[118]

Foundation of the first Table.

(Ph. Tr. for 1777, Part 2d, Page 567.)—It was found by
Experiment that the Decimal

.000262
was the Expansion on 30 Inches of Quicksilver, with each Degree of Temperature from freezing to boiling Water: also, the Decimal

.000042
was the Expansion on 30 Inches of the Glass Tube (containing the Quicksilver), with each Degree of

———
Temperature: therefore by Addition,

.000304
or by taking only 4 Decimals,

.0003

is the Expansion on 30 Inches of Quicksilver, and the Glass Tube containing it, with each Degree of Temperature.

Construction of the first Table.

Thus any vertical Number, shewing the Expansion, may be readily formed, by doubling, first, the Number immediately under each Inch for the Expansion below it: and afterwards, by adding the Number immediately under each Inch, to the Expansion last found.

Note: The vertical Columns, below each Inch of Quicksilver shew the Expansion on that Inch, with corresponding Degrees of Temperature indicated by the Thermometer in the Column to the left Hand. Example: to find the Expansion on 30 Inches of Quicksilver with 1 Degree of Temperature: the Answer in the Table is .003: i. e. such Expansion raises the Quicksilver the 3000th Part of an Inch.

[119] There is seldom Occasion to take more than the four first Decimals out of the Table, the Remainder being of little value.

[120]

The Foundation of the second Table.