delivered the opinion of the Court.
This is a suit brought by employees of Holly Hill Fruit Products, Ino. for wage payments under the Fair Labor Standards Act. 52 Stat. 1060, 29'TJ. S. C. §§ 201 et seq. A judgment for the employees, the petitioners here, was reversed by the Circuit Court of Appeals, which held that Holly Hill’s employees were by virtue of § 13 (a) (10) of the Act exempted from its scope, in that they were “within the area of production (as defined by the Administrator), engaged in . . . canning of agricultural . . . commodities for market . . The court below reached this con-*609elusion by holding that a portion of the definition of “area of production” made by the Administrator of the Wage and Hour Division was invalid and that the remaining portion afforded exemption. 136 F. 2d 323. We brought the case here, 320 U. S. 725, to settle a much litigated question of importance in the administration of the Fair Labor Standards Act.
Holly Hill, a citrus fruit cannery employing some two hundred workers, is located in Davenport, Florida, a town with a population of about 650 people. During the two seasons in controversy — November 14, 1938 to May 26, 1939, and November 16, ,1939 to March 30, 1940 — the Administrator promulgated three regulations based on the scope he gave to his authority under § 13 (a) (10) to define “area of production.” The validity of aspects of these regulations is the crucial issue.
By regulation of October 20, 1938, the Administrator defined “area of production” as used in § 13 (a) (10) to include an individual engaged in canning “if the agricultural or horticultural commodities are obtained by the establishment where he is employed from farms in the immediate locality and the number of employees in such establishment does not exceed seven.” 29 Code Fed. Reg. (Supp. 1938) § 536.2 (b). Effective April 20, 1939', an alternative definition, applicable to perishable or seasonal fresh fruits and vegetables, brought workers into the “area of production” if employed “in an establishment which is located in the open country or in a rural community and which obtains all of its products from farms in its immediate locality.” It was provided that “ ‘open country’ or ‘rural community’ shall not include any city or town of 2,500 or greater population according to the 15th United States Census, 1930, and ‘immediate locality’ shall not include any distance of more than ten miles.” 29 Code Fed. Reg. (Supp. 1939) § 536.2 (e), pp. 2239^-40. Finally, this alternative definition, no longer limited to *610fruits and vegetables, was in substance incorporated into the regulations effective June 17, 1939, but in addition it was provided that an individual might also be within the “area of production” “if he performs those [canning] operations on materials all of which come from farms in the general vicinity of the establishment where he is employed and the number of employees engaged in those operations in that establishment does not exceed seven.” 29 Code Fed. Reg. (Supp. 1939) § 536.2 (a) (d), p. 2240.
Before coming to the main question, that of the validity of adding a limitation on the allowable number of employees in one canning establishment within the exempted geographic bounds, we shall dispose of the applicability of the Administrator’s other exempting definitions to Holly Hill’s employees.
The definitions which contain no employee limitation impose two essential conditions on an exemption sought under § 13 (a) (10): the establishment must be located in a city or town having a population smaller than 2,50o,1 and all of its products must be obtained from within ten miles of the establishment. Since Davenport contains less than 2,500 persons, the first condition is met and we need not pass on its validity.2 As to the second condition, the only evidence introduced indicates that during the 1938-1939 season, about 2% of the fruit used came from beyond ten air miles of the plant, and that for the 1939-1940 season, about 3.75% came from groves more than ten air miles from Holly Hill. Since all of the fruit did not come from within ten miles, Holly Hill did not *611satisfy this condition, of the Administrator’s definitions. There can be no doubt that this conclusion is justified by a literal reading of the regulations, and the court below, in holding that the Administrator’s requirement that all the goods come from within ten miles must be construed to mean “substantially all,” entered the Administrator’s domain. What was said in another connection is relevant here. “Looked, at by itself without regard to the necessity behind it the line or point seems arbitrary. It might as well or nearly as well be a little more to one side or the other. But when it is seen that a line or point there must be, and that there is no mathematical or logical way of fixing it precisely, the decision of the [Administrator] must be accepted unless we can say that it is very wide of any reasonable mark.” Mr. Justice Holmes, dissenting, in Louisville Gas Co. v. Coleman, 277 U. S. 32, 41.3
We come then to the validity of the October 20, 1938, regulation and that of the alternative in the June 17, 1939, regulation which provide in substance that an individual is employed within the “area of production” if an establishment obtains the commodities from the “immediate locality” (1938) or all the materials come from the “general vicinity” (1939), and in addition the number of employees in the establishment “does not exceed seven.” In short, when Congress exempted “any individual employed within the area of production (as defined by the Administrator)” (§ 13 (a) (10)), did it authorize the Administrator not only to designate territorial bounds for the purposes of exemption but also to except establishments from such exemption according to the number of workers employed.
