Mr. Justice Field

delivered the opinion of the court. He stated the facts in .the foregoing language, and continued:

Two questions .are presented for our consideration by the appeal in this case. The first relates to the deficiencies in the sections designated as granted in the act of 1857, arising from sales and the attachment of preemption rights previous to the final determination of the route of the road of the railway company, and the extent to which indemnity, for these deficiencies may be supplied from other lands. The second relates to the reser *625 vation from the operation of the act of 1865 of lands previously granted to Minnesota to aid in the construction of any railroad, which were located within the limits of the extension made by that act to the original grant, and its effect on the amount of lands claimed by the plaintiffs.

The solution of these questions depends, of course, upon the construction given to the acts making the grants; and they are to receive such a construction as will carry out the intent of Congress, however difficult it might be to give full effect to the language used if the grants were by instruments of private conveyance. To ascertain that intent we must look to the condition of the country when the acts were passed, as well as to the purpose declared on their face, and read all parts of them together.

The act of 1857 grants lands to the State to aid the construction of several railroads. These were to be built through large districts of country sparsely settled. ■ Though the termini of each were designated, it was impossible, in advance of surveys, to designate the specific route of any one, even approximately. In many instances, where the sections would fall along such route, sales of land had already been made by the United States, and preemption rights of settlers had attached; and before the- route would be definitely fixed by surveys and maps, many other sales of land falling within the sections would probably bo made and other preemption rights attach. It was not for the interest of the country that any portion of the public lands should be withheld from sale and settlement because, when the route of the roads was definitely determined, they might fall within the limits of the grants; nor was it the purpose of Congress to lessen the extent of its aid because it might ultimately be found that, at the time of its grant, or when the route was determined, portions of the land designated had already been disposed of or preemption rights had attached to- them. The policy of the government was to keep the public lands open at all times to sale and preemption, and thus encourage the settlement of the country, and, at the same time, to advance such settlement by liberal donations to aid in ■ the construction of railways. The acts of Congress, in éffect, *626 said : “We give to the State certain lands to aid in the construction of railways lying along their respective routes, provided they are not already disposed of,, or the rights of settlers under the laws of-the United States have not already attached to them, or they may not be disposed of or such rights may not have attached when the routes are finally determined. If at that time it be found that of the lands designated any have been disposed of, or rights of settlers have attached to them, other equivalent lands may be selected in their place, within certain prescribed limits.” The ^encouragement to settlement by aid for the construction of railways was not intended to interfere with the policy of encouraging such settlement by sales of the land, or the grant of preemption rights. It follows that in our judgment the indemnity clause' covers losses from the grant by reason of sales arid the attachment1 of preemption rights previous to the date of the act, as well as by reason of sales and the attachment of preemption rights between that date and the final determination of the route of road.

It is to no purpose to say, against this construction, that the government could not grant what it did not own, and therefore could not have intended that its language should apply to lands which it had disposed of. As already said, the whole act must be read to reach the intention of the law-maker. It uses, indeed, words of grant, words which purport to convey what the grantor owns, and, of course, cannot operate upon lands with which the grantor had parted; and therefore when it afterwards provides for indemnity for lost' portions of the lands “ granted as aforesaid,” it means of the lands purporting to be covered by those terms. Nor is it to any purpose to cite decisions to the effect that the grant is in prmsenti, passing an immediate interest to the State. Such is undoubtedly the case, except as the operation of the grant is affected by the limitations mentioned ; that is to say, when the sections granted are ascertained, the title to them takes effect as of- the date of the grant, and cuts off all intervening claimants except as tfo such portions as may have been sold, or to which pre-emption rights may have attached.

The language in Railroad Co. v. Baldwin, 103 U. S. 426, does not militate against this construction of the act. It ex *627 presses th,e general purpose of the reservation to keep the lands open at all, times to settlement and preemption, and subject to appropriation for public uses until the route of the road is determined, but does not declare that lands previously sold, or to which the rights of preemption had previously attached, are excluded from the indemnity clause. The court was there drawing attention to the difference between the two grants in the act of .Congress of July 23, 1866 — that of sections of land and that of the right of w.ay, the former being a present grant, • except as its immediate operation was affected by the reservations, the latter being a present absolute grant without any reservation or exception.

