matters of taxation as individuals. 8. A tax law will never be construed as imposing a double tax unless the intention to impose it be so plain that any other conclusion would do violence to its language. Where an act provided that "all mortgages (and) money owing by solvent debtors owned or possessed by any person or persons whatsoever shall be liable to taxation for state purposes," it was held not to impose a tax on mortgages and other moneys at interest in the hands of corporations in addition to a tax paid by them upon their capital stock and invested in such mortgages and loans, it not being manifest from that act that the legislature intended to impose double taxes upon corporations.2 These conclusions may, for convenience, be reduced to a general principle. The federal courts have no jurisdiction to determine the justice or to pass upon the policy of a system of taxation or to prevent oppression under state tax laws which do not conflict with the federal constitution.3 1 California v. Pac. R. R. Co's., 127 U. S. 1; San Mateo County v. S. P. Ry. Co., 13 Fed. Rep. 722; People v. Cent. Pac. R. R. Co., and several other railroad tax cases, 83 Cal. 393. 2 Hunter's App. Adair's App., and Barry's App. (Pa.), 18 Am. & Eng. Corp. Cas. 164; Com. v. Lehigh Coal, etc., Co., Ib. 157; Com v. Dunbar Furnace Co., Id. 160. 3 In San Mateo County v. Southern Pac. Ry. Co., supra, a provision of the California constitution which subjected railroad mortgages to taxation while exempting other mortgages was held repugnant to the fourteenth amendment and void. It is to be regretted on account of the general importance of the principles involved that all the constitutional questions raised in several cases under the system of taxation provided under the constitution and statutes of California, have not been passed upon by the highest federal tribunal. In Santa Clara v. South. Pac. Ry. Companies, 118 U. S. 394, which was heard on writ of error from the circuit court of the United States for the district of Calfornia, bringing up the case reported in 9 Sawy. 165, 210, the decision was but a re-affirmance of the decisions in the circuit court in this and other cases and in the state supreme court on the validity of the assessment under the provisions of the state constitution; and although the constitutional question whether the fourteenth amendment protected corporations from discrimination in the matter of taxation under state laws was ably argued and decided affirmatively in the court below, the supreme court found other reasons for deciding in favor of the companies and re 1102. Must not conflict with the exercise of federal agencies. In the exercise of its functions the central government employs constantly as well as upon occasions a variety of agencies and instruments. These may properly be considered a part of the administrative machinery for the due execution of its laws. To permit a state to impose a burden upon them in the form of a tax would be equivalent to allowing it to interpose conditions to the exercise of its powers by the federal fused to enter into a consideration of the constitutional question. And in California v. Pacific R. R. Co., 127 U. S. 1, the assessment under the statutes of California was again decided to be invalid for the reason that the act under which it was made was in conflict with the state constitution. The constitutional question whether the franchises granted to the railroad companies from the national government could be taxed was in issue and decided in the negative, but the original and more important one was evaded. In this case, the provisions of the statute requiring the state board of equalization to include in their assessment steamers engaged in transporting passengers and freights across waters which divide a railroad was decided to be repugnant to the state constitution and therefore void. The California state constitution prescribes two modes of assessment for taxation, one by a state board of equalization, the other by county boards and local assessors. All property is directed to be assessed in the country, city, etc., in which it is situated, except that the franchise roadway, roadbed, rails and rolling stock of any railroad operated in more than one county are to be assessed by the state board and apportioned to the several counties. In the last mentioned case the Supreme Court followed the decision of the state supreme court in San Francisco v. Cent. Pac. R. R. Co., 63 Cal. 469, and Santa Clara County v. S. P. R. R. Co. in the United States supreme court, 118 U. S. 394, and held that the assessment of the steamers of a railroad company by the state board was in violation of the constitution of California, and it being inseparably blended with the other property assessed made the whole assessment void. In other words, the case announces the familiar principle that if an act is void in part and the invalid portion cannot be separated from the portion which is valid, the act is void in toto. In People v. Cent. Pac. R. R. Co. and other railroad companies, 83 Cal. 393; 23 P. 303, the decision was based upon the insufficiency of the complaint and might well have left the constitutionality of the law providing for the collection of taxes on the roads in more than one county untouched. But with the obvious and commendable view of setting the matter at rest and preventing further litigation under the law, as it now stands, the court with but one dissent, strongly asserted that the special scheme provided by the Political Code, secs. 3665 to 3570, is in conflict with the state constitution as imposing upon railroad companies operated in more than one county burdens of taxation not imposed upon their railroads organized under the same general law. 66 government. The power to tax," said Chief Justice MARSHALL," is a power to destroy, and if a tax may be imposed upon the instrument by which the federal government performs its fiscal operations for revenue, it may be laid for purposes of prohibition, and thus the execution of its laws must come to an end or proceed subject to the will of each state in which its powers are to be exercised. It is a power to be exercised concurrently by the two governments. § 1103. Obligations of the federal government and agencies. Congress has power to provide for the making of contracts by the government with corporations and individuals for the construction of public works of national importance, for transporting the mails and for other services needless to mention, and in aid of the ..... "But such 1 McCulloch v. Maryland, 4 Wheat. 