the theory of the plaintiff is , that once it has established the fact , under the law , that it has authority to expropriate land , it may expropriate any land it may desire ; that the only function of the court in such proceedings is to ascertain the value of the land in question ; that neither the court nor the owners of the land can inquire into the advisible purpose of purpose of the expropriation or ask any questions concerning the necessities therefor ; that the courts are mere appraisers of the land involved in expropriation proceedings , and , when the value of the land is fixed by the method adopted by the law , to render a judgment in favor of the defendant for its value .