Opinion by

This case grows out of a proceeding to condemn a strip of the plaintiff’s land for railroad purposes under the right of eminent domain. The assignments of error relate to the qualification of certain witnesses to testify to market value before and after the taking. It is argued that the witnesses McMillin and Jones did not have such actual personal knowledge of the farm., its area, improvements, productive qualities, the uses for which adapted, and the general selling price of lands in the neighborhood, as to make them competent to express an opinion on market value. The rule is that the possession and sufficiency of such knowledge is a preliminary question to be passed upon by the court before the witness should be permitted-to express an opinion: Michael v. Crescent Pipe Line Co., 159 Pa. 99. The importance'of testing the qualification of a witness to express an opinion as a preliminary question, is *537pointed out by Brother Mestrezat in Davis v. Pennsylvania Railroad Co., 215 Pa. 581, wherein it is said: “After such testimony has gone to the jury it is impossible to eradicate it entirely from their minds by any instructions or directions by the court.” We agree with the learned counsel for appellant that it is the duty of the trial judge to carefully consider the qualification of each witness in such cases as a preliminary question before an opinion is expressed upon market value. However, the test applied must not set the standard, of qualification so high as to exclude the only available kind of testimony ordinarily obtainable in such cases. Market value of land is not capable of exact proof, and at best is a matter of opinion not generally of experts with special knowledge, but of persons familiar with values in the neighborhood. As we view the facts of' the present case, the witnesses objected to were qualified to express an opinion as to market value. McMillin was a farmer, had known the farm through which the railroad was constructed for a period of forty years, frequently passed through it on the public highway, observed the improvements and quality of the land, knew the boundaries, had some familiarity with land values and general selling price in the neighborhood as a county commissioner and man of affairs in that section, had observed the cut made in the location of the railroad and was familiar with the conditions before and after the entry. It is true the witness could not recall any particular sales in the neighborhood ab'out the time of the entry, but there is no evidence of such sales being made and there may have been none. Because sales are few and at long intervals or not at all,- it would be unreasonable and unjust to the landowner to hold that he is precluded from offering any testimony on the subject of land values before and after the taking, on the ground of there having been no particular sales in that neighborhood. The witness must have such knowledge of the subject-matter as can reasonably be expected in view of the circumstances, the frequency or infrequency of sales, the location, improvement and quality of the land, and such other things as enter into a proper estimate of market value. In other words, the rule requires the best evidence' available under the circum*538stances of the case. We think McMillin and Jones, as well as the other witnesses, met this requirement and were qualified to express an opinion as to the market value of the land in question: Smith v. Railroad Co., 205 Pa. 645; Hope v. Railroad Co., 211 Pa. 401; Lally v. Railroad Co., 215 Pa. 436. The answer of the witness to the question complained of in the third assignment was speculative, and upon request should have been stricken from the record, but it could not possibly have done appellant any harm because it was meaningless as bearing upon the amount of damages involved, and certainly does not constitute reversible error.

Assignments of error overruled and judgment affirmed.