S I P 



contain only a load and a half of timber, and that every acre contains 35 

 trees fit for naval purposes j this gives 57 acres of land for a 7-1 gun ship. 

 See Report of the Board of Commissioners of Woods and Forests, 1812. 



SHOT, pile of. 



Shot or shells are usually piled up in a pyramidal form, the base being 

 an equilateral triangle, square, or rectangle. 



The following formulae give the total number of balls in any of these 

 piles : 



Triangular pile = J- ( + 'J ( +JJ. 



Rectangular pile = aJ^LLg-+ D 



Where n in the two first formulae denotes the number of balls in the 

 side of the base ; and in the last n is the number of balls in the length of 

 the base, and m the number of those in the breadth. 



SHOT, weight of.(Hutton.) 



Let W be the weight in pounds, 5 diameter in inches, then 



In iron balls, W = ^ X &. 



Dfc 



In leaden, W = ~ X S 3 . 

 In iron shells, if D and & be the external and internal diameters, W 



= ~ X (1)3 - S3.) 



SHOT. See Gunnery. 



SIDEREAL time. See Time. 



SINES, figure of. See Figure. 



SINES, arithmetic of. See Trigonometry. 



SIPHON, oscillatory motion of water in. (Play fair.) 



1. Let an inverted siphon, partly filled with water, be composed of 



three rectilinear tubes of equal diameters, of which the intermediate one 



IB horizontal, and the two others inclined to the horizon at any angles 



, 0> ; and let an oscillatory motion be communicated to the water; re* 



265 P3 



