To know the time of the Moon's Rising, Southing, and Setting.
FOr her Rising (know this) having found the place, or what Sign she is in, seek out in the following Kalendar what time the Sun is in this Sign and De∣gree, and there you shall find the true time of the Sun-Setting, being in that place: This is half the continuance of the Sun above the Horizon in that Sign and Degree. Add this to the time of the Moon's coming to the South, it shews the time of her Setting; and substracted from it, shews the time of her Rising.
Thus upon the 11th of September, as before, the Moon being 14 days old, and in the 18 Degree of Gemini, I desire to know the time of the Moon's Rising and Setting.
Page 12| H. | M. | |
| ☽ So. | 11 | 12 |
| ☉ Set. | 8 | 10 |
| ☽ Ris. | 3 | 02 |
| Added | 19 | 22 |
| ☽ Set. | 7 | 22 |
First multiply 14, the Moon's Age, by 4. Divide the Product by 5. In the Quotient will be 11 a Clock, and the one Unite upon the Division is Min. 12, that the Moon will be South that night. Secondly, The Sun is in this Sign and Degree about the first day of June, and then sets at 8 a Clock 10 minutes past. This substracted, shews the Rising of the Moon to be at 3 of the Clock 2 minutes in the afternoon. The said 8 hours, 10 being added, makes 19 hours 22 min. which by casting away 12, the remain shews the Moon's Setting to be at 7 of the Clock, and 22 min. past in the morning, which answers the Question desired; which is as neer as can be for your use.
PROP. I. How to find when it is Full-Sea in any Port, Rode, Creek, or River.
I have shewed you already how to find the Prime, Epact, and Age of the Moon, at any time desired. Now we will proceed to shew you the finding of Full-Sea in any Place; as in manner following.— First, Carefully watch the time of High-Water, and what Point of the Compass the Moon is upon, on her Change-day, in that Port or Place where you would know the time of the Full-Sea, or find by the Table what Moon makes a Full-Sea in the said Port. Secondly, Consider the Age of the Moon; then by Arithmetick resolve it in this manner. Multiply the Moon's Age by 4, di∣vide the Product by 5, the Quotient shews the Moon's being South. If any thing remaineth upon the Division, for every Unite you must add 12 Min. If it was 4 re∣maining, it would be 48 Minutes to be added. Then add the hour that it Flows on the Change-day to it, and the Total is the hour of Full-Sea. If it exceed 12, sub∣stract 12 from it, the remain is the hour of the day or night of Full-Sea, in any Port, River, or Creek. Which I will make plain by some Examples, (viz.)
PROP. II. The Moon 16 days old, I demand, What a Clock it will be Full-Sea at Bristol, Start-point, and Waterford, where E. b. S. Moon maketh Full-Sea on Change-day?
Consider here an E. b. S. Moon maketh 6 hours 45 min. and the Age of the Moon is 16 days old: Therefore multiply the Age by 4, and it makes 64; divide that by 5, and it is 12, and 4 remaineth, which is 48 min. To it add 6 hours 45 min. E. b. S. it makes 19 ho. 33 min. Therefore substract 12 hours from it▪ there remaineth 7 a Clock 33 minutes, the time of Full-Sea in the morning at the aforesaid Ports; which you may compare with your Instrument, and find it very well agree. 〈 math 〉
PROP. III. The Moon being 25 days old, I demand, What a Clock it will be Full-Sea at London, Tinmouth, Amsterdam, and Rot∣terdam, where it flows S. W?
Consider that at these Places on the Change-days a S. W. Moon maketh Full-Sea, which is 3 hours. Therefore multi∣ply 25, the Moon's Age, by 4, it makes 100. That divide by 5, in the Quotient will be 20, and nothing remain. To it add 3 ho. S. W. and it makes 23 hours. From it substract 12, and the Remainder shews you, That it will be Full-Sea at all the aforesaid Places, at 11 of the Clock in the mor∣ning. So you will find it agree with your Instrument. 〈 math 〉
PROP. IV. The Moon being 9 days old, I desire to know the hour of Full-Sea at Quinborough, Southam. and Portsmouth.
Note, That a South-Moon on the Change-day, maketh Full-Sea at these Places. Therefore multiply the Moon's Age by 4, it makes 36. That divide by 5, and the Quotient is 7 of the Clock; and 1 remaineth, which is 12 minutes, the time of Full-Sea at the aforesaid Places, the Moon's Age being nine days. Note, If a North or South Moon makes Full-Sea on the Change-day, there is nothing to be added to the Quotient; but the Quotient is the hour of the day, and the Remainder is the min. as before directed. One Example more shall suffice. 〈 math 〉
PROP. V. The Moon 5 days old, I demand the time of Full-Sea at Rochester, Malden, Blacktail, where S. b. W. Moon is Full-Sea.
