Fig. 22 is an illustration of a cash book with columns for the private ledger account. =21. Manufacturing Accounts in the Private Ledger.= Not infrequently, manufacturers find it advisable to keep private certain details which affect costs, or even all knowledge of the exact cost of their manufactured product. This may be done by keeping certain manufacturing controlling accounts in the private ledger. In determining the cost of manufacture of any class of goods, three elements enter into the computation; material, labor, and expense. To determine the cost of the first two items is comparatively simple, requiring only an efficient system of records in the factory. But to determine the amount of expense of all classes, included in the cost of a given article, job, or operation, is more difficult. A system of records that will show the exact cost of such items as power, heat, or taxes properly chargeable to an individual job or operation is obviously impossible, and it has been found necessary to apportion these, and all similar items of expense, on a percentage basis. Usually this percentage is based on some element of cost which can be determined with accuracy. Cost accountants and engineers have worked out this percentage on the basis of various elements of cost, as direct labor, material, machine hour, man hour, or a combination of two or more of these elements. The exact method used, which must be adapted to the conditions existing in the individual factory, does not enter into this discussion. Since there are numerous items of expense of the character referred to, it is customary to group them, for purposes of cost computation. Sometimes all such expense items are grouped under the one head of General Expense. It is by means of a controlling account in the private ledger, that the distribution of expense is made, thereby keeping private the exact cost of manufacture. The known cost of a certain job or article--the cost of material and labor--is frequently referred to as the prime cost. The duties of the cost clerk may end with determining the prime cost, his computations not including expense items. The total cost of material and labor for the month is charged to private ledger account, material and labor accounts receiving proper credit. The exact amounts of the various items of expense for the month are also charged to private ledger account, with credits to expense accounts. In the private journal, these items are charged to various controlling accounts, and credited to the general ledger controlling account. The usual entries are: Manufacturing Account $______ General Ledger $______ For material $______ For labor $______ Expense Distribution $______ General Ledger $______ For rent $______ For power $______ For repairs $______ Etc. Etc.