¶1OFINION.
¶2In deciding this appeal we do not determine that the taxpayer was not entitled to make his income-tax return upon an installment basis. Had sufficient evidence been submitted for our consideration, his appeal might have merited a favorable decision.
¶3Bule 20 of this Board provides that the burden of proof is on the taxpayer. That means that he must introduce sufficient evidence to make a prima facie showing that the Commissioner committed the errors alleged in the petition and to overcome the proofs submitted on behalf of the Commissioner. Such a showing must cover all the elements necessary to establish the averments of the petition. This Board is required by law to make findings of fact. Such findings can not be made upon conjecture, ex parte statements, or argument. They must be supported by evidence presented to the Board. What has been submitted to or considered by the Bureau of Internal Beve-nue is beyond the ken of this Board. This body is “ an independent agency in the executive branch of the Government,” it has no connection with the Bureau of Internal Bevenue, and evidence that has been introduced before any other department of the Government must be reintroduced before this Board before we can consider it.
¶4In this appeal, the taxpayer introduced his cash book and ledger in evidence. The accounts shown therein support the findings of the *380Commissioner as to the amount of net profits in the year at issue. The books of account which were introduced were kept in such a manner that they do not permit a computation of the taxpayer’s income on an installment basis. Allusion in the testimony to other books kept in the office of the taxpayer, and not introduced in evidence, does not satisfy us that error was committed by the Commissioner. We can not assume what might be proven by evidence which was not introduced.
¶5The taxpayer asks us to allow a deduction of $400 estimated by him to be the total expenditures made by him during the year in question for admissions and sales taxes. He produced no vouchers or accounts to show any payments; he admits that the amount is an estimate, and asserts that it is a fair and reasonable allowance for a person in his circumstances of life. This is asking the Board to make a finding without proof. We can not indulge in conjecture.
¶6The deficiency determined by the Commissioner must be approved.