 The First Book of the Cross-Staff Heading Page File CHAP. I. Of the Description of the Cross-Staff 199 2 1. Description of Lines 199 2 CHAP. II. The Use of the Line of Inches for perpendicular heights and distances 202 4 1. To find an height at one Station, by knowing the distance 202 4 2. To find the height by knowing some part of the same height. 203 4 3. To find an height at two stations, by knowing the difference of the same stations. 203 4 4. To find a distance, by knowing the height. 204 5 5. To find a distance, by knowing part of the height. 204 5 6. To find a distance at two stations, by knowing the difference of the same stations. 204 5 7. To find a breadth, by knowing the distanceperpendicular to the breadth. 205 5 8. To find a breadth at two stations in a Line perpenducular to the breadth, by knowing the difference of the same stations. 205 5 CHAP. III. The Use of Tangent Lines to taking Angles. 207 6 1. To find an Angle by the Tangent on the Staff 207 6 2. To find an Angle by the Tangent of 20 upon the Cross. 208 7 3. To find an Angle by the Tangent of 30 upon the Cross. 208 7 4. To observe the altitude of the Sun backward. 208 7 5. To set the Staff to any Angle given. 209 7 6. To observe the Altitude of the Sun another way. 209 7 7. To observe an Altitude by Thread and Plummet. 209 7 8. To apply the Lines of Inches to the taking of Angles. 208 7 CHAP. IV. The use of Lines of equal parts joyned with the Lines of Chords. 210 8 CHAP. V. The Use of the Meridian Line. 212 9 CHAP. VI The Use of the Line of Numbers. 216 11 1. Having two numbers given, to find a third in continual proportion, a fourth, a fifth, and so foreward. 216 11 2. Having two extreme Numbers give,, to find a mean proportional between them. 217 11 3. To find the square Root of any Number given. 217 11 4. Having two extreme Numbers given, to find two mean Proportionals between them. 218 12 5. To find the Cubic Root of a Number given. 218 12 6. To multiply one number by another. 218 12 7. To divide one Number by another. 219 12 8. Three Numbers being given, to find a fourth Proportional. 219 12 9. Three Numbers being given, to find a fourth in a duplicate proportion. 219 12 10. Three Numbers being given, to find a fourth in a triplicate proportion. 220 13 CHAP. VII. The use of the Line of Artifcial Sines. 221 13 CHAP. VIII. The use of the Line of Artificial Tangents. 222 14 CHAP. IX. The use of the Line of Sines and Tangents joyned with the Line of Numbers. 224 15 1. Having three Angles and one side, to find the other two sides. 224 15 2. Having two sides given, and one Angle opposite to either of these sides, to find the other two Angles and the third side. 226 16 3. Having two sides and the Angle between them, to find the two other Angles and the third side. 227 16 4. Having the three sides of a right Line Triangle, to find the three Angles. 229 18 5. Having the Semidiameter of a Circle, to find the Cord of the Ark. 230 18 CHAP. X. The use of the Line of versed Sines. 231 18 The Second Book of the Cross-Staff 233 19 CHAP. I. The use of the Line of Numbers in broad measure, such as Board, Glass, and the like. 234 20 SECT. I. Of the Mensuration of Oblong Superfacies, and Triangles. 235 20 1. Having the breadth and length of an Oblong Superfacies given in Inch-measure, to find the content in Inches. 235 20 2. Having the breadth and length of an Oblong Superfacies given in Inch-measure, to find the content in Feet. 236 21 3. Having the breadth and length of an Oblong Superfacies given in foot-measure, to find the content in Feet. 236 21 4. Having the breadth of an Oblong Superfacies given in inches, and the length in foot measure, to find the content in Feet. 236 21 5. Having the breadth of an Oblong Superfacies given in inches, to find the length of a foot superfacial in inches. 236 21 6. Having the breadth of an Oblong Superfacies given in feet, to find the length of a foot superfacial in foot measure. 237 21 ☞ 7. A four sides Superficies having any of the two sides Parallel, to find the Area. 237 21 ☞ 8. To find the Area or content of a Triangle, the longest side and the Perpenducular being given. 237 21 ☞ 9. The side of an Equilateral Triangle being given, to find the Area. 238 22 ☞ 10. To find the Area of a four sided figure, whose sides are neither equal nor parallel one to the others, which figures are called Trapezias. 