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. VII. To find what proportion is between Bullets of Iron, Lead, and Stone, by knowing the weight of one Shot of Iron; to find the weight of any other Shot of Lead, Brass, or Stone of the like Diameter.

THe proportion between Lead and Iron, is as 2 to 3, so that a shot of 2 pound of Iron, is of like diameter or height as 3 l. of Lead.

As for Example.

A shot of 6 Inches diameter weighs 30 pound, to find the weight of a shot of Lead of the same diameter.

By the Rule of Proportion.

First, if 2 gives 30, what will 3 give? multiply and divide, and the Quotient is 45,* 1.1 the weight of a shot of Lead.

By the Tables, the Logarithm of 2 is	03010300
The Logarithm of 30 is	14771212
The Logarithm of 3 is	04771212
Add the 2 lowermost, the sum is	19542424

Substract the upper Num. the Remain is the

Log. of 45 l. the weight of the shot in Lead of the same diam.

16532124

Extend the Compasses from 2 to 30, the same distance shall reach from 3 to 45; (In like manner work by the rest following.* 1.2)

The porportion between Iron and Stone, is as 3 to 8; so that a shot of 30 pound of Stone, is as big as the like shot of 80 l. of Iron; and 11 l. ¼ of Stone, is of the same diameter 6 Inches, as a shot of 30 l. of Iron and 45 l. of Lead; the proportion between Lead and Stone, is as 4 to 1; so that one shot of Lead of 40 l. is of the height as a Stone shot of 10 l.

The proportion between Lead and Brass, is as 24 to 19,

The proportion between Iron and Brass, is as 16 to 18.

By these Rules aforegoing you may Calculate with ease, if Iron shot be wanting, and the other to be had, what height and weight either shot of Lead, Brass, or Stone, ought to be of to fit any Pieces of Ordnance; and by the same Rules here is a Table faithfully Calculated; and doth shew the weight of any shot of Lead, Iron, and Stone, from 2 Inches diam. to 8 Inches, and Quarters of Inches; the proper Stone for this purpose is Marble, Pibble, Blew hand Stone; (there may be a little difference of weight in some sort of Stone: but these do neer agree in weight; you must remember in load∣ing your Piece with a Shot of stone, you must not have so much Powder as you do with Iron-shot, but abate according to proportion, as is between Stone and Iron.

Inches.	Quart.	Iron. Poun. Ounc.	Lead. Poun. Oun.	Stone. Poun. Oun.
2		1 1	1 10 ½	0 7
2	1	1 9	2 6	0 9
2	2	2 2	3 3	0 12
2	3	2 14	4 5	1 1
3		3 12	5 10	1 7
3	1	4 12	7 2	1 13
3	2	6 0	8 15	2 4
3	3	7 5	11 .00	2 12
4		8 15	13 07	3 6
4	1	10 10 ½	16 0	4 0
4	2	12 10½	18 15	4 12
4	3	14 14	22 5	5 9
5		17 05	26 2	6 8
5	1	20 1	30 2	7 8
5	2	23 2	34 11	8 11
5	3	26 6	39 9	9 14
6		30 00	45 00	11 04
6	1	34 00	51 00	12 12
6	2	38 00	57 00	14 04
6	3	42 00	62 00	15 12
7		48 00	72 00	18 00
7	1	53 00	79 08	20 00
7	2	58 00	87 00	22 12
7	3	64 00	96 00	24 00
8		71	106 8	26 10

The use of the Table, to find the weight of any Shot of Iron, Lead, or Stone from 2 to 8 Inches Diameter.

This Table is exactly Calcu∣lated, and the use thereof is very easy; we will make it plain by two Examples; I would know of Shot of 6 Inches, their weight in Iron, Lead, and Stone: the first Column is Inches, the second Quarters of Inch. the third Poun. and Ounc. of Iron, fourth Pounds and Ounces of Lead, fifth Poun. and Ounces of Stone.

Enter the Table with 6 Inches diam. in the first Column, and in that Line you shall have 30 poun. of Iron, 45 pound of Lead, 11 pound 4 ounces of Stone, the weight of 6 Inches diam. And likewise, for 4 Inches ¾ diam. the weight of an Iron Shot is 14 pound, 14 ounc. of Lead 22 pound 5 ounces, of Stone 5 pound 9 ounces; and so of the rest.

Notes

• * 1.1

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• * 1.2

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