The language in Leavenworth, Lawrence, &c., Railroad Co. v. United States, 92 U. S. 733, is quoted as sanctioning the position of 'the appellant. The court, speaking of the indemnity clause in the grant then under consideration, said its purpose was to give sections beyond the limit designated for those lost within it by the action of the government between the date of the grant and the location of the road.. But it did not say that this was its only purpose; and, if the language must be construed as.ujeaning that, it was a mere- dictum, not essential to the' decision of the case. The question was, what lands could be taken for indemnity, not for what deficiencies indemnity could be had. And it was held that an Indian reservation did not pass by the grant, and could not be taken as indemnity for the lands otherwise lost from it. There was no question before thé court for what deficiencies indemnity could be supplied.

As to the effect of the reservation in the third section of the act of 1865, of lands previously granted to Minnesota, for the purpose of aiding in the construction of any railroad, there should be little doubt. The grant by the act of 1857 is one of description, that is, of lar.,I in place and not of quantity. It is of every alternate section, designated by odd numbers, for six sections on each side of the road, that is, of particular parcels of land lying within certain defined lateral limits to the road and ■described by numbers on the public surveys. And the indemnity clause provides for loss from those parcels by sales or the *628 attachment of preemption rights before the route bécomes definitely fixed — the indemnity lands to be selected within fifteen. miles from the line of the road. The act of 1865 enlarges the quantity grantéd from six sections to ten, and the indemnity -limits from fifteen miles to twenty. The character of the grant, so far as the six sections are. concerned, is not thereby changed from one of lands, in place, or by description, to one of quantity. The use of the terms quantity of lands'granted ” in the first section, in referring to the amount granted-by the act of 1857, is of no significance. It is the same thing as though the act had used the words “ six sections ” instead of the word quantity, and had said they should be increased to ten sections. The four sections are to be selected by the Secretary of the Interior beyond the six and within the twenty miles limit; and as to them the grant' may be regarded as one of quantity, though the coterminous principle applies to them, and they are to be selected along and opposite the completed road.

The reservation of the lands previously granted to Minnesota from the grant of the additional four sections, that is, from the extension of the original grant of 1857, was only a legislative declaration of that which the law would have pronounced independently of it. Previous grants of the same property would necessarily be excluded from subsequent ones. The only embarrassment in the construction of the section arises from the inapt words used to describe the land from which1 the previous grant is to be deducted. • The language of the section is “ that any lands which may have been granted to the Territory or State of Minnesota for the purpose of aiding in the construction of any railroad, which lands may be located within the limits of this extension of such grant or grants, shall be deducted from the full quantity of lands hereby granted.” The only lands granted by the act of 1865 are the four sections for each mile additional to the original six, accompanied with a right to select indemnity lands within twenty miles of the road. The words, “ the full quantity granted,” only denote the entire extension. To the extent of the previous grant that extension must be reduced, even if the whole be taken. Those words do not transfer the loss from the ten sections within which the grant falls *629 to other sections along the line. The sections in which such grant falls are correspondingly reduced.

It follows that where the grant previously made to Minnesota to aid . in the construction of the Minnesota and Cedar Yalley Railroad interferes with the extension of the grant to the defendant by the act of 1865, the extension must be abandoned. The earlier grant takes the land which would otherwise be added to the original six sections. The court below therefore erred in holding that the Winona Company was entitled to ten full sections where such interference occurred, without deducting the lands previously granted to the State.

The cause must, therefore, go back that the proper deduction may be made by reason of this interference of the two grants, and the elder grant be deducted from the extension made by the act of 1865.

Decree reversed, and cause remanded, with directions tó take further proceedings in accordance with this opinion.