238 22 ☞ 11. Having the breadth and length of an Oblong Superficies, to find the side of a Square euqla to the Oblong. 239 22 SECT. II. Of the Mensuration of Regular Polygons. 240 23 ☞ 1. The side and the Perpendicular of a Pentagon being given, to find the Area. 240 23 ☞ 2. The side and the Perpendicular of an Octagon (or figure of 8 sides) being given, to find the Area. 241 23 SECT. III. Of the Mensuration of Circles. 241 23 ☞ 1. The Diameter of the Circle being given, to find the Circumference. 241 23 ☞ 2. The Circumference of a Circle being given, to find the Diameter. 242 24 ☞ 3. the Diameter of a Circle being given, to find the Area. 242 24 ☞ 4. The Area of a Circle being given, to find the Diameter. 242 24 ☞ 5. The Circumference of a Circle being given, to find the Area. 243 24 ☞ 6. The Area of a Circle being given, to find the Circumference. 243 24 ☞ 7. Having the Diameter of a Circle, to find the side of a Square equal to that Circle. 243 24 ☞ 8. Having the Circumference of a Circle, to find the side of a Square equal to the same Circle. 244 25 SECT. IV. Of the Mensuration of Land by Perch and Acres. 244 25 1. Having the breadth and length of an Oblong Superfacies given in Perches, to find the content in Perches. 244 25 2. Having the breadth and length of an Oblong Superfacies given in Perches, to find the content in Acres. 244 25 A table for the Use of the Chain. 245 25 3. Having the breadth and length of an Oblong Superfacies given in Chains, to find the content in Acres. 246 26 4. Having the Perpenducular and Base of a Triangle given in Perches, to find the content in Acres. 246 26 5. Having the Perpendicular and Base of a Triangle given in Chains, to find the content in Acres. 246 26 6. Having the content of a Superficies after one kind of Perch, to find the content of the same Superficies, according to another kind of Perch. 247 26 7. Having the plot of a Plane with the content ion Acres, to find the Scale, by which it was plotted. 247 26 8. Having the length of a Furlong, to find the breadth of the Acres. 247 26 CHAP. III. The use of the Line of Numbers in solid measure, such as Stone, Timber, and the like. 248 27 SECT. I. Of the Mensuration of Regular Solids. 248 27 1. Having the side of a Square euqal to the base of any Solid given in inch measure, to find the length of a foot Solid in inch measure. 248 27 2. Having the side of a Square euqal to the base of any Solid given in foot measure, to find the length of a foot Solid in inch measure. 249 27 3. Having the breadth and depth of a squared Solid given in foot measure, to find the length of a foot solid in foot measure. 249 27 4. Having the breadth and depth of a squared Solid given in inches, to find the length of a foot solid in inch measure. 246 28 5. Having the side of a Square equal to the Base of any Solid, and the length thereof given in inch measure, to find the content thereof in feet. 247 28 6. Having the side of a Square equal to the Base of any Solid, and the length thereof given in foot measure, to find the content thereof in feet. 247 28 7. Having the side of a Square equal to the Base of any Solid given in inch measure, and the length of the Solid in foot measure, to find the content thereof in feet. 247 28 8. Having the length, breadth, and depth of a squared Solid given in inches, to find the content in inches. 248 29 9. Having the length, breadth, and depth of a squared Solid given in inches, to find the content in feet. 248 29 10. Having the length, breadth, and depth of a squared Solid given in foot measure, to find the content in feet. 248 29 11. Having the length and breadth of a squared Solid given in inches, and the length in foot measure, to find the content thereof in feet. 248 29 SECT. II. Of the Mensuration of Cylinders. 251 30 1. Having the Diameter of a Cylinder given in inch measure, to find the length of a foot Solid in inches. 251 30 2. Having the Diameter of a Cylinder given in foot measure, to find the length of a foot Solid in foot measure. 251 30 3. Having the Circumference of e Cylinder given in inches, to find the length of a foot Solid in inch measure. 251 30 4. Having the Circumference of e Cylinder given in foot measure, to find the length of a foot Solid in inch measure. 252 31 5. Having the side of a Square equal to the Base of a Cylinder, to find the length of a foot Solid. 