344 Arithmetical proportion, or equidifference. Properties. 345 Ratio. Geometrical proportion or equiquotient. Properties. 346 Transpositions of the terms of a geometrical proportion. 347 The products of the corresponding terms of two or more geometrical 351 Increasing and decreasing arithmetical and geometrical progressions. 353 The natural series of numbers, &c. are in A. P. 354, 355 Method of finding any term of an A. P. 356 Method of finding the last term of an A. P. 357 Method of finding the difference of an A. P. 358 Method of finding the number of terms of an A. P. 359 Method of finding the first term of an A. P. 360, 361 Methods of finding the sum of the terms of an A. P. 362 Propositions showing the several cases presenting themselves in A.P. 365 Method of finding the sum of the terms of a G. P. 366 Table shewing the several cases presenting themselves in G. P. 370 Application of G. P. to the computation of compound interest. 372 Permutations and combinations. Examples. 373 Permutations of a certain number of things taken all together. 374 Permutations of things taken two and two, three and three, &c., 375 Permutations of things when some recur. Examples. 376 Combinations. Observations. Examples and exercises. 391 The vertical line drawn from a point to a line measures their distance. 392 Definition of a polygon. Kinds of polygons. 393 Definition of a circumference, &c. 394 Method of measuring the length of a line. Perimeter. 395 The diameter of a circle being given, to find the circumference. 398 Mensuration of surfaces. Definition of the superficial unit. 399 Method of finding the area of a rectangle. 400 Dimensions of a rectangle and a square. 401 Method of finding the area of a parallelogram. 402 Methods of finding the area of a triangle. 403 Methods of finding the area of a trapezium. 404 Method of finding the area of a trapezoid. 405 Method of finding the area of a polygon. 406 Method of finding the area of a circle. 407 Method of finding the area of a sector. 411 Superficial measure of solids. 412 Measure of contents of solids. 416 To find the magnitude and the weight of a body by its specific gra- 417 Weight of a cubic foot of water is its specific gravity. ERRATA. Page 17, Exercises 4, for 100076709 read 1000076709. Page 30, Art. 87, for whether a divisor read whether a division. Page 49, line 10 from bottom, for 8=7×2×2 read 8=7×?×7. Page 57, Exercise 10, for I paid £ read I paid 7. Page 63, for Art. 175 read 165. Page 66, line 13 from bottom, for 83 read 8.3. Page 76, Art. 203, for is integer read is an integer. Art. 204, line 9 from bottom, for decimal read decimals. Page 82, Exercises 5, for-.081 of £3.5, read+.081 of £3.5. Page 111, line 16 from bottom, for 252 read 253. line 13 from bottom, for £21 4s. 6d. read £2 14s. 6d. Page 113, for Art. 253 read 254. Page 120, line 5 from top, for 13 Page 127, Exercises, 8, for £2477. 34 21 read 111. 10s. 10d. read £2377. 10s. 10d. Page 190, in the Malta money table, for Garni, read Grani. Page 203, line 5 from bottom, for 38 Russians in 13 days, read 38 Prussians in 13 days Page 266, Ex. 11, for The areas of &c., read The diameters of &c. Page 279, Ex. 46, for an atom of Phosphorus, read 2 atoms of Phosphorus. Page 283, Ex. 97, for 24 square feet, read 15 square feet. COURSE OF ARITHMETIC. PART I. NOTATION AND NUMERATION. 1. A line admits of lengthening or shortening; a surface admits of extension or diminution; a weight allows its being made heavier or lighter; time allows of increase or decrease, so does motion. 2. Quantity or magnitude is anything which will admit of increase or decrease. For instance, lines, surfaces, weight, time, motion are quantities. 3. The science by which we become acquainted with the properties of quantity is called mathematics. 4. If we were told, that in a certain house, there is a room twenty feet long, sixteen broad, and twenty high, we should at once form a correct idea of it, with regard to its dimensions, because we had a previous knowledge of the length of the foot. One foot is here called the unit or unity. Suppose a piece of cloth contain twelve yards; here one yard is the unit; in a basket there are eight pebbles, one pebble is the unit, and so on. 5. Therefore, in mathematics, the unit is a measure of any kind, arbitrarily taken, to which we refer every quantity of the same kind. A collection of units of the same kind constitutes a number, thus ten horses, sixteen yards, forty houses, &c., are numbers. 6. When numbers are considered in a general sense, without referring them to any particular thing, they are called abstract, as four, seven, twelve, &c., but when applied to particular objects, as two pounds, ninepence, fourteen yards, they are termed concrete numbers. 7. To represent numbers, to express them, to give the means of computing by them, and to apply them to practical purposes, constitute a branch of mathematics called arithmetic. 8. Numbers may be expressed in two different ways, by words and by signs or characters, called figures or digits. 9. The method of expressing any number by figures is called notation, and that of reading numbers so expressed, numeration. 10. Words taken from the Saxon are used for the English names of numbers; they are: one, two, three, four, five, six, seven, eight, nine, ten. 11. It is agreed to consider the number ten as a unit of the second order, which is called tens, and to proceed with the tens as we did from one unit to nine units; but, for the sake of brevity, instead of these expressions: one tens, two tens, three tens, four tens, five tens, six tens, seven tens, eight tens, nine tens-we say ten, twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety. 12. Between ten and twenty, there are nine numbers: ten one, ten-two, ten-three, ten-four, ten-five, ten-six, ten-seven, ten-eight, ten-nine, which appellations have been changed into eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen. 13. Likewise, between twenty and thirty, there are also nine numbers, and we say twenty-one, twenty-two, twenty-three, twenty four, twenty-five, twenty-six, twenty-seven, twenty-eight, twenty-nine; thirty-one, thirty-two...thirty-nine; and so on, as far as ninety-nine. Therefore, ninety-nine is the largest number containing tens and units only. 14 Now, if nine tens and nine units, or ninety-nine, be increased by one unit, we obtain ten tens, or one hundred, which commences a third order of units, called hundreds. The hundreds ascend also from one to ten; but, for shortness, we use one hundred, two hundred, and so on, to nine hundred. As there are ninety-nine numbers between any one hundred and the following, by adding successively the first hundred numbers to each, we have: one hundred and one, one hundred and two, &c.; two hundred and one, two hundred and two, &c.; three hundred and one, three hundred and two, &c.; and so on, to |