*612Congress provided for eleven exemptions from the controlling provisions relating to minimum wages or maximum hours of the Fair Labor Standards Act.4 Employment in agriculture is probably the most far-reaching exemption. Closely related to it is the exemption which is our immediate concern — those workers engaged in processes necessary for the marketing of agricultural products and employed “within the area of production” of *613such commodities. Such was the phrase and such its conjunction with the exemption for agriculture of which it formed an integral part as the bill passed both Houses, except that the enumerated exempted employments subsidiary to agriculture varied in the two bills.5 The parenthetical qualification “(as defined by the Administrator)” emerged from the conference committee of the two Houses.6
The textual meaning of “area of production” is thus reinforced by its context: “area” calls for delimitation of *614territory in. relation to the complicated economic factors that operate between agricultural labor conditions and the labor market of enterprises concerned with agricultural commodities and more or less near their production. The phrase is the most apt designation of a zone within which economic influences may be deemed to operate and outside of which they lose their force. In view, however, of the variety of agricultural conditions and industries throughout the country, the bounds of these areas' could not be defined by Congress itself. Neither was it deemed wise to leave such economic determination to' the contingencies and inevitable diversities of litigation. And so Congress left the boundary-making to the experienced and informed judgment of the Administrator. Thereby Congress gave the Administrator appropriate discretion to assess all the factors relevant to the subject matter, that is, the fixing of minimum wages and maximum hours.
In delimiting the area the Administrator may properly weigh and synthesize all such factors. So long as he does that aind no more, judgment belongs to him and not to the courts. For Congress has cast upon him the authority and the duty to define the “area of production” of agricultural commodities with reference to which exemption in subsidiary employments may operate. But if Congress intended to allow the Administrator to discriminate between smaller and bigger establishments within the zone of agricultural production, Congress wholly failed to express its purpose. Where Congress wanted to1 make exemption depend on size, as it did in two or three instances not here relevant, it did so by appropriate language.7 Congress referred to' quantity when it desired to legislate on the basis of quantity.
*615Congressional purpose as manifested by text and context is not rendered doubtful by legislative history. Meagre as that is, it confirms what Congress has formally said. The only extrinsic light cast on Congressional purpose regarding “area of production” is that cast by the sponsors of this provision for enlarging the range of agricultural exemptions. Senator Schwellenbach frankly stated that the largest apple packing plant in the world would be exempt if the “work done in that plant is as described in the amendment.” 81 Cong. Ree. 7877. And in the House, Representative Biermann, while explaining his amendment in somewhat Delphic terms, did indicate plainly enough that he had in mind not differences between establishments within the same territory but between rural communities and urban centers: “may I say that all over this country it has been recognized that there should be a labor differential between the large city and the little town.” 83 Cong. Rec. 7401.8
From such light as Congress gave us beyond its words, it would appear that in giving exemption to an “area of production,” without differentiating as between establishments within such area, Congress might well have considered that a large plant within an area should not be given an advantage over small plants in competing for labor within the same locality, while at the same time it *616gave the Administrator ample power, in defining the area, to take due account of the appropriate economic factors in drawing the geographic lines. In any event, Congress did not leave it to the Administrator to decide whether within geographic bounds defined by him the Act further permits discrimination between establishment and establishment based upon the number of employees. The determination of the extent of authority given to a delegated agency by Congress is not left for the decision of him in whom authority is vested.