252 31 6. Having the Diameter of a Cylinder, and the length given in inches, to find the content in inches. 252 31 7. Having the Diameter and length of a Cylinder in foot measure, to find the content in feet. 253 31 8. Having the Diameter of a cylinder, and the length given in inches, to find the content in feet. 253 31 9. Having the Diameter of a Cylinder, given in inches, and the length in feet, to find the content in feet. 253 31 10. Having the Circumference and length of a Cylinder given in inches, to find the content in inches. 254 32 11. Having the Circumference and length of a Cylinder given in inches, to find the content in feet. 254 32 12. Having the Circumference and length of a Cylinder given in foot measure, to find the content in feet. 254 32 13. Having the Circumference of a Cylinder given in inches and the length in foot measure, to find the content in feet. 254 32 SECT. III. Of the Mensuration of Cones. 255 32 ☞ 1. The Diameter of the base and the length of the side of a Cone being give, to find the superficial content thereof. 255 32 ☞ 2. The Diameter and Axis of a right Cone being given, to find the Solid Content. 255 32 SECT. IV. Of the Mensuration of Spheres. 256 33 ☞ 1. The Diameter of a Sphere being given, to find the Superficial content. 255 32 ☞ 2. The Superficies of a Sphere being given, to find the Axis. 255 32 ☞ 3. The Axis of a Sphere being given, to find the Solid Content. 256 32 ☞ 4. The Solidity of a Sphere being given, to find the Axis. 256 32 SECT. V. Of the Mensuration of Prisms. 257 32 ☞ 1. To find the Solid content of a Triangular Prism. 257 32 ☞ 2. To find the Solid content of a Regular Solid, whose sides at the end thereof are equal and more than 3. As 4, 5, 6, 7, 8, 10 &c. 258 33 SECT. VI. ☞Of the Mensuration of Pyramides. 259 33 SECT. VII. ☞Of the Mensuration of Frustrums or Segments of Pyramides or Cones. 259 33 CHAP. IV. The use of the Line of Numbers in Gauging of Vessels. 261 35 1. Having the Diameter and length of a Vessel with the content thereof, to find the Gauge point. 262 36 2. Having the mean Diameter, and the length of a Vessel, to find the content. 262 36 3. Having the Diameter and Content, to find the length. 263 36 4. Having the length of a Vessel, and the content, to find the Diameter. 263 36 CHAP. V. Containing such Astronomical Propositions as are of ordinary use in the practice of Navigation. 263 36 1. To find the Altitude of the Sun by the shadows on a Gnomon set Perpendicular to the Horizon. 263 36 2. Having the distance of the Sun, from the next Equinoctial point, to find his declination 264 37 3. Having the Latitude of a place, and the Declination of the Sun, to find the time of the Suns rising and setting. 264 37 4. Having the Latitude of a place, and the distance of the Sun, from the next Equinoctial point, to find his Amplitude. 265 37 5. Having the Latitude of a place, and the Declination of the Sun, to find his Amplitude. 265 37 6. Having the Latitude of a place, and the Declination of the Sun, to find the time when the Sun cometh to be due East or West. 266 38 7. Having the Latitude of a place, and the Declination of the Sun, to find what Amplitude the Sun shall have, when he cometh to be due East or West. 266 38 8. Having the Latitude of a place, and the Declination of the Sun, to find what Altitude the Sun shall have at the hour of six. 267 38 9. Having the Latitude of a place, and the Declination of the Sun, to find what Azimtuh the Sun shall have at the hour of six. 267 38 10. Having the Latitude of a place, and the Declination of the Sun, and the Altitude of the Sun, to find the Azimuth. 267 38 11. Having the Latitude of a place, and the Declination of the Sun, and the Altitude of the Sun, to find the hour of the day. 270 40 12. Having the Azimuth, the Suns Altitude, and the Declination, to find the hour of the day. 271 40 13. Having the hour of the day, the Suns Altitude, and the Declination, to find the Azimuth. 271 40 14. Having the distance of the Sun from the next Equinoctial point, to find his right Ascension. 271 40 15 Having the Declination of the Sun, to find his right Ascension. 272 41 16. Having the Longitude and latitude of a Star, to find the right Ascension of that Star. 272 41 17. To find the Declination of that Star. 272 41 CHAP. VI Containing such nautical questions, as are of ordinary use, concerning Longitude, Latitude, Rumb, and Distance. 