the Judges, 61 S.D. 107, 246 N.W. 295; State ex rel. Attorney General v. Cunningham, 81 Wis. 440, 51 N.W. 724. The constitutional provisions construed in these cases are noted below at length.12 To [25]*25attempt to analyze all of these cases is unnecessary. A reading of the provisions is ample to show the lack of similarity with those of our amendment. We conclude that the amendment does not provide for a continuing duty. See State ex rel. Morris v. Bul[26]*26keley, 61 Conn. 287, 367, 23 A. 186. In view of our discussion of the first two questions, it is unnecessary for us to answer the third.
[27]*27To the nine specific questions, onr answers are as follows: “Yes” to question 1 and “No” to questions 2 and 3. All other questions need not be answered.
No costs will be taxed in this court to any party.
In this opinion Quinlan and Wynne, Js., concurred.