Now .6 Tenths of 1 Degree, (more than the 4°) are at some intermediate Point of the Thermometer between 1 and 2 Degrees: above 1; yet not so high as 2: or more than 1; yet less than 2.
Therefore .6 Tenths of 1 Degree above 4 Degrees, are somewhere between the 4th and 5th Degree: above 4; yet not so high as 5: or more than 4; yet less than 5.
Look in the Table ([Section 363]); first with 4 Degrees of Heat, on 24 Inches, and then with 5 Degrees of Heat on 24 Inches; and the respective Numbers are .0097 and .0121: and by taking the Expansion with 4 Degrees on 24 Inches, from the Expansion with 5 Degrees on the same 24 Inches; the Remainder will be the Expansion with 1 Degree above 4° on 24 Inches: viz.
| with |  | 5° = .0121 |  | on 24 Inches, as in whole Numbers. |
4° = .0097 | ||||
—— | ||||
Remainder, .0024 | ||||
This therefore is the Expansion with 1 Degree of Heat, above 4, viz. with the 5th Degree, on 24 Inches of the Barometer.
Then say, if 1 Degree of the Thermometer (above 4, viz. the 5th Degree) gives by Expansion, a certain additional Height, or Part of an Inch, viz. .0024, on 24 Inches of the Barometer; what Height will 6 Degrees give? Answer 6 Times more.
Multiply the 2d and 3d Terms, and divide by the first, thus;
| 1 : | .0024 | :: 6? |
| 6 | ||
| —— | ||
| .0144 |
is the Expansion, or Height, in Parts of an Inch, for 6 Degrees.
And farther, to proportion for the Decimal; say as .1 Tenth of a Degree gives a certain Tenth of the former .0024, in additional Height, viz. .00024; what Height will .6 Tenths give? Answer, .00144.