Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

 USEFUL DATA RELATING r TO DIVING.* WATER. Its Weight. A cubic foot of salt water weighs 641bs. A cubic foot of -fresh water weighs 6 2-51bs. Pressure. Every one foot height of salt water increases the pressure 3V nearly Jib. on the square inch. A column of salt water 33 feet high presses on the bottom with a pressure of about i 51bs. per square inch, or one atmosphere. A column of water 27 inches high = about ilb. pressure per square inch. A ton of fresh water = 35.90 cubic feet = 224 gallons. A ton of sea water = 35 cubic feet = 2i8| gallons. Boiling Point 212 deg F. = too Centigrade. Freezing Point 32 deg. F. = Zero Centigrade. The following table gives the additional pressure above atmospheric pressure per square inch for every fathom of depth (salt water), with the nearest equivalents in metres and kilogrammes per square centimetre respectively : — Lbs. pressure Kilograms Fathoms. Lbs. pressure Kilograms Fathoms. Feet. Metres. per square per square Feet. Matres. per square per square inch. centimetre inch. centimetre — 1 6 1.8 2.7 0.19 26 156 47.6 69,4 4.88 2 12 3.6 5.3 0.37 27 162 49 4 72.0 5.06 3 18 5.5 8.0 0.56 28 168 51.2 74.7 5.25 4 24 7.3 10.7 0.75 29 174 53.0 77.3 5.45 5 30 9.1 13.3 0.93 30 180 54.9 80.1 5.60 6 36 11.0 16.0 1.12 31 186 56.7 82.8 5 80 7 42 12.8 18.7 1.32 32 192 58.5 85.4 6.00 8 48 14.6 21.3 1.50 33 198 (50.3 88.1 6.20 9 54 16.5 24.0 1.70 34 204 62.2 90.7 6.37 10 60 18.3 26.7 1.87 35 210 64.0 93.4 6.50 11 66 20.1 29.3 2.06 36 216 65.8 96.1 6.75 12 72 21.9 32.0 2.25 37 222 67.6 99.0 6.90 13 78 23.8 31.7 2.45 38 228 69.6 101.4 7.12 14 84 25.6 37.4 2.62 39 234 71.3 104.0 7.30 15 90 27.4 40.0 2.82 40 240 73.1 107.0 7.50 16 96 29.3 42.6 3.00 41 246 75.0 109.4 7.70 17 102 31.1 45.2 3.17 42 252 76 8 112.0 7.87 18 108 32.9 48.0 3.37 43 258 78.6 114.7 8.06 19 114 34.7 50.7 3.57 44 264 80.5 117.3 8.25 20 120 36.6 53.4 3.75 45 270 82.3 120.1 8.43 21 126 38.4 56.1 3.90 46 276 84.1 122.7 8.62 22 132 40.2 58.7 4,12 47 282 85.9 125.3 8.80 23 138 42.0 61.4 4.32 48 288 87.8 128.0 9.00 24 144 43.9 64.0 4.5 49 294 89.6 130.6 9.13 25 150 45.7 66.7 4.68 50 300 91.4 133.3 9.37 * The figures given may be assumed sufficiently accurate for all practical purposes. 93