The wider a delegation is made by Congress to an administrative agency the more incomplete is a statute and the ampler the scope for filling in, as it is called, its details. But when Congress wants to give wide discretion it uses broad language. Thus, in the Interstate Commerce Act, Congress prohibited a lower rate for a longer than a shorter haul, but it gave an authority to the Interstate Commerce Commission, undefined except as the general purposes of that Act implied the basis for affording exemption, to grant relief from this prohibition. Intermountain Rate Cases, 234 U. S. 476. Again in the National Labor Relations Act, Congress gave the Board authority to take such action “as will effectuate the policies of this Act.” § 10 (c), 49 Stat. 449, 454, 29 TJ. S. C. § 160 (c). The “policies” of the Act were so broadly defined by Congress that the determination of “the relation of remedy to policy is peculiarly a matter for administrative competence.” Phelps Dodge Corp. v. Labor Board, 313 U. S. 177, 194. In the Fair Labor Standards Act, Congress legislated very differently in relation to the problem before us. To be sure, the Fair Labor Standards Act, like the National Labor Relations Act, was based on findings and a declaration of broad policy. But Congress did not prescribe or proscribe generally and then . give broad discretion for administrative relief as in the Interstate Commerce Act or for remedies as in the *617National Labor Relations Act. Congress did otherwise. It dealt with exemptions in detail and with particularity, enumerating not less than eleven exempted classes based on different industries, on different occupations within the same industry (the classification in some instances to be defined by the Administrator, in some made by Congress itself, in others subject to definition by other legislation), on size and on areas. In short the Administrator was not left at large. A new national policy was here formulated with exceptions, catalogued with particularity and not left within the broad dispensing power of the Administrator. Exemptions made in such detail preclude their enlargement by implication.
We should of course be faithful to the meaning of a statute. But after all Congress expresses its meaning by words. If legislative policy is couched in vague language, easily susceptible of one meaning as well as another in the common speech of men, we should not stifle a policy by a pedantic or grudging process of construction. To let general words draw nourishment from their purpose is one thing. To draw on some unexpressed spirit outside the bounds of the normal meaning of words is quite another. For we are here not dealing with the broad terms of the Constitution “as a continuing instrument of government” but with part of a legislative code “subject to continuous revision with the changing course of events.” United States v. Classic, 313 U. S. 299, 316.
Legislation introducing a new system is at best empirical, and not infrequently administration reveals gaps or inadequacies of one sort or another that may call for amendatory legislation. But it is no warrant for extending a statute that experience may disclose that it should have been made more comprehensive. “The natural meaning of words cannot be displaced by reference to difficulties in administration.” Commonwealth v. Grunseit (1943) 67 C. L. R. 58, 80. For the ultimate question *618is what has Congress commanded, when it has given no clue to its intentions except familiar English words and no hint by the draftsmen of the words that they meant to use them in any but an ordinary sense. The idea which is now sought to be read into the grant by Congress to the Administrator to define “the area of production” beyond the plain geographic implications of that phrase is not so complicated nor is English speech so poor that words were not easily available to express the idea or at least to suggest it. After all, legislation when not expressed in technical terms is addressed to the common run of men and is therefore to be understood according to the sense of the thing, as the ordinary man has a right to rely on ordinary words addressed to him.
The details with which the exemptions in this Act have been made preclude their enlargement by implication. While the judicial function in construing legislation is not a mechanical process from which judgment is excluded, it is nevertheless very different from the legislative function. Construction is not legislation and must avoid “that retrospective expansion of meaning which properly deserves the stigma of judicial legislation.” Kirschbaum Co. v. Walling, 316 U. S. 517, 522. To blur the distinctive functions of the legislative and judicial processes is not conducive to responsible legislation.
