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.

SECT. I. The Qualifications every Gunner ought to have, and the Properties, Duty, and Office of a Gunner.

HE ought to have skill in Arithmetick, to work any Conclusion by the single and double Rule of 3, to abstract both the Square and Cube Roots, and to be perfect in the Art of Decimal Arithmetick, and to be skilful in Geometry; to the end he may be able through his knowledge in these Arts, to measure heights, depthts, breadths and lengths; and to draw the Plot of any Piece of Ground, to make Artificial Fire-Works which are used in the time of War: A Gunner that hath a Charge ought to have in readiness all necessary things for his Artillery:

As Wheels, Axle-trees, Ladles, Rammers, Sheep-skins to make Spunges, Gun-powder, Shot, Tampions, Chain-Shot, Cross-bar-shot, Canvas, or Strong Paper to make Car∣tredges, Fire-works, Artificial Torches, Dark Lanthorns; again, to Mount and Dis∣mount Guns, Hand-spikes, Coyns, Budge-Barrels to carry Powder, and Baskets to carry Shot to your Piece. When leisure will permit, he is to choose good Match-cords, to Arm his Linstocks in readiness to light, for to give Fire, and also a pair of Caleper Com∣passes to measure the Diameters of Shot, or the Muzzle, or Base-ring, or the like; and also a small Brass pair of Scales and Weights, a Ruler divided into Inches, and 8 Parts in every Inch, for the ready measuring of Cartredges, how to fill them.

A Gunner should never be without such a Scale as this as I have here described, and to know the Use thereof perfectly; and thereby be ready to give a reasonable answer to any Man of any Question belonging to any sort of Ordnance used in England in a moment, as this Scale will do, as shall be shewn: He should always carry a pair of Compasses with him to measure the Diameter or Bore of any Piece; and also the length of the Cylinder within, the better to fit her with a Shot, and proportion a Charge.

A Gunner ought to know the Names, Length, Weight and Fortification of every Piece about the Chamber (that is as far as the Piece is Laden with Powder;) and be able to tell readily how much Powder is a due Charge for any Piece, what Shot is fit, how many Matrosses must attend the same, how many Horses or Oxen will draw the said Piece, or Men, if occasion be; He must be careful in making Choice of a sober honest Man, for the Yeoman of the Powder; and he must not beat up the Head of his Powder-Barrels with an Iron tool, but with a Wooden Mallet, which can never Fire the same: A Gunner ought to trie his Piece, to know whether it be true bored or not, to proportion his Charge according to the thinnest side of the Metal, and accordingly take his Obser∣vation at the Britch of the Piece, just over, where by his Art he finds the middle of the Bore within the Piece is; by which means a good Shot may be made out of a bad Piece.

Before he makes a Shot, he is to consider, that if the Piece lie point blank, or under Metal, he ought to put in a sufficient Wadd after the Shot, to keep it close to the Powder; for if it should not be close, but some distance between the Powder and Shot, the Piece will break in the vacant place; but in case you mount your Piece, put no Wadd after the Shot.

And one chief thing is to know very well how to Disport his Piece, be it either true bored, or not true bored, which he may try first.

When a fit Man is entertained, the Mr. Gunner (whom he serves,) should bring him to his Pieces, and give him the Denominations of his Piece, and parts thereof; which when he hath learned, which is the base-ring, and trunnion-ring, the mussel-ring, and the like, (you may see their names all plain in the Fig. of the Gun without more words;) and like∣wise the Crows, Handspikes, the Coyn, and the like; and how far in the Bore is called the Chamber of the Piece: These things, with the Gunner's care well understood, he may give them further Directions, (viz.) But it is great pity, that the Gunners at Sea did not exercise the Sea-men in this knowledge, as the Corporal doth in Mustering of them with their Musquets; for want of the like knowledge, the greatest part of common Sea-men, are as dull and ignorant, when they be required to stand by a great Gun in time of Fight; and therefore it would be much for the Credit and Honour of our En∣glish Nation, to train up their Sea-men in this knowledge especially; but it is taken no∣tice of, that if any man have any Art above another, he is afraid to let another see him do any thing, or understand from him such knowledge, for fear he will be in a short time as able as himself; which many do attain unto in a short time to be as able as himself with∣out their help; therefore it is more for their Credit to teach them what they know.