1 1 34 APPENDICES AND TABLES 



APPENDIX G 



USEFUL NUMBERS AND FORMULA 



Paris line = -088813783 inch. 



Cubic foot of water weighs 62-2786 Ib. avoirdupois at 62 Fahr. 



Cubic inch of water weighs 252-286 grs. at 62 Fahr. 



Gallon of water weighs 10 Ib. avoirdupois at 62 Fahr. 



1 gallon = 277-27384 cubic inches. 



Cubic foot of sea water weighs 63'96 Ib. 



Weight of sea water = 1-027 weight of fresh water. 



1 inch of rainfall = 100 tons per acre. 



Pressure of water in Ib. per sq. inch = '433 head of water. 



Expansion of water between 32 Fahr. and 212 Fahr. = -04775. 



Dip of horizon (including refraction) in nautical miles = 1-16 <v/height. 



Marks on hand lead-line for sea soundings 1, 2, and 3 fathoms, 1, 2, 

 and 3 tags of leather respectively ; 5 and 15 fathoms white rag ; 7 and 

 17 fathoms red rag ; 10 fathoms leather with hole in it ; 13 fathoms blue 

 rag ; 20 fathoms 2 knots : 30 fathoms 3 knots, &c. A small knot is placed 

 at intermediate 5 fathoms after 20 fathoms viz. at 25, 35, 45, &c. 



Pressure of wind in Ib. per sq. foot = 0'002288 (velocity in feet per 

 second) 2 . 



Areas and Volumes 



Area of triangle = base x perpendicular. 



Volume of wedge = area of base x perpendicular height. 



Volume of cone or pyramid = area of base x ^ perpendicular height. 



Surface of side of cone = circumference of base x length of side. 



Area of parabola = base x f height. 



Velocity of light = 186,377 statute miles per second. 1 



Wave-length of yellow light -= - - -- inch. 



4olOO 



Number of vibrations per second 508,961,293,000,000. 



Falling Bodies 



S, space fallen in feet ; V, velocity in feet per second ; g = 32-2 ; t, time 

 in seconds. 



2 /S = 8-025 A/S. 



Arithmetical Progression 



A, first term ; B, last term ; S, sum ; d, difference between terms ; n t 

 number of terms. 



1 Latest determination by Prof. Newcomb, of Washington. 