We agree therefore with the Circuit Court of Appeals in holding invalid the limitations as to the number of employees within a defined area. But we cannot follow that Court in deleting this part of the administrative regulation and, by applying what remains of the definition, exempting Holly Hill’s employees from the requirements of the Act. Since the provision as to the number of employees was not authorized, the entire definition of which that limitation was a part must fall. We can hardly assume that the Administrator would have defined “area of production” merely by deleting the employee pro*619vision, had he known of its invalidity. It would be the sheerest guesswork to believe that elimination of an important factor in the Administrator’s equation would have left his equation unaffected even if he did not here insist upon its importance. It is not for us to write a definition. That is the Administrator’s duty.
Concluding, then, that when Congress granted exemptions for workers within the “area of production (as defined by the Administrator)” it restricted the Administrator to the drawing of geographic lines, even though he may take into account all relevant economic factors in the choice of areas open to' him, the regulations which made discriminations within the area defined by applying the exemption only to plants with less than seven employees are ultra vires. But that leaves the difficult problem of the proper disposition of the case. It is our view that the case should be remanded to the district court with instructions to hold it until the Administrator, by making a valid determination of the area with all deliberate speed, acts within the authority given him by Congress.
Such a disposition is most consonant with justice to all interests in retracing the erroneous course that has been taken. Neither law nor logic dictates an “either-or” conclusion — that is, a conclusion that the employment in these industries is entirely exempt because the Administrator misconceived the bounds of his regulatory powers although plainly enough he meant to exercise them so as not to withdraw all these employments from the requirements of the Act, or that employment in these- industries is subject to the Act because no exception excludes it. The two opposing alternatives do violence to the law as Congress wrote it. To hold that all individuals “engaged in handling, packing, storing, ginning, compressing, pasteurizing, drying, preparing in their raw or natural state, or canning of agricultural or horticultural commodities for market, or in making cheese' or butter or other dairy *620products” are exempt from the operation of the Act is obviously to fly in the face of Congressional purpose. The Act exempts some but not all of the employees engaged in these industries, and it is not for us now to say that all are exempt. So to hold would postpone the operation of the Act in the enumerated instances for at least six years beyond the date fixed by Congress. Equally offending to the purposes of Congress and therefore to fairness in this situation is the suggestion that if the exemption falls all employees engaged in the designated industries are covered by the Act.
The accommodation that we are making assumes, what we must assume, that the Administrator will retrospectively act as conscientiously within the bounds of the power given him by Congress as he would have done initially had he limited himself to his authority. To be sure this will be a retrospective judgment, and law should avoid retroactivity as much as possible. But other possible dispositions likewise involve retroactivity, with the added mischief of producing a result contrary to the statutory design.
Such an adaptation of court procedure to a remolding of the situation as nearly as may be to what it should have been initially is not unprecedented. Such was essentially the procedure which was devised to unravel the skein in United States v. Morgan, 307 U. S. 183. The Court did not feel itself balked by the kind of considerations that seemed controlling to a Baron Parke. The creative analogies of the law were drawn upon by which great equity judges, exercising imaginative resourcefulness, have always escaped the imprisonment of reason and fairness within mechanical concepts of the common law. See, e. g., Atlantic Coast Line v. Florida, 295 U. S. 301; Inland Steel Co. v. United States, 306 U. S. 153; and for some examples of this approach see Graf v. Hope Building Corp., 254 N. Y. 1, 7 (Cardozo, Ch. J., dissenting). That *621such were the large considerations that guided decision in the Morgan case the opinion makes clear:
. . in construing a statute setting up an administrative agency and providing for judicial review of its action, court and agency are not to be regarded as wholly independent and unrelated instrumentalities of justice, each acting in the performance of its prescribed statutory duty without regard to the appropriate function of the other in securing the plainly indicated objects of the statute. Court and agency are the means adopted to attain the prescribed end, and so far as their duties are defined by the words of the statute, those words should be construed so as to attain that end through coordinated action. Neither body should repeat in this day the mistake made by the courts of law when equity was struggling for recognition as an ameliorating system of justice; neither can rightly be regarded by the other as an alien intruder, to be tolerated if must be, but never to be encouraged or aided by the other in the attainment of the common aim.” 307 U. S. atl91.
