In Ronpibon Tin N.L. and Tongkah Compound N.L. v. Federal Commissioner of Taxation [2] , it is said: "For expenditure to form an allowable deduction as an outgoing incurred in gaining or producing the assessable income it must be incidental and relevant to that end In brief substance, to come within the initial part of the sub-section it is both sufficient and necessary that the occasion of the loss or outgoing should be found in whatever is productive of the assessable income or, if none be produced, would be expected to produce assessable income" [3] . Properly understood the place which the banking of money takes in a merchandising business brings the operation within the principle thus stated. It is an essential, or at all events highly expedient, part of the conduct of the business, a necessary or recognised incident or concomitant, and is relevant as well as incidental to the end in view, the gaining of the assessable income. The "occasion of the loss" in the present case was the course pursued in banking the money. In Commissioner of Taxation (N.S.W.) v. Ash [4] , Rich J. said: "There is no difficulty in understanding the view that involuntary outgoings and unforeseen or unavoidable losses should be allowed as deductions when they represent that kind of casualty, mischance or misfortune which is a natural or recognized incident of a particular trade or business the profits of which are in question. These are characteristic incidents of the systematic exercise of a trade or the pursuit of a vocation" [1] . Even if armed robbery of employees carrying money through the streets had become an anachronism which we no longer knew, these words would apply. For it would remain a risk to which of its very nature the procedure gives rise. But unfortunately it is still a familiar and recognised hazard and there could be little doubt that if it had been insured against the premium would have formed an allowable deduction. Phrases like the foregoing or the phrase "incidental and relevant" when used in relation to the allowability of losses as deductions do not refer to the frequency, expectedness or likelihood of their occurrence or the antecedent risk of their being incurred, but to their nature or character. What matters is their connection with the operations which more directly gain or produce the assessable income.