Sea Scale. Wind. Land Scale. ---------- ----- ----------- 0 to 3 = Light = 0 to 1 3 " 5 = Moderate = 1 " 2 5 " 7 = Fresh = 2 " 3 7 " 8 = Strong = 3 " 4 8 " 10 = Heavy = 4 " 5 10 " 12 = Violent = 5 " 6 Pressure in Velocity in Pounds (Land Scale). Miles (Avoirdupois) (Hourly). ------------- --------- ----------- 1/2 = 1 = 10 5 = 2 = 32 10 = 3 = 45 21 = 4 = 65 26 = 5 = 72 32 = 6 = 80 5. Letters to Denote the State of the Weather. _b_ denotes blue sky, whether with clear or hazy atmosphere. _c_ " cloudy, that is detached opening clouds. _d_ " drizzling rain. _f_ " fog. _h_ " hail. _l_ " lightning. _m_ " misty, or hazy so as to interrupt the view. _o_ " overcast, gloomy, dull. _p_ " passing showers. _q_ " squally. _r_ " rain. _s_ " snow. _t_ " thunder. _u_ " ugly, threatening appearance of sky. _v_ " unusual visibility of distant objects. _w_ " wet, that is dew. A letter repeated denotes much, as _r r_, heavy rain; _f f_, dense fog; and a figure attached denotes duration in hours, as 14 _r_, 14 hours rain. By the combination of these letters, all the ordinary phenomena of the weather may be recorded with certainty and brevity. EXAMPLES.--_b c_, blue sky with less proportion of cloud. 2 _r r l l t_, heavy rain for two hours, with much lightning, and some thunder. The above methods of recording the force of wind and state of weather were originally proposed by Admiral Sir Francis Beaufort. They are now in general use at sea, and by many observers on land. 6. Table of Expansion by Heat from 32 deg. to 212 deg. F. Platinum 0.0008842 of the length. Glass, Flint 0.0008117 " " with Lead 0.0008622 " Brass 0.0018708 " Mercury 0.0180180 " Water 0.0433200, from 39 deg. to 212 deg. Alcohol 0.1100 " 32 deg. to 174 deg. Nitric Acid 0.1100 Sulphuric Acid 0.0600 7. Table of Specific Gravity of Bodies at 32 deg. F. except water, which is taken at 39 deg.4. Water 1.000 Alcohol, pure 0.791 " proof 0.916 Mercury 13.596 Glass 3 to 2.7 Brass 7.8 to 8.54 Platinum 21 to 22.00 Weight of a cubic foot of water, at the temperature of comparison, 62.425 lbs. avoirdupois. The pound avoirdupois contains 7,000 grains. Air is 813.67 times lighter than water.