A second Geometrical way.
First you must have exactly the diamet. of a shot that weigheth one pound, and then describe a Circle, whose diamet. shall be just equal thereunto; and Divide it into 4 Qua∣drants,
[illustration] geometrical diagram
The mariners magazine, or, Sturmy's mathematical and practical arts containing the description and use of the scale of scales, it being a mathematical ruler, that resolves most mathematical conclusions, and likewise the making and use of the crostaff, quadrant, and the quadrat, nocturnals, and other most useful instruments for all artists and navigators : the art of navigation, resolved geometrically, instrumentally, and by calculation, and by that late excellent invention of logarithms, in the three principal kinds of sailing : with new tables of the longitude and latitude of the most eminent places ... : together with a discourse of the practick part of navigation ..., a new way of surveying land ..., the art of gauging all sorts of vessels ..., the art of dialling by a gnomical scale ... : whereunto is annexed, an abridgment of the penalties and forfeitures, by acts of parliaments appointed, relating to the customs and navigation : also a compendium of fortification, both geometrically and instrumentally / by Capt. Samuel Sturmy.
About this Item
- Title
- The mariners magazine, or, Sturmy's mathematical and practical arts containing the description and use of the scale of scales, it being a mathematical ruler, that resolves most mathematical conclusions, and likewise the making and use of the crostaff, quadrant, and the quadrat, nocturnals, and other most useful instruments for all artists and navigators : the art of navigation, resolved geometrically, instrumentally, and by calculation, and by that late excellent invention of logarithms, in the three principal kinds of sailing : with new tables of the longitude and latitude of the most eminent places ... : together with a discourse of the practick part of navigation ..., a new way of surveying land ..., the art of gauging all sorts of vessels ..., the art of dialling by a gnomical scale ... : whereunto is annexed, an abridgment of the penalties and forfeitures, by acts of parliaments appointed, relating to the customs and navigation : also a compendium of fortification, both geometrically and instrumentally / by Capt. Samuel Sturmy.
- Author
- Sturmy, Samuel, 1633-1669.
- Publication
- London :: Printed by E. Cotes for G. Hurlock, W. Fisher, E. Thomas, and D. Page ...,
- 1669.
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This text has been selected for inclusion in the EEBO-TCP: Navigations collection, funded by the National Endowment for the Humanities.
- Link to this Item
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http://name.umdl.umich.edu/A61915.0001.001
- Cite this Item
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"The mariners magazine, or, Sturmy's mathematical and practical arts containing the description and use of the scale of scales, it being a mathematical ruler, that resolves most mathematical conclusions, and likewise the making and use of the crostaff, quadrant, and the quadrat, nocturnals, and other most useful instruments for all artists and navigators : the art of navigation, resolved geometrically, instrumentally, and by calculation, and by that late excellent invention of logarithms, in the three principal kinds of sailing : with new tables of the longitude and latitude of the most eminent places ... : together with a discourse of the practick part of navigation ..., a new way of surveying land ..., the art of gauging all sorts of vessels ..., the art of dialling by a gnomical scale ... : whereunto is annexed, an abridgment of the penalties and forfeitures, by acts of parliaments appointed, relating to the customs and navigation : also a compendium of fortification, both geometrically and instrumentally / by Capt. Samuel Sturmy." In the digital collection Early English Books Online 2. https://name.umdl.umich.edu/A61915.0001.001. University of Michigan Library Digital Collections. Accessed June 15, 2024.
Pages
Page 52
with 2 diamet. cutting each other in the Centor orthogonally. Then take the Chord of the whole Quadrant 90 degr. BC in your Compasses, and lay it from the Centor of the first Shot one pound D to 2,* 1.1 and so A 2 will be the Diameter of a Shot of 2 pound; Then extend the Compasses from 2 to the Chord C, and lay that distance from D to 3, so will A 3 be the Diameter of a Shot of 3 l. And so likewise extend the Compasses from 3 to C, it will reach from D to 4, and from 4 to C, and it reaches from D to 5, and from 5 to C, lay it still always from D to 6; and so continuing till you have proceeded as far as you will: You shall find that if AB were the Diameter of one pound, A 2 is the Diameter of 2 pound, and A 3 is the Diam. of 3 l. and A 4 the Diam. of 4 l. and A 5 the Diam. of 5 l. A 6 the Diam. of 6 l. and lastly, A 8 is the Diam. of 8 l. and so you may proceed in like manner infinitely.
Likewise having the Diameter of a Shot of any weight, the double of the Diam. is the Diam. of a Shot which weighs 8 times as much. Thus the double of A 1, which is A 8, makes the Diameter of a Shot of 8 pound; and so the double of A 2, which is the Diameter of a Shot of 2 l. makes A 16, the Diameter of a Shot of 16 pounds, that is 8 times 2 pounds; and so the double of A 3 makes the Diameter of a Shot of 24 pounds, and the double of A 4 makes the Diameter of a Shot of 32 pounds, four times 8 being 32; and so you may proceed as you please, and find the bigness of any Shot.
Notes
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* 1.1
The Diameter of a Shot of 1 pound is 1 Inch 94/100 parts.