How to set it first in Motion.

When it is finished, let it go for a Month or two; after which put the two Indexes right one with the other, and both of them pointing just to 100. Then the Spring being wound up, keep it from Going (with the Key) till the Shadow of the Sun is exactly come to a Meridian Line, which must be rightly prepared for that purpose. Then let it go till the Shadow comes just to the same Line the next Day, or rather 40, 50, or 100 Days after, (the longer the Better.) At which time enter down the Centesms that the swiftest Index points to, as also the Integers and Tenths of the slowest, (but put the last first in your Numbers) by this you will be furnished with two general Numbers, viz. the said Numbers pointed to, and the Time (in Hours) spent therein, to find the Hour of the Day to the Tenth of a Minute, at any time; for that Place where it was so set going, tho’ you remove it afterwards to any Distance whatsoever. Which two Numbers ought to be entered in a Book; to be used whensoever you would find the Hour of the Day.

And it is to be noted, That if the Sun be not then in its Mean Motion, you must Add to, or Substract from what the Indexes do Give, according to the Inequality thereof: But if you try it for one whole Year, there will be no need of either. And that what is said may be the better understood, I shall give an Example.