The Logistical Logarithm of the Difference of the Moon's place at noon that day and her Place at the Crisis subtract the Logistical Logarithm of her Diurnal Motion, and the remainder will be the Logistical Logarithm of the time afternoon of the Crisis or Judicial Day.

 

Chapter VIII.

To find the exact time of the crisis by a table of logistical logarithms.

Seeing that many are unskillful in finding or calculating the true time of the crisis after the decumbiture, I have in this edition inserted a table by which it may be easily performed if the following rules be duly observed (and if they be now, I cannot help it).

In the head of the table is placed the 24 hours of the natural day, which also serve for degrees as occasion serves. In the little column to the left-hand are placed the minutes, as is usual in other tables; in the greater columns are placed the logistical logarithms of any hour and minute of the natural day, &c.

When you would find the logistical logarithms of any hour and minute, or degree and minute, seek the hour or degree in the head, and the minutes in the side, and at the angle of meeting you have the same. 

Example.

I would know the logistical logarithm of 64 hours and 40 minutes. I seek for 6 at the head of the dexter page, and for 40 in the side, and at the angle of meeting I have 12859, the logistical logarithm thereof. 

When you have a logarithm and would know the hours and minutes belonging thereto, seek the same at the nearest thereto (for that will serve very well) in the table, and at the head of that column where you find it, you have the hour, and then cast your eye to the little column on the left hand, and you have the minutes.

Example.

I would know what hours and minutes this logarithm 9025 doth belong to. Having found the same in the table, at the head of that column where I find it is placed 9, and against it in the side 44, viz. 9 hours 44 minutes. 

Having the hour and minute of the decumbiture, find the places of the planets for that time. In the Ephemeris you have their places every day at noon.

When planets are direct, subtract their place the day precedent from their place the day subsequent, and you have their dirurnal motions; but when they are retrograde, subtract their place the subsequent day from their place the precedent day, and you have likewise their dirunal motions.

Upon the logistical logarithm of the hours and minutes afternoon of the decumbiture, add severally the logisitical logarithm of the planets diurnal motions, and the sums shall be the logistical logarithm of the proportional degree or minute, which when planets are direct (the Sun and Moon are always so, if yourself to remembrance) must be added to their place the day precedent; but when they are retrograde, it must be subtracted from their place the day precedent, and their aggregate or remainder will be their true place at the decumbiture.

Having found the Moon's place at the decumbiture by adding 45 degrees thereto, you have her place at the first judicial time; by adding three signs to her place at the decumbiture, you have her place at the first crisis, and so by a continual addition of 45 degrees, the Moon's place at the crisis and judicial days is found, as is showed Chapter 5.

Observe in the Ephemerides what day the Moon's is next less than her place at the crisis or judicial day, and note the difference, and also note the diurnal motion that day.Then, from the logistical logarithm of the difference of the Moon's place at noon that day and her place at the crisis subtract the logistical logarithm of her diurnal motion, and the remainder will be the logistical logarithm of the time afternoon of the crisis or judicial day. 

Example.

A man fell sick of a fever, 1652, November 7, being Sunday at 8 & 9 minutes at night, at which time he was taken with a great horror and with shaking, as in a violent ague, &c.

In my Ephmeris for that year, you will find (if you look) the planets' places upon the 7 & 8 days of that month, as follows:

Then subtract their places, the 7th day from their places the 8th day, because they are all direct, and the diurnal motion will be of:

The logisitical logarithm of 8 hours 10 minutes is 10780, which added unto the logistical logarithm of the planets' diurnal motions, the work will be as the following examples:

to 25.47, which will produce the Sun's place in Scorpio 26 degrees and 8 minutes.

to 20 ♊ 31 🌙 place the 7th day, which will make 25 degrees 8 minutes in ♊, her place at the decumbiture. 

If you deal after the same manner with the rest of the planets, as in these two examples of the Sun and Moon, their places at the decumbiture will be:

Then the first judicial day will be when the Moon comes to 10 degrees 8 minutes of Leo on the 10th day of the same month; the Moon's place in 29 degrees 52 minutes, Cancer being the next less, and wants of 10.8 in Leo, 10.16 and her diurnal motion is 12.27. 

afternoon that the first judicial day falls on, viz. the 11th day at 7 a clock and 48 minutes in the morning.

The first crisis happens when the Moon comes to 25.8 of Virgo on the 14th day, the Moon's place is in Virgo 19.44 and wants of 25.8. 5.24, her diurnal motion is 11.55.

afternoon of the first crisis, viz. at ten a clock and 53 minutes at night, the 14th day of November.

The second crisis will be when the Moon comes to 25.8 of Sagittarius, the 21st day; the Moon's place is 14.50 in Sagittarius and wants of 25.8 (the place of the crisis) 10,18 and her diurnal motion is 12.40.

of the second crisis afternoon, viz. at half an hour 7 in the morning the 22th day.

The like method used in the other, as in these examples, the Moon's place, and time, &c. will be as in the following synopsis: