In reference to municipal corporations , and especially to their powers of taxation, a ” corporate purpose ” is one which shall promote the general prosperity and the welfare of the municipality , (Wetherell v. De- vine, 116 111. 631, 6 N. E. 24.) or a purpose necessary or pToper to carry into effect the object of the creation of the corporate body , (People v. School Trustees, 78 111. 140.) or one which is germane to the general scope of the objects for which the corporation was created or has a legitimate connection with those objects and a manifest relation thereto. (Weightman v. Clark, 103 U. S. 256, 26 L. Ed. 392.)