The art of dialling by a new, easie, and most speedy way. Shewing, how to describe the houre-lines upon all sorts of plaines, howsoever, or in what latitude soever scituated: as also, to find the suns azimuth, whereby the sight of any plaine is examined. Performed by a quadrant, fitted with lines necessary to the purpose. Invented and published by Samuel Foster, professor of astronomie in Gresham Colledge.

AN APPENDIX Shewing a ready way to find out the Latitude of any place by the Sunne.

BEcause in the third Chapter, and quite through this Treatise, the Latitude of the place is supposed to bee knowne, when as every one perhaps cannot tell which way to find it out; I thought good therefore to adde this Appendix as a ready helpe to shew how it may bee attained sufficiently for our purpose. Know then that for the finding out of the Latitude of a place by the Sunne, these things are required.

1. To find the Meridian line.

The readiest way to find the Meridian line is by the North-starre. This starre is within 2 degr. 37 min. of the North-pole. The North-pole lyes very neere betweene Allioth, or the root of the great Beares tayle, and this starre; You may there∣fore imagine where the Pole is, if you conceive a right line drawne from the Pole-starre to Allioth,

and by your imagination suppose ⅔ parts of the distance of the next starre of the little Beares taile from the Pole-starre to∣wards Allioth, for there is the very Pole-point. Now then if you set up two poles aslope, and from the tops of them hang two cords with weights at the ends of them, and turne them till you standing on the South-side of them may see them both toge∣ther

[illustration]

with the Pole-point, as it were all in one line, then be sure these two cords doe hang in the Meridian line, or very neere it, yea so neere it, that though you should erre 3 degrees herein (wherein you need not to erre one degree) yet will not the Meridian altitude in these Climates (especially more Northward) faile you above 3 minutes, which is neere enough to our purpose. I have here given you the chiefe starres of the great and little Beares, that by them you may come to know the starres used in this observation, and so find the very Pole-point it selfe.

2. To find the Sunnes Meridian altitude.

Observe diligently about noone when the sha∣dow of the South cord shall fall upon the North cord, for then is the Sun in the Meridian. At that instant observe the Suns altitude stedily and care∣fully, for that is the Meridian and greatest altitude of the Sun for that day.

3. To find the Sunnes declination.

For this purpose the limbe hath the characters of the 12 Signes fixed to each 30 degree, and a scale of declinations under the limbe noted with MN. The Scale is divided by this table; for looke what degr. and min. of the Eclipt. doe answer to the degr. of declination in the table, the same are to be numbred in the limbe, and by a ruler applyed to them, the degrees of declination are drawne upon the Scale.

A Table to make the Scale for the declination of every part of the Eclipticke.

Degr. of decl.	Deg. of the ecl.	Degr. of decl	Deg. of the ecl.	Degr. declin.	Degr. eclipt.	Degr. declin.	Degr. Eclipt	Degr. declin.	Degr. Eclipt.	Degr. declin.	Degr. Eclipt.
0.0	0.00	4.0	10.04	8.0	20.26	12.0	31.26	16.0	43.44	2.0	59.04
0.15	0.38	4.15	10.43	8.15	21.06	12.15	31.09	16.15	44.34	20.15	60.14
0.30	1.15	4.30	11.21	8.30	21.46	12.30	32.52	16.30	45.25	20.30	61.26
0.45	1.53	4.45	11.59	8.45	22.26	12.45	33.36	16.45	46.17	20.45	62.41
1.0	2.31	5.0	12.37	9.0	23.06	13.0	34.21	17.0	47.09	20.0	46.00
1.15	3.08	5.15	13.16	9.15	23.46	13.15	35.05	17.15	48.03	21.15	65.22
1.30	3.46	5.30	13.54	9.30	24.27	13.30	35.50	17.30	48.57	21.30	66.48
1.45	4.24	5.45	14.33	9.45	25.08	13.45	36.35	17.45	49.52	21.45	68.••••
2.0	5.01	6.0	15.12	10.0	25.49	14.0	37.21	18.0	50.48	22.0	69.58
2.15	5.39	6.15	15.51	10.15	26.30	14.15	38.07	18.15	51.45	22.15	71.44
2.30	6.16	6.30	16.30	10.30	27.12	14.30	38.54	18.30	52.43	22.30	73.41
2.45	6.55	6.45	17.08	10.45	27.53	14.45	39.41	18.45	53.43	22.45	75.53
3.0	7.33	7.0	17.48	11.0	28.36	15.0	40.28	19.0	54.44	23.0	78.30
3.15	8.10	7.15	18.27	11.15	29.17	15.15	41.16	19.15	55.47	23.15	81.52
3.30	8.48	7.30	19.6	11.30	30.00	15.30	42.05	19.30	56.50	23.30	90.00
3.45	9.26	7.45	19.46	11.45	30.43	15.45	42.54	19.45	57.56	Finis.

Before you can find the Declination, you must know the Sunnes place, and for such as know not the use of the Astronomicall tables, an Almanacke

will serve, where for every day at noone, you shall find the Sunnes place in signes, degrees and mi∣nutes. The degr. and min. must bee numbred in their Signes upon the limbe, and the threed applyed thereto will shew the declination answerable. As for example. September 21. 1637 in the Al∣manack for this yeare, the Sunne is found to be in 8 gr. 23 min. of ♎. In the Quadrants limbe I looke for the Signe ♎ and number there, 8 gr. 23 min. whereto apply the threed, I find it to cut in the scale of Declinations 3 gr. 20 min.

4. By the Meridian Altitude, and declination of the Sun had; how to find the Latitude of the place, or the Elevation of the Pole above the Horizon.

Compare the Sunnes Meridian altitude and de∣clination together, and if the Sunne be in a North Signe as ♈♉♊♋♌♍, then substract the declinati∣on out of the Meridian altitude, so shall the diffe∣rence give you the height of the Equinoctiall. But if the Sun be in the South Signes, as ♎♏♐♑♒♓, then adde the declination to the Meridian altitude, so shall the summe give you the height of the E∣quinoctiall, which being taken out of the Quadrant or 90 degrees, leaveth the Latitude of your place, or the Elevation of the Pole above your Ho∣rizen.

For Example. Upon the 21 of September 1637. I observed the Sunnes altitude in the Meridian to be 34 gr. 10 min. Upon which day I find the

Sunnes place to be (as before) 8 gr. 23 min. of ♎, and the declination 3 gr. 20 min. And because the Sun is in a South signe, I adde this declination and Meridian altitude together; the summe 37 gr. 30 min. is the altitude of the Aequator, and this taken out of 90 degrees leaveth 52 gr. 30 min. for the Latitude of Coventrie.

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