A Table fhewing the Altitude of the Sun for every Hour and Quarter, at his Entrance into every of the XII Signs of the Zodiack, in the La ticade of London, 51 deg. 32 min. D. M. D. M. D. M. D. M. D. M. D. M. D. M. A Table of the Sun's Azimuth from the South for every Hour andQuarter, at his Entrance into every of the XII Signs of the Zodiack, in the Latitude of London, 51 deg. 32 min. D. M.D. M. D. M. D. M.D. M. D. M. D. M. An Eafie Way to make a Spot-Dial within a Room, without any Calculation, or Vfe of Threads, &c. TH "His may be done Two Ways, either 1. By the direct Rays of the Sun thorough a little Hole in the Glass: Or, 2. By the Reflected Rays from a small show of a Looking Glass, set in a convenient place in the Window. The first way I account not fo convenient, because the Hour-Lines will many of them fall on the Floor, Tables, &c. The other way is this, 1. Take a little piece of Looking-Glass (common Glass may ferve, but not so well) about the breadth of a fixpence, fasten this fo in the bottom of the Window (or fides if you fee good) that the Rays of the Sun may not be hindred from coming upon it (or as little as may be). 2. It is neceffary that you have with you, upon this occafion, a rightly fet Sun Dial Quadrant, &c. The like to find the feveral hours of the Day by being fo provided, upon a clear Sun-fhine Day, watch the Sun-Dial till the fhadow is juft upon fome Hour-Line, then immediately observe where your fpot of light falls on the Wall or Ceiling; and there with black Lead, or the like, make a mark, and alfo fet a Figure by it of what hour it is. Do the fame by the next hour, and fo on as long as the Sun fhines, fo as to give a fpot in the room. 3. About a Month or more after, obferve in like manner by your Suz Dial where the spot falls on the Wall or Ceiling at the feveral hours, and make marks and figures as you did before, and you will find the hour spots now to fall far diftant from where they were a Month ago. 4. This done with a long Ruler and black Lead, Ink, or the like, draw a long line joyning each pair of marks that have the fame figure annexed to them, and each fuch line produced at both ends fhall be the hour line for that hour; to which put, where you fee fit, its proper figures, and in like manner do by the reft. Note, 1. The beft time of the year for the Operation is the Spring, or Autumn; other times of the year may ferve, fo as the times of obfervations be either both before, or both after the folftizès, June 11, December 11. Note 2. When an hour-line drawn upon the Ceiling comes to the Wall, there will be then needful a third obfervation where the fpot falls on the Wall at that Hour; at which having made a mark, draw a ftraight line from the end of the line on the Ceiling, down to your mark, for that hour on the Wall; fo will you have that hour line compleat. In like manner you may do by the reft if there be need. Note, 3. Your Glafs, and what it stands on must be very firm; for if it be moved ever fo little, 'twill not agree with your hour-lines. They who please and have a convenient Room and Window, may by the very fame method draw hour-lines to a fpot of light coming throw a little hole in a Quarry of Glafs, but then it will be convenient that the rest of the Quarry be darkned by pafting a piece of black paper, or the like, on the inner fide, leaving the hole in the middle. FINIS. I RECREATIONS Cryptographical. T HIS Cryptographical Art is of great use in many refpects, but principally in War. And if we confider to what neceffities great Princes and Potentates have been put unto to communicate their Minds or Intentions to their Correfpondents before the improvement of this Art, it would make a man but of a reasonable understanding admire: Wherefore I'fhall here give you a very brief account of fome of them, and afterwards fhew fome other more Artificial and abfolute ways whereby Communication may be had both fecretly and fwiftly. I. Of fome Antient ways. 1. When Hifteus the Milefan was kept Prifoner by Darius, and defpairing of his return home, unless he could find out fome way to fend to Ariftagoras (who was his Substitute at Miletum) to perfwade his Revolt from Darius, but knowing that all Paffages were ftopt, and all Mefsengers strictly examined and fearched; he at length found out this (both tedious and weak) courfe. He got a trufty Servant of his, the Hair of whofe Head he caused to be shaved off, and then upon his bald Pate he writes his mind to Ariftagoras, keeping his Servant privately about him till his Hair was fomewhat grown, and then bad him hafte to Ariftagoras, and bad him caufe him to be fhaven again, and then upon his Head he fhould find what his Lord had writ unto him. 2. When Harpagus had a mind that Cyrus fhould haften his Invasion on Media (Cyrus being then in Perfia,)his Letter he fent to him he inclofed in the belly of a Hare. 3. The Lacedemonians used this way to communicate their Letters to their Generals abroad, which in cafe of Interception, the Contents should not be discovered. They had made two round Sticks or Cylinders of the fame length and thickness, one of which was delivered to the General when he fet forth, and the other was kept at home by the chief Magiftrate. When occafion was, they wound about the Stick a long narrow fcrowl of Paper or Parchment, in fuch manner, like the threads of a Screw, fo that the edges of the Paper or Parchment fhould always lie clofe together; the Paper thus fitted to the Stick (or Cylinder) they wrote their Letters upon the tranfverfe junctures of the Paper, fo that one part of each Word or Letter was in one place, and the other in an other: When they had finished their Writing, they took off the fcroll and fent it to the General, who knew how to apply it; and if it had been intercepted, the Enemy could make nothing of it; and this manner of Writing they called Scytale. 4. The Milefians used to Write their Letters, and inclose them in a Cake, or Loaf of Bread. 5. The Romans into the hilt or fcabord of a Sword. 6. The Perfians used to fix them to Arrows, and fhoot them to places appointed near hand. 7. Torosthanes by a Pigeon, ftained with Purple, gave notice of his Victory at the Olympick Games, to his Father in Agina, the fame day that he obtained it. And this way of conveyance by Pigeons at great distances is of wonderful Celerity: For in Aleppo they have Pigeons which will fly (with Letters fixed to their Legs, or about their Necks) from Babylon to Aleppo in 48 hours, which is accounted 30 days journey. The manner of tutering their Pigeons is this: They take them when they fit on their Nefts, tranfporting them in open Cages, and return them with Letters; who will never give reft to their Wings until they come to their Young, But let this fufhce for fome of the ways ufed by the Antients, I will proceed now to more Artificial ways of effecting the fame. I. By the 24 Common Letters of the Alphabet. THE Letters of the Alphabet, by which you would reprefent your Mind to your Correfpondent, may be fo difpofed in the form of a Right Angled Parallelogram (with any Number of Cyphers, Intervals, or (rather) fuperfluous Letters between every fignificant Letter ;) fo that the Writing may be read by your Correfpondent any of thefe ways, which of them fhall he agreed upon between you; As, Defcending with 4 intervals. Afcending with 3 intervals. Defcending and Afcending alternately 2 inter, . Or, Direct with 7 intervals. 6(Horizontal-Retrograde 5 intervals. orizon ly in Lines Direct and Retrograde alternately 2 Inter. Retrograde and direct alternately 3 inter.] Example I As in Example. Suppofe that I would write to my Correfpondent thefe Words, II. III IV V VI VII VIII Wherefore I write it in Upright Columns defcending, with 4 Intervals: (Which my Correfpondent is fuppofed to know:) Wherefore I first make 4 Pricks, one under another, and under them I make the fift Letter of my intended Writing [y], under that four Pricks more, and under them the next Letter [], then two Pricks under, and (because your Column will hold no more Pricks below) two above in the next Column, and uuder them []; &c. As in the Parallelogram following. |