Here you may note, That on the Change-day at these Places it flows S. b. W. which is but one Point from the South, being but ¾ of an hour, or 45 min. And it had been all one if it had been North-by-East. Multiply by 4, divide by 5, and the Quotient will be 4; to it add 45 min. S. b. W. shews you it will be Full-Sea at the aforesaid Places at 4 a Clok and 45 min. in the morning. But note, Had it been S. b. E. or N. b. W. it had been 11 ho. 15 min. By this time I hope I have made the Practitio∣ner able to know the time of Full-Sea in any Port, by Instrument and Arithmetick: Therefore I will leave him a small Table for his use.
| H. | M. | |
| Rye, Winchelsey, Culshot, a S. b. E. Moon. | 11 | 15 |
| Rochester, Malden, Blacktaile, S. b. W. | 0 | 45 |
| Yarmouth, Dover, Harwich, S. S. E. | 10 | 30 |
| Gravesend, Downs, Blackness, Silly, S. S. W. | 1 | 30 |
| Needles, Orford, South and North Fore-land, S. E. b. S. | 9 | 45 |
| Dundee, St. Andrews, Lisbone, St. Lucas, S. W. b. S. | 2 | 15 |
| Poole, Isles of Man, Dunbar, Diepe, S. E. | 9 | 00 |
| London, Tinmouth, Amsterdam, Rotterdam, S. W. | 3 | 00 |
| Portland, Hartflew, Dublin, S. E. b. E. | 8 | 15 |
| Barwick, Flushing, Hamborough, S. W. b. W. | 3 | 45 |
| Milford, Bridgewater, Lands-end, E. S. E. | 7 | 30 |
| Baltimore, Corke, Severn, Calice, W. S. W. | 4 | 30 |
| Bristol, Start-point, Waterford, E. b. S. | 6 | 45 |
| Falmouth, Humber, Newcastle, W. b. S. | 5 | 15 |
| Plimouth, Hull, Lyn, St. Davids, W. & E. | 6 | 00 |
| Quinborough, Southam. Portsmouth, N. & S. | 0 | 00 |
Add any two Numbers together of the foregoing Table, and they shall be 12 hours; Except the two last, N, S. and E. W. So that you may perceive, what hath been said from the South, either Eastward or Westward, the same answereth to the North, either Westward or Eastward. And so much for the Tydes. But we will know the Moon's Motion, and the Proportion between Tyde and Tyde.
PROP. VI. The Motion of the Moon, and the Proportion of Time betwixt Tyde and Tyde.
After all this, I will shew you in brief the Motion of the Moon, and the reason of the difference between Tyde and Tyde.
You must note, the Motion of the Moon is twofold. First, A violent Motion, which is from East to West, caused by the diurnal swiftness of the Primum Mobile. Secondly, A natural Motion from West to East, which is the reason the Moon requireth 27 days and 8 hours 8 min. to come into the same minute of the Zodiack from whence Page 14 she departed. But coming to the same Point and Degree where she was in Conjuncti∣on with the Sun last, she is short of the Sun, by reason the Sun's Motion every day is natural East, 1 Degree, or 60 Minutes, which maketh so much difference, that the Moon must go longer 2 days, 4 ho. 36 min. nearest, more than her natural Motion, before she can fetch up the Sun, to come into Conjunction with her: So that betwixt Change and Change is 29 days, 12 hours, 44 min. by my account. The Mariners always allow just 30 days between the Changes, by reason he will not be troubled with small Fractions of Time, in this Account of Tydes, which breedeth no great error: Experience therefore must needs shew me this, That I must allow the some Proportion to the Moon in every 24 hours, to depart from the Sun 12 De∣grees, which is 48 min. of time, untill her full East; but then having performed her Natural Motion above half the Globe, she is to the VVest, as we may know by Reason. Now if the Moon move in 24 hours, 48 min. then in 12 hours she must move 24 min. and in six hours, 12 min. By this proportion each hour she moveth 2 min. So the Tydes differeth as the time differeth.
I will add one old approved Experience for the Mariners use, though it is imper∣tinent in this place; that is, to cut Hair, the Moon in ♉, ♑, ♎: Cutting, shaving, clipping in the Wane, causeth baldness; but the best time in the Wane, is in ♋, ♏, or ♓. So I hope I have satisfied the Learner concerning the Moon.