316, the Chief Justice said: is the paramount character of the constitution, that its capacity to withdraw any subject from the action of even this power is admitted. The states are expressly forbidden to lay any duty on imports or exports, except what may be absolutely necessary for executing their inspection laws. If the obligation of this prohibition must be conceded, if it may restrain a state from the exercise of its taxing power on imports and exports, the same paramount character would seem to restrain, as it certainly may restrain, a state from such other exercise of this power as is in its nature incompatible with and repugnant to the constitutional laws of the Union. . . . . . The people of a state give to their government a right of taxing themselves and their property, and, as the exigencies of government cannot be limited, they prescribe no limits to the exercise of this right, resting confidently on the interest of the legislature, and on the influence of the constituents over their representatives to guard them against its abuse. But the means employed by the government of the Union have no such security, nor is the right of a state to tax them sustained by the same theory. Those means are not given by the people of a particular state, not given by the constituents of the legislature, which claim the right to tax them, but by the people of all the states. They are given by all for the benefit of all, and upon theory should be subjected to that government only which belongs to all." In this case an act of the Maryland legislature required that the notes put in circulation by the branch bank of the United States at Baltimore should be upon stamped paper furnished by the state upon which a tax was charged and made it a penal offence for the cashier of the bank to use any other kind. The cashier refused to comply with the law and was prosecuted in the state court for its violation. On appeal to the supreme court of the United States, the act was held unconstitutional and void as an interference with the execution of the national banking laws. performance of such contracts may loan the credit of the government in the form of bonds and may make land grants and prohibit the states from taxing the agents employed in accomplishing these objects.1 The express exemption declared by congress in such cases does not add any force to the prohibition. The act is only declarative of what the courts have decided from time to time.2 Bonds issued by the government for loans and in aid of railroad and other companies are exempt because, being contracts of the United States, a presumption prevails that the non-taxable quality of its credit was had in view by the money-lender or purchaser of the bonds at the time of making the contract, and formed a part of the consideration for entering into it. Upon this theory, a tax upon the security offered would have the same effect as a tax upon the United States government itself.3 No devices or inventions for evading the exemption, as by taxing personal property of which the government securities form a part in bulk or the premium upon them will be allowed to succeed. The fact that the bonds are above par in the market does not render the owner liable to assessment and taxation on the excess.1 1 Thompson v. Pac. R. R. Co., 9 Wall. 579. 2 State Mut. Life Ins. Co. v. Height, 34 N. J. 148. People v. Commrs. of Taxes, 90 N. Y. 63; overruling People v. Manhattan Fire Ins. Co., 76 Id. 64. Upon the same principle United States treasury notes and national bank notes are exempt, the value of the former depending exclusively upon the promise of the government to redeem them and the latter deriving a part of their value from the secondary liability of the government. Home v. Green, 52 Miss. 452; B'd of Commrs. v. Elston, 32 Ind. 27. But certificates of indebtedness issued by the secretary of the United States treasury for indebtedness which has been audited and allowed are not exempt. The money to pay such certificates is held in trust for the payee until called for and the solvency or insolvency of the government does not affect his claim upon it. People v. Hoffman, 37 N. Y. 9. See U. S. v. Wilson, 106 U. S. 620. But a tax upon the corporate franchise or privilege of being a corporation, and not on the capital stock, to which reference is made only as a basis for fixing the amount of the tax, is valid notwithstanding the fact that part of the capital stock is invested in securities of the United States.1 § 1104. Municipal bonds are governmental agencies.— Bonds issued by a state, or under its authority by its municipal bodies, to railroad companies, to other corporations and to individuals, are means for carrying on the work of the government, and are not taxable even by the United States, it not being a part of the policy of the government which issues them to subject them to taxation for its own purposes. Such securities undoubtedly represent moneyed capital, but as from their nature they are not ordinarily the subjects of taxation, they are not within the reason of the rule established by congress for the taxation of national bank shares.2 § 1105. Distinction between federal agency and property of agent. In the case of agencies employed in interstate commerce, the effect and not the form of the tax is looked to in order to determine whether it is an interference with or hindrance of federal functions, though in some instances the taxation of the property of an agent might be the same thing as if it were laid upon the agent's authority or movements. Although franchises are in one sense property, yet, when granted to a corporation by the federal government, they are to be held and exercised subject to the control of that government, exclusive of the power of the states to tax them.3 1 Home Ins. Co. v. State, 134 U. S. 594. 2 Mercantile Nat. B'k of N. Y. v. Mayor, etc., of N. Y., 121 U. S. 138. * In Cal. v. Pac. R. R. Companies, 127 U. S. 1, 41, the franchises of the com |