280 46 1. To keep an account of the Ships way. 280 46 2. By the Latitude and differences of Longitude, to find the distance upon a course of East or West. 282 47 3. By the Latitude and distance upon a course of East or West, to find the difference of Longitude. 282 47 4. The Longitude and Latitude of two places being given, to find the Rumb leading from the one to the other. 284 48 6. By the Rumb and both Latitudes, to find the distance upon the Rumb. 286 49 7. By the distance and both Latitudes to find the Rumb. 286 49 8. By one Latitude, Rumb, and distance, to find the difference of Latitudes. 287 49 9. by the Rumb and both Latitudes, to find the difference of Longitude. 287 49 10. By the Rumb and both Latitudes, to find the distance belonging to the Chart of Mercators Projection. 288 50 11. By the way of the ship, and two Angles of position, to find the distance between Ship and Land. 289 50 12. By knowing the distance between two places on the Land, and how they bear one from the other, and having the Angles of Position at the Ship, to find the distance between the Ship and the Land. 291 51 PROBL. I. The course and distance that the Ship hath run or sailed, being given, to find the true place or point where the Ship is in Mercators Chart. 294 53 PROBL. II. The course that the Ship hath sailed on, and both Latitudes being know, to find the true place or point that the Ship is on in Mercators Chart, and the true distance that the Ship hath sailed. 296 54 PROBL. III Both the Latitudes given, and the distance run upon a Course, to find the point or place that the Ship is on in Mercators Chart, and the course or point of the Compass that the Ship hath sailed on. 296 54 PROBL. IV. Both Latitudes, and the departure or distance of the Meridian you are upon, and the Meridian you began yours course on, to find the point or place where you are in Mercators Chart, also the course that you have made godd, and the distance that you have run from the place, where you began your course. 297 54 PROBL. V. Both latitudes being given, and the difference of Longitude, to find the distance the Ship hath kept, and the distance it hath run. 298 55 PROBL. VI. One Latitude, with the course, and the difference of Longitude given, to find the other Latitude, and distance run. 298 55 An Appendix Concerning the description and use of an Instument, made in form of a Cross-bow, for more easie finding of the Latitude at Sea. 299 55 1. The day of the month being known, to find the declination of the Sun. 301 56 2. The declination being given, to find the day of the month. 301 56 3. To find the Altitude of the Sun, or Star. 302 57 4. To find any North Latitude, by the Meridian Altitude of the Sun at a forward observation, knowing either the day of the month, or the declination of the Sun. 302 57 5. To find any North latitude, by the Meridian Altitude of the Stars to the Southward. 303 57 6. To find any North latitude, by the Meridian Altitude of the Stars to the Northward. 303 57 7. To find any South Latitude, by the Meridian Altitude of the Sun at a forward observation, knowing either the day of the month, or the declination of the Sun. 305 58 8. To find any South latitude by the Meridian Altitude of the Stars to the Northward. 305 58 9. To observe the Altitude of the Sun by the Bow, or with an Astrolabe. 305 58 10. To find the South latitude by the Meridian Altitude of the Stars to the Southward. 306 59 11. To observe the Altitude of the Sun backward. 306 59 12. To find any North Latitude by the Meridian Altitude of the Sun at a back observation, knowing either the day of the month, or the declination of the Sun. 307 59 13. To find any South Latitude by the Meridian Altitude of the Sun at a back observation, knowing either the day of the month, or the declination of the Sun. 307 59 14. To find the day of the month, by knowing the Latitude of the place, and observing the Meridian Altitude of the Sun. 308 60 15. To find the declination of any unknown Star, and so to place it on the Bow, knowing the Latitude of the place, and observing the Meridian Altitude of the Star. 308 60 16. To find any North latitude on land by observation with Thread and Plummet. 308 60 17. To find any Latitude on Land, by observation with Thread and Plummet. 309 60 ☞ (Table of) The right Ascension of these Stars is to the year 1670. 