If it be said that in the Morgan case the Court was dealing with a fund in court — irrelevant though that be to the governing principles of that decision — no such constriction can be made of the import of our decision in General American Tank Car Corp. v. Terminal Co., 308 U. S. 422. That, like this, was an action at law and not a suit in equity involving a res. The respondent was seeking to recover a sum admittedly due under a car-leasing agreement with petitioner. The Interstate Commerce Commission urged that since the Commission had not, as the law required, passed upon the validity of the practice involved in the agreement, the district court was without jurisdiction. And so, technically speaking, the district court was. But this Court remanded the case to the district court with instructions to hold the cause “pending the conclusion of an appropriate administra*622tive proceeding.” The petition for rehearing claimed that our decision involved retroactivity. 309 U. S. 694. So it did. But as against retroactivity we balanced the considerations that made retroactivity seem the lesser evil.
In short, the judicial process is not without the resources of flexibility in shaping its remedies, though courts from time to time fail to avail themselves of them. The interplay between law and equity in the evolution of more just results than the hardened common law afforded, has properly been drawn upon in working out accommodating relationships between the judiciary and administrative agencies. And certainly in specific cases, such as those already referred to and in this, it is consonant with judicial administration and fairness not to be balked by the undesirability of retroactive action any more than courts have found it difficult to sanction legislative ratification of acts originally unlawful, United States v. Heinszen & Co., 206 U. S. 370; Tiaco v. Forbes, 228 U. S. 549; Graham & Foster v. Goodcell, 282 U. S. 409; Hirabayashi v. United States, 320 U. S. 81, 91, or retroactively to give prior legislation new scope. Paramino Lumber Co. v. Marshall, 309 U. S. 370. And in habeas corpus proceed- \ ings, even though a petitioner was unlawfully in custody, ft this Court has allowed continued retention of custody | until a valid order could be made. Mahler v. Eby, 264 U. S. 32; Tody. Waldman, 266 U. S. 113.
Finally, there is no difficulty upon such a remand in requiring the Administrator to promulgate his definition. This Court has on several occasions required the Interstate Commerce Commission to take jurisdiction when it declined to do so or to discharge a duty laid upon the Commission by statute. Interstate Commerce Commission v. Humboldt Steamship Co., 224 U. S. 474; Louisville Cement Co. v. Interstate Commerce Commission, 246 U. S. 638. See also Kansas City Southern Ry. Co. v. Interstate Commerce Commission, 262 U. S. 178. The district court *623would not be telling the Administrator how to exercise his discretion but would merely require him to exercise it. It is a remedy against inaction.
Holly Hill also contended that if it is not entirely exempt from paying the overtime rates here awarded, it is entitled to the advantage of the partial seasonal exempt-tions afforded by §§ 7 (b) (3) and 7 (c). The district court ruled adversely to Holly Hill on these claims, but the Circuit Court of Appeals did not reach them. It will be time enough to reach them if they survive the disposition now made of this case.
Accordingly, the case is remanded to the district court to proceed in conformity with this opinion.
So ordered.
The fact that Davenport is within four miles of Haines City, with a population greater than 2,500, led the district court to conclude that Holly Hill was not located in the “open country” or a “rural community.” This appears to be a plain solecism. 29 Code Fed. Reg. (Supp. 1939) § 536.2 (e), pp. 2239-40, and § 536.2 (d), p. 2240.
It is conceded that a specific ruling on the population criterion is unnecessary.
Holly Hill here attacked the finding of the district court that all of the fruit did not come from within ten miles, but we see no reason to disturb it.
