Example the first: to find the Expansion of Air on one thousand Feet, with one Degree of Temperature; the Answer in the Table is 2.4, or 2.43: i. e. 2 Feet and 4 Tenths of a Foot, rejecting the 2d Decimal as too minute.
Example the second: to find the Expansion on 8 thousand Feet, with 99 Degrees of Heat: the Answer is 1924.56: and so of the Rest.
Thus any of the vertical Numbers shewing the Expansion, may be readily formed, by doubling, first, the Number immediately under each thousand in the horizontal Line, for the nine first thousands, (of which the Breadth of the Table properly consists, exclusive of the thermometric Column) for the Expansion below it: and, afterwards, for each Expansion immediately below the former, by adding, to the Expansion last found, the Number immediately under its respective thousand.
First Example: to find the vertical Number for the Expansion under the first thousand, viz. 1000, with 2 Degrees of Heat: the Number under 1000 is 2.43: double this: and the Answer is 4.86.
Second Example: suppose the Expansion last found be that on one thousand Feet with 24 Degrees of Heat; viz. 58.32: and the Expansion on the same thousand, with one Degree of Heat more, viz. on 25 Degrees, be required; add the Expansion
| on one thousand Feet, with 24 Degrees, viz. | 58.32 |
| to the Expansion on the same 1000, with 1 Degree, viz. | 2.43 |
| ——— | |
| and the Answer is, by Addition, | 60.75 |
Third Example: supposing the Expansion last found to be the Expansion on 9000 Feet with 99 Degrees of Heat, which in the Table is 2165.1.
It is required to find the Expansion on the same 9000 Feet, with 100 Degrees of Heat; add to the Expansion last found,
| viz. | 2165.13, | the Expansion on the same 9000 Feet, |
| viz. | 21.87 | with one Degree of Heat, and |
| ——— | ||
| 2187.00 | is the Answer by Addition. |
Any vertical Number shewing the Expansion may likewise be found, first, by multiplying the first Figure, or Number, of the given thousand Feet (in the horizontal Line,) into the Answer or Expansion on the first thousand Feet, with one Degree of Heat: for Example;