309 60 FINIS 311 61 The Third Book of the Cross-Staff The use of the Line of Numbers, Sines and Tangents for the drawing of Hour-lines on all sorts of Planes. 1 1 To describe the Fundamental Diagram 3 2 To find the Inclination of any Plane. 5 3 To find the Declination of a Plane. 6 4 CHAP. I. To draw the Hour-lines in an Equinoctial plane. 9 5 CHAP. II. To draw the Hour-lines in a Direct Polar Plane. 10 6 CHAP. III. To draw the Hour-lines in a Meridian Plane 14 8 CHAP. IV. To draw the Hour-lines in an Horizontal Plane. 15 8 CHAP. V. To draw the Hour-lines in a Vertical Plane. 19 10 CHAP. VI. To draw the Hour-lines in a Vertical Inclining Plane. 21 11 CHAP. VII. To draw the Hour-lines in a Vertical Declining Plane. 24 12 1. To find the Height of the Pole above the Plane. 26 14 2. To find the Distance of the Substylar from the Meridian. 26 14 3. To find the Distance of each Hour-line from the Substylar. 27 14 4. To find the Inclination of the Meridians. 26 15 A Second Example 31 17 A Third Example, of a Plane falling near a Meridian. 32 17 CHAP. VIII. To draw the Hour-lines in a Meridian Inclining Plane. 37 19 CHAP. IX. To describe the Hour-lines in a Polar Declining Plane. 42 22 1. The Ark of the Plane between the Horizon and the Pole. 43 22 2. The Installation of the Meridian of the Plane to the Meridian of the Place. 44 23 CHAP. X. To draw the Hour-lines in a Declining Inclining Plane. 47 24 A Second Example of a Plane falling between the Pole and the Zenith. 53 27 A Third Example of a Plane Inclining to the Southward. 54 28 CHAP. XI. To Describe the Tropicks and other Circles of Declination in an Equinoctial Plane. 55 28 CHAP. XII. To Describe the Tropicks and other Circles of Declination in a Polar Plane. 57 29 CHAP. XIII. To Describe the Tropicks and other Circles of Declination in such a Plane as is neither Equinoctial nor Polar. 63 32 1. To Proportion the Style unto the Plane. 65 33 2. Having the Length of the Axis, and the Height of the Style above the Plane, to find the Length of the Sides of the Style. 67 34 3. To find the Distance between the Center and the Equator upon the Substylar Line. 67 34 4. To find the Angles contained between the Equator and the Hour-lines upon your Plane. 68 35 5. To find the Distance between the Center and the Parallels of Declination. 69 35 CHAP. XIV. To Describe the Parallels of the Sines in any of the former Planes. 71 36 CHAP. XV. To Describe the Parallels of the length of the Day in any of the former Planes. 71 36 CHAP. XVI. To draw the Old Unequal Hours in the former Planes. 74 38 CHAP. XVII. To draw the Hours from Sun-rising to Sun-setting in the former Planes. 76 39 CHAP. XVIII. To draw the Horizontal Line in the former Planes. 77 39 CHAP. XIX. To Describe the Vertical Circles in the former Planes. 79 40 1. To find the distance between the Foot of the Style and the Vertical Point. 81 42 2. To find the distance between the Foot of the Style and the Horizontal-line. 82 42 3. To find the Angles made by the Azimuth-lines at the Vertical Point. 82 42 CHAP. XX. To Describe the Parallels of the Horizon in the former Planes. 85 43 1. To find the distance between the top of the Style, and the several Points wherein the Azimuths do cross the Horizontal-lines. 44 2. To find the distance between the Horizon and the Paralles. 89 45 1. To find the length of the Axis of the Horizon. 91 46 2. To find the Angles contained between the Horizon and the Vertical Lines upon the Plane. 91 46 3. To find the distance between the Vertical Points, and the Parallel of the Horizon. 94 48 4. To describe such Parallels on the former Planes, as may shew the proportion of the Shadow unto the Gnomon. 95 49 An Appendix concerning the Description and Use of a small Portable Quadrant, For the more easie finding of the Hour and Azimuth, and other Astronomical and Geometrical Conclusions. 96 49 CHAP. I. Of the Description of the Quadrant. 97 49 CHAP. II. Of the Use of the Quadrant, in taking the Altitude of the Sun, Monn, and Stars. 113 57 CHAP. III. Of the Ecliptick. 114 58 1. The Place of the Sun being given, to find the Right Ascension. 114 58 2. The Right Ascension being give, to find his Place to the Ecliptick. 114 58 CHAP. IV. Of the Line of Declination. 115 58 1. The Place of the Sun being given, to find his Declination. 115 58 2. The Declination of the Sun being given, to find his Place in the Ecliptick. 