The description and use of two arithmetick instruments together with a short treatise, explaining and demonstrating the ordinary operations of arithmetick, as likewise a perpetual almanack and several useful tables : presented to His most excellent Majesty Charles II ... / by S. Morland.

The use of the Table in Page 6.

By the Table in Page 6. you may immediately find the Dominical Letter from the first year of our Lord, to the year 3400, &c. so long as the world shall last.

For example, For any year of Our Lord under 100. they are exprest in the Marginal Columnes of Numbers, and are answered in the first Columne of Letters. Thus for the years of Our Lord 28, 56, and 84. The Domi∣nical Letters are DC. For the years 1, 29, 57, and 85. the Dominical Letter is B. For the years 11, 39, 67, and 95. the Dominical Letter is D.

Now for all the even Hundreds or Thousands from 100. to 3400. (which are all Leap-years) the Domi∣nical Letters are to be found above them in the 1, 2, 3, 4, 5, 6, and 7th Columne.

And for any other Numbers, the Rule is for ever this; Where the Marginal Number (equal to the Fracti∣on or part of an Hundred sought) meets with the Columne where that Number of Hundreds or Thousands (which is the other part of the Number sought) is exprest; That is the Dominical Letter (or Letters) for that year.

For example, Let the Dominical Letter be demanded for the year of Our Lord 1672. The number of Hun∣dreds is, 1600. and is found in the third Columne. And the broken part (72) among the Marginal Numbers meets with that third Columne in the Letters GF. which are the Dominical Letters for that year, namely the first of them (G.) from the first of January to S. Matthias Eve, the twenty fourth of February, and the other Letter F. to the years end, which is a constant Rule for all Leap-years.

If the Dominical Letter be demanded for 1481. The Hundreds are 1400. and are found in the first Co∣lumne, the broken part of an Hundred (81) meets with that Columne in G. which is the Dominical Letter for that year.

So if the Dominical Letter be demanded for 1349, 1300. is found in the 7 Columne, where the broken part (49) among the Marginal Numbers; meets in the Letter D. which is the Dominical Letter for that year.

Again, Let the Dominical Letter be demanded for the year 1729. 1700. is found in the 4 Columne, and 29. meets with that Columne in E.

And so for any year past or to come.