“Sec. 13 (a) The provisions of sections 6 and 7 shall not apply with respect to (1) any employee employed in a bona fide executive, administrative, professional, or local retailing capacity, or in the capacity of outside salesman (as such terms are defined and delimited by regulations of the Administrator); or (2) any employee engaged in any retail or service establishment the greater part of. whose selling or servicing is in intrastate commerce; or (3) any employee employed as a seaman; or (4) any employee of a carrier by air subject to the provisions of title II of the Railway Labor Act; or (5) any employee employed in the catching, taking, harvesting, cultivating, or farming of any kind of fish, shellfish, Crustacea, sponges, seaweeds, or other aquatic forms of animal and vegetable life, including the going to and returning from work and including employment in the loading, unloading, or packing of such products for shipment or in propagating, processing, marketing, freezing, canning, curing, storing, or distributing the above products or byproducts thereof; or (6) any employee employed in agriculture; or (7) any employee to the extent that such employee is exempted by regulations or orders of the Administrator issued under section 14; or (8) any employee employed in connection with the publication of any weekly or semiweeHy newspaper with a circulation of less than three thousand the major part of which circulation is within the county where printed and published; or (9) any employee of a street, suburban, or interurban electric railway, or local trolley or motor bus carrier, not included in other exemptions contained in this section; or (10) to any individual employed within the area of production (as defined by the Administrator), engaged in handling, packing, storing, ginning, compressing, pasteurizing, drying, preparing in their raw or natural state, or canning of agricultural or horticultural commodities for market, or in making cheese or butter or other dairy products; or (11) any switchboard operator employed in a public telephone exchange which has less than five hundred stations.” 52 Stat. 1067, as amended, 53 Stat. 1266.
The exemptions provided in § 13 (a) (10) did not appear in the bill as reported to the Senate, but in the debate on the floor of that body an effort was made to extend the exemption accorded to agricultural workers, and as passed by the Senate the bill provided that “The term 'person employed in agriculture’, as used in this act, insofar as it shall refer to fresh fruits and vegetables, shall include persons employed within the area of production engaged in preparing, packing, or storing such fresh fruits or vegetables in their raw or natural state.” 81 Cong. Rec. 7876, 7949, 7957. This provision, varied somewhat by extending its coverage to all “agricultural commodities” (82 Cong. Rec. 1783-1784), remained as part of the definition of “Employee employed in agriculture” (H. Rep. No. 2182, 75th Cong., 3d Sess., p. 2) until shortly before the bill was finally adopted by the House, at which time the so-called Biermann amendment included within the definition of employees engaged in agriculture “individuals employed within the area of production, engaged in the handling, packing, storing, ginning, compressing, pasteurizing, drying, or canning of farm products and in making cheese and butter.” 83 Cong. Ree. 7401, 7407. At the conference on the disagreeing votes of the two Houses, the “area of production” provision was given the form in which it was finally enacted, and there the parenthetical phrase “as defined by the Administrator” was inserted after “area of production.” 83 Cong. Ree. 9249.
Compare this provision with § 13 (a) (1) exempting employees in “a bona fide executive, administrative, professional, or local retailing capacity, or in the capacity of outside salesman (as such terms are defined and delimited by regulations of the Administrator).” For this class, the Administrator is given the authority to define and delimit the “terms” used. But in the same section, subdivision 10 grants authority to define not the term “area,” but to define the “area.”
See ■§§ 13 (a) (2) (8) (11) dealing respectively with retail or service establishments, weekly or semi-weekly newspapers and public telephone exchanges.
Representative Biermann was asked whether his amendment “would apply to a packing house located in Iowa and Illinois in the area of production, which employs two or three hundred men.” This was his complete answer: “Speaking frankly, I think that is something that would have to be worked out. There are some packing houses in the State of Iowa that this amendment would apply to perhaps; but may I say that all over this country it has been recognized that there should be a labor differential between the large city and the little town.” Certainly Mr. Biermann did not give the remotest intimation that “area of production” was meant to convey any idea other than that which area usually conveys.