This entry is rendered necessary from the circumstance that both the parties whose names appear were debited for the cost of Insurance in July, and they are again charged for the same cost in the account of the sales in the prece ling entries. They must accordingly be only once charged in the Ledger, and this entry effects the required purpose. .86 .87 .85 7079 7096 7112 7129 7145 7161 7178 7194 7211 7228 2 3 7379 7396 2 3 7551 7568 2 3 8 10 12 13 11 12 14 11 13 14 9 11 13 14 10 11 13 15 10 12 13 15 10 12 13 15 344 12 14 14 16 16 13 14 16 8974 8995 9016 9036 9057 9078 9099 2 4 ARITHMETICAL LOGARITHMS. THE second table which we have given above, is the Table of Antilogarithms mentioned in our last lesson. An Antilogarithm plainly means the opposite of a Logarithm, that is, the number corresponding to any given Logarithm. The preceding table is arranged exactly like the first table, and contains the mantis æ of all logarithms lying between 0000 and 9999. As a Logarithm, according to the rules laid down regarding the first table, always consists of four figures, and the table of Antilogarithms contains no more, and no less, one rule will be quite sufficient to enable the student to take out the number answering to any given Logarithm. It is as follows: Look for the first two figures of the mantissa of the given Logarithm in the first column of the Table of Antilogarithms, headed First Two Figures, and in the same horizontal line with these two figures, in one of the ten adjoining columns on the right, under the third figure of the mantissa at the top, you will find the Antilogarithm answering to the first three figures of the mantissa; next in the same horizontal line with this number, in one of the nine other colums, headed fourth figure, and under the fourth figure of the mantissa at the top, you will find a number which is to be added to the Antilogarithm already found, in order to make it the complete Antilogarithm required. Now, according to the nature of the index of the given Logarithm, by the rules laid down in our preceding lessons, point this Antilogarithm, that is, mark it either as integer or decimal or mixed number, as the case may be, and you will have the number required. Example. Let it be required to find the number corresponding to the Logarithm 01635. Here, looking for 16 in the first column of the table, you find in the same horizontal line in one of the ten adjoining columns on the right, under 3 the third figure of the mantissa at the top, the antilogarithm 1455; and in the same horizontal line with this Antilogarithm, in one of the next nine adjoining columns, under 5 the fourth figure of the mantissa at the top, the number 2, which is to be added to 1455, this being done, you have 1457 for the complete Antilogarithm required. Now, as the index of the given Logarithm is 0, this indicates that the number must con tain only one integer figure; and the Antilogarithm 1457 being pointed according to this index, you have 1457 for the number required. Had the given Logarithms been 1·1635, 2-1635, 5-1635, and 2-1635, the corresponding numbers would have been 11.57, 115-7, 145709, and 01457. |