The price of corporate stock at public sales which are sufficiently numerous to attract the attention of investors competent to investigate the question of its value, is ordinarily the best evidence of its market value. In ascertaining the value of railroad stock, taken by eminent domain, it is error to admit evidence of corporate mismanagement to show that its market value ought to have been greater, or to allow other elements of value to be added to the market price. Evidence that New Hampshire railroad stock, owned by residents of Massachusetts, is taxable there, is not admissible to show that it has a higher market value in this state. The notoriety of many facts is so great, that the administration of justice requires the exclusion of evidence based on an assumption of their nonexistence.