115 58 CHAP. V. Of the Circle of Months and Days. 115 58 1. The Day of the Month being give, to find the Altitude of the Sun at Noon. 116 59 2. The Meridian Altitude being given, to find the day of the Month. 116 59 CHAP. VI. Of the Hour-lines. 117 59 1. The day of the Month, or the Height at Noon being known, to find the Place of the Sun in the Ecliptick. 117 59 2. The Place of the Sun in the Ecliptick being known, to find the Day of the Month. 118 60 3. The Hour of the day being given, to find the Altitude of the Sun above the Horizon. 118 60 4. The Altitude of the Sun being given, to find the Hour of the day. 120 60 5. The Hour of the Night being given, to find how much the Sun is below Horizon. 120 60 6. The Depression of the Sun supposed, to give the Hour of the Night with us, or the Hour of the Day to our Antipodes. 120 61 7. The time if the Year, or the place of the Sun being given, to find the beginning of Day-break, and the end of Twiligth. 120 61 CHAP. VII. Of the Horizon. 121 61 1. The Day of the Month, or the Place of the Sun being known, to find the Amplitude of the Suns Rising and Setting. 121 62 2. The Day of the Month, or the Place of the Sun being given, to find the Ascensional Difference. 121 61 CHAP. VIII. Of the Five Stars. 122 62 The Altitude of any of these five Stars being known, to find the Hour of the Night. 122 62 CHAP. IX. Of the Azimuth-lines. 124 63 1. The Azimuth whereupon the Sun beareth from us being known, to find the Altitude of the Sun above the Horizon. 124 63 2. The Altitude of the Sun being given, to find on what Azimuth he beareth from us. 125 63 CHAP. X. Of the Quadrat. 125 63 1. Any point being given, to find whether it is level with the Eye. 126 64 2. To find an Height above the Level of the Eye, or a Distance at one observation. 126 64 3. To find a Height, or a Distance at two Observations. 127 64 A Second Appendix Concerning the Description and Use of another Quadrant, fitted for daily Practice; For finding the Hour and Azimuth, and other things.... 128 64 Invented by Mr. Sam. Foster 129 65 The Description of the Quadrant 129 65 How to Inscribe the Additional Lines upon the Quadrant 131 66 1. For the Lines on the Fortside. 131 66 2. For the Lines on the Backside. 133 67 The Uses of the Quadrant. 135 68 1. To find the Suns Declination. 135 68 2. To rectifie the Bead for Observation of Hour or Azimuth; and to perform those things that are done by the usual Lines upon the Quadrant. 136 69 3. To find when Twilight begins in the Morning, and ends at Evening; which Moments are the two utmost Terms of Dark Night. 138 70 4. To find the Suns Ascensional Difference &c. 139 70 5. To find the Suns Amplitude, &c. 139 70 6. Having the Declination of an upright Plane, to find the elevation of the Style, &c. 139 70 7. To find the Deflection, &c. 140 71 8. To find the Difference of Longitude, &c. 140 71 9. To make an Horizontal Dial. 140 71 10. To find what Angle any Hour-circle maketh with the Horizon, or any Azimuth maketh with the Equinoctial. 141 71 11. To find what Ark of any Hour-circle is intercepted between the Equinoctial (or any Parallel) and the Horizon. 141 71 12. How high the Sun shall be upon any Azimuth, and in any Declination. 142 72 13. To find how high the Sun shall be at any Hour, and in any Declination. 144 73 14. To find the Suns Azimuth. 144 73 15. To find the Hour of the Day by the Sun. 146 74 16. To find the Declination of a Plane. 147 74 17. How to draw an upright declining Dial. 148 75 18. Of the upright full South-Dial. 150 76 19. Of upright far declining Planes. 150 76 20. Concerning the forming and the placing of the Stile. 152 77 21. Of the East and West upright Dial. 154 78 For the Stile. 154 78 22. In East and West Re-incliners, to get the Deflection. 156 79 23. To find the Angle between 12 and 6. 156 79 24. To get the Stiles elevation. 156 79 25. To find the Difference of Longitude. 156 79 26. How to draw the Dial. 157 79 27. To make the Horizontal Dial to any Latitude. 158 80 28. To find the Hour of the Night by the Stars. 159 80 To use the Altrimetrick Scale 161 81 1. To find any Height at one Observation. 161 81 2. To find part of an Altitude. 162 82 3. Standing upon a known Height to find a Distance. 162 82 4. To find part of a Distance. 163 82 5. To find a Height at two Observation. 163 82 Finis 164 83   © Rainer Stumpe URL: http://www.rainerstumpe.de