§ 24. Appraisal of estate in the hands of assignee. Whenever it shall become necessary to appraise in whole or in part any estate in the hands of any assignee for the benefit of creditors, the persons whose duty it shall be to make such appraisal shall value the real estate at its full and true value, taking into consideration actual sales of neighboring real estate similarly situated during the year immediately preceding the date of such appraisal, if any; and they shall value all such property, stocks, bonds or securities as are customarily bought or sold in open markets in the city of New York or elsewhere, for the day on which such appraisal or report may be required, by ascertaining the range of the market and the average of prices as thus found, running through a reasonable period of time.